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  • Articles  (21,897)
  • Springer  (20,354)
  • Society of Exploration Geophysicists  (1,543)
  • 1985-1989  (18,710)
  • 1950-1954  (3,187)
  • Geosciences  (21,897)
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  • Articles  (21,897)
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  • 1
    Electronic Resource
    Electronic Resource
    Predictors of the peak width for networks with exponential links (1989)
    Springer
    Stochastic environmental research and risk assessment 3 (1989), S. 1-16 
    Details
    ISSN: 1436-3259
    Keywords: Width function ; instantaneous unit hydrograph ; peak ; regression ; birth-death process
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract We investigate optimal predictors of the peak (S) and distance to peak (T) of the width function of drainage networks under the assumption that the networks are topologically random with independent and exponentially distributed link lengths. Analytical results are derived using the fact that, under these assumptions, the width function is a homogeneous Markov birth-death process. In particular, exact expressions are derived for the asymptotic conditional expectations ofS andT given network magnitudeN and given mainstream lengthH. In addition, a simulation study is performed to examine various predictors ofS andT, includingN, H, and basin morphometric properties; non-asymptotic conditional expectations and variances are estimated. The best single predictor ofS isN, ofT isH, and of the scaled peak (S divided by the area under the width function) isH. Finally, expressions tested on a set of drainage basins from the state of Wyoming perform reasonably well in predictingS andT despite probable violations of the original assumptions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01543424
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  • 2
    Electronic Resource
    Electronic Resource
    Technical comments (1989)
    Springer
    Stochastic environmental research and risk assessment 3 (1989), S. 68-69 
    Details
    ISSN: 1436-3259
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01543428
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  • 3
    Electronic Resource
    Electronic Resource
    Single station and regional analysis of daily rainfall extremes (1989)
    Springer
    Stochastic environmental research and risk assessment 3 (1989), S. 281-292 
    Details
    ISSN: 1436-3259
    Keywords: Generalised Pareto distribution ; Peaks over threshold ; Probability weighted moments ; Regionalisation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract A peaks over threshold (POT) method of analysing daily rainfall values is developed using a Poisson process of occurrences and a generalised Pareto distribution (GPD) for the exceedances. The parameters of the GPD are estimated by the method of probability weighted moments (PWM) and a method of combining the individual estimates to define a regional curve is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01543461
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  • 4
    Electronic Resource
    Electronic Resource
    Basinwide flood control system by combining prediction and reservoir operation (1989)
    Springer
    Stochastic environmental research and risk assessment 3 (1989), S. 31-49 
    Details
    ISSN: 1436-3259
    Keywords: Reservoir operation ; prediction ; Kalman filtering ; flood prevention ; fuzzy control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract Japan has traditionally performed flood prevention through the construction and use of dikes, storage reservoirs, and basins which are costly and time consuming options. Another non-structural option is to operate the flood control system appropriately with a view to reducing flood damage. In this paper, a flood control system combining the runoff prediction model in the whole river basin with the reservoir operation is discussed. Different models of the runoff process are introduced in order to compare their accuracies and the computational time for the flood forecasting system. The reservoir operational rule is formulated in terms of fuzzy inference theory. Historical data are applied in a case study for verification of the proposed theories.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01543426
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  • 5
    Electronic Resource
    Electronic Resource
    Reply (1989)
    Springer
    Stochastic environmental research and risk assessment 3 (1989), S. 69-69 
    Details
    ISSN: 1436-3259
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01543429
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  • 6
    Electronic Resource
    Electronic Resource
    Announcements (1989)
    Springer
    Stochastic environmental research and risk assessment 3 (1989), S. 154-154 
    Details
    ISSN: 1436-3259
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01544078
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  • 7
    Electronic Resource
    Electronic Resource
    A survey of numerical methods for stochastic differential equations (1989)
    Springer
    Stochastic environmental research and risk assessment 3 (1989), S. 155-178 
    Details
    ISSN: 1436-3259
    Keywords: Stochastic differential equations ; Stochastic Taylor formula ; Numerical methods ; Simulations ; Strong convergence ; Weak convergence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract The development of numerical methods for stochastic differential equations has intensified over the past decade. The earliest methods were usually heuristic adaptations of deterministic methods, but were found to have limited accuracy regardless of the order of the original scheme. A stochastic counterpart of the Taylor formula now provides a framework for the systematic investigation of numerical methods for stochastic differential equations. It suggests numerical schemes, which involve multiple stochastic integrals, of higher order of convergence. We shall survey the literature on these and on the earlier schemes in this paper. Our discussion will focus on diffusion processes, but we shall also indicate the extensions needed to handle processes with jump components. In particular, we shall classify the schemes according to strong or weak convergence criteria, depending on whether the approximation of the sample paths or of the probability distribution is of main interest.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01543857
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  • 8
    Electronic Resource
    Electronic Resource
    Evaluation of rainfall-runoff performance using the stochastic integral equation method (1989)
    Springer
    Stochastic environmental research and risk assessment 3 (1989), S. 217-226 
    Details
    ISSN: 1436-3259
    Keywords: Stochastic integral equation method ; rainfall-runoff models ; confidence interval
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract The stochastic integral equation method (S.I.E.M.) is used to evaluate the relative performance of a set of both calibrated and uncalibrated rainfall-runoff models with respect to prediction errors. The S.I.E.M. is also used to estimate confidence (prediction) interval values of a runoff criterion variable, given a prescribed rainfall-runoff model, and a similarity measure used to condition the storms that are utilized for model calibration purposes. Because of the increasing attention given to the issue of uncertainty in rainfall-runoff modeling estimates, the S.I.E.M. provides a promising tool for the hydrologist to consider in both research and design.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01543861
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  • 9
    Electronic Resource
    Electronic Resource
    A practical method for outlier detection in autoregressive time series modelling (1989)
    Springer
    Stochastic environmental research and risk assessment 3 (1989), S. 241-260 
    Details
    ISSN: 1436-3259
    Keywords: Hat matrix ; Mahalanobis distance ; Additive outliers ; Innovation outliers ; Influential data ; Autoregressive models ; Threshold autoregression ; Lake Huron
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract A practical method is developed for outlier detection in autoregressive modelling. It has the interpretation of a Mahalanobis distance function and requires minimal additional computation once a model is fitted. It can be of use to detect both innovation outliers and additive outliers. Both simulated data and real data re used for illustration, including one data set from water resources.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01543459
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  • 10
    Electronic Resource
    Electronic Resource
    A stability analysis of the geostatistical approach to aquifer transmissivity identification (1989)
    Springer
    Stochastic environmental research and risk assessment 3 (1989), S. 293-316 
    Details
    ISSN: 1436-3259
    Keywords: Confined aquifer ; Transmissivity identification ; Geostatistics ; Inverse problem ; Ill-posedness ; Ill-conditioning ; Stability analysis ; Regularization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract In recent years, geostatistical concepts have been applied to the inverse problem of transmissivity estimation from piezometric head data. It has been claimed that such methods overcome various difficulties encountered in other approaches. However, the reconstruction of transmissivity from head measurements is ill-posed as it depends on derivatives of the head field. Consequently, any accurate method for its solution is likely to encounter numerically ill-conditioned systems. This paper reviews the geostatistical approach, and uses the stability analyses of linear algebra to show that, as the amount of available data increases and the discretization of the system is refined, both a numerically ill-conditioned parameter estimation problem and ill-conditioned cokriging equations may appear. Therefore, while the geostatistical approach does have conceptual appeal, it does not avoid the fundamental difficulties arising out of the ill-posed nature of transmissivity identification. Instead, the method is likely to be quite sensitive to these difficulties, so care must be taken in its formulation to minimize their effects. A means to stabilize the geostatistical method is suggested and numerical experiments that highlight key points of our analysis are given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01543462
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  • 11
    Electronic Resource
    Electronic Resource
    Fitting a stochastic partial differential equation to aquifer data (1989)
    Springer
    Stochastic environmental research and risk assessment 3 (1989), S. 85-96 
    Details
    ISSN: 1436-3259
    Keywords: Stochastic equations ; irregularly spaced observations ; prediction, interpolation ; random fields
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract The steady state two dimensional groundwater flow equation with constant transmissivities was studied by Whittle in 1954 as a stochastic Laplace equation. He showed that the correlation function consisted of a modified Bessel function of the second kind, order 1, multiplied by its argument. This paper uses this pioneering work of Whittle to fit an aquifer head field to unequally spaced observations by maximum likelihood. Observational error is also included in the model. Both the isotropic and anisotropic cases are considered. The fitted field is then calculated on a two dimensional grid together with its standard deviation. The method is closely related to the use of two-dimensional splines for fitting surfaces to irregularly spaced observations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01544074
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  • 12
    Electronic Resource
    Electronic Resource
    Stochastic analysis of estuarine hydraulics (1989)
    Springer
    Stochastic environmental research and risk assessment 3 (1989), S. 71-84 
    Details
    ISSN: 1436-3259
    Keywords: Hydraulics ; quasilinearization ; simulation ; stochastic ; estuarine system ; Monte Carlo methods ; random differential equations ; parameter uncertainty
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract A new methodology is presented for the solution of the stochastic hydraulic equations characterizing steady, one-dimensional estuarine flow. The methodology is predicated on quasi-linearization, perturbation methods, and the finite difference approximation of the stochastic differential operators. Assuming Manning's roughness coefficient is the principal source of uncertainty in the model, stochastic equations are presented for the water depths and flow rates in the estuarine system. Moment equations are developed for the mean and variance of the water depths. The moment equations are compared with the results of Monte Carlo simulation experiments. The results confirm that for any spatial location in the estuary that (1) as the uncertainty in the channel roughness increases, the uncertainty in mean depth increases, and (2) the predicted mean depth will decrease with increasing uncertainty in Manning'sn. The quasi-analytical approach requires significantly less computer time than Monte Carlo simulations and provides explicit
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01544073
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  • 13
    Electronic Resource
    Electronic Resource
    Stochastic partial differential equations in groundwater hydrology (1989)
    Springer
    Stochastic environmental research and risk assessment 3 (1989), S. 135-153 
    Details
    ISSN: 1436-3259
    Keywords: Stochastic partial differential equations ; maximum likelihood estimation ; parameter estimation ; moment equations ; stodhastic contaminant transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract Many problems in hydraulics and hydrology are described by linear, time dependent partial differential equations, linearity being, of course, an assumption based on necessity. Solutions to such equations have been obtained in the past based purely on deterministic consideration. The derivation of such a solution requires that the initial conditions, the boundary conditions, and the parameters contained within the equations be stipulated in exact terms. It is obvious that the solution so derived is a function of these specified, values. There are at least four ways in which randomness enters the problem. i) the random initial value problem; ii) the random boundary value problem; iii) the random forcing problem when the non-homogeneous part becomes random and iv) the random parameter problem. Such randomness is inherent in the environment surrounding the system, the environment being endowed with a large number of degrees of freedom. This paper considers the problem of groundwater flow in a phreatic aquifer fed by rainfall. The goveming equations are linear second order partial differential equations. Explicit form solutions to this randomly forced equation have been derived in well defined regular boundaries. The paper also provides a derivation of low order moment equations. It contains a discussion on the parameter estimation problem for stochastic partial differential equations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01544077
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  • 14
    Electronic Resource
    Electronic Resource
    Some results comparing Monte Carlo simulation and first order Taylor series approximation for steady groundwater flow (1989)
    Springer
    Stochastic environmental research and risk assessment 3 (1989), S. 179-190 
    Details
    ISSN: 1436-3259
    Keywords: Groundwater ; Stochastic ; Monte Carlo simulation ; First order Taylor series approximation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract The expected head and standard deviation of the head from the first order Taylor series approximation is compared to Monte Carlo simulation, for steady flow in a confined aquifer with transmissivity as a random variable. Emphasis is on the effect of changes in the covariance structure of the transmissivity, and pumping rates, on the errors in the first order Taylor series approximation. The accuracy of the first order Taylor series approximation is found to be particularly sensitive to pumping rates. With significant pumping the approximation is found to under estimate both the expected drawdown and head variance, and the error increases as the pumping rate increases. This can lead to large errors in probability constraints based on moments from the first order Taylor series approximation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01543858
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  • 15
    Electronic Resource
    Electronic Resource
    Kalman filter estimation for periodic autoregressive-moving average models (1989)
    Springer
    Stochastic environmental research and risk assessment 3 (1989), S. 227-240 
    Details
    ISSN: 1436-3259
    Keywords: Kalman filter ; Maximum likelihood estimation ; Periodic models ; Stochastic hydrology ; Time series analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract An exact maximum likelihood procedure is presented for estimating the parameters of a periodic autogressive-moving average (PARMA) model. To develop an estimator which is both statistically and computationally efficient, the PARMA class of models is written using a state-space representation and a Kalman filtering algorithm is used to estimate the parameters. In order to demonstrate how to fit PARMA models in practice, the most appropriate types of PARMA models are identified for fitting to two average monthly riverflow time series and the new estimator is employed for estimating the model parameters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01543862
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  • 16
    Electronic Resource
    Electronic Resource
    An application of Karmarkar's interior-point linear programming algorithm for multi-reservoir operations optimization (1989)
    Springer
    Stochastic environmental research and risk assessment 3 (1989), S. 17-29 
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    ISSN: 1436-3259
    Keywords: Stochastic optimization ; linear programming ; simplex method ; Karmarkar's method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract Optimization of multi-reservoir systems operations is typically a very large scale optimization problem. The following are the three types of optimization problems solved using linear programming (LP): (i) deterministic optimization for multiple periods involving fine stage intervals, for example, from an hour to a week (ii) implicit stochastic optimization using multiple years of inflow data, and (iii) explicit stochastic optimization using probability distributions of inflow data. Until recently, the revised simplex method has been the most efficient solution method available for solving large scale LP problems. In this paper, we show that an implementation of the Karmarkar's interior-point LP algorithm with a newly developed stopping criterion solves optimization problems of large multi-reservoir operations more efficiently than the simplex method. For example, using a Micro VAX II minicomputer, a 40 year, monthly stage, two-reservoir system optimization problem is solved 7.8 times faster than the advanced simplex code in MINOS 5.0. The advantage of this method is expected to be greater as the size of the problem grows from two reservoirs to multiples of reservoirs. This paper presents the details of the implementation and testing and in addition, some other features of the Karmarkar's algorithm which makes it a valuable optimization tool are illuminated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01543425
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  • 17
    Electronic Resource
    Electronic Resource
    Spatial rainfall estimation by linear and non-linear co-kriging of radar-rainfall and raingage data (1989)
    Springer
    Stochastic environmental research and risk assessment 3 (1989), S. 51-67 
    Details
    ISSN: 1436-3259
    Keywords: Spatial rainfall estimation ; kriging ; ordinary co-kriging ; disjunctive co-kriging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract The feasibility of linear and nonlinear geostatistical estimation techniques for optimal merging of rainfall data from raingage and radar observations is investigated in this study by use of controlled numerical experiments. Synthetic radar and raingage data are generated with their hypothetical error structures that explicitly account for sampling characteristics of the two sensors. Numerically simulated rainfall fields considered to be ground-truth fields on 4×4 km grids are used in the generation of radar and raingage observations. Ground-truth rainfall fields consist of generated rainfall fields with various climatic characteristics that preserve the space-time covariance function of rainfall events in extratropical cyclonic storms. Optimal mean areal precipitation estimates are obtained based on the minimum variance, unbiased property of kriging techniques under the second order homogeneity assumption of rainfall fields. The evaluation of estimated rainfall fields is done based on the refinement of spatial predictability over what would be provided from each sensor individually. Attention is mainly given to removal of measurement error and bias that are synthetically introduced to radar measurements. The influence of raingage network density on estimated rainfall fields is also examined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01543427
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  • 18
    Electronic Resource
    Electronic Resource
    Parameter estimation in low order fractionally differenced ARMA processes (1989)
    Springer
    Stochastic environmental research and risk assessment 3 (1989), S. 97-110 
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    ISSN: 1436-3259
    Keywords: ARMA processes ; fractionally differencedARMA processes ; long memory ; spectral density ; maximum likelihood estimates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract A class of regression type estimators of the parameterd in a fractionally differencedARMA (p, q) process is introduced. This class is an extension of the estimator considered by Geweke and Porter-Hudak. In a simulation study, we compared three estimators from this class together with two approximate maximum likelihood estimators which are based on two separate approximations to the likelihood. One approximation ignores the determinant term in the likelihood and the other includes a compensating factor for the determinant. When the determinant term is included, the estimate tends to be much less biased and is in general superior to the other estimate. The approximate maximum likelihood estimator out performed, by a large margin, the regression type estimators for pureARIMA (0,d,0) processes. However, forARIMA (1,d,1) processes, a regression type estimator turned out to be the best for realizations of length 400 in 3 out of the 5 cases we tried.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01544075
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  • 19
    Electronic Resource
    Electronic Resource
    Basin-scale relations via conditioning (1989)
    Springer
    Stochastic environmental research and risk assessment 3 (1989), S. 111-133 
    Details
    ISSN: 1436-3259
    Keywords: Rainfall-runoff models ; random channel network ; regionalization ; flood frequency ; instanteous unit hydrograph
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract A rainfall-runoff model is used in conjunction with a probabilistic description of the input to this model to obtain simple regression-like relations for basin runoff in terms of basin and storm characteristics. These relations, similar to those sought in regionalization studies, are computed by evaluating the conditional distribution of model output given basin and storm characteristics. This method of conditioning provides a general way of examining model sensitivity to various components of model input. The resulting relations may be expected to resemble corresponding relations obtained by regionalization using actual runoff to the extent that the rainfall-runoff model and the model input specification are physically realistic. The probabilistic description of model input is an extension of so-called “random-model” of channel networks and involves postulating an ensemble of basins and associated probability distributions that mimic the variability of basin characteristics seen in nature. Application is made to small basins in the State of Wyoming. Parameters of the input variable distribution are estimated using data from Wyoming, and basin-scale relations are estimated both, parametrically and nonparametrically using model-generated runoff from simulated basins. Resulting basin-scale relations involving annual flood quantiles are in reasonable agreement with those presented in a previous regionalization study, but error estimates are smaller than those in the previous study, an artifact of the simplicity of the rainfall-runoff model used in this paper. We also obtain relations for peak of the instantaneous unit hydrograph which agree fairly well with theoretical relations given in the literature. Finally, we explore the issues of sensitivity of basin-scale, relations and error estimates to parameterization of the model input probability distribution and of how this sensitivity is related to making inferences about a particular ungaged basin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01544076
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  • 20
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    A cross entropy method for flood frequency analysis (1989)
    Springer
    Stochastic environmental research and risk assessment 3 (1989), S. 191-202 
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    ISSN: 1436-3259
    Keywords: Random variable ; Distribution ; Estimation ; Probability analysis ; Cross-entropy ; Fractile constraints ; Flood
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract The cross-entropy method with fractile constraints has been developed to estimate a random variable when the data are a set of independent observations of the variable. The method can claim several advantages over existing methods. It uses a reference distribution like the prior distribution in Bayesian analysis and likewise generates a posterior distribution. The method is of interest, in particular, because it satisfies two fundamental requirements for selfconsistency in the analysis of a probabilistic system based on data: a principle of invariance and a principle of data monotonicity. The method is applied to flood analysis. Robustness of the minimum cross-entropy method is compared with other methods: the methods of moments and the maximum likehood.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01543859
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  • 21
    Electronic Resource
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    Estimation of flow enhancement in the Kinneret watershed due to cloud seeding (1989)
    Springer
    Stochastic environmental research and risk assessment 3 (1989), S. 203-216 
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    ISSN: 1436-3259
    Keywords: Cloud seeding ; Rainfall enhancement ; Regression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract A comparison is carried out between historical records of the flow measured in Kinneret watershed during and prior to the time of cloud seeding for rainfall enhancement. Precipitation series for the control area of the meteorological experimentation serve as a reference for the comparison. The fluctuations of the flow, which would have occurred unless the effect of the seeding, are estimated by a linear regression on the precipitation as the control. The regression parameters are calibrated separately for the unseeded and for the seeded time series. The model with the parameters calibrated for the unseeded series is applied on the rainfall recorded during the seeded time, and vice versa. The difference between the measured and the computed data is attributed to the effect of cloud seeding. Similar comparisons are carried out with respect to rainfall series recorded at the target area and at the edge of the enhanced area. The results indicate that the flow from the affected sector of the watershed has been enhanced, with respect to the control, by 31×106 m 3/year, at a significance level of 31. This enhancement is 5% of the volume which is generated in that area. The rates found with respect to the rainfall at the edge are higher than those found with respect to the control, while those with respect to the rainfall at the center of the target area are lower.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01543860
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  • 22
    Electronic Resource
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    A radar-based stochastic model for the time-space arrivals of the rain fields onto a geographical region (1989)
    Springer
    Stochastic environmental research and risk assessment 3 (1989), S. 261-280 
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    ISSN: 1436-3259
    Keywords: Rain fields ; time-space arrivals ; stochastic model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract Rainfall in time at any ground location can be described by the rain intensity distribution over the subtrajectories which are drawn by the ground location point on the radar-detected incremental rain fields (IRFs) that pass over this location. Based on this conceptualization, this study develops a stochastic description of the arrivals of IRF subtrajectories (SIRFs) onto any given set of ground locations over a geographical region. The arrivals of SIRFs is described by a multivariate doubly stochastic Poisson process, excited by the time-space arrival process of IRFs onto the designated geographical region. The arrival process of IRFs is described by a 3-level time-space nonhomogeneous Poisson cluster model. At the primary level of this model are the arrivals of synoptic cyclonic systems; at the secondary level are the arrivals of large mesoscale rain areas (LMSAs) and at the tertiary level are the arrivals of IRFs onto the designated geographical region, all detected by the weather radar. The models are substantiated both by the graphical analysis of rain fields, as detected on a radar scope, and by the statistical analysis of the arrivals data at all of the four levels at three different ground locations over a rectangular geographical region in Northern Kentucky. It is pointed out that a doubly stochastic Poisson process is basically a Poisson cluster process. Hence, the final process of SIRF arrivals onto any ground location may be interpreted as a 4-level Poisson cluster process. Finally, heavy tails in the sample covariance density functions of the IRF and SIRF arrivals are detected. This study shows that the appropriate incorporation of clustering at all observable distinct scales of the rain fields models the heavy tail behavior of the covariance density adequately.
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    Anticancer agent development: X-ray crystal structure and keto-enol tautomerism of dimethyl 1-hydroxy-6,7-methylenedioxy-4-(3′,4′,5′-trimethoxyphenyl-trans-3,4-dihydronaphthalene-2,3-dicarboxylate (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 135-145 
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    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Structural and conformational information obtained from the crystal structure and solution1H nmr investigations of the title compound are compared. The 4-aryltetralone, C24H24O10, crystallizes as a chloroform solvate in the monoclinic space group, P21/n, witha=12.519(4),b=17.938(6),c=12.534(9)Å,β=111.90(5)°, and Dcalc=1.51 g cm−3 forZ=4. The data for this compound were collected at −150°C. Least-squares refinement of 2796 observed [F o≥5σ(F o)] reflections led to the final agreement index ofR=0.062. A threefold static disorder was observed for one of the carboxyl groups. The second carboxyl group participates in an intramolecular hydrogen bond and is thus ordered. The1H nmr spectrum revealed the title compound to exist as a keto-enol tautomeric mixture in solution. Vicinal hydrogen coupling constant analysis proved reliable in ascertaining B-ring stereochemistry of 2,3-disubstituted-4-aryltetralones.
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    A far infrared investigation of anionic species present in solution during the crystallization of a polynuclear bromocuprate(I) cluster containing three-coordinated copper (I) (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 147-157 
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    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Ethanolic solutions of tetrapropylammonium bromide and copper(I) bromide, from which bis(tetrapropylammonium) hexa-μ-bromo-tetrahedro-tetracuprate(I), [N(C3H7)4]2[Cu4Br6], a bromocuprate(I) cluster comprised of three-coordinated copper(I), crystallizes have been shown, by means of far i.r. spectroscopy, to contain the centrosymmetric, monomeric [CuBr2]− anion as the major, and probably the sole, bromocuprate(I) species,υ 3=323 cm−1. Crystalline [N(C3H7)4]2[Cu4Br6], [N(CH3)4]3[Cu2Br5] and [P(CH3)4]2[CuBr3], all of which contain anions in which copper(I) is three-coordinated, dissolve in nitro-methane to give solutions of the dibromocuprate(I) monomer. Variation of the coordination number of copper(I) in bromocuprates(I) crystallizing with symmetrically substituted quaternary ammonium and related unipositive cations is discussed in terms of dilution of the bromide ions by the cations, and a tentative mechanism for the formation of such compounds is proposed. Toward the end of the precipitation of [N(C3H7)4]2[Cu4Br6] from the ethanolic solution of tetrapropylammonium bromide and copper(I) bromide, a few crystals of a second bromocuprate(I) phase were obtained. This compound has been identified as tetrapropylammonium dibromocuprate(I), and its crystal structure determined from X-ray diffraction data. [N(C3H7)4][CuBr2] crystallizes in space groupP2/n, witha=13.010(15),b=7.577(5),c=8.858(4) Å,β=91.09(7)° andZ=2. The anion is a monomer in which Cu-Br is 2.194(3) Å and Br-Cu-Br 178.4(1)°, copper(I) being situated on a twofold axis.
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    Crystal and molecular structure of 17-β-methyl-α-isolupanineN-(16)-oxide perchlorate monohydrate (1989)
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    Journal of chemical crystallography 19 (1989), S. 193-201 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract [C16H27N2O2]+·ClO 4 − ·H2O,M r=396.87, orthorhombicP212121 a=13.708(4),b=16.930(7),c=8.311(3) Å,V=1928.3(13) Å3,Z=4,D x=1.367(2) g cm−3,λ(MoKα)=0.71068 Å,μ(MoKμ)=1.95 cm−1,F(000)=848,T=292 K,R=0.061 for 1324 unique reflections. RingsA,B,C,D have half-chair, chair, chair and chair conformations, respectively; the quinolizidone moietyA/E has a quasi-trans and the quinolizidine moietyC/D has a trans configuration. The cations are connected into chains along the crystallographic direction [001] by strong hydrogen bonds utilizing the water molecule: C(2)=O(5)⋯O(W)⋯O(6)-N(16) of 2.623(7) and 2.574(7) Å, respectively. The water molecule is also hydrogen-bonded to one oxygen atom of the perchlorate anion: O(W)⋯O(2) is 3.106(10) Å. A very short intramolecular distance between N(1) and O(6) of 2.696(7) Å, due to the quasitrans-trans configuration of theα-isolupanine skeleton, is observed.
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    Crystal and molecular structure of 4-aminoacetyl-N-p-nitrophenylsulfanilamide (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 289-298 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The crystal and molecular structure of 4-aminoacetyl-N-p-nitrophenylsulfanilamide (C14H13N3O5S), a derivative of sulfonamide, has been determined from X-ray diffraction data using Cu-Kα radiation. The compound crystallised in the monoclinic space groupP21/c, witha=12.258(9),b=7.339(5),c=16.359(9) Å,β=98.84(4)°. The structure was solved by direct methods and refined by full-matrix least-squares to a finalR value of 0.047 with 2487 unique reflections. In packing, the molecules are found to be stabilised by N-H⋯ O hydrogen bonds.
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    Crystal structure oftrans-[PtCl2(Me2PhP)(cis-2,5-dimethylpyrrolidine)] (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 299-306 
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    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The complextrans-[PtCl2 (Me2PhP)(cis-2,4-dimethylpyrrolidine)] has been characterized by X-ray crystallography. It crystallizes in the monoclinic space group P 22/c witha=8.762(3),b=16.034(5),c=12.600(4)Å,β=93.43(3)° andZ=4. The structure was solved by heavy atom method and refined toR=0.052 for 3251 observed counter reflections. The coordination sphere of the Pt atom is square-planar with a geometry very similar to that of the studied complexes of the type trans-[PtCl2(R3P)L] whereL is either one of the possible isomers of theC,C′-dimethylpyrrolidine or the unsubstituted pyrrolidine. In the present complex the puckered five-membered ring of the dimethylpyrrolidine ligand assumes an envelope conformation with the maximum puckering at the N atom.
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    Vibrational spectra and thermodynamic properties of 2,4,6-tribromobenzonitrile (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 671-681 
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    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The infrared and Raman spectra of 2,4,6-tribromobenzonitrile have been recorded in the solid state and in solutions. Assignments of the fundamental vibrations based on Raman polarization data and comparison with the spectra of benzonitrile and its trichloro derivative are given and discussed. The thermodynamic functions have been evaluated for a rigid-rotor harmonic oscillator approximation at several temperatures.
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    Geometric alignment in the structure of 6,8-dichloro-2-trichloromethyl-4-dichloromethylene-1,3-benzdioxin consistent with incipientcis-elimination of HCl (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 661-670 
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    Notes: Abstract Crystals of the title compound are monoclinic, P21/c, a=11.464(14),b=21.027(9),c=12.806(3) Å,β=108.00(6)°,V=2935.85 Å3,Z=8. The structure was solved by direct methods, from data collected at room temperature on an Enraf-Nonius CAD4 diffractometer, and refined by full matrix least squares to a finalR value of 0.089 using 3949 reflections. The two nonequivalent molecules are both disordered to the same extent, the ratio of the two models being 0.8∶0.2. In the minor model the substituent hydrogen atom at the 2-position is exactly eclipsed by a chlorine atom in the 2-CCl3 group whereas in the major model the normal staggered conformation is observed. C-Cl bond lengths and C-C-Cl angles in the major model are normal whereas those in the minor model are C-Cl(A) 1.51(3), C-Cl(B) 1.67(3), C-Cl(C) 1.95(3) Å, where Cl(C) is eclipsed, for one molecule and 1.85(3), 1.67(3), 1.94(2) Å for the other. Corresponding C-C-Cl bond angles (deg) are 115(1), 114(1), 80(1); and 120(1), 126(1), 90(1). A comparison is given with a structure which is not disordered but in which similar changes in the geometry of a∶CCl.CCl3 group are found.
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    Crystal structure of racemic 5-(p-nitrobenzoylamino)-5-methyl-4-oxo-1,3-dioxane (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 695-700 
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    Topics: Geosciences , Physics
    Notes: Abstract C12H12N2O6 crystallized from methanol in the monoclinic space group P21/c (Z=4) witha=13.333(4),b=10.154(3),c=9.597(2) Å andβ=102.37(2)°.M r=280.24,V=1269.1(6) Å3,D x=1.466 g cm−3,λ(Mo Kα)=0.71069 Å,μ=1.29 cm−1,T=295 K. The structure was solved by direct methods and refined by full-matrix least-squares to a finalR (R w)=0.049 (0.057) for 916 observed reflections. The molecules are linked by strong N-H⋯O(4) hydrogen bonds with N⋯O distance of 2.995(4) Å. The infinite racemic chains run in [001] direction.
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    Crystal structure of the diacetate of (+)-epipinoresinol, C24H26O8 (1989)
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    Journal of chemical crystallography 19 (1989), S. 733-744 
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    Topics: Geosciences , Physics
    Notes: Abstract The crystal structure of the diacetate of (+)-epipinoresinol, C24H26O8, has been determined by single-crystal diffraction methods. The compound crystallizes in the monoclinic space groupP21 witha=7.506(3),b=8.526(4),c=17.746(8) Å,β=97.12(4)° andZ=2. A total of 3504 reflexion intensities were recorded on a Syntex P21 diffractometer (MoKα radiation) at room temperature. The structure was solved by direct methods and electron density calculations. Full-matrix least-squares refinement gaveR=0.056 for 2297 observed [I〉3σ(I] reflexions. The individual central tetrahydrofuran rings have envelope conformations with coplanar carbon atoms and the oxygen atoms as flaps; the carbon atom planes form an angle of 119.9(3)°. Bond distances are C-C (aromatic) 1.386(12) Å, C(sp 3)-O 1.421(12) Å, C(sp 2)-O 1.372(20) Å, and C(sp 2)=O 1.186(9) Å. The influence of molecular structure on the positions of signals in the1H nmr spectrum of the diacetate of (+)-epipinoresinol is discussed.
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    Crystal and molecular structure ofp-chlorothymols, I: 4-chloro-2-isopropyl-5-methylphenol (PCNT) (1989)
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    Journal of chemical crystallography 19 (1989), S. 765-773 
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    Crystal structure of a decahydroquinoline thiocarbamate derivative (SR33434) with anticalcic properties (1989)
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    Journal of chemical crystallography 19 (1989), S. 775-785 
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    Complexation with diol host compounds. Part 2. Structures of 1,1,2,2-tetraphenylethane-1,2-diol and its 1∶2 molecular inclusion complex with dimethylsulphoxide (1989)
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    Journal of chemical crystallography 19 (1989), S. 809-822 
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    Notes: Abstract The structures of 1,1,2,2-tetraphenylethane-1,2-diol and its 1∶2 molecular inclusion complex with dmso have been elucidated by X-ray crystallography from single crystal diffraction data. Crystals of the host, compound I, are monoclinic, space groupP21/n, witha=17.669(6) Å,b=6.144(6) Å,c=17.873(6) Å,β=92.67(3)°,z=4. Crystals of the clathrate, compound II, are triclinic,P¯1, witha=9.138(5) Å,b=18.384(6) Å,c=18.496(3) Å,α=61.16(2)°,β=83.22(3)°, γ=88.06(3)°,Z=4. Both structures were solved by direct methods and refined to finalR values of 0.072 and 0.107, respectively. Compound I is partially disordered and its packing is governed by strong intermolecular hydrogen bonds. Compound II is characterized by crossing channels which accommodate the guest dmso molecules. The thermal properties of the latter compound have been characterized by DTA and TGA thermograms.
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    Studies in molecular structure and conformation of aminophosphonic acids: Crystal and molecular structure ofN-phosphonomethyl-l-threonine (1989)
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    Journal of chemical crystallography 19 (1989), S. 861-871 
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    Notes: Abstract The crystal structure ofN′-phosphonomethyl-l-threonine has been determined from three-dimensional X-ray diffractometer data. The molecule crystallizes in the space groupP212121, witha=5.381(1),b=10.558(2),c=15.542(3)Å andz=4. The structure was solved by direct methods, and refined to anR value of 0.038 for 2477 reflections. The molecule exists as a zwitterion in the crystal, with the amino group portonated and the carboxyl group unionized; the phosphonic acid group is ionized. The molecule is in an extended conformation, with the P-C(1)-N-C(2) and C(1)-N-C(2)-C(4) torsion angles −171.1(2) and 166.7(2)°, respectively. The crystal structure is stabilized by five intermolecular and one intramolecular hydrogen bonds.
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    2α-Hydroxy-3α-[N-alkyl(aryl)]-pinanoamines. Part II. Synthesis and the nature of some pinanoamines and crystal and molecular structure of 2α-hydroxy-3α-(N-n-butyl)-pinanoamine hydrochloride (1989)
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    Journal of chemical crystallography 19 (1989), S. 893-903 
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    Notes: Abstract Several optically pure representatives of 2α-hydroxy-3α-[N-alkyl (aryl)] pinanoamines, potential chiral auxiliaries in organic synthesis, were obtained. In addition, a structural examination of 2α-hydroxy-3α-(N-n-butyl)-pinanoamine hydrochloride was conducted. Results of these studies confirm the structure of the amines obtained and the correctness of the proposed reaction pathway.Crystal data: C12H28NOCl,P21/c,a=13.196(1),b=8.562(1),c=14.276(1) Å,β=110.41(3)°,R=0.034 for 2046 reflections.
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    The crystal field theory for D2d symmetric complexes and the splitting of d-orbitals of Mo5+ in Mo[S2CN(C2H5)2]4I3 (1989)
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    Journal of chemical crystallography 19 (1989), S. 929-931 
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    Notes: Abstract The energy order assignment of the d-orbitals of Mo5+ in Mo[S2CN(C2H5)2]4I3 given by Jasimet al. (1985) is restudied and corrected. It is indicated that, in general, the energy order of the d-orbitals of D2d symmetric complexes is depending on the bond angles and bond lengths of the ligands, thus there cannot be any universal energy order.
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    Structure of 6β-acetoxyprogesterone, C23H32O4 (1989)
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    Journal of chemical crystallography 19 (1989), S. 949-955 
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    Notes: Abstract The X-ray crystal structure of 6β-acetoxyprogesterone, C23H32O4, has been determined. This compound crystallizes in space groupP212121 witha=13.195(3),b=15.035(4),c=10.705(3) Å,V=2139.8(9) Å3,M r=372.5,Z=4,D x=1.156g cm−3; MoKα radiation (λ=0.7107 Å),μ=0.72 cm−1,F(000)=808;R=0.069, andR w=0.052 for 1292 reflections. RingA adopts a normal 1α,2β-half-chair conformation. The side chain is typical for a 20-ketosteroid conformation.
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    Important announcement (1989)
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    Journal of chemical crystallography 19 (1989), S. 1-1 
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    The crystal and molecule structure of three 2,4,6-trinitrobenzene derivatives:α,α,α-trifluoro-2,4,6-trinitrotoluene (C7H2F3N3O6), 2,4,6-trinitrobenzamide (C7H4N4O7), 2,4,6-trinitrobenzoic acid (C7H3N3O8) (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 25-37 
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    Notes: Abstract The crystal and molecular structures of three 2,4,6-trinitrobenzene derivatives have been determined. Forα,α,α-trifluoro-2,4,6-trinitrotoluene (1): monoclinic,P21/n,a=7.510(2),b=9.273(2),c=14.984(0) Å,β=99.02(2)°,V=1028.1(4)° Å3,Z=4,D=1.816 g cm−3,R(F)=0.051, andR(wF)=0.055. For 2,4,6-trinitrobenzamide (2): orthorhombic,Pbca,a=9.248(3),b=14.377(6),c=17.729(4) Å,V=1958(1) Å3,Z=8,D=1.737 g cm−3,R(F)=0.073, andR(wF)=0.077. For 2,4,6-trinitrobenzoic acid (3): orthorhombic,P212121,a=6.553(1),b=11.405(2),c=12.796(2) Å,V=956.3(3) Å3,Z=4,D=1.785 g cm−3,R(F)=0.045, andR(wF)=0.046.1 crystallizes as discrete molecules,2 as weakly hydrogen-bonded dimers and3 as a chiral polymer of hydrogen-bonded helices. In1, the presence of the nonplanar CF3 substituent causes a large twisting of theα-nitro groups out of the plane of the benzene ring, whereas the nearly planar C(O)NH2 and C(O)OH substituents in2 and3 are perpendicular to the benzene plane and do not cause a significant rotation of theα-nitro groups.
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    Crystal and molecular structure of inner-chelatetrans-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diacetatozinc(II), C16H28N2O8Zn (1989)
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    Journal of chemical crystallography 19 (1989), S. 369-378 
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    Notes: Abstract The molecular structure of trans-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diacetatozinc(II), complex (I), has been investigated by X-ray diffraction methods. It crystallizes in the monoclinic space groupP21/c, witha=16.229(2),b=12.001(1),c=9.778(1) Å,β=95.59(1)°, andZ=4. The structure was solved by direct methods, and refined by full-matrix least-squares toR=0.048. The zinc cation, placed asymmetrically in the macro-ring cavity, is six-coordinated to 2 N- and 2 O-atoms of the macrocycle, and to 2 O-atoms of two acetate groups, thus forming an irregular octahedral coordination sphere. The 18-diaza-crown-6 ring reveals approximate twofold symmetry (Δs=0.1 Å), with the axis through C2-C3 and C11-C12 midpoints.
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    2α-Hydroxy-3α-[N-alkyl(aryl)]pinanoamines. Part I. Preparation and nature of some Schiff bases of 2α-hydroxypinan-3-one. Crystal and molecular structure of α-hydroxy-2,6,6-trimethylbicyclo[3.1.1]hepta-3-ylidenaminobenzene (1989)
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    Journal of chemical crystallography 19 (1989), S. 535-545 
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    Notes: Abstract Some Schiff bases of 2α-hydroxypinan-3-one, being precursors of 2α-hydroxy3α-[N-alkyl(aryl)]pinanoamines, were obtained. The crystal structure of racemic 2α-hydroxy-2,6,6-trimethylbicyclo-[3.1. 1]hept-3-ylidenaminobenzene was determined. The Schiff bases were obtained in two forms: solid form (racemate) and liquid form (optically pure). As it appeared from crystallographic studies of the racemic form, in the solid state there are intramolecular-H-bonded dimers.
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    Structure of crystal violet tetraphenylborate (1989)
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    Journal of chemical crystallography 19 (1989), S. 589-596 
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    Notes: Abstract The crystal structure of crystal violet tetraphenylborate has been determined. C25H30N3·C24H20B is orthorhombic, Pn21a, witha=9.497(6) Å,b=16.474(5) Å,c=25.894(9) Å,V=4051 Å3,M r =691.77,D calc =1.13 g cm−3 forZ=4,F(000)=1480, finalR=0.045, andR w =0.044 for 1842 observed reflections [F 0≥5σ(F 0)]. The compound was crystallized from acetone. It was found to conduct poorly in either the crystalline state or as a pressed pellet although it serves well as a solution electrolyte.
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    A novel mixed valence iodide bridged Te(II)-Te(IV) complex featuring diisopropyldithiocarbamate(L) and iodide: ILTeII(I)TeIVL2I (1989)
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    Journal of chemical crystallography 19 (1989), S. 745-753 
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    Notes: Abstract The title compound is a novel mixed ligand and mixed valence complex of tellurium, the crystal structure of which is reported here. The compound crystallizes in the orthorhombic space group, Pca21 with four molecules per unit cell, the dimensions of which area=15.209(1),b=20.159(2),c=12.453(1) Å. The structure was solved by the heavy-atom method and refined by fullmatrix least-squares method to a finalR=0.046 andR w=0.046 for 3011 unique reflections. The structure could be considered as 1∶1 adduct of TeIVL2I2 and TeIILI (L=diisopropyldithiocarbamate). The two tellurium atoms, TeII[Te(1)] and TeIV[Te(2)] display entirely different coordinations and are bridged through iodine I(1) in a symmetrical manner. There is a short Te(1)⋯Te(2) contact distance of 3.542(1) Å.
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    Crystal structure of 1,3-(N,N′-benzamide)-2-methyl-1-pentene (1989)
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    Journal of chemical crystallography 19 (1989), S. 841-846 
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    Notes: Abstract Crystals of the title compound are monoclinic (C20H22N2O2): space groupP21/n,a=11.800(3),b=13.820(2),c=11.004(3) Å,β=92.74(3)°. The structure was solved by direct methods and refined by block-matrix least-squares procedure to giveR=0.078 andRw=0.076 for 1960 reflections above 3σ(I). The two amide groups are not coplanar with respect to their benzene rings. An intramolecular N-H⋯O hydrogen bond was found in the molecules which are joined in chains by other strong N-H⋯O hydrogen bonds.
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    Complexation with diol host compounds. Part 3. Molecular inclusion of 4-methylcyclohexanone and 2-methylcyclohexanone by the host,trans-9,10-dihydroxy-9,10-diphenyl-9,10-dihydroanthracene (1989)
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    Journal of chemical crystallography 19 (1989), S. 847-859 
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    Notes: Abstract The structures of the 1∶2 molecular complexes oftrans-9,10-dihydroxy-9,10-diphenyl-9,10-dihydroanthracene with 4-methylcyclohexanone (1) and with 2-methylcyclohexanone (2) have been determined by X-ray crystallography. The crystal data are as follows: Compound (1):P22/c,a=8.838(2) Å,b=8.92(1) Å,c=20.879(8)=Å,β=98.67(2)°,V=1627(2) Å3,Z=2 andR=0.062 for 2201 unique MoKα reflections; Compound (2):P¯1,a=8.917(3) Å,b=9.900(2) Å,c=11.250(4) Å,a=68.72(2)°,β=64.39(3)°, γ=74.86(2)°,V=828.1(5) Å3,Z=1 andR=0.098 for 2563 unique reflections. Both inclusion compounds exhibit O-H⋯O=C hydrogen bonding interactions. The thermal properties of these compounds have been characterized by DTA and TGA thermograms.
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    Crystal and molecular structure of 1-(2-isopropylcarbamoylpropan-2-ylamino) 3-(1-naphthyloxy)propan-2-ol (C20H28N2O3) (1989)
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    Journal of chemical crystallography 19 (1989), S. 883-892 
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    Notes: Abstract The crystal structure of the title compound has been determined with three-dimensional MoKα X-ray diffraction data. The space group and unit-cell parameters are:P21/c,a=8.610(3) Å,b=13.516(5) Å,c=16.818(5) Å,β=94.95(3)° andV=1950.0(7) Å3. The structure was solved by direct methods, and refined by full-matrix least-squares techniques toR=0.0608 andR w=0.0648. The compound is a derivative of the popularβ-adrenolytic propranolol, and in the propanol part of the side chain shows the typicalgauche conformation.
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    On the absolute configuration of the synthetic macrolide patulolide C (1989)
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    Journal of chemical crystallography 19 (1989), S. 919-924 
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    Preparation and electron spin resonance study of copper(II) complexes with sugar type ligands (1989)
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    Journal of chemical crystallography 19 (1989), S. 911-918 
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    Notes: Abstract A series of copper(II) complexes with sugar type ligands (polyalcohols, sugar acids, di- and trisaccharides) was prepared. The compositions of the complexes were determined by standard analytical methods. The results showed that carboxylato and deprotonated alcoholic hydroxy groups participate in the complex formation. The EPR spectra and magnetic susceptibility data reflected the formation of species containing isolated copper(II) centers indicating that in those molecules which contain two copper ions, these are separated by sugar ligands.
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    Raman spectroscopic studies of gadolinium trichloride as a function of temperature (1989)
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    Journal of chemical crystallography 19 (1989), S. 39-49 
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    Notes: Abstract Laser Raman spectrometry is being used in our laboratory to identify the crystal structures of lanthanide and actinide compounds. The phonon Raman spectrum of an ionic, crystalline sample is characteristic of the particular crystal structure(s) exhibited by the sample. GdCl3 exhibits two crystal structures, UCl3-type hexagonal and PuBr3-type orthorhombic. In the literature it is proposed that the low-temperature form is the PuBr3-type orthorhombic. Results of experiments in our laboratory suggest that the low-temperature form is the UCl3-type hexagonal. Interconversion between these two forms can be accomplished with temperature. In the present work, laser Raman spectrometry was used to monitor crystal structure changes in GdCl3 as a function of temperature and to determine the temperature at which the orthorhombic-to-hexagonal phase transformation occurs.
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    Structural and spectroscopic properties of 2-thiophenecarboxaldehyde 2-thienylhydrazone (1989)
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    Journal of chemical crystallography 19 (1989), S. 93-98 
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    Notes: Abstract In this paper the crystal and molecular structure of the title compound is reported. The crystals are monoclinic, P21/c,Z=4,a=13.406(4),b=5.367(1),c=15.545(6)Å,β=110.00(5)°. The structure was solved by direct and Fourier methods and refined by full-matrix least squares toR=0.0497 andRw=0.0537 for 1094 unique reflections. The molecule shows an E-conflguration with respect to the C=N double bond. Mass and IR spectra are also discussed.
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    Crystal structure and vibrational spectra of the methylmercury complex withl-alanine (1989)
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    Journal of chemical crystallography 19 (1989), S. 123-134 
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    Notes: Abstract The 1∶1 methylmercury complex withl-alanine belongs to the orthorhombic space groupP212121. The unit cell of dimensionsa=5.763(3),b=6.851(6),c=18.75(2) Å contains four molecules. The structure was refined on 584 nonzero reflections toR=0.050. The methylmercury ion has replaced an ammonium proton and is linearly bonded to the nitrogen atom. Mercury is also involved in secondary inter- and intramolecular contacts with carboxylate oxygen atoms. Infrared and Raman spectra of the amino-deuterated complex are discussed and compared with those of the undeuterated compound. A correlation is found between backbone conformation and the pattern ofυ Hg-N andυ Hg-C bands in the Raman spectra.
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    Synthesis and structure of 1-(2-amino)phenyl-2-phenyl-12H-indolo[3,2-c]carbazole ethylacetate solvate, a new indolocarbazole compound (1989)
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    Journal of chemical crystallography 19 (1989), S. 277-287 
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    Notes: Abstract The structure of a new indolo-carbazole compound, unique in having two indole rings with NH groupstrans-fused to a phenyl ring, has been determined by X-ray crystallography. The crystals are monoclinic, space groupP21/n,a=25.548(7),b=8.532(3),c=12.594(4) Å,β=93.50(2)°,V c=2740.1(2) Å3,Z=4,D k=1.240 g cm−3, λ (CuKα)=1.54178 Å,μ=5.79 cm−1,F(000)=1080,R=0.071,R w=0.080 for 2939 unique significant reflections measured at 298 K. The crystals retain one mole of ethyl acetate per molecule, which shows disorder. Restricted rotation of the phenyl and aminophenyl groups was detected by13C nmr. The title Indolo-carbazoles are easily obtained by reaction of 3-bromoindoles with 2,3′-biindolyls and show an interesting planar structure which could be investigated for anticancer properties.
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    Molecular and crystal structure of 1,4-diacethoxy naphthalene: Structural analysis of methyl substituted 1,4-diacethoxynaphthalenes (1989)
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    Journal of chemical crystallography 19 (1989), S. 307-316 
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    Notes: Abstract Methyl substituted 1,4-diacethoxynaphthalenes have been synthetized and analyzed by means of ultraviolet and1H-nmr. Positional effects of the methyl substitution on the spectroscopic parameters have been rationalized. 6,7-Dimethyl-1,4-diacethoxynaphthalene,V, has been analyzed by X-ray diffraction techniques. Crystals are monoclinic P21,a=8.816(1),b=26.676(7),c=6.189(1) Å,β=103.9 (2) ° and four molecules in the unit cell.
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    Crystal and molecular structure of 3-(4-chlorobenzoylimino)-5,6-dihydro-3H-imidazo[2,1-c]-1,2,4-dithiazole (1989)
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    Journal of chemical crystallography 19 (1989), S. 507-512 
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    Notes: Abstract Crystal structure of the title compound belonging to the group ofα-acylimino derivatives of sulfur(II) compounds has been determined by X-ray structure analysis. The crystals are monoclinic, P21/c,a=11.210(2),b=8.197(1),c=13.659(2) Å,β=102.36(2)°,V=1226.0(3) Å3,Z=4,D x =1.61 g cm−3, λ(MoKα)=0.71069 Å,μ=6.3 cm−1. The structure has been refined to a finalR value of 0.035 for 1401 observed reflexions. The molecule is nearly planar with symmetrym. The title compound contains a very short intramolecular C=O⋯S contact of 2.328(3) Å, suggesting a ‘bond-non-bond’ resonance interaction.
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    Structure of 3α,12β-dihydroxy-2β-morpholino-5α-pregnan-20-one, C25H41O4N (1989)
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    Journal of chemical crystallography 19 (1989), S. 561-568 
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    Notes: Abstract The crystal and molecular structure of 3α,12β-dihydroxy-2β-morpholino-5α-pregnan-20-one, C25H41O4N, has been determined:M r =419.6,P21,a=13.5778(8),b=14.4340(8),c=5.8943(5) Å,β=94.32(1)°,V c =1151.9(3) Å3,Z=2,D x =1.21 g cm−3, $$\bar \lambda $$ (CuKα) = 1.5418 Å, μ=5.6 cm−1,F(000)=460,R=0.039,R w =0.040 for 2421 unique observed reflections. All six-membered rings have chair conformations, and theD ring has a 13β-envelope conformation. The progesterone side chain has an unusual conformation, and the C16-C17-C20-O20 torsion angle, which defines the conformation, is −152.6(3)°. The unusual conformation seems to be forced by the intramolecular hydrogen bond between the hydroxyl group at C12 and the O20 atom from the side-chain.
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    Structure of 17α-methyl-testosterone semihydrate, C20H30O2·1/2 H2O (1989)
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    Journal of chemical crystallography 19 (1989), S. 577-587 
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    Notes: Abstract The crystal structure of 17α-methyltestosterone hemihydrate, C20H30O2·1/2H2O, has been determined:M r =312.5, space groupP21212121,a=6.374(2),b=12.807(2),c=43.398(5)Å,V c =3543(2)Å3,Z=8,D x =1.172 mg−3, CuKα radiation ( $$\bar \lambda $$ = 1.54184 Å),μ(CuKα)=5.5 cm−1,F(000)=1376. The structure was solved usingMultan. The final conventionalR=0.053 (R w =0.052) for 3634 reflections. The structure contains two crystallographically independent molecules in the asymmetric part of the unit cell that have almost identical geometry.
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    Erratum (1989)
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    Journal of chemical crystallography 19 (1989), S. 623-623 
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    Steroids and related studies, Part 76: Crystal and molecular structure of 4,17a-di(2-hydroxyethyl)-4,17a-diaza-d-homo-5α-androstane (HS461) (1989)
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    Journal of chemical crystallography 19 (1989), S. 629-640 
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    Notes: Abstract The crystal structure of 4,17a-di(2-hydroxyethyl)-4,17a-diaza-d-homo-5α-androstane, C22N2O2H40 (HS461), the tertiary amine related to HS781, a potential bisquaternary neuromuscular blocking agent, has been determined by direct methods and refined by full-matrix least squares toR=0.0867 for 2049 reflections (R=0.0597), CuKα radiation θ≦65°. The space group is P212121 a=20.295(4),b=7.278(6),c=14.052(4) Å,Z=4. The rings in the modified steroid nucleus are alltrans connected symmetrical chairs. Hydroxyethyl side groups at N(4) and N(17a) both have an equatorial disposition, and the side chains assumetrans conformations.
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    1,4-Benzodiazepines as ligands. Synthesis, characterization and crystal and molecular structure ofbis(8-chloro-6-(o-chlorophenyl)-1-methyl-4H-s-triazolo[4,3-a]1,4-benzodiazepine (triazolam)) cadmium (II) dichloride (1989)
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    Journal of chemical crystallography 19 (1989), S. 651-660 
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    Notes: Abstract The compound C34H24CdN8Cl6 was prepared and characterized by means of X-ray, IR, and Raman measurements. The crystals are monoclinic, space groupC2/c, (No. 14) witha=22.284(3),b=14.501(2),c=14.595(2) Åβ=129.77(1)° andZ=4. The structure was solved by the heavy-atom method, and least-squares refinement of structural parameters led to a conventionalR factor of 0.040 for 2379 independent reflections. The structure consists of discrete molecules, in which the Cd atom is coordinated in a distorted tetrahedral geometry by two chlorine atoms and by two nitrogens of two triazolic rings of triazolam molecules. Infrared and Raman bands are assigned on the basis of the known structure. An electronic charge calculation has been performed on the unbonded ligand.
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    Crystal structure of 7-cyano-6,7-dimethyl-1-phenyl-1,3,6,7-tetrahydro-2,1-benzoxaphospole 1-oxide (1989)
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    Journal of chemical crystallography 19 (1989), S. 701-705 
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    Notes: Abstract The crystals (C16H18NO2P,M r=287.30) are orthorhombic, space group Pbca witha=8.200(2),b=14.857(2), andc=24.396(5)Å,V=2972.1 Å3,Z=8,D x=1.284 mg m−3,λ(MoKα)=0.71069 Å,μ=1.90 cm−1,F(000)=216,T=295K. FinalR=0.044 for 1673 observed reflections collected on a diffractometer. Structure solved by direct methods.Cis-junction and double bond in the six-membered ring cause its almost ideal sofa conformation. The two neighboring methyl groups are cis, and cyano substituent is in an equatorial position. There is a shortintramolecular H(o-phenyl)⋯O(endocyclic) contact of 2.53(3)Å and the phenyl ring is in a less favorable rotational orientation due to molecular packing.
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    Crystal and molecular structure of voacangine: An alkaloid fromStemmadenia Donnell-Smithii (1989)
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    Journal of chemical crystallography 19 (1989), S. 725-732 
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    Notes: Abstract C22H28N2O3,M r=368.5, orthorhombic, D 2 4 -P212121. Unit cell dimensions at 293 K area=8.753(3),b=9.252(2),c=24.422(7) Å,V=1978(1) Å3,D c=1.24 g cm−3, andZ=4. The structure has been determined from single-crystal data collected with a four-circle diffractometer and refined from 1562 reflections down toR=0.050 andwR=0.055. The structural features determined from chemical and spectroscopic studies are confirmed and extended. The stereochemistry at C(4) and C(18) is 4S and 18S. The indole ring is not planar and the seven-membered nitrogen-containing ring adopts a distorted-chair conformation. The indole and seven-membered rings lie on the same plane with a dihedral angle of 0.7 (1)°, while the C(5)-N(6)-C(19)-C(2) atoms of the central axis of the iso-quinuclidine tricyclic structure is perpendicular to seven-membered ring [dihedral angle is 92.7 (1)°]. The packing in the crystal is entirely due to van der Waals forces.
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    Synthesis, spectroscopic studies, and crystal structure of theophyllinium tetrabromopalladate(II) (1989)
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    Journal of chemical crystallography 19 (1989), S. 755-763 
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    Notes: Abstract The theophyllinium tetrabromopalladate(II), [Thph]2PdBr4, has been synthesized and its molecular structure has been determined by single crystal X-ray diffraction. The salt crystallizes in the monoclinic space group C2 with two formula units in a cell of dimensionsa=11.074(1),b=8.545(2),c=11.804(2) Å;β=95.22(1)°,V=1112.3(4) Å3,D c=2.353 mg m−3,D exp=2.352 mg m−3,M w=788.4, μ(MoKα)=84.5 cm−1,F(000)=752. The structure has been refined by full-matrix least-squares techniques to a final value of theR factor of 0.058 based on 907 independent intensities. The compound consists of theophyllinium cations protonated at N(9). The [PdBr4]2− anion is planar, with distances Pd-Br(1)=2.441(12) and Pd-Br(2)=2.412(6) Å, and Br(1)-Pd-Br(2) and Br(1)-Pd-Br(3) angles of 90.34(14)° and 89.66(14)°, respectively. The1H-NMR spectrum of [Thph]2PdBr4 in DMSO-d6 (300 MHz) is consistent with the observed solid-state structure, and its thermal behavior shows two steps: (i) a dehalogenation process about 327°C and (ii) a rapid pyrolitic decomposition in the 340–575°C temperature range giving PdO as final product.
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    X-ray structure determination of cyclobutane photodimers from (Z)-α, β-diarylacrylonitriles (1989)
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    Journal of chemical crystallography 19 (1989), S. 791-808 
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    Notes: Abstract Irradiation of(Z)-α, β-diarylacrylonitriles (1) ArCH=C(CN)Ar′ (a: Ar=2-thienyl, Ar′=Ph;b: Ar=p-MeC6H4, Ar′=Ph) in the solid state gives cyclobutane dimers (2) in good yield. The mass spectra of the dimers, where no fragments derived from dimers with equal groups on adjacent carbons are present, suggest a “truxillic” structure (head to tail dimerization). X-Ray determinations confirm a centrosymmetric arrangement with a D2d symmetry of the cyclobutane ring and a puckering constantϕ=24.0° for (2a) significantly higher than that of (2b) (ϕ=19.2°).
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    X-ray structure and UV spectroscopic studies of (adenmato-N9)triethylphosphinegold(I) (1989)
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    Journal of chemical crystallography 19 (1989), S. 823-839 
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    Notes: Abstract The preparation, characterization, and X-ray structure analysis of (adeninatoN9)triethylphosphinegold(I) is reported. The crystal structure consists of discrete molecules, the adeninate anion coordinates via the N(9) atom with a Au-N(9) bond distance of 2.057(5) Å and the linear geometry about the Au atom is completed by the P atom of a disordered Et3P ligand; the Au-P(1) bond distance is 2.238(2) Å and the N(9)-Au-P(1) bond angle is 178.8(2)°. The crystals are orthorhombic, space groupPbca, with unit cell dimensionsa=8.528(1),b=17.797(3),c=18.526(2) Å andZ=8. The structure was refined by a full-matrix least-squares procedure to finalR=0.030 andR w =0.033 for 1749 reflections withI〉2.5a(I). The electronic spectrum of the complex dissolved in water in the near ultraviolet is consistent with essentially separate π-electron systems of the adenine and phosphinegold moieties; a conclusion which corroborates the X-ray structural results.
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    Crystal structure and spectroscopic study of 2-(p-methoxycarbonylphenyl)-1,3,5,5,7,8,8-heptamethyl-2,4,5,6,7,8-hexahydroindeno[1,2-c]-pyrrole-7-carbonitrile (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 873-882 
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    Source: Springer Online Journal Archives 1860-2000
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    Notes: Abstract The crystal structure of the title compound has been determined. The crystals are orthorhombic:Pbnb, (bca setting of Pccn, No 56),a=18.053(8),b=15.532(4),c=16.915(6) Å,V c =4743(3) Å3,Z=8,D x =1.17 Mg m−3,λ=(MoKα)=0.71069 Å. The structure was solved by direct methods and refined with 1352 reflections to a finalR value of 0.067. Mass and spectral data (IR, UV,1H and13C NMR) are also reported.
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    Structural investigation on hexasubstituted benzene derivatives. Part 1. The structure of ortho-dinitrotetramethylbenzene (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 905-910 
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    Notes: Abstract C10H12N2O4 (M r =224.2) crystallizes in the triclinic system, space groupP¯1 witha=8.327(3),b=8.734(3),c=8.453(3) Å;a=63.6(1),β=97.0(1), γ=100.4(1)°;V=541.0(6) Å3,Z=2,D c =1.38 g cm−3,μ(Cu-Kα)=8.7 cm−1, λ=1.5418 Å, F(000)=236. Deviation from theoretic geometry of the benzene ring and from planarity is observed in accordance with theσ-electron-withdrawing character of the NO2 groups and the high steric hindrance of the substituents.
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    Structure of 17β-hydroxy-4-pregnen-20-yn-3-one, C21H28O2 (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 941-947 
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    Notes: Abstract The crystal structure of 17β-hydroxy-4-pregnen-20-yn-3-one, C21H28O2, was determined by means of X-ray diffraction methods.M r=312.5, space groupP21,a=6.493(1),b=21.065(3),c=6.478(1) Å,β=105.97(1)°,V c=851.9(3) Å3,Z=2,D x=1.22 Mg m−3, CuKα radiation (λ=1.54184 Å),μ(CuKα)=5.5 cm−1,F(000)=340. The structure was solved withMultan; final conventionalR=0.032 (R w=0.032) for 1803 reflections. The molecule studied (I) has an overall conformation almost identical to 19-norethindrone (II), although ringA of molecule (I) is slightly more bent toward theα direction of the steroid skeleton in comparison with molecule (II).
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    A13C and15N NMR study of some furoxans and related compounds (1989)
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    Journal of chemical crystallography 19 (1989), S. 1003-1008 
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    Notes: Abstract Carbon and nitrogen NMR results are reported for a collection of furoxans and related compounds, taken on DMSO solutions. The15N chemical shifts and those of neighboring13C nuclei have characteristic values for the structures studied. Relative14N signal widths are used to identify the nitro group resonances. Valence tautomerism at room temperature is reported for one compound. The INADEQUATE technique is used to determine some1J(13C-13C) data.
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    Crystal and molecular structure of the rutheniumcarbene-tetraborohydrate complex [Ru(BH4)(LAr)(PPh3)2]; (LAr=CN(C6H4Me-4)CH2CH2NC6H3Me-4) (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 1017-1031 
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    Notes: Abstract The structure of the title compound has been determined by single crystal X-ray diffraction analysis:P21/c,M r=889.9,a=15.940(1),b=23.357(2),c=18.767(2) Å,β=132.62(1)°,V c=5141.6 Å3,Z=4,D x=1.150 mg m−3,F(000)=1848; finalR f=0.074 (R w=0.085). The BH 4 − ligand in the complex is bidentate. A comparative study indicates that the lengths of the Ru-carbene carbon bond and other bonds to the Ru atom are determined by a combination of several factors, and not just by a purely σ- or π-bonding interaction.
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    On the stereochemistry of lignin model compounds of the arylglycerol-β-aryl ether type: Crystal structure oferythro-1-(4-hydroxy-3,5-dimethoxyphenyl)-2-(4-hydroxymethyl-2,6-dimethoxyphenoxy)-1,3-propanediol, C20H26O9 (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 331-339 
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    Notes: Abstract The crystal structure of erythro-1-(4-hydroxy-3,5-dimethoxyphenyl)-2-(4-hydroxymethyl-2,6-dimethoxyphenoxy)-1,3-propanediol, C20H26O9, has been determined from single-crystal X-ray diffraction data. The compound crystallizes in the triclinic space groupP¯1 witha=8.705(6),b=8.893(5),c=13.211(8) Å,α=106.23(5),β=93.71(5), υ=82.97(5)° andZ=2. The structure was solved by direct methods. Full matrix least-squares refinement of 366 structural parameters gaveR=0.039 for 1402 observed [I〉3a(I)] reflexions. The molecules are held together by van der Waals forces and moderately strong hydrogen bonds. Average bond distances: C(sp 2)-O 1.370(6) Å and C(sp 3)-O 1.426(14) Å.
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    Crystal and molecular structure of 1,4,10-trioxa-7,13-diaza-cyclopentadecane-7,13-diacetatocopper (II) dihydrate, C114H24N2O7Cu · 2H2O (1989)
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    Journal of chemical crystallography 19 (1989), S. 387-397 
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    Notes: Abstract l,4,10-Trioxa-7,13-diazacyclopentadecane-7,13-diacetatocopper(II) dihydrate: space groupP43, witha=b=7.217(1),c=34.553(7) Å, andZ=4. The structure was solved by direct methods, and refined by full-matrix least-squares toR=0.039 andR w=0.043. The Cu(II) atom is seven-coordinated (deformed pentagonal bipyramidal coordination) by the two nitrogens and three oxygens of the 15-membered ring and by two oxygens from acetato groups. These groups form 5-membered chelate rings positioned on opposite sides of the macrocycle.
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    Crystal and molecular structures of 1-(2-iso butylylcarbamoyl propan-2-ylamino) 3-(1-naphthyloxy)propan-2-ol hydrochloride (1) (C21H31N2O3Cl) and 1-(2-isobutyloxycarbonylo propan-2-ylamino) 3-(1-naphthyloxy)propan-2-ol hydrochloride (2) (C21H30NO4Cl) (1989)
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    Journal of chemical crystallography 19 (1989), S. 967-982 
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    Notes: Abstract This paper shows the crystal structures of two newβ-adrenergic antagonists, derivatives of propranolol, which were determined with three-dimensional x-ray diffraction data. The space groups and unit-cell parameters are: compound1 (C21H31N2O3Cl) monoclinic space groupP21/c,a=20.523(4),b=6.909(2),c=15.950(2) Å,β=105.03(1)°; compound2 (C21H31NO4Cl) monoclinic space groupP21/c,a=6.364(2),b=36.043(8),c=10.149(1) Å,β=104.48(2)°. The structures were solved with direct methods, and refined with full-matrix least-squares techniques toR indices of 0.059 and 0.067, respectively. The-CH(OH)-CH2-NH-sections of the side chains show the conformation approximate togauche.
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    Synthesis and UV photoelectron investigation of the “peptide units” of α,β-dehydroamino acids (1989)
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    Journal of chemical crystallography 19 (1989), S. 993-1001 
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    Notes: Abstract The He(I) and He(II) photoelectron (PE) spectra of the N-methylamides of N-acetyldehydroalanine (1) and N-acetyldehydrophenylalanine (2) are presented and discussed, within a comprehensive investigation of the electronic structure and conformation ofα, β-dehydroamino acid derivatives. Three different procedures have been adopted for the synthesis of1. The PE results of the “peptide units” are in tune with theoretical predictions and they support the view that in the vapor phase the tendency towards a planar arrangement around the torsion angle φ is much more marked for N-acetyldehydroalanine-NHR systems than for (Z)-substituted ones.
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    Crystal and molecular structure of [dicarbonyl (η-cyclopentadienyl)ferrio]triphenylarsine tetrafluoroborate, [(C6H5)3As{Fe(CO)2(C5H6)}][BF4] (1989)
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    Journal of chemical crystallography 19 (1989), S. 1033-1039 
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    Cobaloxime derivatives: synthesis and spectroscopic studies of alpha-furilglyoximate of cobalt (III), X-ray structure of bis(thiourea)bis(alpha-furilglyoximato)cobalt(III) nitrate (1989)
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    Journal of chemical crystallography 19 (1989), S. 77-91 
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    Notes: Abstract α-Furilglyoxime (H2afdo) complexes of cobalt(III) were used to synthesize H2afdo-cobaloximes with thiourea, triphenylphosphine, and aniline astrans-axial ligands. Encapsulation of the H-bonded species with BF3∶OEt2 resulted in stable BF2-capped macrocycles which mimic the central metal core of the biological molecules such as vitamin B12 etc. Solution chemistry and spectroscopic measurements of the BF2-macrocycles as well as H-bonded cobaloximes revealed six-coordinated cobalt(III) as the central atom and a short hydrogen bond in the case of latter. X-Ray structure of a representative complex [Co(Hafdo)2(thiourea)2]NO3 (Haldo=α-furilglyoxime anion) confirmed a pseudo-octahedral geometry around cobait(III) with thiourea bonded to axial positions. The oxygen atoms of furyl groups are not involved in any kind of bonding and the overall structure of the complex differs from that of the H2dmg-cobaloximes (H2dmg=dimethylglyoxime).
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    Crystal and molecular structure of diaqua-bis-(3,5-dimethyl-1-guanyl pyrazole) nickel (II) nitrate, [Ni(C6N4H10)2(H2O)2](N03)2 (1989)
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    Journal of chemical crystallography 19 (1989), S. 71-76 
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    Notes: Abstract The title compound crystallizes in space groupP21/n witha=10.651(3),b=11.082(2),c=8.993(3) Å,β=106.79(3)°;R=0.064 andR w=0.074 for 3399 observed reflections (I≥3σ(I)) from 3674 measured. The structure was solved by direct methods and refined by least squares. The Ni atom of the complex is located at a center of inversion, and is surrounded by four nitrogen atoms of the two ligands in square-planar geometry. The oxygen atoms of the two centrosymmetrically related water molecules complete the coordination around the metal ion to form an elongated octahedron.
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    Structure of the larvicideN-(2-chlorobenzoyl)-N′-[4-(2-chloro-3,3,3-trifluoroprop-1-enyl)phenyl]urea, C17H11Cl2F3O2N2 (1989)
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    Journal of chemical crystallography 19 (1989), S. 99-108 
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    Notes: Abstract Mw=403,2 amu,P21/c,a 18.944(8) Å,b=8.540(4) Å,c=10.794(7) Å,β=98.11(4)°,V=1729(2) Å3,Z=4,D x=1.548 g·cm−3,μ (MoKα)=4.26 cm−1; m.p. 202–204°C. FinalR=0.083 for 1632 independent observed reflections having 2θ (Mo Kά)〈50° andI〉2 σ(I). The molecule has an extended overall nonplanar conformation with onecis and twotrans-C(O)-NH- units and intramolecular hydrogen bridges. The relatively highR factor is on account of conformational disorder of the trifluoromethyl and chloro substituents of the 2-chloro-3,3,3-trifluoropropenyl moiety.
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    Erratum (1989)
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    Journal of chemical crystallography 19 (1989), S. 231-231 
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    Crystal and molecular structure of 4-bromo-2,2,3,3-tetramethyl-1-benzyl-1-phenylphosphetanium bromide (1989)
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    Journal of chemical crystallography 19 (1989), S. 267-275 
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    Notes: Abstract The title compound crystallizes in the monoclinic space groupP21/n, witha=8.881(1),b=17.718(1),c=13.077(8) Å,β=99.17(2)° andZ=4. The structure was solved by the heavy-atom method and refined to a finalR value of 0.059. The four-membered ring is nonplanar, with a puckering angle of 22.0°. The Br and phenyl are in pseudoaxial positions and aretrans to each other in the solid state.
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    Steroids and related studies, part 75: The crystal and molecular structure of 17a-(2-hydroxyethyl)-17a-aza-D-homo-5-androsten-3βol (HS407) (1989)
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    Journal of chemical crystallography 19 (1989), S. 483-498 
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    Notes: Abstract The crystal structure of 17a-(2 hydroxyethyl)-17a-aza-D-homo-5-androsten-3βol, C22 NO2 H33 (HS407), an intermediate in the formation of azasteroidal neuromuscular blocking agents, has been determined by Vector Verification and refined by full-matrix least-squares toR=0.058 for 1805 reflections, Cu Kα radiation,θ≦65.49°. The space group is P21212,a=25.537(5),b=9.847(4),c=7.545(5) Å,Z=4. The rings in the modified steroid nucleus are alltrans connected, with A and C in distorted chair conformations, D a symmetrical chair, and B a half-chair. The hydroxyethyl side-chain in position N (17a) adopts two distinct conformations with approximately equal statistical occupancies: the first, having a coiled conformation, forms a close intramolecular contact with N(17a) in the enlarged ring D of the steroid nucleus, while the alternative side chain position, which is extended, participates in tail-to-tail intermolecular hydrogen bonding. A switch mechanism is thus formed which could influence the mode of binding of this type of drug moleculein vivo.
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    The crystal structure of UO2Cl2(OH2)(MeCN)2·2MeCN (1989)
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    Journal of chemical crystallography 19 (1989), S. 499-505 
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    Notes: Abstract The crystal structure of UO2Cl2(OH2)(MeCN)2·2MeCN has been determined at 123 K. The crystal is orthorhombic, space group Pnma, witha=14.891(8),b=6.733(6),c=15.931(9) Å, andD calc=2.18 g cm−3 forZ=4. The finalR value for 951 unique observed [F 0≥5σ(F 0)] reflections is 0.064. The U atom is seven-coordinate, pentagonal bipyramidal. The two axial positions are occupied by the uranyl oxygen atoms. Within the equatorial plane lie two acetonitrile groups, two chlorine atoms and a water molecule, the latter positioned between the two chlorine atoms. All of the atoms except the uranyl oxygen atoms lie in crystallographic mirror planes. The water molecule is hydrogen bonded to the two uncoordinated solvent molecules. Several close contacts between the solvent methyl groups and chlorine atoms suggest weak C-H acidic interactions of the type C-H⋯Cl.
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    Crystal and molecular structure of 6-chloro-3-cyclopentylmethyl-3,4-dihydro-7-sulfamyl-2H-1,2,4-benzothiadiazine-1,1-dioxide (1989)
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    Journal of chemical crystallography 19 (1989), S. 547-560 
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    Notes: Abstract The crystal structure of the title compound, C13H18N3O4S2C1, a sulfa drug, has been determined by X-ray diffraction data using MoKα radiation. The crystals are orthorhombic,Pbca, witha=9.441(4),b=29.633(11),c=12.167(8) Å andZ=8. The structure was solved by the heavy-atom method, and refined by full matrix least-squares to a finalR value of 0.054 with 2062 observed reflections. In the crystal, the molecules are linked by N-H⋯O hydrogen bonds.
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    Synthesis, structural, and spectroscopic study of rhenium(III) and rhenium(V) 4,6-dimethylpyrimidine-2-thiolate/triphenylphosphine mixed complexes: Crystal and molecular structure of ∥ReCl2(pymS)(PPh3)2∥·C3H6O and ∥ReOCl2(pymS)(PPh3)∥ (1989)
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    Journal of chemical crystallography 19 (1989), S. 513-534 
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    Notes: Abstract 4,6-dimethylpyrimidine-2(1H)-thione reacts with rhenium(V) precursorstrans-∥ReOX3(PPh3)2∥ (X=Cl, Br) in acetone, to afford two classes of crystalline pyrimidinethiolate/triphenylphosphine mixed complexes:trans-∥ReIIIX2(C6H7N2S)(PPh3)2∥·C3H6O and ∥RevOX2(C6H7N2S)(PPh3)∥ (X=Cl, Br). The crystal structures oftrans-∥ReCl2(C6H7N2S)(PPh3)2∥·C3H6O (I) and ∥ReOCl2(C6H7N2S)(PPh3)∥ (II) have been determined from single-crystal diffractometer data and refined toR factors of 0.0496 and 0.0365, respectively. (I) crystallizes in the triclinic space group P¯1 witha=16.875(4),b=13.969(7),c=9.510(2) Å;α=81.78(2)°,β=85.15(12)°, γ=107.97(8)° andZ=2. The coordination geometry around the rhenium center exhibit mutuallytrans phosphine groups and chloride ligands disposedtrans to the nitrogen and sulfur donors of the pyrimidinethiolate ligand which form a four-membered chelate ring with the metal. (II) crystallizes in the monoclinic space group P21/c witha=12.554(3),b=10.501(1),c=19.200(5) Å;β=106.54(2)° andZ=4. The rhenium atom presents a very distorted octahedral configuration with a chlorine atomtrans to phosphine ligand in the axial position and the N,S-chelate ligand in the equatorial plane with the sulfur donor atomtrans the Re=Ooxo group. The compounds were characterized also by means of ir and nmr spectroscopic measurements; reaction pathways are discussed on the basis of structural data.
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    Crystal and molecular structure of lapachenole (1989)
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    Journal of chemical crystallography 19 (1989), S. 597-602 
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    Structure of 9α, 11β-dichloro-4-pregnene-3,20-dione, C21H28O2Cl2 (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 569-576 
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    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The crystal and molecular structure of 9α, 11β-dichloro-4-pregnene-3,20-dione, C21H28O2C12, has been determined:M r =383.4,P31,a=7.358(2),c=30.137(20) Å,V c =1413(2)Å3,Z=3,D x =1.35 g cm−3, λ(MoKα)=0.71073Å,μ=3.6 cm−1,F(000)=612,T≈80K,R=0.060,R w =0.052 for 2376 unique observed reflections. The steroid skeleton exhibits a flattening of theA ring relative to the rest of the molecule caused by halogen substituents. The title compound has a very high relative binding affinity for the rabbit uterine progesterone receptor. The high binding affinity may result from the flattening of theA ring relative to the rest of the steroid skeleton.
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  • 87
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    Crystal and molecular structure of four compounds resulting from nucleophilic addition of 2H-pyrroles to dimethyl acetylene-dicarboxylate, methyl propiolate and phenyl isocyanate (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 603-621 
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    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01185396
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  • 88
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    X-ray structural investigation of two optically active 1N-epimers of 2,5,7,10,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-dienenickel(II) diperchlorate. A novel conformation of the macrocyclic ligand (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 51-70 
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    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The structures oftrans-1NH,8NH- (I) andcis-1NH,8NH-(II)-2,5,7,10,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-dienenickel(II) diperchlorates have been investigated by X-ray diffractometric methods. CompoundI crystallizes in a monoclinic system, space groupP21,Z=4,a=11.225(1),b=13.710(1),c=15.898(2) Å,β=109.22(1)°. CompoundII crystallizes in an orthorhombic system, space groupP212121,Z=4,a=15.529(2),b=14.129(2),c=10.621(1) Å. The structures were solved by the heavy-atom method followed by a series of Fourier syntheses, and refined by full-matrix least squares to give forI andII R=0.051 (for 3787 independent reflections) andR=0.048 (for 1494 reflections), respectively. Conformational analysis of chelate rings and of the macrocyclic ring was performed forI andII, and the results were compared with those of some known 1,4,8,11-tetraazacyclotetradeca-4,11-dienenickel (II) complexes. A novel conformation of the macrocycle was found in cationI. Conformations of the methyl groups are forI andII 2(a),7(e),10(a),14(e) and 2(a),7(e),10(a),14(a), respectively, with a 1,3-syn-axial interaction of the 2,14-methyl groups inII. The absolute configuration of cationI is 1N(S), 2(R), 7(R), 8N(S), 10(R), 14(S), and differs from that of cationII by 1N(R) exclusively (1N-epimeric compounds).
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  • 89
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    Studies of systemic acylanilide fungicides: Part V. Crystal structure and molecular conformation ofDL-methylN-(2,6-dimethylphenyl)-N-(2-phenylacetyl) alaninate (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 109-121 
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    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The crystal structure of the title compound (C20H23NO3) was determined by three-dimensionalx-ray analysis from diffractometer data. Crystal data are: monoclinic,C2/c,a=22.425(18) Å,b=11.201(5) Å,c=15.388(16) Å,β=108.95(7)°,Z=8,D x=1.182 g·cm−3,μ (MoKα)=0.075 mm−1. FinalR=0.083 for 1148 observed reflexions. The 2,6-dimethylphenyl ring is almost perpendicular to the amidic plane of the molecule (dihedral angle of 92.5°) whereas the phenyl group of the phenylacetyl moiety is inclined at 65.4° with respect to the plane through the central part of the molecule. The distance between the two carbonyl oxygens is 3.095 Å, i.e., within the hitherto observed range of 3.028–3.100 Å for related systemic acylanilide fungicides.
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    URL: http://dx.doi.org/10.1007/BF01160848
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  • 90
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    Nitrogen NMR studies on some fused ring N-heterocycles (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 159-166 
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    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract 15N and14N NMR data are reported for a number of fused ring N-heterocycles.14N line widths,15N-1H couplings and nitrogen shielding additivity rales are used for15N signal assignments. The results obtained lead to some progress in the generalization of the effects of nitrogen-nitrogen interactions on nitrogen shieldings.
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    URL: http://dx.doi.org/10.1007/BF01160852
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  • 91
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    The N,N-diacetylaminobenzene group in the structure of 6-methyl-8-N,N-diacetylamino-2,4-bis(trichloromethyl)-1,3-benzdioxin (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 175-182 
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    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Crystals of 6-methyl-8-N,N-diacetylamino-2,4-bis(trichloromethyl)-1,3-benzdioxin are triclinic, P¯1,Z=2,a=9.586(3),b=9.914(2),c=12.308(5) Å,α=67.19(3),β=71.95(3), γ=74.14(2)°. The structure was solved by direct methods, from data collected at room temperature on an Enraf-Nonius CAD4 difFractometer, and refined by least squares to a finalR value of 0.039 using 3038 reflections. The heterocyclic ring has an envelope conformation. Of thecis-CCl3 groups one CC13 group is pseudoequatorial while the −(CAr·C)CCl3 group is pseudoaxial. (CAr)O-C 1.405(4); (CAr·O)C-O 1.387(4) Å; CAr-C(Cax)-0 112.3(3); C(Cax)-O-C(Ceq) 116.1(2)°; (CAr)O-C-O-C(CAr)58.2(3)°. The configuration of the diacetylamino group (DAA) issyn-anti. The π-systems of the DAA and of the aromatic ring are approximately orthogonal, the deviations from orthogonality probably being caused by an intermolecular bifurcated hydrogen bond, each such interaction involving two molecules only, between thesyn O(=C) of the DAA and both hydrogen atoms bonded to the heterocyclic ring in a molecule of the enantiomer. The geometry of the DAA-benzene fragment is compared with those found in the other three published X-ray structures containing this group.
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    URL: http://dx.doi.org/10.1007/BF01160854
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  • 92
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    Disorder arising from the location of enantiomers in a twist-boat structure: 2,6-trans-2,4,6-tris(trichloromethyl)-1-oxa-3,5-dithian (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 183-191 
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    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Crystals of the title compound are orthorhombic, Pca21;a=27.586(4),b=10.509(3),c=11.080(2) Å,V=3212(1) Å3,Z=8. The structure was solved by direct methods, from data collected at room temperature on an Enraf-Nonius CAD4 diffractometer, and refined by full-matrix least squares to a finalR value of 0.055 using 2043 reflections. One of the two independent molecules in the asymmetric unit is disordered. The disorder is manifested mainly between the oxygen atom and one sulfur atom and is caused by opposite enantiomers occupying corresponding positions in different unit cells. The endocyclic torsion angles in both independent molecules are very similar but the disposition of the heteroatoms on the twist-boat framework is different in the two molecules. Site occupancy of the two models on this framework in the disordered molecule is in the ratio 21∶79 with the smaller proportion being very similar to the ordered molecule and the remainder similar to that found in the ‘normal’ molecule oftrans-4-chloro-2,4,6-tris(trichloromethyl)-1-oxa-3,5-dithian (Irving and Irving, 1988).
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  • 93
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    Crystal and molecular structure of S-(+)-ethyl-O-(4-phenylbenzoyl)lactate, C18H18O4 (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 215-222 
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    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
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    URL: http://dx.doi.org/10.1007/BF01160858
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  • 94
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    Crystal and molecular structure of 4,17a-methy1-4, 17a-diaza-5α-androstane (HS353): An intermediate in the design of azasteroid neuromuscular blocking agents (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 237-256 
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    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The crystal and molecular structure of 4, 17a-methyl-4, 17a-diaza-5α-androstane (HS353), C20N2H36 has been determined by direct methods and successive electron density calculations. The crystals are triclinic,a=7.419(2),b=20.300(4),c=12.866(2)Å,α=105.91(2),β=76.33(2),γ=99.32(2)°, space groupP1,Z=4. Block-matrix least-squares refinement converged toR=0.0660 for 3243 reflections withI≧3σI (CuKα radiation). The four independent molecules show only minor conformational variations, all rings being trans-connected chairs. Introduction of N at positions 4 and 17a of ringsA andD creates asymmetry in both conformation and bond angles, producing outward bending of the C-N side groups at both ends of all four molecules.
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    URL: http://dx.doi.org/10.1007/BF01194120
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  • 95
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    (−)-S-Benzyl-α-hydroxymethylcysteine: Confirmation of its (S)-configuration by x-ray analysis of itsN-benzoyl derivative (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 257-265 
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    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract LaevorotatoryN-benzoyl-S-benzyl-α-hydroxymethylcysteine (1) crystallizes in space groupP21 with cell parameters:a=8.972(1),b=10.004(1),c=10.302(1)Å,β=106.4(1)°,V c=887.2(5)Å3,Z=2. The structure was solved by direct methods and refined toR w=0.054 with 1324 independent reflections. The absolute configuration of1 was determined asS by the application of Hamilton test and by the estimation of the Bijvoet coefficientB. Theα-amino acid residue adopts the C5 ring conformation similar to the fully extended form. The two side chains also adopt an extended conformation around the C α atom. X-Ray analysis of1 confirms theS configuration assigned previously for laevorotatoryS-benzyl-α-hydroxymethylcysteine (2) by chemical correlation.
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  • 96
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    Structural investigation on hexasubstituted benzene derivatives. Part 2: The structure of metadinitrotetramethylbenzene and molecular mechanics analysis on meta and ortho derivatives (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 341-348 
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    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract C10H12N2O4 (M r=224.2) crystallizes in the monoclinic system, space groupP21/mwitha=15.462(4),b=7.926(3),c=8.972(3) Å;β=90.2(1)°;V=1099.5(6) Å3;Z=4;D c=1.35 gcm−3;μ(Cu-Kα)=8.6 cm−1; λ=1.5418 Å;F(000)=472. The position of the molecule on a crystallographic mirror plane forces the NO2 plane to be normal to the benzene ring. Theσ-electron-withdrawing character of the NO2 groups induces a deformation on the geometry of the benzene.
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    URL: http://dx.doi.org/10.1007/BF01194129
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  • 97
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    Crystal structures of 4-amino-1,2,4-triazolidine-3,5-dione (urazine) (C2H4N4O2) and dichlorobis (4-amino-1,2,4-triazolidine-3,5-dione-N, O) copper (II) (C4H8Cl2CuN8O4) (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 357-367 
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    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Crystal structure analyses of urazine and of its adduct with CuCl2 show that this ligand can exchange interactions of stacking that cannot be defined as simple π-π interactions. The copper atoms are octahedrally coordinated by two oxygen atoms and two aminic nitrogen from chelating uraxines and two chlorine atoms. The crystals of urazine are monoclinicP21 c:a=6.741(1),b=5.815(1),c=11.141(2) Å,/gb=92.13(1)°,V c=436.4(1) Å3,Z=4,R=0.0402 for 714 independent observed reflections; the crystals of [CuCl2(urazine)2] are triclinicP¯1:a=5.236(1),b=6.662(1),c=8.411(1) Å,α=93.00(1),β=104.87(1), υ=105.69(1)°,V c=270.66(8) Å3,Z=1,R=0.0380 for 875 independent observed reflections.
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  • 98
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    The crystal and molecular structure of 14-β-N-pentylaminomorphinone, C22H28N2O3 (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 415-431 
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    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The crystal and molecular structure of 14-β-N-pentylaminomorphinone (14-β-N-PAM), C22H28N2O3, has been determined by analysis of single crystal X-ray diffraction data. The compound crystallized at room temperature in the orthorhombic system, space group P212121 witha=12.4535(8),b=13.7855(8),c=11.710(1) Å,V c =2010.3(2) Å3,Z=4,D x =1.22 gm/cm3,μ(Cu Kα)=6.58 cm−1, andF(000)=792. The final refinement yieldedR=0.051,R w =0.059 for 328 variables with 1133 unique observed reflections. The absolute configuration is established via the synthesis from thebaine by the noninvolvement of certain asymmetric centers. The molecule is found to have as its central structure a T shape similar to that found in morphine and codeine. The distinctive feature of the molecule is the 14-β-N-pentylamino lipophilic side chain. Molecular modeling studies on the alkylamino chain result in the identification of clusters of conformations based on energy and dihedral angle criteria. Selected conformations are compared to 19-propylthevinol (etorphine), another potent analgesic which contains a lipophilic hydroxyalkyl substituent at C19. The enhanced analgesic activity of 14-β-N-pentylaminomorphinone is postulated to arise from an overall morphine-like contact with the receptor augmented by the interaction of the aliphatic chain with a lipophilic receptor pocket.
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  • 99
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    Relating infra red spectral data to structure for a series of M2(CO)10−n(L)n complexes (M=Re, Mn; L=CNR, PR3; R=Alkyl, Aryl; n=1−4) (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 451-464 
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    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract An analysis of the IR spectral patterns of a series ofM 2(CO)10−n (L) n complexes (whereM=Re, Mn; L=CNR, PR 3;R=Alkyl, Aryl;n=1−3), taking as far as possible example structures that have been determined by X-ray crystallography, has enabled a correlation to be established between the number and intensity ofv(CO) IR bands and the substitution geometry of the complex. Such a set of standard IR spectral patterns can be used as an easy means of verifying the substitution geometry of such complexes.
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    URL: http://dx.doi.org/10.1007/BF01185382
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  • 100
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    Crystal structure of DMAP-C-HMTCAQ, C30H20N6O2, N,N-dimethylaminophenyl-carbamate-2′-hydroxymethyl-11,11,12,12-tetracyano-anthraquinodimethan (1989)
    Springer
    Journal of chemical crystallography 19 (1989), S. 475-482 
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    ISSN: 1572-8854
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract C30H20N6O2,M r =496.53, triclinic, P¯1,a=8.748(4) Å,b=10.989(3) Å,c=13.541(8) Å,α=90.67(4)°,β=99.15(4)°, γ=98.62(4)°,V=1269.8 Å3,Z=2,D c =1.30 g cm−3, λ (Mo Kα)=0.71069 Å,μ=1.02 cm−1,F(000)=516.0,T=295(3) K,R=0.127% for 1839 observed reflections, 363 parameters. The molecule has an extended, rather than a folded geometry. The HMTCAQ moiety has mm symmetry, and is shaped like a hawk about to land. The anthraquinone ring system is folded, with a dihedral angle of 37.3°; the two propanedinitrile groups have a mutual dihedral angle of 80.2°. The dihedral angle between the central ring of the TCAQ moiety and the phenyl ring is 37.2°. The phenyl rings stack over each other with a perpendicular distance of 3.36 Å. The dipole moment of the molecule is 6.254 Debyes; the crystal Madelung energy isE M=−8.989 kJ/mol; the dispersion energy isE d =−318.370 kJ/mol; the repulsion energy isE r =130.139 kJ/mol.
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    URL: http://dx.doi.org/10.1007/BF01185384
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