ALBERT

Description: Although catchment storage is an intrinsic control on the rainfall-runoff response of streams, direct measurement remains a major challenge. Coupled models that integrate long-term hydrometric and isotope tracer data are useful tools that can provide insights into the dynamics of catchment storage and the volumes of water involved. In this study, we use a tracer-aided hydrological model to characterize catchment storage as a dynamic control on system function related to streamflow generation, which also allows direct estimation of the non-stationarity of water ages. We show that in a wet Scottish upland catchment dominated by runoff generation from riparian peats (histosols) with high water storage, non-stationarity in water age distributions are only clearly detectable during more extreme wet and dry periods. This is explained by the frequency and longevity of hydrological connectivity and the associated relative importance of flow paths contributing younger or older waters to the stream. Generally, these saturated riparian soils represent large mixing zones that buffer the time variance of water age and integrate catchment-scale partial mixing processes. Although storage simulations depend on model performance, which is influenced by input variability and the degree of isotopic damping in the stream, a longer-term storage analysis of this model indicates a system which is only sensitive to more extreme hydroclimatic variability. This article is protected by copyright. All rights reserved.

Description: 2-Pivaloylpterin, an acylated derivative of the biochemically relevant pterin [2-amino-4-oxo-(3 H )pteridine] heterocyclus, undergoes stepwise metallation by the 1, 1′-bis(diphenylphosphanyl)ferrocene-copper(I) cation, [(dppf)Cu] + . The final product obtained, [Cu 3 (dppf)(μ 2 -dppf)(PP)(PP-H + )] 2 (BF 4 ) 4 , could be structurally characterized to reveal coordinative saturation with binding of central Cu + ions to N 1 ,N 3 ,O 4 ,N 5 ,N 8 and pivaloyl-O donor atoms.

Description: Abstract . Two coordination polymers, namely, {[Cd(cdpc)(hmt)(H 2 O)] · H 2 O} n ( 1 ), and [Mn(Hcdpc) 2 (4, 4′-bpy)(H 2 O)] n ( 2 ), were constructed by synergistic assembly through the mixed-ligand synthetic strategy (H 2 cdpc = 1-carboxymethyl-3, 5-dimethyl-1H-pyrazole-4-carboxylic acid, hmt = hexamethylenetetramine, and 4, 4′-bpy = 4, 4′-dipyridine). Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, powder X-ray diffraction (PXRD), and thermogravimetric (TG) analyses. Single X-ray diffraction analysis reveals that complex 1 is a 2D 4-connected sql sheet, and complex 2 is an interesting 1D loop chain. The two complexes are further expanded to 3D supramolecular structure through non-covalent bonds. Besides, luminescent properties of two complexes in the solid state and magnetic property of 2 were also investigated.

Description: The chemical preparation, structure, luminescence, and electronic properties are given for a new potassium holmium cyclotetraphosphate KHoP 4 O 12 , a promising optics material for applications. Single-crystal X-ray diffraction analysis shows that the newly synthesized compound crystallizes in the monoclinic system with space group C 2/ c and Z = 4. [P 4 O 12 ] 4– anionic rings and HoO 8 polyhedra display a three-dimensional (3D) framework by corner-sharing. The ten-coordinated potassium atoms are located in the delimited tunnels. KHoP 4 O 12 exhibits the blue light emission under the excitation of 330 nm. To gain further insights into electronic properties of crystal KHoP 4 O 12 , theoretical calculation based on density functional theory (DFT) was performed using the total-energy code CASTEP with the LDA + U approach. The calculated bandgap with U = 3.0–3.5 eV is in good agreement with the experimental measurement.

Description: The facile synthesis, molecular structure, and reactivity of [Cu(C 7 H 7 NH 2 )Cl] 4 ( 1 ) towards dioxygen and derivatives is reported. The compound could easily be prepared in good yields by mixing CuCl and benzylamine under inert conditions in dichloromethane. Surprisingly this copper(I) compound, a copper(I) tetramer with Cu I ··· Cu I interactions of 2.89 Å, was formed instead of an expected cubane cluster. Oxidation reactions led to formation of μ-oxido-species as intermediates, however 1 did not show any catalytic activity in the activation of CH bonds. In contrast it turned out that 1 was quite stable towards oxidation. Analogous reactions with CuBr or CuI were different and neither cluster units or polynuclear copper(I) complexes were obtained.

Description: The effect of different factors, such as pH of the medium (1.5 〈 pH 〈 4.0; 1 × 10 –4 mol · L –1 〈 [SO 4 2– ] 〈 1 × 10 –1 mol · L –1 ), the concentration of extracting agent, temperature and the type of the solvent, on the extraction of vanadium(V) by trioctylamine was studied. It was shown that the extraction of vanadium(V) by trioctylamine at 25 ± 0.5 °C takes place in the pH range 2.0–3.5 and the extracting complex contains decavanadate anion H 2 V 10 O 28 4– and four molecules of the extracting agent. This allows the reaction of vanadium(V) extraction by trioctylamine to be described by the following equation: 2( R 3 NH) 2 SO 4 + H 2 V 10 O 28 4– ( R 3 NH) 4 H 2 V 10 O 28 + 2SO 4 . The effect of the length of the alkyl chain of alcohol (propyl, butyl, isododecyl alcohol) on the homogeneity of the system V V -TOA-toluene-alcohol was investigated. It was established that the solubility of the extracting complexes of vanadium(V) with trioctylamine can be increased by using isododecyl alcohol C 12 H 25 OH as a modifying agent. It was shown that under optimal conditions in the presence of isododecyl alcohol at temperatures above 25 °C in the pH interval 2.0–3.5 trioctylamine extracts vanadium(V) with a high distribution coefficient (lg D V V 〉 2).

Description: The tetraalkyldigallium(II) compound R 2 Ga–Ga R 2 ( 1 ) [ R = CH(SiMe 3 ) 2 ] reacted with amino and hydroxo functionalized carboxylic acids by retention of the Ga–Ga bond and release of CH 2 (SiMe 3 ) 2 . New heterocyclic or cage-like compounds were formed with three, two, or six Ga–Ga bonds in a single molecule. The latter dodecagallium compounds encapsulated THF or dioxane molecules in their molecular cavities (carcerands), the other compounds have up to six THF molecules coordinated by N–H ··· O hydrogen bonds.

Description: Reduction of chalcogen-rich Pb:Ch (1:2) phases in ethane-1,2-diamine ( en ) by elemental alkali metals results in the formation of solutions of [Pb 2 Ch 3 ] 2– of high purity and abundance. In contrast, application of the same reaction conditions to a binary Bi:Te (1:2) phase yields the mononuclear [BiTe 3 ] 3– anion. Instead of the expected [Tl 2 Te 3 ] 4– or [Tl 2 Te 2 ] 2– anions, analogous reactions with a Tl:Te (1:1) phase end up with a C–C-bond cleavage of the solvent en with formation of a salt of the telluridocyanate (N≡C–Te) – anion. Side reactions of en and elemental cesium are presented and metalate solutions are investigated with NMR spectroscopy.

Description: Seven lanthanide containing strand-like coordination polymers and dimeric complexes were obtained in a reversible reaction from 1, 3-thiazole (thz) and Ln Cl 3 ( Ln = La, Ce, Pr, Nd). The reactions do not require activation and render coordination polymers accessible at room temperature, already. The product constitutions depend on the lanthanide and the thiazole-to-halide ratio. For lanthanum and cerium formation of the coordination polymers 1 ∞ [ Ln Cl 3 (thz) 3 ] · thz as well as dimeric complexes [ Ln 2 Cl 6 (thz) 8 ] · 3thz were observed. For praseodymium and neodymium dimeric complexes were observed with and without non-coordinating thz. Upon heating, the compounds release thiazole under re-formation of Ln Cl 3 , the formation reaction thus being a thermally reversible reaction. Compounds and conversion processes were characterized by temperature dependent X-ray powder and single-crystal X-ray diffraction, in-situ temperature dependent gas phase IR spectroscopy, DTA/TG, and elemental analysis.

Description: The structural and vibrational data for the CF 3 XX CF 3 ( X = O, S, Se, Te) molecules were compared using DFT quantum chemistry calculations. The experimental vibrational frequencies and their assignments to the different normal modes of vibration could be confirmed. The data was also used to define a scaled quantum mechanics force field and sets of derived internal force constants for each molecule. A linear relationship between the experimental X – X bond lengths and the corresponding force constants was found. Additionally, some calculations for the mixed molecule CF 3 SOCF 3 were made.

Description: The coordination polymer [Zn(bpdc)(bimb)(H 2 O)] n ( 1 ) [H 2 bpdc = biphenyl-3,4′-di carboxylate, bimb = 1,4-bis(1-imidazol-yl)-2,5-dimethyl benzene] was constructed under hydrothermal conditions. The structure of complex 1 was determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, XRD, IR spectroscopy, and TG analysis. Complex 1 shows an exceptional self-penetrating 4-connected net derived from a threefold interpenetrating 6 3 -hcb subnet. Furthermore, the luminescent property of complex 1 is investigated

Description: The new dithiophosphate anion P 2 S 6 (OEt) 2 2– was obtained from the reaction of commercially available P 4 S 10 with Na 2 S in pyridine, subsequent ethanolysis and isolated as the stable bis(pyridinium) salt 1 . The molecular structure of 1 in the crystal was determined by single-crystal X-ray diffraction and reveals a PSSP dihedral angle of 87.3(1)° within the anion. The compound is a rare representative of a thiodiphosphate anion with a disulfide bridge between the two phosphorus atoms.

Description: The ureates of the alkali metals Na – Cs were synthesized from urea and the metals in liquid ammonia at temperatures below 50 °C. The crystal structures were determined using single-crystal X-ray diffraction. NaCN 2 H 3 O crystallizes in the monoclinic system [ P 2 1 / c , Z = 16, a = 17.529(1) Å, b = 6.4784(5) Å, c = 10.8211(9) Å, β = 96.938(1)°]. All other ureates are orthorhombic, with KCN 2 H 3 O and RbCN 2 H 3 O being isotypic [ Pbca , Z = 8, KCN 2 H 3 O: a = 7.102(4) Å, b = 7.221(4) Å, c = 13.533(8) Å; RbCN 2 H 3 O: a = 7.1973(8) Å, b = 7.3531(8) Å, c = 13.921(2) Å]. CsCN 2 H 3 O adopts a smaller unit cell [ P 2 1 2 1 2 1 , Z = 4, a = 6.3520(3) Å, b = 7.1645(4) Å, c = 9.0911(5) Å]. The ureates of K, Rb, and Cs contain hydrogen-bond networks, the imino nitrogen atom acting as the hydrogen-bond acceptor in CsCN 2 H 3 O. In KCN 2 H 3 O and RbCN 2 H 3 O, however, the carbonyl oxygen atom accepts the hydrogen bonds.

Description: Phosphorus (P) is one of the major limiting nutrient in many freshwater ecosystems. During the last decade, attention has been focused on the fluxes of suspended sediment and particulate P through freshwater drainage systems because of severe eutrophication effects in aquatic ecosystems. Hence, the analysis and prediction of phosphorus and sediment dynamics constitutes an important element for ecological conservation and restoration of freshwater ecosystems. In that sense, the development ofa suitable prediction model is justified and the present work is devoted to the validation and application of a predictive Soluble Reactive Phosphorus (SRP) uptake and sedimentation models, to a real riparian system of the middle Ebro river floodplain. Both models are coupled to a fully distributed 2D shallow water flow numerical model. The SRP uptake model is validated using data from three field experiments. The model predictions show a good accuracy for SRP concentration, where the linear regressions between measured and calculated of the three experiments were significant ( r 2  ≥ 0.62; p  ≤ 0.05), and a Nash-Sutcliffe coefficient (E) that ranged from 0.54 to 0.62. The sedimentation model is validated using field data collected during 2 real flooding events within the same river reach. The comparison between calculated and measured sediment deposition showed a significant linear regression ( p  ≤ 0.05; r 2  = 0.97) and an E that ranged from 0.63 to 0.78. Subsequently, the complete model that includes flow dynamics, solute transport, SRP uptake and sedimentation is used to simulate and analyze floodplain sediment deposition, river nutrient contribution and SRP uptake. According to this analysis, the main SRP uptake process appears to be the sediment sorption. The analysis also reveals the presence of a lateral gradient of hydrological connectivity that decreases with distance from the river, and controls the river matter contribution to the floodplain. This article is protected by copyright. All rights reserved.

Description: The inherent effects of global sea surface temperature (SST) anomalies on hydrological cycle and vegetation cover complicate the structure of tropical climate at the regional scale. Assessing hydrological processes related to climate forcing is important in Central America because it is surrounded by both the Pacific and Atlantic oceans and two continental landmasses. In this study, the use of high-resolution remote sensing imagery in wavelet analysis helps identify nonstationary characteristics of hydrological and ecological responses. The wavelet-based empirical orthogonal function (WEOF) further reflects the nonlinear relationship between the Atlantic and Pacific SST and the greenness of a pristine forested site in Panama, La Amistad International Park. Integrated WEOF and descriptive statistics for data analysis reveal a higher temporal variability in terrestrial precipitation relative to in-situ land surface temperature and its probable effects on the presence of dry periods. Such teleconnection signals of SST were identified as a driving force of decline in tropical forest greenness during dry periods. The results of our remote sensing-based wavelet analysis showed intrannual high frequency and biennial to triennial low frequency signals between enhanced vegetation index (EVI)/precipitation datasets and SST indices in both Atlantic and Pacific oceans. A spatiotemporal priority search further confirmed the importance of the effects of the El Niño-Southern Oscillation (ENSO) over terrestrial responses in the selected study site. Coincidence of the effect of ENSO teleconnection patterns on precipitation and vegetation suggest possible impacts of El Niño-associated droughts in Central America, accompanied by reduced rainfall, especially during the first months of rainy season (June, July and August), and decline in vegetation cover during the dry season (March and April). This article is protected by copyright. All rights reserved.

Description: Chromium tricarbonyl η 6 complexes of 3 cyclacene are considered quantum chemically at the levels of B3LYP/6-31G(d), B3LYP/6-31++G(d, p), B3LYP/LANL2DZ, and RF/6-31G(d, p)//B3LYP/6-31++G(d, p). One of the complexes involves the top ring (A-type) and the other one (B-type) makes use of ring of the acene belt of the cyclacene in the complex formation. Energy calculations reveal that B-type complex is more stable than A-type. Some geometrical and quantum chemical properties were obtained. Additionally, vibrational and UV/Vis spectra of the complexes were produced.

Description: Three mononuclear copper(II) complexes of copper nitrate with 2, 6-bis(pyrazol-1-yl)pyridine ( bPzPy ) and 2, 6-bis(3′,5′-dimethylpyrazol-1-yl)pyridine ( bdmPzPy ), [Cu(bPzPy)(NO 3 ) 2 ] ( 1 ), [Cu(bPzPy)(H 2 O)(NO 3 ) 2 ] ( 2 ) and [Cu(bdmPzPy)(NO 3 ) 2 ] ( 3 ) were synthesized by the reaction of copper nitrate with the ligand in ethanol solution. The complexes have been characterized through analytical, spectroscopic and EPR measurements. Single crystal X-ray structure analysis of complexes 1 and 2 revealed a five-coordinate copper atom in 1 , whereas 2 contains a six-coordinate (4+2) Cu II ion with molecular units acting as supramolecular nodes. These neutral nodes are connected through O–H ··· O(nitrate) hydrogen bonds to give couples of parallel linear strips assembled in 1D-chains in a zipper-like motif.

Description: The organic-inorganic hybrid compounds, [Cu 2 Cl 6 ] 2– ( 1 ), [Fe 2 Cl 6 O] 2– ( 2 ), and [FeCl 4 ] – ( 3 ), based on [(C 8 H 12 NO)(18-crown-6)] + (C 8 H 12 NO = 4-methoxybenzylammonium) supramolecular cations, were synthesized and structurally characterized. Crystal structure analyses and thermal and dielectric studies showed that compounds 1 and 2 have similar crystal packings and undergo reversible phase transitions at 230 K and 358 K, respectively. Compound 3 shows a phase transition at 361 K, though its crystal structure is remarkably different from 1 and 2 . These results indicate that the phase transitions may arise from the [(C 8 H 12 NO)(18-crown-6)] + supramolecular cations. The role of the chlorometalate anions is to tune the crystal packings and thus the phase transition points and types.

Description: This paper evaluates the IBIS land surface model using daily soil moisture data over a three-year period (2005–2007) at a semi-arid site in southeastern Australia, the Stanley catchment, using the Monte-Carlo GLUE approach. The model was satisfactorily calibrated for both the surface 30 cm and full profile 90 cm. However, full-profile calibration was not as good as that for the surface, which results from some deficiencies in the evapotranspiration component in IBIS. Relatively small differences in simulated soil moisture were associated with large discrepancies in the predictions of surface runoff, drainage and evapotranspiration. We conclude that while land surface schemes may be effective at simulating heat fluxes they may be ineffective for prediction of hydrology unless the soil moisture is accurately estimated. Sensitivity analyses indicated that the soil moisture simulations were most sensitive to soil parameters, and the wilting point was the most identifiable parameter. Significant interactions existed between three soils parameters: porosity, saturated hydraulic conductivity and Campbell “b” exponent so they could not be identified independent of each other. There were no significant differences in parameter sensitivity and interaction for different hydroclimatic years. Even though the data record contained a very dry year and another year with a very large rainfall event, this indicated that the soil model could be calibrated without the data needing to explore the extreme range of dry and wet conditions. IBIS was much less sensitive to vegetation parameters. The leaf area index (LAI) could affect the mean of daily soil moisture time series when LAI 〈 1, while the variance of the soil moisture time series was sensitive to LAI 〉 1. IBIS was insensitive to the Jackson rooting parameter, suggesting that the effect of the rooting depth distribution on predictions of hydrology was insignificant. This article is protected by copyright. All rights reserved.

Description: The chemical bonding in the intermetallic compounds ZnPd and ZnPt with the tetragonal CuTi type of structure, and in the chemically related intermetallic compounds ZnNi, ZnCu, ZnAg, and ZnAu with the cubic CsCl type of structure, is examined applying the electron localizability approach. The analysis of the chemical bonding reveals charge transfer from zinc to the transition metal ( TM ), in line with the respective electronegativities. While in ZnNi, ZnCu, and ZnAg as well as ZnPd and ZnPt the Zn– TM interactions are described by multi-center bonding and ionic interactions, mainly ionic interactions are found in the intermetallic compound ZnAu. Going from ZnNi over ZnPd to ZnPt, a gradual change from isotropic to more and more anisotropic distribution of the atomic interactions is detected, resulting in a more pronounced tetragonal distortion.

Description: Two new three-dimensional frameworks with zeolite-like channels were prepared in the presence of 1,6-diaminohexane. Cu 1.5 (H 3 N–(CH 2 ) 6 –NH 3 ) 0.5 [C 6 H 2 (COO) 4 ] · 5H 2 O ( 1 ) crystallizes in the triclinic space group P with a = 772.56(7), b = 1110.36(7), c = 1111.98(8) pm, α = 98.720(7)°, β = 108.246(9)°, and γ = 95.559(7)°. Cu 2 (H 3 N–(CH 2 ) 6 –NH 3 ) 0.5 (OH)[C 6 H 2 (COO) 4 ] · 3H 2 O ( 2 ) crystallizes in the monoclinic space group P2 / c with a = 1159.34(11), b = 1059.44(7), c = 1582.2(2) pm, and β = 106.130(11)°. The Cu 2+ coordination polyhedra are connected by [C 6 H 2 (COO) 4 ] 4– anions to yield three-dimensional frameworks with wide centrosymmetric channel-like voids. Complex 1 reveals voids extending along [100] with diagonals of 900 pm and 300 pm, whereas in complex 2 the diagonal of the nearly rectangular crossection of the channels extending parallel to [001] is 900 pm. The negative excess charges of the frameworks are compensated by [H 3 N–(CH 2 ) 6 –NH 3 ] 2+ cations, which occupy the voids along with water molecules. The [H 3 N–(CH 2 ) 6 –NH 3 ] 2+ cations are not connected to Cu 2+ and have served as templates.

Description: The molecular alumosiloxanes (O-SiPh 2 -O-SiPh 2 -O) 3 Al 2 and (O-SiPh 2 -O-SiPh 2 -O) 4 [Al(OH)] 4 react either with water in diethyl ether, or with 1,4-butane-diol to form the new macro-cyclic compounds Al 6 (OH) 8 (O-SiPh 2 -O-SiPh 2 -O) 4 (O-SiPh 2 -O-SiPh 2 -OH) 2 ·6H 2 O ( 2 ) or Al 6 (OH) 8 (O-SiPh 2 -O-SiPh 2 -O) 4 (O-SiPh 2 -O-SiPh 2 -O-CH 2 –CH 2 –CH 2 –CH 2 –OH) 2 ( 3 ). As shown by single crystal structure analyses, both compounds 2 and 3 have a center of symmetry, resemble each other structurally and display in their center an [Al 2 (OH) 8 ] 2– unit, which is coordinated in a similar fashion to a 24-membered [Al 4 (O-SiPh 2 -O-SiPh 2 -O) 4 ] 2+ cycle branched at two aluminum atoms displaying either two (O-SiPh 2 -O-SiPh 2 -OH) ( 2 ) or two (O-SiPh 2 -O-SiPh 2 -O-CH 2 –CH 2 –CH 2 –CH 2 –OH) ( 3 ) arms. The [Al 2 (OH) 8 ] 2– groups are connected to the cycles through oxygen atoms of their hydroxide groups which link to the aluminum atoms of the ring (of the four aluminum atoms in the ring two have a double contact and two a single). Parallel to this bonding, the aluminum atoms of [Al 2 (OH) 8 ] 2– have either a water molecule in their coordination sphere, which is incorporated in a complex hydrogen bridged network including the silanol function ( 2 ), or are bonded to the –CH 2 -OH group of the siloxane-alcohol arm of the cycle ( 3 ). The aluminum atoms of the central part are in both compounds in the centers of two distorted edge sharing oxygen octahedra (mean Al–O = 1.881(7) Å ( 2 ), 1.893(7) Å ( 3 )), while the other four aluminum atoms display a tetrahedral oxygen environment (Al–O = 1.752(8) Å ( 2 ), 1.754(8) Å ( 3 )). Whereas all hydroxy groups of the [Al 2 (OH) 8 ] 2– unit in 2 are engaged in hydrogen bonding including further water molecules which make part of the network, the [Al 2 (OH) 8 ] 2– unit in 3 shows fewer hydrogen bridges. We have here a rare example of the same chemical species in a more hydrophilic and a less hydrophilic surrounding. This allows a detailed study of the impact of secondary hydrogen bonding on the structure.

Description: The mechanochemical synthesis offers an easy access to obtain alkaline earth metal terephthalates M (C 8 H 4 O 4 ) · n H 2 O ( M = Ca, Sr, Ba). In the presented study we describe for the first time the mechanochemical synthesis of powders of Ca(C 8 H 4 O 4 ) · 3H 2 O, Ca(C 8 H 4 O 4 ), Sr(C 8 H 4 O 4 ) · H 2 O, and Ba(C 8 H 4 O 4 ), which so far were only synthesized as single crystals from aqueous solutions or by reactions in an autoclave. Furthermore, a new hydrate Ba(C 8 H 4 O 4 ) · 2(1.5)H 2 O, not described so far in the literature, was prepared. All compounds were characterized by X-ray powder diffraction, thermal analysis, elemental analysis, FT-IR, and MAS NMR spectroscopic measurements.

Description: Over the past few decades ground water has become an essential commodity due to increased demand as a result of growing population, industrialization, urbanization etc. The water supply situation is expected to become more severe in the future because of continued unsustainable water use and projected change in hydro-meteorological parameters due to climate change. This study is based on the integrated approach of Remote Sensing (RS), Geographical Information System (GIS) and Multi-Criteria Decision Making (MCDM) techniques to determine the most important contributing factors that affect the ground water resources and to delineate the ground water potential zones. Ten thematic layers viz. geomorphology, geology, soil, topographic elevation (DEM), land use/land cover, drainage density, lineament density, proximity of surface water bodies, surface temperature and post-monsoon ground water depth were considered for the present study. These thematic layers were selected for ground water prospecting based on literature, discussion with the experts of Central Ground Water Board (CGWB), Government of India, field observations, geophysical investigation and multivariate techniques. The thematic layers and their features were assigned suitable weights on the Saaty's scale according to their relative significance for ground water occurrence. The assigned weights of the layers and their features were normalized by using Analytic Hierarchy Process (AHP) and eigenvector method. Finally, the selected thematic maps were integrated using weighted linear combination method to create the final ground water potential zone map. The final output map shows different zones of ground water potential, viz., very good (16%), good (35%), moderate (28%) low (17%) and very low (2.1%). The ground water potential zone map was finally validated using the discharge and ground water depth data from 28 and 98 pumping wells respectively which showed good correlation. This article is protected by copyright. All rights reserved.

Description: Bank erosion is the main source of suspended sediment (SS) and diffuse total phosphorus (TP) in many lowland catchments. This study compared a physically based sediment routing method (Physical method), which distinguishes between stream bed and bank erosion, with the original sediment routing method (Original method) within the Soil and Water Assessment Tool (SWAT) version 2009, for simulating SS and TP losses from a lowland catchment. A SWAT model was set up for the lowland River Odense catchment in Denmark and calibrated against observed stream flow and phosphate (PO 4 ) loads. Based on an initial calibration of hydrological and PO 4 parameters, the SWAT model with the Original method (Original model) and the SWAT model with the Physical method (Physical model) were calibrated separately against observed SS and TP loads. The SWAT model simulated daily stream flow well, but underestimated PO 4 loads. The Physical model simulated daily SS and TP better than the Original model. The simulated contribution of bank erosion to SS in the Physical model (99%) was close to the estimated contribution from in-situ erosion measurements (90-94%). Compared with the Original method, the Physical method is not only more conceptually correct, but also improves model performance. This article is protected by copyright. All rights reserved.

Description: This paper focuses on surface-subsurface water exchange in a steep coarse-bedded stream with step-pool morphology. We use both flume experiments and numerical modelling to investigate the influence of stream discharge, channel slope and sediment hydraulic conductivity on hyporheic exchange. The model step-pool reach, whose topography is scaled from a natural river, consists of 3 step-pool units with 0.1 m step heights, discharges ranging between base and over bankfull flows (scaled values of 0.3-4.5 L/s) and slopes of 4 and 8%. Results indicate that the deepest hyporheic flow occurs with the steeper slope and at moderate discharges and downwelling fluxes at the base of steps are highest at the largest stream discharges. In contrast to pool-riffle morphology, these findings show that steep slopes cause deeper surface-subsurface exchanges than gentle slopes. Numerical simulation results show that the portion of the hyporheic zone influenced by surface water temperature increases with sediment hydraulic conductivity. These experiments and numerical simulations emphasize the importance of topography, sediment permeability and roughness elements along the channel surface in governing the locations and magnitude of downwelling fluxes and hyporheic exchange. Our results show that hyporheic zones in these steep streams are thicker than previously expected by extending the results from streams with pool-riffle bed forms. This article is protected by copyright. All rights reserved.

Description: The objective of this analysis is to demonstrate the feasibility of using a composite L2 SMOS soil moisture product for determining drought conditions by taking advantage of its spatial and temporal resolution. The work investigates the potential relationships between soil moisture anomalies and two drought indices, the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI), both calculated on a ten-day basis. As the two drought indices can be applied to different time scales for precipitation series, the influence of time scale on the drought definition is also studied. The anomalies were calculated both for the in situ soil moisture by REMEDHUS (Soil Moisture Measurement Stations Network, Spain) and from the SMOS L2 soil moisture product. In general, in situ anomalies exhibit higher correlation coefficients for the drought indices than those of SMOS, except for the shortest time scale. As expected, the short-term remotely sensed anomalies have a high response to precipitation events. This effect may be due to the greater sensitivity of SMOS data to rainfall, as well as to the spatial averaged nature of its observations. The optimal time scale was one month for the SMOS values and ranged between 30 and 50 days for the in situ values. The use of evapotranspiration in the calculation of the indices did not improve the description of the anomalies. The relationship between indices and soil moisture conditions provides encouraging results. Indeed, this method generates preliminary but valuable insights for future satellite products. This article is protected by copyright. All rights reserved.

Description: The cage compound Ba 3 Ge 16 Ir 4 crystallizes with the Ba 3 Ge 16 Rh 4 type of crystal structure, which represents a hierarchical derivative of the BaAl 4 type. The crystal structure [Pearson symbol tI 46, space group I 4/ mmm ; a = 6.5312(2) Å, c = 22.2845(6) Å] was refined from single-crystal X-ray diffraction data. The phase was obtained after 10 d at 910 °C with small impurities of clathrate-I, BaGe 7 Ir 2 and α-Ge remaining at the grain boundaries. Ba 3 Ge 16 Ir 4 is a Pauli-paramagnetic metal, which becomes superconducting below T c = 5.1 K. Electronic structure and analysis of the chemical bonding were performed based on density functional theory calculations. The physical properties are discussed in comparison to the isotypic phase Ba 3 Ge 16 Rh 4 .

Description: Remote estimation of river discharge from river width variations is an intriguing method for gauging rivers without conventional measurements. Entirely cloud-free imagery of an entire river reach is often rare, but partial coverage is more frequent. Discharge is estimated from spatially discontinuous imagery via construction of multiple width-discharge rating curves within a 62 km reach of the Tanana River, Alaska. The resulting discharge error is as low as 6.7% RMSE. Imagery covering 〈20% of the study reach can be used. This article is protected by copyright. All rights reserved.

Description: Reports of abruptly declining flows of Canada's Athabasca River have prompted concern because this large, free-flowing river could be representative for northern North America, provides water for the massive Athabasca oil-sands projects, and flows to the extensive and biodiverse Peace-Athabasca, Slave and Mackenzie River deltas. To investigate historic hydrology along the river and its major tributaries we expanded the time series with interpolations for short data gaps; calculations of annual discharges from early, summer-only records; and by splicing records across sequential hydrometric gauges. These produced composite, century-long records (1913 to 2011) and trend detection with linear Pearson correlation provided similar outcomes to non-parametric Kendall τ−b tests. These revealed that the mountain and foothills reaches displayed slight increases in winter discharges versus larger declines in summer discharges, and consequently declining annual flows (~0.16%/yr at Hinton; p 〈 0.01). Conversely, with contrasting boreal contributions, the Athabasca River at Athabasca displayed no overall trend in monthly or annual flows, but there was correspondence with the Pacific Decadal Oscillation (PDO) that contributed to a temporary flow decline from 1970 to 2000. These findings from century-long records contrast with interpretations from numerous shorter-term studies, and emphasize the need for sufficient time series for hydrologic trend analyses. For Northern Hemisphere rivers, the study interval should be at least 80 years to span two PDO cycles and dampen the influence from phase transitions. Most prior trend analyses considered only a few decades and this weakens interpretations of the hydrologic consequences of climate change. This article is protected by copyright. All rights reserved.

Description: Four zinc(II) complexes, namely, Zn(Hdmpz) 2 (L1) 2 ( 1 ) (Hdmpz = 3, 5-dimethylpyrazole, HL1 = trichloroacetic acid), Zn(Hdmpz) 2 (L2) 2 ( 2 ) (HL2 = 2, 4-dichlorophenoxyacetic acid), [Zn 2 (μ-dmpz) 2 (Hdmpz) 2 (L3) 2 ] ( 3 ) (HL3 = 1-naphthylacetic acid), and [Zn(Hdmpz) 2 (L4) 2 ] · H 2 O ( 4 ) (HL4 = indole-3-acetic acid) were prepared and structurally characterized by different techniques including elemental analysis, IR spectroscopy, TG, and single-crystal X-ray diffraction analysis. The complexes display 2D to 3D structures with tetrahedral to pentagonal coordination around the central zinc atom. The X-ray studies suggested that 1 , 2 , and 4 are mononuclear complexes, whereas 3 is a centrosymmetric dinuclear complex. The pyrazole ligand is coordinated in both terminal as well as a bridging fashion in the dinuclear moiety but the pyrazole ligand in the mononuclear complexes is coordinated only in monodentate terminal fashion with its neutral N group. The carboxylate groups behave as monodentate ligands in 1 – 3 , whereas the carboxylate in 4 functioned as both monodentate and chelating bidentate ligand. On the basis of X-ray crystallographic study the rich intra- and intermolecular weak interactions such as classical hydrogen bonds, C–H ··· O, CH 3 ··· O, CH–Cl, Cl–Cl, C–H ··· π, CH 2 –π, CH 3 –π, O–π, and π–π are analyzed. All these noncovalent interactions help to assemble the discrete complexes into high-dimensional ordered superamolecular structures.

Description: Acetate trinuclear metal complexes of Zn II and Co II with the potentially tridentate Schiff base ligand, having mixed phenolate, imine, and pyridine donor groups, HL, were synthesized. The complexes were characterized by microanalysis, LSI mass spectrometry, IR, UV/Vis spectroscopy, and magnetic measurements. Crystal structures of [ M 3 L 2 (OAc) 4 ] ( M = Zn II , Co II ) complexes, were also determined. The X-ray structures show the presence of trinuclear complexes with metal ions joined by phenolate and acetate bridging groups. The ligands coordinate to the metal ions through the imine nitrogen and their corresponding attached pyridyl and phenolate groups. The coordination environment for the metal ions is completed by bridging acetate anions to generate an octahedral coordination arrangement for the Co II complex and mixed distorted, bipyramidal trigonal and octahedral arrangements for the Zn II complex.

Description: Recent studies have suggested that the hydrologic connectivity of northern headwater catchments is likely controlled by antecedent moisture conditions and land cover patterns. A water storage model ( EWS ), based on water levels ( WLs ), specific yield ( Sy ) and surface elevation ( SE ) changes was compared to a basic water budget of a small, boreal, patterned fen (13 ha) during the ice-free period. Results showed that the EWS model reproduced well storage variations derived from the water budget. These results suggest that storage variations can be properly represented by the fluctuations of WLs when we consider the heterogeneous soil properties. However, storage deviations occurred at the daily scale and could be explained by a lack of information on water retention in unsaturated layers, canopy interceptions and preferential flows. Despite the significant impact of SE changes on the different peatland cover storage budgets (strings and lawns), using Sy mean values had low impact on storage estimations. This can be explained by the large proportion of pools and high WLs throughout the fen. At the fen scale, high storage in the pools seemed to reduce the Sy difference between strings and lawns. The results of this study provide new insights about the complex hydrological behaviour of northern catchments and allow for conceiving new hydrological modeling perspectives. This article is protected by copyright. All rights reserved.

Description: Starting from a flexible tri-carboxylic acid ligand H 3 L {H 3 L = 2,4,6-tris[(4′-carboxyphenoxy)methyl]-1,3,5-trimethylbenzene}, a 3D metal-organic framework [Zn(HL)(H 2 O)] n ( 1 ) and a 2D polymeric layered solid {[(CH 3 ) 2 NH 2 )] 2 [Cd 2 L 2 (DMA) 2 ]} n ( 2 ) were hydrothermally synthesized. The complexes were characterized by elemental analyses, FT-IR spectroscopy, TGA, and single-crystal X-ray diffraction. The X-ray structural analyses reveal that the complex 1 is an example of a doubly interpenetrated 3D helical MOF with mutually entwined right- and left-handed helices to form an overall racemic framework. Complex 2 is made up of fourfold interwoven 2D nets in the solid state.

Description: Oxidovanadium(IV) complexes, [VO(acac)(L)Cl] ( 1 ), [VO(cur)(L)Cl] ( 2 ), and [VO(scur)(L)Cl] ( 3 ) {acac = acetylacetonate, cur = curcumin monoanion, scur = diglucosylcurcumin monoanion, L = 11-(9-acridinyl)dipyrido[3, 2-a:2',3'-c]phenazine (acdppz)}, were prepared and characterized. The complexes are non-electrolytic in DMF and 1:1 electrolytic in aqueous DMF. The one-electron paramagnetic complexes showed a d-d band near 725 nm in aqueous DMF and green emission near 520 nm in aqueous DMSO. The complexes exhibited an irreversible V IV /V III redox response near –0.85 V versus SCE in aqueous DMF. The complexes showed good binding strengths to calf thymus DNA ( K b : 3.1 × 10 5 –9.6 × 10 5 M –1 ) and efficient pUC19 DNA photocleavage activity in red light of 705 and 785 nm by singlet oxygen ( 1 O 2 ) pathway. Complexes 1 and 2 exhibited significant photocytotoxicity (IC 50 : 0.1–1.0 μM) in visible light (400–700 nm) with low dark toxicity (IC 50 : 〉20 μM) in HeLa and HaCaT cells. Complex 3 was cytotoxic in both light and dark. DNA ladder formation experiments indicated cell death via apoptotic pathway. Confocal microscopy done with 1 and 2 revealed primarily cytosolic localization of the complexes with significant presence of the complex in the mitochondria as evidenced from the imaging data using mitotracker red.

Description: The coordination polymer [Cd(HL)(BPDA)] n · n H 2 O ( 1 ) based on 3-(5-(pyridin-4-yl)-1 H -1,2,4-triazol-3-yl)pyridine (HL) and 1,1′-biphenyl-4,4′-dicarboxylic acid (H 2 BPDA) was hydrothermally synthesized and characterized by single-crystal X-ray diffraction, XRPD, IR spectroscopy, and elemental analysis. The asymmetric unit of compound 1 consists of one crystallographically independent Cd II ion, one HL ligand, “two half” BPDA 2– ligand, and one lattice water molecule. There are two crystallographically different BDPA 2– moieties, but each of them is placed in a symmetry element. The BPDA 2– ligands and Cd II ions connected to2D sheet, and the 2D sheets are connected to a 3D MOF by the HL ligands. Each dimeric Cd II unit links six nearest neighbors through the BPDA 2– and HL ligands, and the dimeric Cd II units are centrosymmetric. Two parallel HL ligands connect two dimeric Cd II units, generating long Cd2–HL–Cd2–HL rings, also centrosymmetric. So we can define the dimeric Cd II unit as a 6-connected node. Thus, the 3D structure can be described as a threefold parallel interpenetrated bsn beta-Sn topology. In addition, the optical properties of compound 1 and the free ligand H L were investigated.

Description: The 4-connected dmp -type cadmium(II)-isonicotinate framework [Cd(isonic) 2 (H 2 O)] n · n (DMA) ( 1 ) (isonic = isonicotinate, DMA = N , N ′-dimethylacetamide) was obtained by the solvothermal reactions of Cd(NO 3 ) 2 and isonicotinic acid (Hisonic). Compound 1 features a 3D porous framework with the opened channels occupied by the lattice DMA molecules. Thermal analysis reveals that such framework remains much stable after removal the free DMA molecules. CO 2 adsorption measurement shows that such framework exhibits notable CO 2 adsorption behavior.

Description: The reaction of the basic bismuth nitrate [Bi 6 O 4 (OH) 4 (NO 3 ) 6 ] · H 2 O with either thiosalicylic acid or sulfuric acid gave the novel bismuth hydrogen sulfate [Bi 2 (SO 4 ) 2 (dmso) 8 ](HSO 4 ) 2 ( 1 ) (DMSO = dimethyl sulfoxide). The formation of sulfate ions is observed in the presence of either Bi 3+ or [Bi 6 O 4 (OH) 4 ] 6+ indicating bismuth-induced oxidation of thiosalicylic acid. Compound 1 was characterized by elemental analysis, infrared spectroscopy, thermal analysis (TGA), and temperature dependent in situ X-ray powder diffraction. Crystals suitable for single crystal structure analysis were obtained from a DMSO/acetone solution. The title compound 1 crystallizes in the triclinic space group P with the following lattice parameters: a = 9.5240(4) Å, b = 9.9535(4) Å, c = 12.6620(5) Å, α = 109.943(4)°, β = 93.952(3)°, γ = 102.868(3)°, V = 1086.17(8) Å 3 , and Z = 1. Analysis of the thermally induced decomposition revealed the formation of Bi 2 O(SO 4 ) 2 and Bi 2 O 2 (SO 4 ) as intermediate products and Bi 28 O 32 (SO 4 ) 10 as final product.

Description: Recently, the synthesis of hexadentate ligands based on N , N ′-bis-(2,2′-bipyridine-6-ylmethyl)-2,2′-biphenylenediamine ( 1a – d ) and the corresponding iron(II) complexes ( 3a – d ) was reported by our group. In this contribution we present the synthesis of the analogous cobalt(II) complexes 4a – d . Together with the iron(II) complex the electrochemical behavior of the complexes 3 and 4 was investigated by cyclic voltammetry (CV). The aminomethyl substructure was identified as the main source of ligand degradation caused by chemical oxidation with air. Upon exposure to air the amine group in complexes 3 and 4 is oxidized to imine and even amide groups. Some examples ( 8 , 9 ) of the oxidation products were characterized by X-ray structure analysis. In order to increase the robustness of the Fe II and Co II complexes towards oxidation, the ligand scaffold of 1a was modified by N -methylation of the amino group yielding the tertiary amine 2 . The corresponding iron(II) and cobalt(II) complexes employing 2 as ligand were synthesized {[Fe( 2 )][PF 6 ] 2 ( 5 ), [Co( 2 )][PF 6 ] 2 ( 6 )} and fully characterized, their redox behavior and spin-state was investigated by CV and Evans' method. It was found, that the introduced N -methyl group leads to a substantial anodic shift of the M II – M III redox potential and the stabilization of Fe II and Co II high-spin state. By means of X-ray structure analysis these effects could be explained by repulsive steric effects of the methyl group.

Description: The intermetallic compounds Y 2 RuB 6 , Y 2 ReB 6 , Y 2 RhSi 3 , YRh 2 Si, and YPdSi were synthesized from the elements by arc-melting and subsequent annealing in sealed silica ampoules. The samples were studied by X-ray diffraction on powders. The structures of Y 2 RuB 6 and Y 2 RhSi 3 were refined from single crystal diffraction data: Y 2 ReB 6 type, Pbam , a = 916.3(2) pm, b = 1150.3(3) pm, c = 364.37(9) pm, wR 2 = 0.1056, 942 F 2 values, 38 variables for Y 2 RuB 6 and Er 2 RhSi 3 type, a = 812.6(2), c = 787.2(1) pm, wR 2 = 0.0682, 369 F 2 values, 17 variables for Y 2 RhSi 3 . The five compounds are characterized by two or three (YPdSi), crystallographically independent yttrium sites, which were all well resolved in 89 Y solid state NMR spectra. The NMR signal shifts were correlated with the density of states of the s electrons at the Fermi level, resulting in a non-ambiguous assignment of the NMR signals to the various sites in the crystal structures.

Description: The title complexes were obtained by reactions of [(η 5 -C 5 H 5 )(CO) 2 Fe] – , [(η 5 -C 5 H 4 CH 3 )(CO) 2 Fe] – , [Re(CO) 5 ] – , or [Mn(CO) 5 ] – with the mixed anhydride from the respective pyridine carboxylic acid and pivalic acid or with isonicotinic acid chloride, and were characterized by spectroscopic data and elemental analysis.

Description: The N -(2, 6-diisopropylphenyl)- N ′-benzoylthiourea ligand (shown as L ) ( 1 ) was synthesized and characterized. Reactions of 1 with CuCl 2 and CuBr 2 afforded the monomeric L 2 CuCl ( 2 ) and dimeric [ L BrCu(μ- L )] 2 ( 3 ), respectively, due to the reduction of Cu II . The reaction of 1 and CuCl gave the same product L 2 CuCl ( 2 ), while the treatment of 1 with CuBr led to the formation of a rare example of adamantanoid cage ( L Cu) 2 (μ- L ) 2 Cu 2 (μ-Br) 4 ( 4 ) containing enantiomeric couple. The product of 1 and CuI was found to be dimeric [ L ICu(μ- L )] 2 ( 5 ), which is isomorphous to 3 . All compounds obtained were fully characterized by elemental analysis, IR, 1 H NMR and 13 C NMR spectroscopy, and single-crystal X-ray diffraction.

Description: Thermodynamic data for gaseous SiF 2 and SiCl 2 known from literature show that these binary subhalides are formed nearly quantitatively at 1376 °C and 1076 °C, respectively, as products of the reaction of elemental silicon with SiF 4 or SiCl 4 at 1 × 10 –2 mbar. Applying the co-condensation technique SiF 2 as well as SiCl 2 can be trapped at –196 °C and prepared in synthetic scale. Herein, first analysis of metastable SiF 2 and SiCl 2 solutions are presented, showing that SiF 2 is more reactive than SiCl 2 leading to compounds of low boiling point of so far unknown composition. The metastable SiCl 2 solution can be used as a SiCl 2 source, which is shown by the trapping reaction with Idipp [Idipp = 1, 3-bis(2, 6- i Pr 2 -C 6 H 3 )imidazol-2-ylidene] leading to Idipp-SiCl 2 . The reactivity of the solution might be fine-tuned by changing the donor opening the door for further applications.

Description: Minor changes to seasonal air temperature and precipitation can have a substantial impact on the availability of water resources within large watersheds. Two such watersheds, the north-flowing Mackenzie and east-flowing Saskatchewan Basins have been identified as highly vulnerable to such changes, and, therefore, selected for study as part of the Climatic Redistribution of western Canadian Water Resources (CROCWR) project. CROCWR aims to evaluate spatial and temporal changes to water resource distribution through the analysis of a suite of hydroclimatic and streamflow variables. As part of this analysis, dominant summer (May-Oct) circulation patterns at 500-hPa for 1950-2011 are identified using the method of Self-Organizing Maps (SOM). Surface climate variables associated with these patterns are then identified, including both daily air temperature and precipitation, and seasonal Standardized Precipitation-Evapotranspiration Index (SPEI) values. Statistical methods are applied to assess the relationships between dominant circulation patterns and the Southern Oscillation Index (SOI) and Pacific Decadal Oscillation (PDO). Results indicate that mid-summer (Jul-Aug) is dominated by a split-flow blocking pattern, resulting in cool (warm), wet (dry) conditions in the southern (northern) portion of the study area. By contrast, the shoulder season (May and Oct) is dominated by a trough of low-pressure over the North Pacific Ocean. The frequency of weak split-flow blocking is higher during positive SOI and negative PDO, while ridging over the western continent is more frequent during negative SOI and positive PDO. Results from this analysis increase our knowledge of processes controlling the distribution of summer water resources in western Canada. This article is protected by copyright. All rights reserved.

Description: Lithium transition metal silicates, Li 2 M SiO 4 ( M = Fe, Mn, Co), have attracted much interest as positive electrodes for Li-ion batteries due to their high theoretical capacities and their rich crystal chemistry. Low (β) and high (γ) temperature forms of these tetrahedral structures differ in the ordering/distribution of cations within tetrahedral sites of an hcp based packing of oxygen. We have carried out VT powder neutron and X-ray diffraction on Li 2 M SiO 4 ( M = Fe, Mn) to characterize the rich polymorphism observed across the Li 2 M SiO 4 ( M = Fe, Mn) system as a function of temperature. For Li 2 FeSiO 4 below 500 °C a β II phase was observed with slight Li/Fe disorder. Above this temperature there was a sluggish transition to the γ s phase, which was observed up to ca. 820 °C, with the γ II polymorph seen at highest temperatures. Excellent agreement with phases obtained by quenching was observed, except that the γ phases exhibit a statistical distribution of Li/Fe, in contrast to the well-ordered structures of quenched phases. The Li 2 MnSiO 4 polymorphism is less complex, the β II phase is stable from room temperature to 750 °C, at which temperature it transforms to the γ structure with disordered Li/Mn.

Description: Ag@Au core-shell nanoparticles were synthesized by using a fluorescent dipeptide β -Ala-Trp in water medium and at a room temperature without using any external reducing and stabilizing agents. The shell thickness of gold in core-shell Ag@Au nanoparticles has also been varied by changing the concentration of the gold(III) precursor keeping the other conditions same. The optical property of these core-shell nanoparticles varies with the shell thickness. Interestingly, these core-shell nanoparticles exhibit good catalytic property for the reduction of nitrophenols to aminophenols and nitroanilines to aminoanilines. A series of nitrophenol and nitroaniline compounds were taken as substrates for reduction. Moreover, this core-shell nanoparticle displays remarkable difference in catalytic property for reduction of nitro group with the variation of shell thickness. This catalyst (Ag@Au core-shell nanoparticle) can also be recycled for several times indicating its reusability.

Description: Two coordination polymers, namely {[Mn(2,4′-bpdc)(bimb)(H 2 O) 0.5 ] · 0.5H 2 O} n ( 1 ) and [Mn(4,4′-bpdc)(bimb)] n · 2.5H 2 O ( 2 ) [2,4′-bpdc = biphenyl-2,4′-dicarboxylate, 4,4′-bpdc = biphenyl-4,4′-dicarboxylate, and bimb = 1,4-bis(1-imidazol-yl)-2,5-dimethyl benzene], were hydrothermally synthesized by reactions of manganese(II) salt with the rigid ligand 1,4-bis(1-imidazol-yl)-2,5-dimethyl benzene and isomeric biphenyl dicarboxylate ligands. Complex 1 has an unusual 6-connected three-dimensional (3D) architecture with point symbol (4 4 .6 11 ). Complex 2 has also a 3D structure with two-interpenetrated pcu topology with point symbol (4 12 .6 3 ). Structural comparisons show that the positions of the carboxylate groups in the ligand backbone play an important role in governing the structural topologies of these complexes.

Description: Little research has examined whether forests reduce stream water eutrophication in agricultural areas during spring snowmelt periods. This study evaluated the role of forests in ameliorating deteriorated stream water quality in agricultural areas, including pasture, during snowmelt periods. Temporal variation in stream water quality at a mixed land-use basin (565 ha: pasture 13%, forestry 87%), northern Japan, was monitored for 7 years. Synoptic stream water sampling was also conducted at 16 sites across a wide range of forest and agricultural areas in a basin (18.3 km 2 ) in spring, summer, and fall. Atmospheric nitrogen (N) and phosphorus (P) deposition were measured for 4 years. The results showed that concentration pulses of nitrate (NO 3 – ), organic N (ON), and total P (TP) in stream water were observed when discharge increased during spring snowmelt. Their concentrations were high when silicate concentrations were low, suggesting surface water exported from pasture largely contributed to stream water pollution during snowmelt. Atmospheric N and P deposition (4.1 kg N ha –1 y –1 ; 0.09 kg P ha –1 y –1 , respectively) was too low to affect the background concentrations of N and P in streams from forested areas. Reduction of eutrophication caused by nutrients from pasture was mainly due to dilution by water containing low concentrations of N and P exported from forested areas, while in-stream reduction were not dominant processes. Results indicate that forests have a limited capacity to reduce the concentration pulses of N and P in stream water during snowmelt in this study basin. This article is protected by copyright. All rights reserved.

Description: The semirigid exo -bidentate ligand 1, 4-bis{[(2′-picolylaminoformyl)phenoxyl]methyl}-2, 5-bismethylbenzene (L) was designed, synthesized, and used as building blocks for constructing luminescent lanthanide polymers. Two new lanthanide coordination polymers were characterized by elemental analysis, X-ray diffraction analysis, and IR spectroscopy. The coordination polymers exhibit the metal-to-ligand molar ratio of 1:1 and the semirigid exo -bidentate ligand bridges lanthanide nitrates forming a zigzag chain, which further interconnected to three dimensional supramolecular structure in aid of cooperative C–H ··· O hydrogen bonds. The luminescence properties of the europium(III) complex are discussed in detail.

Description: In NLDAS-2 Noah simulation, the NLDAS team introduced an intermediate “fix” to constrain the surface exchange coefficient when the atmospheric boundary layer is stable. In the current NLDAS-2 Noah version, this fix is used for all stable cases including snow-free grid cells. In this study, we simply apply this fix to the grid cells in which both stable atmospheric boundary layer and snow exist simultaneously, excluding the snow-free grid cells as we recognize that the fix in NLDAS-2 is too strong. We conduct a 31-year (1979-2009) NLDAS-2 Noah interim (Noah-I) run, and use observed streamflow, evapotranspiration, land surface temperature, soil temperature, and ground heat flux to evaluate the results, including comparisons with the original NLDAS-2 Noah run. The results show that Noah-I has the same performance as NLDAS-2 Noah for snow water equivalent; however, Noah-I significantly improved the simulation of other hydrometeorological products as noted above when compared to NLDAS-2 Noah and the observations. This simple modification is being included in the next Noah version used in NLDAS. The hydrometeorological products from the improved NLDAS-2 Noah-I are being staged on the NCEP public server. This article is protected by copyright. All rights reserved.

Description: Large-scale watershed modelling presents a unique challenge in terms of physiographic and climatological heterogeneity and spatially varied hydrologic responses. In particular, the spatial variability in hydrologic processes may introduce a high degree of uncertainty in the modelling of a large watershed. This study assessed the uncertainties in annual/seasonal streamflow and annual peak flow simulations with respect to selection of climate data and model parameter sets for the Variable Infiltration Capacity (VIC) model of the Athabasca River Basin (ARB) in Alberta, Canada. Two high-resolution gridded climate data sets over the 1979 to 2010 period, and six different model parameter sets calibrated corresponding to different time periods and various hydrologic patterns, were employed to quantify the uncertainty in VIC simulations. Moreover, the possibility of an ensemble approach to predict hydrologic responses in the ARB has been investigated. The results indicated that stramflow simulations near the headwater and along the Athabasca River mainsteam have high uncertainty corresponding to selection of climate data mainly due to greater difference of precipitation between the two climate data sets, whereas sub-basin stations at low-elevations were more sensitive to the selection of parameter set for interflow-dominated runoff cycle. All stations showed higher uncertainty corresponding to the selection of parameter set for annual peak flows. In addition, this study confirmed that the ensemble means can provide more accurate and consistent hydrologic information for the low-elevation area where higher internal variability exists. This article is protected by copyright. All rights reserved.

Description: Multilayer covers are widely accepted reclamation designs in the oil sands region of northern Alberta, Canada, with an ultimate goal of revegetating to species characteristic of predisturbance native plant communities. To determine the optimal depth of reclamation material required to reclaim overburden shale from an oil sands mine, an evaluation was made of the long-term performance of six reclamation soil cover depths all placed over overburden. The measured soil water contents from different cover thicknesses at South Bison Hills located at the Syncrude Mine site north of Fort McMurray, Alberta were used to calibrate and validate a dual-porosity model in HYDRUS-1D. The calibrated and validated model was then used to evaluate the influence of cover thickness and climatic variability on plant available water for forest growth. The frequency distributions of actual transpiration (T r ) for six cover treatments with a range of leaf area index (LAI) cases were developed. These T r frequency distributions were then modified by coupling T r and LAI. The modified frequency distributions for annual T r for the six simulated cover thickness highlight the strong non-linearity between the distribution of T r over a long-term (60 year) climate cycle in that incremental increases in cover thickness do not produce proportional increases in T r . The results indicated that, once the cover thickness exceeds 100 cm, there is little incremental increase in the median value of T r over the 60 year climate cycle. This article is protected by copyright. All rights reserved.

Description: Within peatland ecosystems small deviations in surface elevation result in microforms that differ in depth to water-table, plant type and rate of biogeochemical cycling, possibly leading to differences in peat physical and hydrological properties that could feed back to whole ecosystem hydrological and biogeochemical function. However, hydrological parameters for peatland microforms have not been quantified. This study determined bulk density, pore size distribution and saturated hydraulic conductivity (K sat ) at hummocks and hollows of four, Sphagnum -dominated Canadian peatlands. Study sites included both a bog and poor fen in each of Alberta and Quebec allowing for investigation of differences in peat hydrophysical properties between microforms across a range of Sphagnum -dominated peatlands. Hydraulic conductivity was determined in the laboratory on peat from the surface (0.03-0.08 m) and the saturated zone (0.20 m below the local water-table position). Peatland type, climate region, microform and depth of peat were all significant descriptors of variation in K sat . Deeper peat was less conductive than surface peat. Hummocks generally had higher K sat than hollows at both surface and saturated zones, although differences between microforms varied between sites. Differences in K sat between samples were correlated with bulk density, von Post humification and macroporosity. These results indicate that there are microtopographical differences in peat hydrophysical properties; however, the strong decline in K sat with depth indicates that differences in the local water-table, resulting in a change in depth of water flow, is likely a stronger control on local K sat than microform type. This article is protected by copyright. All rights reserved.

Description: A regional, or pooled, approach to frequency analysis is explored in the context of the estimation of rainfall quantiles required for the formation of Intensity-Duration-Frequency (IDF) curves. Resampling experiments are used, in conjunction with two rainfall data sets with long record lengths, to explore the merits of a pooled approach to the estimation of extreme rainfall quantiles. The width of the 95% confidence interval for quantile estimates is used as the primary basis to evaluate the relative merits of pooled and single site estimates of rainfall quantiles. Recommendations are formulated for applying the regional approach to frequency analysis and these recommendations are used in the application of the regional approach to 40 sites with IDF data in southern Ontario, Canada. The results demonstrate that the regional approach is preferred to single site analysis for estimating extreme rainfall quantiles for conditions and data availability commonly encountered in practice. This article is protected by copyright. All rights reserved.

Description: Integrated river basin models should provide a spatially distributed representation of basin hydrology and transport processes to allow for spatially implementing specific management and conservation measures. To accomplish this, the Soil and Water Assessment Tool (SWAT) was modified by integrating a landscape routing model to simulate water flow across discretized routing units. This paper presents a grid-based version of the SWAT landscape model that has been developed to enhance the spatial representation of hydrology and transport processes. The modified model uses a new flow separation index that considers topographic features and soil properties to capture channel and landscape flow processes related to specific landscape positions. The resulting model is spatially fully distributed and includes surface, lateral, and groundwater fluxes in each grid cell of the watershed. Furthermore it more closely represents the spatially heterogeneous distributed flow and transport processes in a watershed. The model was calibrated and validated for the Little River Watershed (LRW) near Tifton, Georgia (USA). Water balance simulations as well as 30 the spatial distribution of surface runoff, subsurface flow and evapotranspiration are examined. Model results indicate that groundwater flow is the dominant landscape process in the LRW. Results are promising and satisfactory output was obtained with the presented grid-based SWAT landscape model. Nash-Sutcliffe model efficiencies for daily stream flow were 0.59 and 0.63 for calibration and validation periods and the model reasonably simulates the impact of the landscape position on surface runoff, subsurface flow and evapotranspiration. Additional revision of the model will likely be necessary to adequately represent temporal variations of transport and flow processes in a watershed. This article is protected by copyright. All rights reserved.

Description: Direct sediment inputs from forest roads at stream crossings are a major concern for water quality and aquatic habitat. Legacy road-stream crossing approaches, or the section of road leading to the stream, may have poor water and grade control upon reopening, thus increasing the potential for negative impacts to water quality. Rainfall simulation experiments were conducted on the entire running surface area associated with six reopened stream crossing approaches in the southwestern Virginia Piedmont physiographic region, USA. Event-based surface runoff and associated total suspended solids (TSS) concentrations were compared among a succession of gravel surfacing treatments that represented increasing intensities of best management practice (BMP) implementation. The three treatments were No Gravel (10-19% cover), Low Gravel (34-60% cover), and High Gravel (50-99% cover). Increased field hydraulic conductivity was associated with maximized surface cover, and ranged from 7.2 to 41.6, 11.9 to 46.3, and 16.0 to 58.6 mm h -1 , respectively, for the No Gravel, Low Gravel, and High Gravel treatments. Median TSS concentration of surface runoff for the No Gravel treatment (2.84 g L -1 ) was greater than Low Gravel (1.10 g L -1 ) and High Gravel (0.82 g L -1 ) by factors of 2.6 and 3.5, respectively. Stream crossing approaches with 90-99% surface cover had TSS concentrations below 1 g L -1 . Reducing the length of road segments that drain directly to the stream can reduce the costs associated with gravel surfacing. This research demonstrates that judicious and low-cost BMPs can ameliorate poor water control and soil erosion associated with reopening legacy roads. This article is protected by copyright. All rights reserved.

Description: The following study discusses the synthesis of macroporous glass beads, featuring variable pore sizes, and their application as starting material for a double templating route according to the nanocasting principle. In the first step, the initial porous glass was filled with the carbon precursor, a mesophase pitch, which after the subsequent carbonization and dissolution of the glass matrix results in an inverse macroporous carbon replica. Afterwards, the carbon beads were filled with amorphous silica by a typical sol-gel-process. The next step can be divided into two phases. The silica gel phase was first “structured” inside the macropores of the inverse carbon replica by converting it into an ordered mesoporous phase via pseudomorphic transformation. This process demanded alkaline conditions and a surfactant, that finally converts the silica into hierarchically structured beads with the dimension and the pores of the initial glass and MCM-41 pores inside the walls. The final step comprised the template removal via calcination. The obtained materials were characterized by mercury intrusion, nitrogen adsorption, scanning electron microscopy, x-ray powder diffraction and particle size analysis. In comparison to the previously reported approaches, the new method allows a higher flexibility in the texture properties of the resulting hierarchically structured materials including a variable ratio between ordered mesopores and additional macropores by parallel control of the total porosity and wall thickness in the starting porous glass.

Description: New periodic mesoporous organosilicas were synthesized using [bis(triethoxysilyl)vinyl]aniline (BTEVA) and [bis(triethoxysilyl)vinyl]benzene (BTEVB) as precursors and by functionalizing the BTEVA PMO with aminopropyl groups. All PMO materials showed a high degree of hexagonal order in the respective P-XRDs as well as high surface areas with narrow pore size distributions. The PMOs together with activated carbon were investigated with regards to their hexanal adsorption capacity in a gravimetric apparatus with an attached GC-MS. For the amine PMOs two different regions during adsorption were found. In the first region loadings in the range of 30 wt% were reached by a fast adsorption process. In the second region the loading reached 50 wt% but with slower kinetics. In desorption experiments up to 150 °C the loading decreased from 50 wt% to 30 wt%, where an equilibrium state was observed. With GC-MS and NMR the first region could be assigned to a chemisorption process, where the hexanal forms an imine group with the amine function in a Schiff base reaction. The subsequent second region can be assigned to weaker and thus reversible physisorption. The total capacity (first and second region) is substantially higher for the amine PMOs than for the activated carbon. Due to the chemical bonding in the chemisorption process, the desorption behavior is completely different: compared to the activated carbon the bonding of hexanal is much stronger for the amine PMOs.

Description: The cover picture shows a section of the crystal structure of the coordination polymer Cu 1.5 (H 3 N-(CH 2 ) 6 -NH 3 ) 0.5 [C 6 H 2 (COO) 4 ]·5H 2 O( 1 ), which features channel-like voids accommodating hexane-1,6-diammonium cations that compensate for the negative charge of the three-dimensional framework. A space-filling view of the framework is inserted. The compound can be dehydrated to a trihydrate and rehydrated to the starting composition retaining the crystal structure. Cu 2 (H 3 N-(CH 2 ) 6 -NH 3 ) 0.5 (OH)[C 6 H 2 (COO) 4 ]·3H 2 O ( 2 ) has a similar framework structure with channels of different dimensions accommodating hexane-1,6-diammonium cations as well. The different compounds have been obtained from aqueous solution by employing the same method, however, at different temperatures. More details are discussed in the article by R. Köferstein and C. Robl on page 310ff.

Description: Groundwater modeling has emerged as a powerful tool to develop a sustainable management plan for efficient groundwater utilization and protection of this vital resource. This study deals with the development of five hybrid artificial neural network (ANN) models and their critical assessment for simulating spatio-temporal fluctuations of groundwater in an alluvial aquifer system. Unlike past studies, in this study, all the relevant input variables having significant influence on groundwater have been considered and the hybrid ANN technique (ANN-cum-Genetic Algorithm) has been used to simulate groundwater levels at 17 sites over the study area. The parameters of the ANN models were optimized using Genetic Algorithm (GA) optimization technique. The predictive ability of the five hybrid ANN models developed for each of the 17 sites was evaluated using six goodness-of-fit criteria and graphical indicators, together with adequate uncertainty analyses. The analysis of the results of this study revealed that the MLP-LM model is the most efficient in predicting monthly groundwater levels at almost all the 17 sites, while the RBF model is the least efficient. The GA technique was found to be superior to the commonly used trial-and-error method for determining optimal ANN architecture and internal parameters. Of the goodness-of-fit statistics used in this study, only RMSE, r 2 and NSE were found to be more powerful and useful in assessing the performance of the ANN models. It can be concluded that the hybrid ANN modeling approach can be effectively used for predicting spaio-temporal fluctuations of groundwater at basin or sub-basin scales. This article is protected by copyright. All rights reserved.

Description: Phosphorus (P) loss from agricultural watersheds has long been a critical water quality problem, the control of which has been the focus of considerable research and investment. Preventing P loss depends on accurately representing the hydrological and chemical processes governing P mobilization and transport. The Soil and Water Assessment Tool (SWAT) is a watershed model commonly used to predict runoff and non-point source pollution transport. SWAT simulates runoff employing either the curve number ( CN ) or Green and Ampt methods, both assume infiltration excess runoff, although shallow soils underlain by a restricting layer commonly generate saturation excess runoff from variable source areas (VSA). In this study, we compared traditional SWAT to a re-conceptualized version, SWAT-VSA, which represents VSA hydrology, in a complex agricultural watershed in east central Pennsylvania. The objectives of this research were to provide further evidence of SWAT-VSA's integrated and distributed predictive capabilities against measured surface runoff and stream P loads and to highlight the model's ability to drive sub-field management of P. Thus, we relied on a detailed field management database to parameterize the models. SWAT and SWAT-VSA predicted discharge similarly well (daily Nash-Sutcliffe Efficiencies of 0.61 and 0.66, respectively), but SWAT-VSA outperformed SWAT in predicting P export from the watershed. SWAT estimated lower P loss (0.0 - 0.25 kg ha -1 ) from agricultural fields than SWAT-VSA (0.0 - 1.0+ kg ha -1 ), which also identified critical source areas - those areas generating large runoff and P losses at the sub field level. These results support the use of SWAT-VSA in predicting watershed-scale P losses and identifying critical source areas of P loss in landscapes with VSA hydrology. This article is protected by copyright. All rights reserved.

Description: This article presents results of mercury in surface waters from Hunza River basin, Northern Areas, Pakistan. Small-scale gold mining activities along Hunza and Gilgit rivers are long known to be discharging mercury in the amalgamation and roasting processes. Previous studies reported high mercury concentrations in soils close to mining operations as well as serious health problems for miners. However, none of the studies have focused on the level of contamination in aqueous environments. This is the first study on the investigation of source and fate of sediment and river-borne mercury in Hunza River. Samples collected near panning sites showed higher mercury concentrations than critical levels established by the U.S. Environmental Protection Agency. The observed dissolved mercury concentrations ranged from 5.10 to 25.25 ng/L, whereas particulate-bound mercury ranged from 4.85 to 154.62 ng/L. Particulate phase mercury corresponded to more than 75% of the total observed mercury concentrations for all of the sampled rivers. Thus, suspended sediments represented the major pathway of the riverine mercury transport. A mass balance calculation suggested a 48.6 g/km 2 of annual mercury flux into Hunza River basin. The samples collected from the most affected river, Shimsal River, averaged to have 108 ng/L total mercury concentration. This number was close to the average soil mercury data from PMDC (2001) of 151 ng/L. The dominant source of contamination was shown to be the leaching of large quantities of mercury from the Hg-rich sediment and flood plain soil into the rivers rather than the direct release from mining activities. Significant decrease in both dissolved and particulate-bound mercury concentration downstream of Attabad Lake suggested that mercury is being accumulated or consumed in the lake. Although minimization or elimination of mercury loses from mining process seems important for the wellbeing of the miners, preventing remobilization of accumulated mercury is equally important in mercury control in this region. This article is protected by copyright. All rights reserved.

Description: Perovskite-type LaVO 2.78 N 0.10 powder was synthesized by thermal ammonolysis of the oxide precursor LaVO 4 . By X-ray, neutron, and electron diffraction an orthorhombic crystal structure with space group Pnma was identified. XANES spectra showed that the oxidation state of vanadium changes from 5+ in LaVO 4 to approximately 3+ in LaVO 2.78 N 0.10 . The temperature dependence of the electrical conductivity revealed an Arrhenius-type behavior with an activation energy of 0.103 eV in the temperature range of 119–302 K indicating that the conduction process is thermally activated band transition. Based on the positive Seebeck coefficient, holes were identified as the dominant charge carriers in the temperature range of 100–302 K. Both the Seebeck coefficient and the thermal conductivity showed an anomaly at 138 K, which is attributed to the Néel temperature for antiferromagnetic ordering according to magnetic susceptibility measurements.

Description: The study of the multiannual thermal dynamics of Lake Iseo, a deep lake in the Italian pre-alpine area, is presented. Interflow was found to be the dominant river entrance mode, suggesting future susceptibility of the lake thermal structure to the overall effects of climate change expected in the upstream alpine watershed. A lake model employed the results of a long-term hydrologic model to simulate the effects of a climate change scenario on the lake's thermal evolution for the period 2012-2050. The model predicts an overall average increase in the lake water temperature of 0.012 °C/year and a reinforced Schmidt thermal stability of the water column in winter up to 800 Jm -2 . Both these effects may further prevent the deep circulation process, which is vital for the oxygenation of deep water. This article is protected by copyright. All rights reserved.

Description: Changes in water temperature can have important consequences for aquatic ecosystems, with some species being sensitive even to small shifts in temperature during some or all of their lifecycle. While many studies report increasing regional and global air temperatures, evidence of changes in river water temperature has thus far been site-specific and often from sites heavily influenced by human activities that themselves could lead to warming. Here we present a tiered assessment of changing river water temperature, covering England and Wales with data from 2,773 locations. We use novel statistical approaches to detect trends in irregularly sampled spot measurements taken between 1990 and 2006. During this 17 year period, on average, mean water temperature increased by 0.03 °C per year (± 0.002 °C) and positive changes in water temperature were observed at 2,385 (86%) sites. Examination of catchments, where there has been limited human influence on hydrological response, shows that changes in river flow have had little influence on these water temperature trends. In the absence of other systematic influences on water temperature, it is inferred that anthropogenically-driven climate change is driving some of this trend in water temperature. This article is protected by copyright. All rights reserved.

Description: Parametric method of flood frequency analysis (FFA) involves fitting of a probability distribution to the observed flood data at the site of interest. When record length at a given site is relatively longer and flood data exhibits skewness, a distribution having more than three parameters is often used in FFA such as Log Pearson Type 3 distribution. This paper examines the suitability of a 5-paramter Wakeby distribution for the annual maximum flood data in eastern Australia. We adopt a Monte Carlo simulation technique to select an appropriate plotting position formula and to derive a probability plot correlation coefficient (PPCC) test statistic for Wakeby distribution. The Weibull plotting position formula has been found to be the most appropriate for the Wakeby distribution. Regression equations for the PPCC tests statistics associated with the Wakeby distribution for different levels of significance have been derived. Furthermore, a power study to estimate the rejection rate associated with the derived PPCC test statistics has been undertaken. Finally, an application using annual maximum flood series data from 91 catchments in eastern Australia has been presented. Results show that the developed regression equations can be used with a high degree of confidence to test whether the Wakeby distribution fits the annual maximum flood series data at a given station. The methodology developed in this paper can be adapted to other probability distributions and to other study areas. This article is protected by copyright. All rights reserved.

Description: From the reaction of 2,3-dihydro-1,3,4,5-tetraisopropylimidazol-2-ylidene ( 4 ) (Carb) with iodine a compound of composition Carb · I 2 was obtained. Crystals were isolated from dichloromethane and the X-ray structure analysis revealed the presence of both Carb-I 2 ( 6 ) and [Carb–I 3 –Carb]I ( 7 ) moieties including disordered solvent according to the composition of {[Carb–I 3 –Carb]I · 2Carb-I 2 · 2CH 2 Cl 2 } ( 5 ).

Description: The isovalent substitution of strontium for barium in CaBaCo 4 O 7 destroys the ferrimagnetism in a striking way though it keeps the same orthorhombic crystal symmetry and cobalt valence as the parent phase. The gradual weakening of ferrimagnetism in CaBa 1– x Sr x Co 4 O 7 (0 〈 x ≤ 0.10) leaves place to magnetic frustration together with antiferrimagnetism. The phase separation that appears, due to the strong competition between long range ferrimagnetic ordering and magnetic frustration, is interpreted by local melting of charge ordering. The latter originates from local structural distortion around the Ba(Sr) site. The dynamic scaling theory, τ = τ 0 ( T f / T g – 1) – zv , suggests that the frustrated magnetic phase is cluster glass in nature with strongly interacting spins. This finding reveals that the orthorhombic symmetry in CaBaCo 4 O 7 is not a sufficient condition to manifest ferrimagnetic ordering.

Description: Three iron(II)-2-aminophenolate complexes [(L 1 )Fe II (4- t Bu-HAP)] ( 2 ), [(L 1 )Fe II (HAP)] ( 3 ), and [(L 1 )Fe II (4-NO 2 -HAP)] ( 4 ) [L 1 = tris(2-pyridylthio)methanido anion, 4- t Bu-HAP = 2-amino-4- tert -butylphenolate, HAP = 2-aminophenolate, and 4-NO 2 -HAP = 2-amino-4-nitrophenolate] were isolated and characterized to study their reactivity towards dioxygen. The complexes were synthesized from the iron(II)-acetonitrile complex [(L 1 )Fe II (CH 3 CN) 2 ] + ( 1 ) using substituted 2-aminophenolates. Single crystal structure of 4 reveals that the mononuclear central iron atom is coordinated by a tetradentate N 3 C ligand and a monoanionic bidentate 4-NO 2 -HAP giving rise to a distorted octahedral coordination arrangement. The six-coordinate iron(II) complexes, 2 and 4 , react with dioxygen to form the corresponding iron(III)-2-iminobenzosemiquinonato radical complexes, [(L 1 )Fe III (4- t Bu-ISQ)] + ( 2 Ox ) and [(L 1 )Fe III (4-NO 2 -ISQ)] ( 4 Ox ). Complex 3 , on the other hand, undergoes an oxidative C–S bond forming reaction between HAP and pyridine-2-thiolate (PyS) to afford [(L 1 )Fe III (ISQ′)] + ( 3 Ox ) [ISQ′ = 5-(2-thiopyridyl)-2-iminobenzosemiquinonato radical]. In each case, the reaction proceeds via a low-spin iron(III)-2-amidophenolate intermediate species. All the complexes exhibit strong iron–carbon bonding interaction. The bond parameters of the oxidized complexes, obtained from the single crystal structures, clearly establish the presence of ligand-centered radical.

Description: Two coordination compounds of the ligand tetrazolate-5-carboxylate (tzc) with zinc(II), namely, [Zn 2 (tzc) 2 (bpp)] ( 1 ) and [Zn 2 (tzc) 2 (bpea)] ( 2 ) [bpp = 1,3-bis(4-pyridyl)propane, bpea = 1,2-bis(4-pyridyl)ethane] were synthesized by hydrothermal methods involving the in situ generation of the ligand from sodium ethyl tetrazolate-5-carboxylate. Both compounds 1 and 2 exhibit a three-dimensional structure with 3,4-connected self-penetrating net topology in which two-dimensional Zn II -tzc layers are interlinked by the bpp or bpea spacers, with the tzc ligand being in the μ 3 -N1,O1:N4,O2:N2 coordination mode. The luminescence properties of 1 and 2 were also investigated.

Description: Soft metal-organic grafting of periodic mesoporous silica (PMS) has recently been demonstrated to give gadolinium-loaded nanostructured hybrid materials with interesting 1 H relaxometric properties. Here, the sterically demanding alkoxide and aryloxide complexes, [ Ln (OCH 2 CMe 3 ) 3 ] 4 and Ln (OC 6 H 3 t Bu 2 -2,6) 3 ( Ln = La, Gd), respectively, were grafted onto PMS materials MCM-41, SBA-15, and SBA-1. Support materials with distinct topology and pore diameters were utilized in order to direct the metal precursors towards the PMSs internal or external surfaces. All hybrid materials were examined by N 2 physisorption, Diffuse Reflectance Infrared Fourier Transform (DRIFT) and solid-state NMR spectroscopy, as well as elemental analysis. The characterization data demonstrated the successful silica attachment of the alk(aryl)oxide complexes via the surface silanol groups. Careful design of the hybrid materials based on findings in our previous studies resulted in Gd III loaded materials with particularly high 1 H longitudinal relaxivities at high magnetic field strength (400 MHz). The highest relaxivity of r 1 = 31 mM –1 s –1 was found for material [Gd(OCH 2 CMe 3 ) 3 ] 4 @SBA-1 showing no intrapore metal loading. This value is amongst the highest relaxivities reported for Gd III loaded mesoporous nanomaterials so far at such high field strength. The metal loading, localization of metal centers (directed by the topology of the PMS), and the particular properties of the metal-organic precursor are factors found to influence r 1 .

Description: A need for more accurate flood inundation maps has recently arisen due to the increasing frequency and extremity of flood events. The accuracy of flood inundation maps is determined by the uncertainty propagated from all of the variables involved in the overall process of flood inundation modeling. Despite our advanced understanding of flood progression, it is impossible to eliminate the uncertainty due to the constraints involving cost, time, knowledge, and technology. Nevertheless, uncertainty analysis in flood inundation mapping can provide useful information for flood-risk management. The twin objectives of this study were firstly to estimate the propagated uncertainty rates of key variables in flood inundation mapping by using the first-order approximation (FOA) method and secondly to evaluate the relative sensitivities of the model variables by using the Hornberger–Spear–Young (HSY) method. Monte Carlo simulations using the Hydrologic Engineering Center's River Analysis System (HEC–RAS) and triangle-based interpolation were performed to investigate the uncertainty arising from discharge, topography, and Manning's n in the East Fork of the White River near Seymour, Indiana, and in Strouds Creek in Orange County, North Carolina. We found that the uncertainty of a single variable is propagated differently to the flood inundation area depending on the effects of other variables in the overall process. The uncertainty was linearly/nonlinearly propagated corresponding to valley shapes of the reaches. In addition, the HSY sensitivity analysis revealed the topography of Seymour reach and the discharge of Strouds Creek to be major contributors to the change of flood inundation area. This article is protected by copyright. All rights reserved.

Description: This paper provides evidence of the recovery of a small, moorland catchment to a severe drought, the most extreme on record in the UK. We present a detailed water quality time series for the post-drought recovery period, from the first significant storm event at the end of the drought through three very wet months during which time the catchment fully wetted up. High-frequency observations were obtained using pump water samplers, at 15-minute intervals for storm events and 2-hourly at other times. There are significant shifts in discharge-concentration response as the catchment wets up; initial behaviour is very different to later storms. Extreme drought may become more common in a warmer world, so it is increasingly important to understand water quality response during and after such episodes, if their impact on water resources and in-stream ecology is to be better anticipated. This article is protected by copyright. All rights reserved.

Description: Based on interactions between landscape characteristics and precipitation inputs, watersheds respond differently to different climatic inputs. The objective of this study was to quantitatively characterize controls on runoff generation from two first order micro-catchments in the Amazonia region. The study investigated the variation of hydrological signatures at micro-catchment scale, and relates these to landscape and land cover differences and weather descriptors that control the observed responses. One catchment is a pasture cleared of all natural vegetation in the early 1980's and the second catchment is a primary tropical forest with minor signs of disturbance. Water levels and meteorological variables were continuously monitored during the study period (December 2012-May 2013). Water level measurements were converted to discharge, evapotranspiration was quantified using Penman-Monteith equation and catchment pedohydrological properties were also determined. During the study period, mean total rainfall was 1200 mm and direct runoff ratios were 0.29 and 0.12 for the pasture and forest catchments, respectively. Base flow index was relatively higher in the forest catchment (0.76) compared to pasture catchment (0.63). Results from this study showed that the pasture catchment had a 35% higher mean stream flow. Analysis of selected individual rainstorm events also showed peak discharges were attained much faster in the pasture catchment compared to the forest catchment. At both sites, rainfall-runoff responses were highly dependent on surface and subsurface flow generation. Overland flow was observed in the pasture site during intense rainfall events. The pasture catchment exhibited higher event water contribution than the forest catchment. Findings from this research suggest that shallow lateral pathways play a significant role in controlling runoff generation processes in the forest catchment, while infiltration excess runoff generation processes dominate in the pasture catchment. The findings in this study suggest that the conversion of forest to pasture may lead to important changes in runoff generation processes and water storage in these head water catchments. This article is protected by copyright. All rights reserved.

Description: Salts of cyano borates bear potential of forming coordination polymers with solvent-filled voids as a source for porous materials. Herein we describe the synthesis and properties of novel cyano borates Na[H–B(O–C 12 H 8 –CN) 3 ], Na[B(O–C 12 H 8 –CN) 4 ] (C 12 H 8 = biphenyl) and Na[B{O–C 6 H 3 –(CN) 2 } 4 ], as well as a new modification of Na[B(O–C 6 H 4 –CN) 4 ]. Crystal structures of the sodium borates and the starting materials HO–C 6 H 3 –(CN) 2 and HO–C 12 H 8 –CN (new modification) are discussed as well. Data of nitrogen sorption experiments revealed a notable surface area in solvent-free Na[H–B(O–C 12 H 8 –CN) 3 ].

Description: The hydrothermal reaction of Zn(NO 3 ) 2 · H 2 O and a linear 2, 2′-bis-trifluoromethyl-biphenyl-4, 4′-dicarboxylic acid ( H 2 L ) ligand with –CF 3 groups at each phenyl moiety of the biphenyl rings leads to the formation of a three-fold interpenetrated metal-organic framework (MOF), {[Zn 2.66 O 0.66 ( L ) 2 ] · 2H 2 O} n ( 1 ) at 180 °C. Single-crystal X-ray diffraction studies revealed that 1 is constructed from polynuclear clusters [Zn 4 O(COO) 6 ] as secondary building units (SBU). These SBU are connected through the L 2– to generate an overall three-dimensional structure with a 6-connected primitive cuboidal (α-Po) network. Thermogravimetric analyses and variable temperature powder X-ray diffraction measurements suggested that 1 is thermally stable. The porosity of 1 was estimated by N 2 , CO 2 , H 2 , and CH 4 at different temperatures. The framework showed high selectivity of CO 2 uptake over N 2 and CH 4 . Furthermore, solid-state photoluminescence studies were carried out for complex 1 upon excitation at 275 nm at room temperature.

Description: Two Ln III complexes based on a nitronyl nitroxide radical were synthesized and characterized structurally and magnetically: [ Ln (hfac) 3 [NITPh m -Cl] 2 ][0.5CH 3 (CH 2 ) 5 CH 3 ] [ Ln = Er ( 1 ), Nd ( 2 )] [hfac = hexafluoroacetylacetonate, NITPh m -Cl = 2-(3′-chlorophenyl)-4, 4,5, 5-tetramethylimidazoline-1-oxyl-3-oxide]. X-ray crystal structure analysis revealed that the two complexes have similar mononuclear tri-spin structures, in which the metal ions are octacoordinated by two radicals and three hfac molecules to form a slightly distorted dodecahedral arrangement. Each tri-spin unit connects through intermolecular hydrogen bonds, resulting in the formation of one-dimensional wave-like chain. Both of the complexes form a one-dimensional structure by intermolecular hydrogen bonds. Variable temperature magnetic susceptibility measurements studies revealed that there are antiferromagnetic interactions between the paramagnetic ions ( Ln III and radical).

Description: The solid solution Ba 1– x Rb x Fe 2 As 2 (0 ≤ x ≤ 1) was synthesized by solid state reactions and characterized by X-ray powder and single crystal diffraction. The compounds crystallize in the ThCr 2 Si 2 -type structure (space group I 4/ mmm ) and contain layers of edge-sharing FeAs 4/4 -tetrahedra without bonds between the layers. Rubidium substitution decreases the temperature of the structural phase transition in BaFe 2 As 2 ( I 4/ mmm → Fmmm ) until the orthorhombic distortion is completely suppressed at x = 0.33. Superconductivity already emerges at x = 0.15, reaches the highest critical temperature of 37.5 K close to x = 0.4 and exists up to x = 1. The T c ( x ) phase diagram of Ba 1– x Rb x Fe 2 As 2 is remarkably similar to those of Ba 1– x K x Fe 2 As 2 and Ba 1– x Na x Fe 2 As 2 in spite of opposing volume effects. The highest critical temperature coincides with an almost ideal As–Fe–As bond angle (109.5°) in the FeAs 4 -tetrahedra. The reduced critical temperatures T c / T c, max of the so far known hole-doped 122-type superconductors exhibit a generic behavior, where the highest transition temperatures occur near 0.19 holes per iron, which is comparable to the hole-doped copper-oxides, where the maximum is near 0.16 holes per copper. Such remarkably similar values in the two classes of high- T c superconductors may not be fortuitous, and suggest parallels of both systems concerning the unresolved mechanism of unconventional superconductivity.

Description: It is a formidable challenge to arrange tin nanoparticles in a porous matrix for the achievement of high specific capacity and current rate capability anode for lithium-ion batteries. This article discusses a simple and novel synthesis of arranging tin nanoparticles with carbon in a porous configuration for application as anode in lithium-ion batteries. Direct carbonization of synthesized three-dimensional Sn-based MOF: [K 2 Sn 2 (1,4-bdc) 3 ](H 2 O) ( 1 ) (bdc = benzenedicarboxylate) resulted in stabilization of tin nanoparticles in a porous carbon matrix (abbreviated as Sn@C). Sn@C exhibited remarkably high electrochemical lithium stability (tested over 100 charge and discharge cycles) and high specific capacities over a wide range of operating currents (0.2–5 Ag –1 ). The novel synthesis strategy to obtain Sn@C from a single precursor as discussed herein provides an optimal combination of particle size and dispersion for buffering severe volume changes due to Li-Sn alloying reaction and provides fast pathways for lithium and electron transport.

Description: Single crystals of Cu 3 TaSe 4 were obtained by chemical vapor transport with iodine as transport agent. Cu 3 TaSe 4 crystallizes in the sulvanite structure type with space group P 3 m and a = 5.6613(3) Å at room temperature. Structure refinements against single-crystal X-ray diffraction data result in a Cu–Se distance slightly longer than the Ta–Se distance, whereas previous Rietveld refinements obtained a Cu–Se distance shorter than the Ta–Se distance [G. E. Delgado et al., J. Alloys Comp. 2007 , 439 , 346]. The structural variations of sulvanite type compounds Cu 3 MX 4 ( M = V, Nb, Ta; X = S, Se, Te) are discussed in view of small distortions of Cu X 4 and MX 4 tetrahedra and the atomic valences.

Description: Three metal organic coordination compounds, namely, {[Cd 2 (L1) 4 ] 2 · 9H 2 O} n ( 1 ), {[Zn(L1) 2 · 2H 2 O] 2 · H 2 O} n ( 2 ), and [Cu(L2) 2 ] n ( 3 ), [L1 = 3-chloro-2-(5 H -tetrazol-5-yl)pyridine; L2 = 3-chloropicolinic acid], were hydrothermally synthesized, in which L1 and L2 were synthesized by in situ reactions. X-ray diffraction analyses revealed that the 2D layer of complex 1 is built from a dinuclear Cd II second building blocks, whereas complex 2 shows 0D structure, which is built based on two L1 ligands, one zinc ion, and two water molecules. 3 shows a 1D infinite rod-shaped chain. Additionally, the solid-state fluorescence properties for compound 1 and 2 are also presented.

Description: Four new hybrid fluoroferrates synthesized with 1,4-diazabicyclooctane ( dabco ) are discussed. They were obtained through the use of conventional solvothermal synthesis in Teflon vessels to explore the composition space diagram of the (Fe 2+ ,Fe 3+ )- dabco -HF aq . chemical system with ethanol or dimethylformamide as solvent. These Class I hybrid fluorides exhibit isolated hydrated and/or fluorinated iron entities associated to mono or diprotonated amines according to the synthesis conditions. Their structures were determined from single crystal diffraction: ( dabco H 2 )[Fe III 2 F 8 (H 2 O) 2 ] ( I ), triclinic, space group P , Z = 2, a = 7.1657(2) Å, b = 7.6031(2) Å, c = 13.1497(3) Å, α = 73.631(1)°, β = 76.210(1)°, γ = 84.286(1)°, V = 667.1(1) Å 3 , R = 0.0299; ( dabco H 2 ) 2 [Fe III 2 F 10 ] · 2H 2 O ( II ), orthorhombic, space group Pbca , Z = 4, a = 12.9801(7) Å, b = 11.4624(6) Å, c = 13.8641(7) Å, V = 2062.7(2) Å 3 , R = 0.0425; ( dabco H) 4 [Fe III 2 F 10 ] · 10H 2 O ( III ), triclinic, space group P , Z = 1, a = 8.921(3) Å, b = 9.468(4) Å, c = 13.452(4) Å, α = 76.87(2)°, β = 74.62(2)°, γ = 74.86(2)°, V = 1042.2(6) Å 3 , R = 0.0549; ( dabco H)[(Fe II (H 2 O) 6 )(Fe III F 6 )] ( IV ), trigonal, space group P 31 c , Z = 2, a = 9.2866(2) Å, c = 10.2401(2) Å, V = 764.8(3) Å 3 , R = 0.0252. The paper focuses on structural descriptions, environment of dabco cations or iron species, and hydrogen bonding modes in the light of literature examples.

Description: Undoped and doped CeO 2 nanoparticles were synthesized through a combination of microwave-assisted nonaqueous sol-gel route and thermal treatment at 300 °C. Nanocrystals of 3 nm were obtained and characterized in detail by Rietveld refinement analysis of the X-ray diffraction data and by electron microscopy. The refinement indicated that the doping with 3d transition metals (Co, Cu, Fe, and Ni) was successfully achieved and this result was additionally confirmed by EDX measurements. Investigation of the particle morphology by electron microscopy revealed that the nanocrystals were generally not present as primary particles, but self-assembled into often intergrown flakes with uniform diameters of about 150 nm. In selected cases, the ceria nanocrystals are crystallographically oriented with respect to each other within one flake. BET measurements revealed a high surface area of 126 m 2 · g –1 .

Description: Single phase cobalt disulfide (CoS 2 ) nanoparticles were prepared by thermal decomposition of cobalt-thiourea complex at a low temperature (400 °C). CoS 2 nanoparticles exhibit ferromagnetic ordering at 122 K below which the temperature dependent resistivity of cold pressed nanoparticles deviates from metallic behavior and shows a broad maximum. Just below T C , it also exhibits a large magnetoresistance effect (6.5 %). A mixture of CoS and Co 9 S 8 phases were obtained between the temperature interval 400 °C 〈 T 〈 1000 °C. At 1000 °C, a pure bulk Co 9 S 8 phase was obtained. It exhibits magnetic hysteresis typical of a ferromagnet at room temperature and a peak in magnetization at low temperature with a strong relaxation indicating possible spin glass state.

Description: An ionic liquid assisted strategy for the synthesis of zeolitic material is reported. This strategy is a solid state synthetic method and the ionic liquid is employed as structure directing agent. A TON-type zeolite, which contains one-dimensional 10-member-ring, is successfully synthesized with the assistance of the ionic liquid, 1-ethyl-3-methylimidazolium bromide. This finding improves our understanding about the challenge of ionothermally synthesizing siliceous and aluminosilicate zeolites.

Description: Changes in the water table level result in variable water saturation and variable hydrological fluxes at the interface between the unsaturated and saturated zone. This may influence the transport and fate of contaminants in the subsurface. The objective of this study was to examine the impact of a decreasing and an increasing water table on solute transport. We conducted tracer experiments at downward flow conditions in laboratory columns filled with two different uniform porous media under static and transient flow conditions either increasing or decreasing the water table. Tracer breakthrough curves were simulated using a mobile-immobile transport model. The resulting transport parameters were compared to identify dominant transport processes. Changes in the water table level affected dispersivities and mobile water fractions depending on the direction of water table movement and the grain size of the porous media. In fine glass beads the water flow velocity was similar to the decline rate of the water table and the mobile water fraction was decreased compared to steady-state saturated conditions. However, immobile water was negligible. In coarse glass beads water flow was faster due to fingered flow in the unsaturated part and the mobile water fraction was smaller than in the fine material. Here, a rising water table led to an even smaller mobile water fraction and increased solute spreading due to diffusive interaction with immobile water. We conclude that changes of the water table need to be considered to correctly simulate transport in the subsurface at the transition of the unsaturated-saturated zone. This article is protected by copyright. All rights reserved.

Description: Stemflow is an important hydrological process of rainfall partitioning, but it has rarely been studied in the alpine riparian shrub Myricaria squamosa in the Qinghai-Tibet Plateau. This study aimed to measure and model the stemflow of the unstudied M . squamosa and to identify the key controlling factors of stemflow yield. Correlations and stepwise regression analysis between stemflow and five meteorological and ten biological factors indicated that the rainfall amount and the aboveground biomass were the best variables for modeling and predicting stemflow. We used the best model to estimate annual and stand stemflow, as well as rainfall threshold for stemflow generation. Annual stemflow accounted for 2.3 to 10.2% of the annual rainfall amount, varying with different vegetation coverage and leaf area index. The annual stemflow percentage increased linearly with the annual total rainfall amount of events 〉 7.3 mm. For M . squamosa stands, branches with diameters of 10 to 25 mm were less frequent but contributed much more stemflow than branches with diameters smaller than 10 mm. The stemflow percentage increased sharply with increasing rainfall amounts when the rainfall amounts were less than 4, 8, or 13 mm for the M . squamosa stands with coverage of 32.6%, 47.6%, or 56.1%, respectively, but increased gently when the rainfall amounts were greater than these values. The rainfall threshold for stemflow generation decreased as the branch aboveground biomass increased, and the estimated median value of the rainfall threshold was 0.8 mm for M . squamosa stands, with a range of 3.0 to 0.4 mm for branches weighing 10 to 300 g, respectively. This article is protected by copyright. All rights reserved.

Description: Warming will affect snowline elevation, potentially altering the timing and magnitude of streamflow from mountain landscapes. Presently, the assessment of potential elevation-dependent responses is difficult because many gauged watersheds integrate drainage areas that are both snow- and rain-dominated. To predict the impact of snowline rise on streamflow, we mapped the current snowline (1980 m) for the Salmon River watershed (Idaho, USA) and projected its elevation after 3 °C warming (2440 m). This increase results in a 40% reduction in snow-covered area during winter months. We bolster this analysis by collecting streamflow records from a new, elevation-stratified gauging network of watersheds contained within high (2250 – 3800 m), mid (1500 – 2250 m) and low (300 – 1500 m) elevations that isolate snow, mixed, and rain-dominated precipitation regimes. Results indicate that lags between percentiles of precipitation and streamflow are much shorter in low elevations and that their annual percentiles (Q 25 & Q 75 ) of streamflow occur 30 – 50 days earlier than in mid- and high-elevation watersheds. Extreme events in low elevations are dominated by low- and no-flow events whereas mid- and high-elevations experience large magnitude floods. Only mid- and high-elevation watersheds are strongly cross-correlated with catchment-wide flow of the Salmon River, suggesting that changes in contributions from low-elevation catchments may be poorly represented using mainstem gauges. As snowline rises, mid-elevation watersheds will likely exhibit behaviors currently observed only at lower elevations. Streamflow monitoring networks designed for operational decision making or change detection may require modification to capture elevation-dependent responses of streamflow to warming. This article is protected by copyright. All rights reserved.

Description: Primary explosives, unlike secondary explosives, show a very rapid transition from combustion (or deflagration) to detonation and are considerably sensitive to small stimuli, such as impact, friction, electrostatic discharge, and heat. Primary explosives generate either a large amount of heat or a shockwave, which makes the transfer of the detonation to a less sensitive propellant or secondary explosive possible. 1 Primary explosives are key components in detonators and primers, which are the initiating elements to many military items such as small, medium, and large caliber munitions, mortars, artillery, warheads, etc. The two most common military primary explosives are lead azide and lead styphnate. Lead based compounds such as these have well-established hazards to health and the environment. To overcome these concerns, in common U.S. Army detonators and primers lead azide was replaced with DBX-1 [copper(I) nitrotetrazolate], recently developed by Pacific Scientific Energetic Materials Company and the U.S. Naval Surface Warfare Center at Indian Head. Further, in order to minimize the dangers to personnel and equipment associated with synthesizing and handling primary explosives, a dedicated, remote-operated facility for the synthesis and testing of primary explosives has been developed.

Description: Five mixed-linkers based coordination polymers, namely { M (1, 3-Hadc)(bpy)(H 2 O) 2 } n [ M = Ni II ( 1 ), Co II ( 2 )], {Zn(1, 3-adc)(bpy) 0.5 } n ( 3 ), {Cd(1, 3-Hadc) 2 (bpy)} n ( 4 ), and {Cu(1, 3-Hadc) 2 (bpp)} n ( 5 ) [1, 3-H 2 adc = 1, 3-adamantanediacetic acid, bpy = 4, 4′-bipyridine, bpp = 1, 3-bis(4-pyridyl)propane] were synthesized by solvent diffusion reactions. Their structures were determined by single-crystal X-ray diffraction analyses. Compounds 1 and 2 are isostructural and they have 1D linear coordination polymer structure that are further interdigitated via hydrogen bonding resulting in 2D extended networks. The dehydrated 1 shows type-I profile for H 2 O vapor suggesting hydrophilic nature of the framework. In compound 3 , a paddle-wheel type secondary building unit (SBU) directs the overall structure to form a 2D square grid type structure. The 2D sheets further stack along the c axis in a AB fashion and leaves no void space. Compound 4 has a hexacoordinate Cd II and forms a zigzag coordination polymer chain-like structure and these chains form a 2D structure by hydrogen bonding interactions. Compound 5 contains a longer linker bpp compared to bpy and forms a 2D structure similar to that of 4 . These results demonstrate that by changing the metal ions coordination mode versatile structures with different dimensionalities and network topologies can be realized in a same mixed linkers system.

Description: Cs 2 Ga 2 Se 5 was obtained by the reaction of CsN 3 with stoichiometric amounts of GaSe and Se at elevated temperature. It forms yellow crystals embedded in a pure orange microcrystalline powder. The crystal structure of Cs 2 Ga 2 Se 5 was determined by single-crystal X-ray diffraction at 123 K. The compound crystallizes monoclinically in the space group C 2/ c (No. 15) with a = 15.3911(5) Å, b = 7.3577(2) Å, c = 12.9219(3) Å, β = 126.395(3)°, V = 1177.89(7) Å 3 , and Z = 4. The structure features one-dimensional chains 1 ∞ [Ga 2 Se 3 (Se 2 ) 2– ], consisting of edge- and corner sharing GaSe 4 tetrahedra. Raman spectroscopic measurements reveal vibrational bands of the Se 2 2– units at 236 cm –1 , and the bands of Ga–Se vibrations at 254 and 273 cm –1 . UV/Vis diffuse reflectance spectroscopy shows the bandgap at about 1.95 eV.

Description: Two complexes with formulas [Ni(bpndc)(bpe)] n · 4 n H 2 O ( 1 ) and [Co(bpndc) (bpy) 1.5 ] n · 0.25 n (bpy) · 0.25 n H 2 O ( 2 ) (H 2 bpndc = benzophenone-4,4′-dicarboxylic acid, bpe = 4,4′-bipyridinediethene, bpy = 4,4′-bipyridine) were synthesized and characterized. In complex 1 , each bpndc ligands adopt bis(monodentate) modes, and Ni II ions are bridged by bpndc and bpe ligands into a 3D CdSO 4 -like porous metal-organic framework with channels. But triple interpenetration occurs. In complex 2 , each bpndc ligands adopt tridentate modes, and Co II ions are linked by bpndc and bpy ligands into 2D bilayer structures with the Schläfli symbol of (4 8 .6 2 ). Each bilayer is bicatenated in a parallel fashion by two other bilayers, which results in the formation of a 2D→3D polycatenation network.

Description: The reaction of selenium and NbCl 5 with arsenic in the Lewis-acidic ionic liquid BMImCl · 4.8AlCl 3 at 100 °C yielded dark-red block-shaped crystals of Nb 2 Se 4 (AlCl 4 ) 4 , which immediately decompose when exposed to humid air. Arsenic takes the part of the reducing agent for niobium as well as selenium. The crystal structure was described in the monoclinic space group P 2 1 / n (no. 14) with a = 898.0(1) pm, b = 991.3(1) pm, c = 1629.1(2) pm, and β = 92.43(1)° at 296(1) K. The unit cell contains two C 2h symmetric Nb 2 (Se 2 ) 2 (AlCl 4 ) 4 molecules. The latter consist of a central rectangular bipyramid [Nb 2 (Se 2 ) 2 ] 4+ and four η 2 -coordinating AlCl 4 – tetrahedra. Diamagentism of the compound and DFT-based real-space bonding analysis imply a chemical bond between the niobium(IV) cations, which are 292.2(2) pm apart. Nb 2 Se 4 (AlCl 4 ) 4 can be interpreted as the AlCl 3 adduct of NbSe 2 Cl 2 .