ALBERT

Description: In the title compound, [CdBr2(C8H8N2)2], the CdII atom has a distorted tetrahedral coordination formed by the two imino N atoms of two 2-methylbenzimidazole ligands and two terminal bromide ligands. The CdII atom is slightly out of the benzimidazole planes by 0.320 (3) and 0.210 (3) Å. The dihedral angle between the benzimidazole planes is 71.6 (2)°. In the crystal, molecules are linked by N—H...Br hydrogen bonds into puckered layers parallel to (001).

Description: In the title hydrated molecular salt, C22H25N2+·C6H4FO3S−·H2O, the cation displays whole molecule disorder over two sets of sites in a 0.780 (5):0.220 (5) ratio. The quinolinium ring system is essentially planar, with r.m.s. deviations of 0.0162 and 0.0381 Å for the major and minor disorder components, respectively. The dihedral angles between the mean plane of the quinolinium ring system and the benzene ring are 5.1 (3) and 7.7 (11)°, respectively, for the major and minor components in the cation. In the crystal, cations, anions and water molecules are linked into chains along [010] by O—H...O hydrogen bonds and are further connected into a three-dimensional network by weak C—H...O and C—H...F interactions. In addition, π–π interactions with centroid–centroid distances of 3.634 (3), 3.702 (5) and 3.838 (5) Å are observed.

Description: In the title compound, C20H19NOS, the pyrrolizine ring is essentially planar (r.m.s. deviation = 0.001 Å) while the fused dihydro-pyrrolizine ring adopts an envelope comformation with the C atom bearing the methyl substituents as the flap. The dihedral angles between the pyrrolizine and the phenyl and thiophene rings are 34.54 (7) and 44.93 (7)°, respectively. In the crystal, weak C—H...O hydrogen bonds link the molecules into infinite zigzag chains parallel to the b-axis direction.

Description: In the title compound, C27H22N2O4, the two indole ring systems are approximately perpendicular to each other, with a dihedral angle of 84.5 (5)° between their planes; the benzene ring is twisted with respect to the two indole ring systems at angles of 78.5 (5) and 86.5 (3)°. In the crystal, molecules are linked by N—H...O hydrogen bonds, weak C—H...O and C—H...N hydrogen bonds, and C—H...π interactions into a three-dimensional supramolecular architecture.

Description: The title compound, C9H3F5O2, crystallizes as O—H...O hydrogen-bonded carboxylic acid dimers that, together with C—H...F interactions and O...F [2.8065 (13) and 2.9628 (13) Å] and F...F [2.6665 (11), 2.7049 (12) and 2.7314 (12) Å] contacts, form a sheet-like structure. The sheets are stacked via short π–π interactions [centroid–centroid distance = 4.3198 (11) Å]. An intramolecular C—H...F interaction is also observed.

Description: The asymmetric unit of the title compound, C12H12ClNOS, contains three independent molecules, with the thiochroman ring adopting a sofa conformation in each one. The crystal structure features C—H...O interactions; one of the O atoms accepts three such bonds. Together, the hydrogen bonds give rise to a molecular tape propagating in [010].

Description: In the title molecule, C30H35NO8, the acenaphthylenone moiety, two atoms of a methyl pyrrolidine ring (N and C atoms) and four atoms of an ethyl acetate moiety (two C and two O atoms) are disordered over two sets of sites in ratio 0.532 (7):0.468 (7). The three C atoms of a dimethoxyethane ring and dioxolane ring attached with two methyl groups are disordered over two sets of sites in 0.66 (2):0.34 (2) and 0.62 (2):0.38 (2) ratios, respectively. The major and minor components of the acenaphthylene ring are essentially planar (r.m.s. deviations = 0.0254 and 0.0436 Å, respectively). The major and minor components of the pyrrolidine ring adopt C-envelope conformations with C atoms displaced by 0.492 (11) and 0.595 (7) Å from the remaining ring atoms. One of the dioxolane rings is disordered with its major component in an envelope conformation [C displaced by 0.511 (11) Å] and the minor fraction is more or less planar with an r.m.s. deviation of 0.070 Å. The other dioxolane ring is in an envelope conformation, with a C atom displaced by 0.438 (3) Å from the remainder of the ring atoms. The crystal packing features C—H...O interactions, which generate C(9) chains.

Description: By using the monthly ERA-40 reanalysis data and observed rainfall data, we investigated the effect of the Indian summer monsoon (ISM) on the South Asian High (SAH) at 200 hPa, and the role played by the SAH in summer rainfall variation over China. It is found that in the interannual timescale the east–west shift is a prominent feature of the SAH, with its center either over the Iranian Plateau or over the Tibetan Plateau. When the ISM is stronger (weaker) than normal, the SAH shifts westward (eastward) to the Iranian Plateau (Tibetan Plateau). The east–west position of SAH has close relation to the summer rainfall over China. A westward (eastward) location of SAH corresponds to less (more) rainfall in the Yangtze-Huai River Valley and more (less) rainfall in North China and South China. A possible physical process that the ISM affects the summer rainfall over China via the SAH is proposed. A stronger (weaker) ISM associated with more (less) rainfall over India corresponds to more (less) condensation heat release and anomalous heating (cooling) in the upper troposphere over the northern Indian peninsula. The anomalous heating (cooling) stimulates positive (negative) height anomalies to its northwest and negative (positive) height anomalies to its northeast in the upper troposphere, causing a westward (eastward) shift of the SAH with its center over the Iranian Plateau (Tibetan Plateau). As a result, an anomalous cyclone (anticyclone) is formed over the eastern Tibetan Plateau and eastern China in the upper troposphere. The anomalous vertical motions in association with the circulation anomalies are responsible for the rainfall anomalies over China. Our present study reveals that the SAH may play an important role in the effect of ISM on the East Asian summer monsoon.

Description: National Centers for Environmental Prediction recently upgraded its operational seasonal forecast system to the fully coupled climate modeling system referred to as CFSv2. CFSv2 has been used to make seasonal climate forecast retrospectively between 1982 and 2009 before it became operational. In this study, we evaluate the model’s ability to predict the summer temperature and precipitation over China using the 120 9-month reforecast runs initialized between January 1 and May 26 during each year of the reforecast period. These 120 reforecast runs are evaluated as an ensemble forecast using both deterministic and probabilistic metrics. The overall forecast skill for summer temperature is high while that for summer precipitation is much lower. The ensemble mean reforecasts have reduced spatial variability of the climatology. For temperature, the reforecast bias is lead time-dependent, i.e., reforecast JJA temperature become warmer when lead time is shorter. The lead time dependent bias suggests that the initial condition of temperature is somehow biased towards a warmer condition. CFSv2 is able to predict the summer temperature anomaly in China, although there is an obvious upward trend in both the observation and the reforecast. Forecasts of summer precipitation with dynamical models like CFSv2 at the seasonal time scale and a catchment scale still remain challenge, so it is necessary to improve the model physics and parameterizations for better prediction of Asian monsoon rainfall. The probabilistic skills of temperature and precipitation are quite limited. Only the spatially averaged quantities such as averaged summer temperature over the Northeast China of CFSv2 show higher forecast skill, of which is able to discriminate between event and non-event for three categorical forecasts. The potential forecast skill shows that the above and below normal events can be better forecasted than normal events. Although the shorter the forecast lead time is, the higher deterministic prediction skill appears, the probabilistic prediction skill does not increase with decreased lead time. The ensemble size does not play a significant role in affecting the overall probabilistic forecast skill although adding more members improves the probabilistic forecast skill slightly.

Description: The south peninsular part of India gets maximum amount of rainfall during the northeast monsoon (NEM) season [October to November (OND)] which is the primary source of water for the agricultural activities in this region. A nonlinear method viz., Extreme learning machine (ELM) has been employed on general circulation model (GCM) products to make the multi-model ensemble (MME) based estimation of NEM rainfall (NEMR). The ELM is basically is an improved learning algorithm for the single feed-forward neural network (SLFN) architecture. The 27 year (1982–2008) lead-1 (using initial conditions of September for forecasting the mean rainfall of OND) hindcast runs (1982–2008) from seven GCM has been used to make MME. The improvement of the proposed method with respect to other regular MME (simple arithmetic mean of GCMs (EM) and singular value decomposition based multiple linear regressions based MME) has been assessed through several skill metrics like Spread distribution, multiplicative bias, prediction errors, the yield of prediction, Pearson’s and Kendal’s correlation coefficient and Wilmort’s index of agreement. The efficiency of ELM estimated rainfall is established by all the stated skill scores. The performance of ELM in extreme NEMR years, out of which 4 years are characterized by deficit rainfall and 5 years are identified as excess, is also examined. It is found that the ELM could expeditiously capture these extremes reasonably well as compared to the other MME approaches.

Description: The title compound, [Cu2(C9H10NO2)4], is built of discrete centrosymmetric dimers. The CuII atoms are each five coordinated by two deprotonated Schiff base ligands that are bonded differently to the metal atoms. Of the two phenolate O atoms, one is coordinated to one CuII atom, whereas another bridges the two metal atoms. The basal plane of the square pyramid around CuII atoms is formed by the imino N and phenolate O atoms of the bidentate and the monodentate/bidentate Schiff base ligands. The bridging phenolate oxygen occupies the apical position of the coordination sphere with a considerably longer Cu—O bond length. In the crystal, the dimeric molecules pack relative to each other in such a way that the Cu2O2 planes of adjacent dimers are orthogonal.

Description: In the title complex, [HgI2(C21H19N5)2], the HgII ion is located on a twofold rotation axis and is coordinated by two I atoms and two N atoms from two (E)-2-(3-(4-(1H-1,2,4-triazol-1-yl)styryl)-5,5-dimethylcyclohex-2-enylidene)malononitrile ligands in a distorted tetrahedral geometry. In the crystal, the molecules are linked by intermolecular π–π interactions between the triazole and benzene rings [centroid–centroid distance = 3.794 (3) Å] into a band extending in [010]. These bands are further connected by C—H...N hydrogen bonds into a two-dimensional network parallel to (100).

Description: In the title compound, C30H29BrN2O5, the β-lactam ring is essentially planar, with the O atom displaced from this plane by 0.856 (9) Å, and forming dihedral angles of 24.35 (13) and 89.42 (14)° with the planes of the benzene substituent groups on this ring. The tetrahydropyran ring adopts an envelope conformation with the C atom bearing the β-lactam ring as the flap. In the crystal, weak C—H...O hydrogen bonds with carboxyl and tetrahydropyran O-atom acceptors give rise to a chain structure extending along the b-axis direction.

Description: In the title salt [systematic name: 3-imidazol-1-yl-propyl-ammonium 2,4,6-trinitrophenolate], C6H12N3+. C6H2N3O7−, there are five independent cation–anion pairs (A, B, C, D, E) in the asymmetric unit. In the cation, the ammonium group is protonated with the aminopropyl group nearly at right angles to the mean plane of the imidazole ring showing C—N—C—C torsion angles ranging from 79.6 (2) to 99.79 (19)° in the five cations. The nitro groups in the anion are twisted from the benzene mean plane with maximum dihedral angles subtended by nitro substituents ortho to the phenolate O atom of 26.0 (2) and 37.3 (7) (A), 28.9 (5) and 35.3 (1) (B), 34.7 (7) and 36.9 (7) (C), 14.7 (4) and 36.9 (2) (D) and 33.1 (1) and 35.4 (3)° (E). In contrast, the nitro groups in the para positions lie much closer to the aromatic ring plane, subtending dihedral angles of 1.8 (3) (A), 3.5 (3) (B), 6.03 (C), 2.1 (3) (D) and 7.7 (1)° (E). Disorder is observed for one O atom of an ortho nitro group in anion D with an occupancy ratio of 0.53 (5):0.47 (5). In the crystal, N—H...O cation–anion and N—H...N cation–cation hydrogen bonds are observed, linking the ions into chains along [010]. In addition, weak C—H...O cation–anion interactions occur.

Description: In the title compound, [Ru(C10H10N6)(C7H10N2)3](PF6)2·C4H10O, the RuII cation is coordinated by one tris(1-pyrazolyl)methane (Tpm) and three dimethylaminopyridine (dmap) ligands in a slightly distorted octahedral geometry. The asymmetric unit consists of one complex cation, two hexafluoridophosphate anions and one diethyl ether solvent molecule in general positions. Although quite a large number of ruthenium complexes of the facially coordinating tridentate Tpm ligand have been structurally characterized, this is only the second one containing three pyridyl co-ligands. The average Ru—N(Tpm) distance is 2.059 (12) Å, while the average Ru—N(dmap) [dmap = 4-(dimethylamino)pyridine] distance is somewhat longer at 2.108 (13) Å. The orientation of the dmap ligands varies greatly, with dihedral angles between the pyridyl and opposite pyrazolyl rings of 14.3 (2), 23.2 (2) and 61.2 (2)°.

Description: The crystal structure of tamarugite [sodium aluminium bis(sulfate) hexahydrate] was redetermined from a single crystal from Mina Alcaparossa, near Cerritos Bayos, southwest of Calama, Chile. In contrast to the previous work [Robinson & Fang (1969). Am. Mineral. 54, 19–30], all non-H atoms were refined with anisotropic displacement parameters and H-atoms were located by difference Fourier methods and refined from X-ray diffraction data. The structure is built up from nearly regular [Al(H2O)6]3+ octahedra and infinite double-stranded chains [Na(SO4)2]3− that extend parallel to [001]. The Na+ cation has a strongly distorted octahedral coordination by sulfate O atoms [Na—O = 2.2709 (11) – 2.5117 (12) Å], of which five are furnished by the chain-building sulfate group S2O4 and one by the non-bridging sulfate group S1O4. The [Na(SO4)2]3− chain features an unusual centrosymmetric group formed by two NaO6 octahedra and two S2O4 tetrahedra sharing five adjacent edges, one between two NaO6 octahedra and two each between the resulting double octahedron and two S2O4 tetrahedra. These groups are then linked into a double-stranded chain via corner-sharing between NaO6 octahedra and S2O4 tetrahedra. The S1O4 group, attached to Na in the terminal position, completes the chains. The [Al(H2O)6]3+ octahedron (〈Al—O〉 = 1.885 (11) Å) donates 12 comparatively strong hydrogen bonds (O...O = 2.6665 (14) – 2.7971 (15) Å) to the sulfate O atoms of three neighbouring [Na(SO4)2]3− chains, helping to connect them in three dimensions, but with a prevalence parallel to (010), the cleavage plane of the mineral. Compared with the previous work on tamarugite, the bond precision of Al—O bond lengths as an example improved from 0.024 to 0.001 Å.

Description: The title compound, tetrasodium lithium cobalt aluminium hexa(orthoarsenate), was synthesized by a solid state reaction route. In the crystal structure, Co2+ ions are partially substituted by Al3+ in an octahedral environment [M1 with site symmetry 2/m; occupancy ratio Co:Al = 0.286 (10):0.714 (10)]. The charge compensation is ensured by Li+ cations sharing a tetrahedral site with Co2+ ions [M2 with site symmetry 2; occupancy ratio Co:Li = 0.690 (5):0.310 (5)]. The anionic unit is formed by two octahedra and three tetrahedra linked only by corners. The CoM1M2As2O19 units associate to an open three-dimensional framework containing tunnels propagating along the a-axis direction. One Na+ cation is located in the periphery of the tunnels while the other two are situated in the centres: all Na+ cations exhibit half-occupancy. The structure of the studied material is compared with those of various related minerals reported in the literature.

Description: The asymmetric unit of the title compound, [Ir(C9H7)(C2H4)2], consists of two independent molecules. The bonding between iridium and the five-membered ring of the indenyl ligand shows the usual asymmetry associated with the typical ring slippage responsible for the enhanced activity of indenyl metal compounds when compared with the analogous cyclopentadienyl metal compound. There are three short Ir—C bonds of 2.210 (3), 2.190 (4) and 2.220 (3) Å and two long Ir—C bonds to the C atoms that are part of the fused six-membered ring of 2.349 (4) and 2.366 (3) Å for one of the independent molecules [2.208 (4), 2.222 (3), 2.197 (4) Å for the short distances and 2.371 (3) and 2.358 (3) Å for the long distances in the second molecule]. This results in both indenyl ligands being slightly kinked, with dihedral angles of 6.8 (4)° and 6.5 (4)°.

Description: The molecule of the title compound, [Ti2(C48H72O6)] or {[Ti(Me)(μ-OCH3)(OC6H3CMe3-2-Me-6)]2}, has a centrosymmetric, dimeric structure with a distorted square pyramidal array about each titanium atom. The methoxide ligands form an asymmetric bridge between the two TiIV atoms [Ti—O bond lengths of 1.9794 (12) and 2.0603 (12) Å] with the two phenolato ligands occupying the remaining basal sites [Ti—O 1.8218 (11) and 1.8135 (11) Å]. The Ti—O—C phenolato bond angles are similar at 161.24 (10) and 160.66 (11) °. The methyl ligand attached to the metal atom has a Ti—C bond length of 2.0878 (17) Å.

Description: The sea surface temperature anomaly pattern differs between the central Pacific (CP) and eastern Pacific (EP) El Niños during boreal summer. It is expected that the respective atmospheric response will be different. In order to identify differences in the responses to these two phenomena, we examine the Community Atmosphere Model Version 4 simulations forced with observed monthly sea surface temperature during 1979–2010 and compare with the corresponding observations. For CP El Niño, a triple precipitation anomaly pattern appears over East Asia. During EP El Niño, the triple pattern is not as significant as and shifts eastward and southward compared to CP El Niño. We also examine the influence of CP La Niña and EP La Niña on East Asia. In general, the impact of CP (EP) La Niña on tropics and East Asia seems to be opposite to that of CP (EP) El Niño. However, the impacts between the two types of La Niña are less independent compared to the two types of warm events. Both types of El Niño (La Niña) correspond to a stronger (weaker) western North Pacific summer monsoon. The sensitivity experiments support this result. But the CP El Niño (La Niña) may have more significant influence on East Asia summer climate than EP El Niño (La Niña), as the associated low-level anomalous wind pattern is more distinct and closer to the Asian continent compared to EP El Niño (La Niña).

Description: Since the Mediterranean Sea is halfway between subtropical and middle latitudes, and it represents a marginal oceanic region, research has tended to focus on how large-scale modes of atmospheric variability modulate its surface temperature. Conversely, the present study examines the potential influence of the Mediterranean Sea surface temperature (SST) anomalies on the Northern Hemisphere atmospheric circulation. In particular, this work explores the large-scale changes in the global circulation forced/influenced by the eastern Mediterranean summer-autumn SST pattern. To isolate the atmospheric response, AGCM sensitivity experiments with prescribed SST over the Mediterranean Sea and climatology elsewhere are analysed. Observational diagnostics upon the period used to define the boundary conditions (1979–2002) are also interpreted. Our results support the hypothesis of an atmospheric pattern initiated in the Mediterranean basin, pointing out both a local baroclinic response and a barotropic circumglobal anomaly. This atmospheric teleconnection pattern projects onto a hemispheric wave-like structure, reflecting the waveguide effect of the westerly jets. Results suggest, thereby, that the recurrent summer-autumn circumglobal teleconnection pattern can be excited locally by changes in the atmosphere over the Mediterranean region. A linear behaviour is found upon a regional impact over northeastern Africa. The remote impacts present however a nonlinear signature: anomalous warm conditions influencing on northern Europe and Euro–Asia, whereas anomalous cold conditions impacting more on the North Pacific basin. Limitations in our model setup are also discussed.

Description: In the title complex, [Na(C7H7O4S)]n, the NaI ion is coordinated in a slightly distorted pentagonal-bipyramidal environment by seven O atoms [Na—O = 2.3198 (16)–2.5585 (17) Å]. The 4-methoxybenzenesulfonate anions act as bis-chelating and bridging ligands, forming a two-dimensional polymer parallel to (001), which is further linked into a three-dimensional network by weak C—H...O hydrogen bonds.

Description: In the title compound, C20H22N5O+·Br−·C2H6O, the tetrahydropyrimidine ring of the bicyclic cation adopts a half-chair conformation with an equatorial orientation of the phenyl and methyl substituents. The amino group is nearly coplanar with the 1,2,4-triazole ring [interplanar angle = 4.08 (8)°] and has a slightly pyramidal configuration. The mean planes of the triazole ring and the benzene ring of the phenacyl group form a dihedral angle of 88.58 (7)°. In the crystal, N—H...Br, N—H...O and O—H...Br hydrogen bonds link the cations, anions and ethanol molecules into layers parallel to the bc plane.

Description: The structure of tetrasodium pentadecamolybdenum nonadecaselenide, Na3.88Mo15Se19, is isotypic with the In3+xMo15Se19 compounds [Grüttner et al. (1979). Acta Cryst. B35, 285–292]. It is characterized by two cluster units, Mo6Sei8Sea6 and Mo9Sei11Sea6 (where i represents inner and a apical atoms), that are present in a 1:1 ratio. The cluster units are centered at Wyckoff positions 2b and 2c and have point-group symmetry -3 and -6, respectively. The clusters are interconnected through additional Mo—Se bonds. In the title compound, the Na+ cations replace the trivalent as well as the monovalent indium atoms present in In3.9Mo15Se19. One Mo, one Se and one Na atom are situated on mirror planes, and two other Se atoms and one Na atom [occupancy 0.628 (14)] are situated on threefold rotation axes. The crystal studied was twinned by merohedry with refined components of 0.4216 (12) and 0.5784 (12).

Description: In the title compound, C17H16Br2N2O2, the dihedral angle between the benzene rings is 57.7 (3)°. The conformation of the central N—C—C—C—N chain is gauche-anti [torsion angles = −64.2 (4) and −167.8 (4)°]. Two intramolecular O—H...N hydrogen bonds occur. In the crystal, molecules are linked by pairs of C—H...O hydrogen bonds, forming inversion dimers.

Description: In the title complex, [Ni(C17H16N2O5)]·2H2O, the NiII ion is four-coordinated by two azomethine N and two phenolato O atoms of the tetradentate Schiff base ligand in a slightly distorted square-planar geometry. In the six-membered ring containing the metal, the azomethine N atoms and the three C atoms of the connecting 1,3-diaminopropane-2-ol, all atoms except the metal are disordered over two sets of sites with an occupacy ratio of 0.566 (3):0.434 (3). The central C atom of the major component is significantly out of the mean plane of the remaing atoms while the conformation of this ring in the minor component is noticeably different. In the crystal, O—H...O hydrogen bonds involving the lattice water molecules and the hydroxy groups are observed.

Description: In the title compound, C26H20N4O2S, the central pyrrolidine ring adopts a twist conformation on the C—C bond involving the spiro C atom. Its mean plane makes dihedral angles of 78.83 (14), 65.91 (15) and 44.49 (18)° with the mean planes of the adjacent oxindole ring system, the indole system and the thiophene ring, respectively. The indole and indoline units are essentially planar, with maximum deviations of 0.019 (3) and 0.090 (3) Å, respectively. In the oxindole fused-ring system, the pyrrole ring adopts an envelope conformation with the spiro C atom as the flap. In the crystal, pairs of N—H...O hydrogen bonds link the molecules, forming inversion dimers with an R22(8) ring motif. The dimers are linked by further N—H...O hydrogen bonds, forming a two-dimensional network lying parallel to (100).

Description: Atlantic Multidecadal Variability (AMV) is investigated in a millennial control simulation with the Kiel Climate Model (KCM), a coupled atmosphere–ocean–sea ice model. An oscillatory mode with approximately 60 years period and characteristics similar to observations is identified with the aid of three-dimensional temperature and salinity joint empirical orthogonal function analysis. The mode explains 30 % of variability on centennial and shorter timescales in the upper 2,000 m of the North Atlantic. It is associated with changes in the Atlantic Meridional Overturning Circulation (AMOC) of ±1–2 Sv and Atlantic Sea Surface Temperature (SST) of ±0.2 °C. AMV in KCM results from an out-of-phase interaction between horizontal and vertical ocean circulation, coupled through Irminger Sea convection. Wintertime convection in this region is mainly controlled by salinity anomalies transported by the Subpolar Gyre (SPG). Increased (decreased) dense water formation in this region leads to a stronger (weaker) AMOC after 15 years, and this in turn leads to a weaker (stronger) SPG after another 15 years. The key role of salinity variations in the subpolar North Atlantic for AMV is confirmed in a 1,000 year long simulation with salinity restored to model climatology: No low frequency variations in convection are simulated, and the 60 year mode of variability is absent.

Description: Based on a generated time series for the central pressure of the Siberian High, and on defining a robust Siberian High Index (SHI), the behavior of this atmospheric center of action is examined from 1949 to 2010 with regard to inter-annual variations, persistence, trends, abrupt changes, spectral analysis and interactions. The interannual variability in the central pressure of the Siberian High is considerable. The mean downward linear and non-linear trend over the entire period (1949–2010) is estimated and is found to be statistically significant at the 95 % confidence level. Low frequency variation and linearity within the SHI time series are found from the persistence analysis. Using spectral analysis, the center of action of the Siberian High is characterized by non-periodic behavior; the peaks occur only at the lowest frequency and may be related to the Sea Surface Temperature (SST) over the El Niño region. The Siberian High is affected by the Hadley circulation cell; there is no detectable connection between the Walker circulation cell and the Siberian High. SSTs over the El Niño region may affect the Siberian High. Interactions between the Siberian High and the SSTs over the tropical Atlantic Ocean are absent. The SHI is positively correlated to surface air temperatures over Saudi Arabia, and this is statistically significant in the western and north-western regions.

Description: This study investigates the spatial and temporal characteristics of cold surges that propagates northward along the eastern flank of the Andes from subtropical to tropical South America analysing wintertime in situ daily minimum temperature observations from Argentina, Bolivia and Peru and ERA-40 reanalysis over the 1975–2001 period. Cold surges usually last 2 or 3 days but are generally less persistent in the southern La Plata basin compared to tropical regions. On average, three to four cold surges are reported each year. Our analysis reveals that 52 % of cold episodes registered in the south of La Plata basin propagate northward to the northern Peruvian Amazon at a speed of around 20 m s −1 . In comparison to cold surges that do not reach the tropical region, we demonstrate that these cold surges are characterized, before they reach the tropical region, by a higher occurrence of a specific circulation pattern associated to southern low-level winds progression toward low latitudes combined with subsidence and dry condition in the middle and low troposphere that reinforce the cold episode through a radiative effect. Finally, the relationship between cold surges and atmosphere dynamics is illustrated for the two most severe cold intrusions that reached the Peruvian and Bolivian Amazon in the last 20 years.

Description: The Greenland ice sheet is projected to be strongly affected by global warming. These projections are either issued from downscaling methods (such as Regional Climate Models) or they come directly from General Circulation Models (GCMs). In this context, it is necessary to evaluate the accuracy of the daily atmospheric circulation simulated by the GCMs, since it is used as forcing for downscaling methods. Thus, we use an automatic circulation type classification based on two indices (Euclidean distance and Spearman rank correlation using the daily 500 hPa geopotential height) to evaluate the ability of the GCMs from both CMIP3 and CMIP5 databases to simulate the main circulation types over Greenland during summer. For each circulation type, the GCMs are compared to three reanalysis datasets on the basis of their frequency and persistence differences. For the current climate (1961–1990), we show that most of the GCMs do not reproduce the expected frequency and the persistence of the circulation types and that they simulate poorly the observed daily variability of the general circulation. Only a few GCMs can be used as reliable forcings for downscaling methods over Greenland. Finally, when applying the same approach to the future projections of the GCMs, no significant change in the atmospheric circulation over Greenland is detected, besides a generalised increase of the geopotential height due to a uniform warming of the atmosphere.

Description: The East Asian summer monsoon (EASM) features strong humid low-level southerly flows and abundant rainfall over the subtropical East Asia. This study identified how condensational heating generated by the EASM rainfall can affect the EASM circulation by contrasting two 10-member ensembles of atmospheric General Circulation Model experiments with Community Climate Model version 3/National Center for Atmospheric Research respectively with and without feedback of condensational heating over the East Asian domain. Major results inferred from the experiments are as follows. Condensational heating is found to absolutely dominate diabatic heating over East Asia. Exclusion of the feedback of condensational heating leads to a significant weakening of summertime tropospheric warming over land and thus a large reduction of the land-sea thermal contrast between entire Asian continent and surrounding oceans. Associated with this, the lower-level EASM flows are weakened, South Asian High at 200 hPa migrates southward with reduced intensity and breaks over East Asia with southerly flows prevailing in the upper troposphere, in contrast to northerly flows in reality. Consequently, local EASM meridional cell disappears and the baroclinic structure featured by the EASM circulation that is dynamically determined by convective condensational heating over East Asia is altered to a barotropic structure. Therefore, it is concluded that the feedback of condensational heating acts to largely enhance lower-level flows of the EASM and essentially determine its baroclinic structure and meridional cell, once the solar radiation and inhomogeneity of the Earth’s surface form low-level monsoon flows in East Asia by enhancing land-sea thermal contrast.

Description: Based on experiments using a coupled general circulation model which resolves tropical ocean–atmosphere coupled phenomena such as El Niño/Southern Oscillation (ENSO) and the Indian Ocean Dipole, forcing mechanisms of the Indian Ocean subtropical dipole (IOSD) are investigated. In the control experiment, as in the observation, several types of the IOSD are generated by the variations in the Mascarene High during austral summer and characterized by a dipole pattern of sea surface temperature (SST) anomalies in the northeastern and southwestern parts of the southern Indian Ocean. In another experiment, where the SST outside the southern Indian Ocean is nudged toward the monthly climatology of the simulated SST, one type of the IOSD occurs, but it is less frequent and associated with the zonal wavenumber four pattern of equivalently barotropic geopotential height anomalies in high latitudes, suggesting an interesting link with the Antarctic Circumpolar Wave. This indicates that, even without the atmospheric teleconnection from tropical coupled climate modes, the IOSD may develop in association with the atmospheric variability in high latitudes of the Southern Hemisphere. In the other experiment, where only the southern Indian Ocean and the tropical Pacific are freely interactive with the atmosphere, two types of both positive and negative IOSD occur. Since the occurrence frequency of the IOSD significantly increases as compared to the second experiment, this result confirms that the atmospheric teleconnection from ocean-atmosphere coupled modes in the tropical Pacific such as ENSO may also induce the variations in the Mascarene High that generate the IOSD. The present research, even within the realm of model studies, shows clearly that the predictability of the IOSD in mid-latitudes is related to both low and high-latitudes climate variations.

Description: The title compound, C22H26N2O2, crystallizes with three independent molecules, two of which are situated on inversion centers, so the asymmetric unit contains two independent half-molecules and one molecule in a general position. The two hydroxy groups in each molecule are involved in intramolecular O—H...N hydrogen bonds, which generate S(6) rings. In the crystal, weak intermolecular C—H...π interactions link the molecules into two crystallographically independent columns propagating along [001]; one column consists of molecules in general positions, while the other column is built from alternating independent centrosymmetric molecules.

Description: The title N-benzylphthalimide derivative, C16H13NO3, consists of two planar moieties, viz. the phthalimide system (r.m.s. deviation = 0.007 Å) and the phenyl ring, which make a dihedral angle of 84.7 (6)°. The methoxy group is almost coplanar with the phathalimide ring, as shown by the C—C—O—C torsion angle of −171.5 (2)°. In the crystal, the molecules are self-assembled via non-classical C—H...O hydrogen bonds, forming a tape motif along [110].

Description: In the title compound, C17H17N3O3.0.5H2O, the indazole system makes a dihedral angle of 46.19 (8)° with the plane through the benzene ring and is nearly perpendicular to the allyl group, as indicated by the dihedral angle of 81.2 (3)°. In the crystal, the water molecule, disordered over two sites related by an inversion center, forms O—H...N bridges between indazole N atoms of two sulfonamide molecules. It is also connected via N—H...O interaction to the third sulfonamide molecule; however, due to the water molecule disorder, only every second molecule of sulfonamide participates in this interaction. This missing interaction results in a slight disorder of the sulfonamide S,O and N atoms which are split over two sites with half occupancy. With the help of C–H...O hydrogen bonds, the molecules are further connected into a three-dimensional network.

Description: In the title m-terphenyl derivative, C22H17NO4, the dihedral angles between the aromatic rings of the benzoic acid–acetophenone, acetophenone–benzamide and benzoic acid–benzamide units are 45.39 (8), 48.02 (8) and 42.93 (8)°, respectively. The carbamoyl and carboxyl groups are disordered with a refined occupancy ratio of 0.558 (15):0.442 (15). In the crystal, molecules are linked through O—H...O and N—H...O hydrogen bonds between terminal carboxyl and carbamoyl groups in a bidentate manner, and antiparallel helices are formed which extend along the b-axis direction.

Description: In the title furancarboxamide derivative, C11H8N2O4, the benzene and furan rings are rotated from the mean plane of the central fragment by 2.68 (5) and 7.03 (4)°, respectively. The nitro group forms a dihedral angle of 10.15 (5)° with the adjacent benzene ring. In the crystal, molecules are linked by weak C—H...O interactions, forming helical chains running along [010].

Description: Previous studies have linked the rapid sea level rise (SLR) in the western tropical Pacific (WTP) since the early 1990s to the Pacific decadal climate modes, notably the Pacific Decadal Oscillation in the north Pacific or Interdecadal Pacific Oscillation (IPO) considering its basin wide signature. Here, the authors investigate the changing patterns of decadal (10–20 years) and multidecadal (〉20 years) sea level variability (global mean SLR removed) in the Pacific associated with the IPO, by analyzing satellite and in situ observations, together with reconstructed and reanalysis products, and performing ocean and atmosphere model experiments. Robust intensification is detected for both decadal and multidecadal sea level variability in the WTP since the early 1990s. The IPO intensity, however, did not increase and thus cannot explain the faster SLR. The observed, accelerated WTP SLR results from the combined effects of Indian Ocean and WTP warming and central-eastern tropical Pacific cooling associated with the IPO cold transition. The warm Indian Ocean acts in concert with the warm WTP and cold central-eastern tropical Pacific to drive intensified easterlies and negative Ekman pumping velocity in western-central tropical Pacific, thereby enhancing the western tropical Pacific SLR. On decadal timescales, the intensified sea level variability since the late 1980s or early 1990s results from the “out of phase” relationship of sea surface temperature anomalies between the Indian and central-eastern tropical Pacific since 1985, which produces “in phase” effects on the WTP sea level variability.

Description: RbH2AsO4, rubidium dihydrogenarsenate (RDA), was synthesized by partial neutralization of an aqueous H3AsO4 solution with aqueous Rb2CO3. Its paraelectric room-temperature phase is composed of virtually regular tetrahedral [AsO2(OH)2]− anions and Rb+ cations, both located on \overline{4} positions. The [AsO2(OH)2] units are connected via O—H...O hydrogen bonds into a three-dimensional network, whereby the H atoms are equally disordered between the O atoms. The Rb+ cations are located in channels running along the directions and coordinated by eight O atoms located at the vertices of a snub disphenoid.

Description: The title compound, [FeZr2(C5H5)4Cl2(C13H18B2)], is a heteronuclear complex that consists of a [3]ferrocenophane moiety substituted at each cyclopentadienyl (Cp) ring by a BH3 group; the BH3 group is bonded via two H atoms to the Zr atom of the zirconocene chloride moiety in a bidentate fashion. The two Cp rings of the [3]ferrocenophane moiety are aligned at a dihedral angle of 8.9 (4)° arising from the strain of the propane-1,3-diyl bridge linking the two Cp rings. [One methylene group is disordered over two positions with a site-occupation factor of 0.552 (18) for the major occupied site.] The dihedral angles between the Cp rings at the two Zr atoms are 50.0 (3) and 51.7 (3)°. The bonding Zr...H distances are in the range 1.89 (7)–2.14 (7) Å. As the two Cp rings of the ferrocene unit are connected by an ansa bridge, the two Zr atoms approach each other at 6.485 (1) Å. The crystal packing features C—H...Cl interactions.

Description: In the title molecule, C24H20Cl2O2, the central methylbenzene ring forms dihedral angles of 42.47 (10) and 34.34 (10)° with the terminal 4-chlorophenyl fragments. The dihedral angle between the chlorobenzene rings is 34.45 (11)°. A weak intramolecular C—H...O interaction generates an S(6) ring motif. The crystal packing exhibits weak C—H...O hydrogen bonds and C—H...π interactions.

Description: The title carbohydrate, C13H22O6, is a derivative of d-glycose, in which the furanosidic and isopropylidene rings are in twisted conformations. The mean plane of the furanosidic ring makes a dihedral angle of 70.32 (18)° with the mean plane of the fused isopropylidene ring. The methyl groups in the other isopropylidene ring are disordered over two sets of sites, with an occupancy ratio of 0.74 (6):0.26 (6). In the crystal, molecules are linked by O—H...O hydrogen bonds into chains with graph-set notation C(5) along [100]. Weak C—H...O interactions also occur.

Description: In the title compound, C14H12N2O3, the pyridine ring is twisted with respect to the phenyl ring and the carboxylic acid group at angles of 37.1 (5) and 8.1 (3)°, respectively; the phenyl ring forms a dihedral angle of 41.4 (1)° with the mean plane of the C—NH—C=O fragment. An intramolecular O—H...O hydrogen bond occurs between the carboxylic acid and carbonyl groups. In the crystal, N—H...O hydrogen bonds link molecules into a supramolecular chain running along the a-axis direction.

Description: The title compound, C15H12N4O, adopts an E conformation with respect to the azomethine bond and crystallizes in its hydrazinylidene tautomeric form. The dihedral angle between the ring systems is 15.98 (7)°. The phenol O—H group forms an intramolecular O—H...N hydrogen bond. In the crystal, pairs of N—H...N and C—H...O hydrogen bonds link neighbouring molecules into centrosymmetric dimers. These dimers are interconnected by means of three types of π–π stacking interactions. One, with a centroid–centroid distance of 3.577 (1) Å [interplanar separation = 3.4673 (6) Å], connects adjacent molecules into centrosymmetric dimers. The other two interactions, on the outward facing sides of the dimers, are between phenol rings of neighboring molecules [centroid–centroid separation = 3.7907 (13) Å and interplanar separation = 3.5071 (8) Å], and between phthalazin units [centroid–centroid separation = 3.6001 (12) Å and interplanar separation = 3.4891 (7) Å]. In combination, the π–π interactions lead to the formation of infinite layers with molecules stacked along [0\overline{1}1]. These layers are, in turn, connected with neighbouring layers through the N—H...N and C—H...O hydrogen bonds, yielding a three-dimensional supramolecular architecture.

Description: The goal of this study is to develop a high-resolution atmospheric hindcast over the Mediterranean area using the WRF-ARW model, focusing on offshore surface wind fields. In order to choose the most adequate model configuration, the study provides details on the calibration of the experimental saet-up through a sensitivity test considering the October–December 2001 period (the 2001 super-storm event in the West Mediterranean). A daily forecast outperforms the spectral technique of previous products and the boundary data from ERA-Interim reanalysis produces the most accurate estimates in terms of wind variability and hour-to-hour correspondence. According to the sensitivity test, two data sets of wind hindcast are produced: the SeaWind I (30-km horizontal resolution for a period of 60 years) and the SeaWind II (15-km horizontal resolution for 20 years). The validation of the resulting surface winds is undertaken considering two offshore observational datasets. On the one hand, hourly surface buoy stations are used to validate wind time series at specific locations; on the other hand, wind altimeter satellite observations are considered for spatial validation in the whole Mediterranean Sea. The results obtained from this validation process show a very good agreement with observations for the southern Europe region. Finally, SeaWind I and II are used to characterize offshore wind fields in the Mediterranean Sea. The statistical structure of sea surface wind is analyzed and the agreement with Weibull probability distribution is discussed. In addition, wind persistence and extreme wind speed (50 year return period) are characterized and relevant areas of wind power generation are described by estimating wind energy quantities.

Description: Proxy-data suggest that the Last Interglacial (LIG; ~130–116 ka BP) climate was characterized by higher temperatures, a partially melted Greenland Ice Sheet (GIS) and a changed Atlantic meridional overturning circulation (AMOC). Notwithstanding the uncertainties in LIG palaeoclimatic reconstructions, this setting potentially provides an opportunity to evaluate the relation between GIS melt and the AMOC as simulated by climate models. However, first we need to assess the extent to which a causal relation between early LIG GIS melt and the weakened AMOC is plausible. With a series of transient LIG climate simulations with the LOVECLIM earth system model, we quantify the importance of the major known uncertainties involved in early LIG GIS melt scenarios. Based on this we construct a specific scenario that is within the parameter space of uncertainties and show that it is physically consistent that early LIG GIS melting kept the AMOC weakened. Notwithstanding, this scenario is at the extreme end of the parameter space. Assuming that proxy-based reconstructions of early LIG AMOC weakening offer a realistic representation of its past state, this indicates that either (1) the AMOC weakening was caused by other forcings than early LIG GIS melt or (2) the early LIG AMOC was less stable than indicated by our simulations and a small amount of GIS melt was sufficient to keep the AMOC in the weak state of a bi-stable regime. We argue that more intensive research is required because of the high potential of the early LIG to evaluate model performance in relation to the AMOC response to GIS melt.

Description: We measured the annual variation in the stable isotopes of oxygen (δ 18 O) and hydrogen (δD) in tree rings of Abies georgei on the Batang–Litang Plateau of western China. Although correlations between tree-ring δ 18 O and δD are relatively weak in semi-arid regions, we found a strong correlation between the δ 18 O and δD time series from 1755 to 2009 under the wetter environment. Tree-ring δ 18 O and δD time series are both significantly and negatively correlated with moisture conditions from June to August, including relative humidity and total precipitation, respectively, from 1960 to 2009. Considering the difference in low-frequency domain between the two isotopes, the relative humidity histories from June to August, reconstructed separately from the tree-ring δ 18 O and δD data with instrumental climate data, reveal a persistent drying trend since 1850s, especially since the early 1970s. There is an obvious offset of reconstructed relative humidity from tree-ring δ 18 O and δD in the period 1755–1820, despite the strong similarity in their 21-year moving averages. The decreased relative humidity since the 1850s may be associated with the thermal contrast between the sea surface temperature of the Indian Ocean and the Qinghai-Tibetan Plateau, which determines the strength of moisture transfer via the Indian summer monsoon.

Description: Observations show a multidecadal signal in the North Atlantic ocean, but the underlying mechanism and cause of its timescale remain unknown. Previous studies have suggested that it may be driven by the North Atlantic Oscillation (NAO), which is the dominant pattern of winter atmospheric variability. To further address this issue, the global ocean general circulation model, Nucleus for European Modelling of the Ocean (NEMO), is driven using a 2,000 years long white noise forcing associated with the NAO. Focusing on key ocean circulation patterns, we show that the Atlantic Meridional Overturning Circulation (AMOC) and Sub-polar gyre (SPG) strength both have enhanced power at low frequencies but no dominant timescale, and thus provide no evidence for a oscillatory ocean-only mode of variability. Instead, both indices respond linearly to the NAO forcing, but with different response times. The variability of the AMOC at 30°N is strongly enhanced on timescales longer than 90 years, while that of the SPG strength starts increasing at 15 years. The different response characteristics are confirmed by constructing simple statistical models that show AMOC and SPG variability can be related to the NAO variability of the previous 53 and 10 winters, respectively. Alternatively, the AMOC and the SPG strength can be reconstructed with Auto-regressive (AR) models of order seven and five, respectively. Both statistical models reconstruct interannual and multidecadal AMOC variability well, while on the other hand, the AR(5) reconstruction of the SPG strength only captures multidecadal variability. Using these methods to reconstruct ocean variables can be useful for prediction and model intercomparision.

Description: The asymmetric unit of the title molecular salt, C10H26N42+·2C4H3O4−, contains two half-cations (both completed by crystallographic inversion symmetry) and two maleate anions. The cyclam macrocycles adopt trans-III conformations, supported by two intramolecular N—H...O hydrogen bonds. The O-bonded H atom of each maleate ion is disordered over two positions with an occupancy ratio of 0.61 (5):0.39 (5): each one generates an intramolecular O—H...O hydrogen bond. In the crystal, the cations are linked to the anions by N—H...O hydrogen bonds, generating [001] chains.

Description: In the title molecule, the pyridine rings make a dihedral angle of 13.1 (1)°. The phenyl ring is approximately perpendicular to both of them, forming dihedral angles of 87.4 (1)and 81.9 (1)°. In the crystal, pairs of O—H...N hydrogen bonds link the molecules into centrosymmetric dimers. Additional C—H...O, π–π [centroid–centroid distance = 3.971 (2) Å] and C—H...π interactions consolidate the dimers into a three-dimensional network.

Description: In the title compound, C32H25NO5, the furan and pyrrole rings each adopt an envelope conformation, the respective flap atoms being the C atom bearing the pyrene substituent and the CH2 atom adjacent to the N atom. The molecular conformation is stabilized by an intramolecular O—H...N hydrogen bond. In the crystal, C—H...O contacts link the molecules, forming a two-dimensional network parallel to (001).

Description: In the title compound, C20H18N4O3, the dihedral angles between the central benzene ring and the 1H-1,2,3-triazole ring and the fused benzene ring are 65.34 (19) and 3.64 (18)°, respectively. The dioxole ring adopts a shallow envelope conformation, with the methylene C atom displaced by 0.156 (5) Å from the other four atoms (r.m.s. deviation = 0.007Å). In the crystal, the molecules are linked by C—H...O and C—H...N hydrogen bonds, generating a three-dimensional network.

Description: In the title compound, [ZnI2(C34H31N3)], the ZnII atom is four-coordinated by two I atoms and the pyridine N atoms from the bidentate 6′-phenyl-2,2′-bipyridine ligand in a distorted tetrahedral geometry.

Description: The title compound, C16H23N3O3, contains two morpholine rings, each of which adopts a chair conformation. The molecular conformation is stabilized by an intramolecular O—H...N hydrogen bond, leading to a S(6) ring. In the crystal, molecules are linked into zigzag chains along the c-axis direction by C—H...O and C—H...π interactions.

Description: In the title compound, [HgI2(C22H20N4)2], the HgII cation is situated on a twofold rotation axis and is coordinated by two iodide anions and two imidazolyl N atoms in a distorted tetrahedral geometry. In the crystal, C—H...I interactions link the molecules into chains extending in [010], which are further linked into sheets parallel to (100) through C—H...N hydrogen bonding interactions.

Description: In the title compound, C20H27N5O3, the central piperazine ring adopts a chair conformation, with the N-bound carboxylate and methylene substituents occupying bisectional and equatorial orientations, respectively. A twist is evident between the aromatic rings [dihedral angle = 25.61 (9)°] but an intramolecular O—H...N hydrogen bond persists between these. Supramolecular tapes along [1-10] are formed in the crystal packing through N(amino)—H...O(hydroxyl) and N(amino)—H...N(pyrimidinyl) hydrogen bonds, and these are linked into layers in the ab plane by π–π interactions [inter-centroid distance between pyrimidinyl rings = 3.5919 (9) Å].

Description: In the title compound, C12H16NO2Br, the dioxane ring adopts a chair conformation and its mean plane makes a dihedral angle of 60.63 (12)° with the 4-bromophenyl ring. In the crystal, molecules are linked by pairs of N—H...O hydrogen bonds, forming inversion dimers with an R22(8) ring motif. These dimers are consolidated by pairs of C—H...O hydrogen bonds with an R22(16) ring motif. Adjacent dimers are connected via C—H...O hydrogen bonds, forming infinite chains propagating along the c-axis direction.

Description: In the title compound, C27H28N2O3, each of the pyrrolidine rings adopts a twisted conformation, as does the cyclopentane ring. The indane ring has an r.m.s deviation of 0.0693 Å. The dihedral angle between the mean plane of the pyrrolizine ring and indane system is 82.58 (1)°. The piperidine ring has the methyl substituent in an equatorial position and adopts a twisted chair conformation. The molecular structure is stabilized by a weak intramolecular O—H...N interaction.

Description: In the title molecule, C13H8Cl2O2, the dihedral angle between the benzene rings is 74.53 (9)°. An intramolecular O—H...O hydrogen bond leading to a S(6) ring is observed. In the crystal, the molecules are connected into a three-dimensional network by C—H...O and π–π [inter-centroid distance = 3.6254 (10) Å] interactions.

Description: In the title compound C13H10ClN3O3S, the benzoyl group maintains its trans conformation against the thiono group about the C—N bond and the intramolecular hydrogen bond between the benzoyl O atom and thioamide H atom. In the crystal, N—H...O and C—H...O hydrogen bonds link the molecules, forming chains along the b-axis direction. In addition, C—H...π interactions occur between a phenyl H atom and the furan ring.

Description: Driving data and physical parametrizations can significantly impact the performance of regional dynamical atmospheric models in reproducing hydrometeorologically relevant variables. Our study addresses the water budget sensitivity of the Weather Research and Forecasting Model System WRF (WRF-ARW) with respect to two cumulus parametrizations (Kain–Fritsch, Betts–Miller–Janjić), two global driving reanalyses (ECMWF ERA-INTERIM and NCAR/NCEP NNRP), time variant and invariant sea surface temperature and optional gridded nudging. The skill of global and downscaled models is evaluated against different gridded observations for precipitation, 2 m-temperature, evapotranspiration, and against measured discharge time-series on a monthly basis. Multi-year spatial deviation patterns and basin aggregated time series are examined for four globally distributed regions with different climatic characteristics: Siberia, Northern and Western Africa, the Central Australian Plane, and the Amazonian tropics. The simulations cover the period from 2003 to 2006 with a horizontal mesh of 30 km. The results suggest a high sensitivity of the physical parametrizations and the driving data on the water budgets of the regional atmospheric simulations. While the global reanalyses tend to underestimate 2 m-temperature by 0.2–2 K, the regional simulations are typically 0.5–3 K warmer than observed. Many configurations show difficulties in reproducing the water budget terms, e.g. with long-term mean precipitation biases of 150 mm month −1 and higher. Nevertheless, with the water budget analysis viable setups can be deduced for all four study regions.

Description: El Niño/Southern Oscillation (ENSO) is the predominant interannual variability of the global climate system. How might ENSO change in a warmer world? The dominant two Combined Empirical Orthogonal Functions (CEOF) of the equatorial ocean temperature and zonal and vertical motion identify two modes that shown a transition in the eastern Pacific from a warming eastward/downward motion to a cooling westward/upward flow. These results also suggest consistent changes to the west and at depths down to 300 m. These dominate CEOFs provide a compact tool for assessing Coupled Model Intercomparison Project Phase 5 ocean model output for both the recent historical period and for the latter part of the twenty first century. Most of the analyzed models replicate well the spatial patterns of the dominant observational CEOF modes, but nearly always underestimate the magnitudes. Comparing model output for the twentieth and twenty first centuries there is very little change between the spatial patterns of the ENSO modes of the two periods. This lack of response to climate change is shown to be partly related to competing influences of climatic changes in the mean ocean circulation.

Description: In this work, authors examine the variabilities of precipitation and surface air temperature (T2m) in Northeast China during 1948–2012, and their global connection, as well as the predictability. It is noted that both the precipitation and T2m variations in Northeast China are dominated by interannual and higher frequency variations. However, on interdecadal time scales, T2m is shifted significantly from below normal to above normal around 1987/1988. Statistically, the seasonal mean precipitation and T2m are largely driven by local internal atmospheric variability rather than remote forcing. For the precipitation variation, circulation anomalies in the low latitudes play a more important role in spring and summer than in autumn and winter. For T2m variations, the associated sea surface pressure (SLP) and 850-hPa wind (uv850) anomalies are similar for all seasons in high latitudes with significantly negative correlations for SLP and westerly wind anomaly for uv850, suggesting that a strong zonal circulation in the high latitudes favors warming in Northeast China. The predictability of precipitation and T2m in Northeast China is assessed by using the Atmospheric Model Inter-comparison Project type experiments which are forced by observed sea surface temperature (SST) and time-evolving greenhouse gas (GHG) concentrations. Results suggest that T2m has slightly higher predictability than precipitation in Northeast China. To some extent, the model simulates the interdecadal shift of T2m around 1987/1988, implying a possible connection between SST (and/or GHG forcing) and surface air temperature variation in Northeast China on interdecadal time scales. Nevertheless, the precipitation and T2m variations are mainly determined by the unpredictable components which are caused by the atmospheric internal dynamic processes, suggesting low predictability for the climate variation in Northeast China.

Description: In the title compound, C21H24O5, the dihedral angle between the benzene rings is 19.57 (15)°. In the crystal, the molecular arrangement makes up head-to-head centrosymmetric dimers assembled by pairs of O—H...O bonds; this arrangement builds a graph-set ring motif of R22(8). The dimers are linked into a tape running along the b-axis direction through C—H...O interactions. The packing is further consolidated by C—H...π interactions, forming layers parallel to (10-2).

Description: In the title compound, C29H25N5O3, the dihedral angle between the benzene ring and the pendant quinazoline ring system (r.m.s. deviation = 0.036Å) is 87.60 (17)°. The equivalent angle between the pyrazole ring and the phenyl group is 70.0 (2)°. The dihedral angle between the benzene and pyrazole rings is 30.7 (2)° and overall, the molecular conformation approximates to a Z shape. A short intramolecular C—H...O contact occurs. In the crystal, the molecules are linked by Cπ—H...O-type hydrogen bonds and aromatic π–π stacking interactions [centroid–centroid distance = 3.860 (3) Å], generating a three-dimensional network.

Description: A land–sea surface warming ratio (or φ ) that exceeds unity is a robust feature of both observed and modelled climate change. Interestingly, though climate models have differing values for φ , it remains almost time-invariant for a wide range of twenty-first century climate transient warming scenarios, while varying in simulations of the twentieth century. Here, we present an explanation for time-invariant land–sea warming ratio that applies if three conditions on radiative forcing are met: first, spatial variations in the climate forcing must be sufficiently small that the lower free troposphere warms evenly over land and ocean; second, the temperature response must not be large enough to change the global circulation to zeroth order; third, the temperature response must not be large enough to modify the boundary layer amplification mechanisms that contribute to making φ exceed unity. Projected temperature changes over this century are too small to breach the latter two conditions. Hence, the mechanism appears to show why both twenty-first century and time-invariant CO 2 forcing lead to similar values of φ in climate models despite the presence of transient ocean heat uptake, whereas twentieth century forcing—which has a significant spatially confined anthropogenic tropospheric aerosol component that breaches the first condition—leads to modelled values of φ that vary widely amongst models and in time. Our results suggest an explanation for the behaviour of φ when climate is forced by other regionally confined forcing scenarios such as geo-engineered changes to oceanic clouds. Our results show how land–sea contrasts in surface and boundary layer characteristics act in tandem to produce the land–sea surface warming contrast.

Description: We present a validation analysis of a regional climate model coupled to a distributed one dimensional (1D) lake model for the Caspian Sea Basin. Two model grid spacings are tested, 50 and 20 km, the simulation period is 1989–2008 and the lateral boundary conditions are from the ERA-Interim reanalysis of observations. The model is validated against atmospheric as well as lake variables. The model performance in reproducing precipitation and temperature mean seasonal climatology, seasonal cycles and interannual variability is generally good, with the model results being mostly within the observational uncertainty range. The model appears to overestimate cloudiness and underestimate surface radiation, although a large observational uncertainty is found in these variables. The 1D distributed lake model (run at each grid point of the lake area) reproduces the observed lake-average sea surface temperature (SST), although differences compared to observations are found in the spatial structure of the SST, most likely as a result of the absence of 3 dimensional lake water circulations. The evolution of lake ice cover and near surface wind over the lake area is also reproduced by the model reasonably well. Improvements resulting from the increase of resolution from 50 to 20 km are most significant in the lake model. Overall the performance of the coupled regional climate—1D lake model system appears to be of sufficient quality for application to climate change scenario simulations over the Caspian Sea Basin.

Description: Climate changes over China from the present (1990–1999) to future (2046–2055) under the A1FI (fossil fuel intensive) and A1B (balanced) emission scenarios are projected using the Regional Climate Model version 3 (RegCM3) nests with the National Center for Atmospheric Research (NCAR) Community Climate System Model (CCSM). For the present climate, RegCM3 downscaling corrects several major deficiencies in the driving CCSM, especially the wet and cold biases over the Sichuan Basin. As compared with CCSM, RegCM3 produces systematic higher spatial pattern correlation coefficients with observations for precipitation and surface air temperature except during winter. The projected future precipitation changes differ largely between CCSM and RegCM3, with strong regional and seasonal dependence. The RegCM3 downscaling produces larger regional precipitation trends (both decreases and increases) than the driving CCSM. Contrast to substantial trend differences projected by CCSM, RegCM3 produces similar precipitation spatial patterns under different scenarios except autumn. Surface air temperature is projected to consistently increase by both CCSM and RegCM3, with greater warming under A1FI than A1B. The result demonstrates that different scenarios can induce large uncertainties even with the same RCM-GCM nesting system. Largest temperature increases are projected in the Tibetan Plateau during winter and high-latitude areas in the northern China during summer under both scenarios. This indicates that high elevation and northern regions are more vulnerable to climate change. Notable discrepancies for precipitation and surface air temperature simulated by RegCM3 with the driving conditions of CCSM versus the model for interdisciplinary research on climate under the same A1B scenario further complicated the uncertainty issue. The geographic distributions for precipitation difference among various simulations are very similar between the present and future climate with very high spatial pattern correlation coefficients. The result suggests that the model present climate biases are systematically propagate into the future climate projections. The impacts of the model present biases on projected future trends are, however, highly nonlinear and regional specific, and thus cannot be simply removed by a linear method. A model with more realistic present climate simulations is anticipated to yield future climate projections with higher credibility.

Description: Teleconnections associated with warm El Niño/southern oscillation (ENSO) events in 20 climate model intercomparison project 5 (CMIP5) models have been compared with reanalysis observations. Focus has been placed on compact time and space indices, which can be assigned a specific statistical confidence. Nearly all of the models have surface temperature, precipitation and 250 hPa geopotential height departures in the Tropics that are in good agreement with the observations. Most of the models also have realistic anomalies of Northern Hemisphere near-surface temperature, precipitation and 500 hPa geopotential height. Model skill for these variables is significantly related to the ability of a model to accurately simulate Tropical 250 hPa height departures. Additionally, most models have realistic temperature and precipitation anomalies over North America, which are linked to a model’s ability to simulate Tropical 250 hPa and Northern Hemisphere 500 hPa height departures. The skills of temperature and precipitation departures over the Northern Hemisphere and North America are associated with the ability to realistically simulate realistic ENSO frequency and length. Neither horizontal nor vertical resolution differences for either the model atmosphere or ocean are significantly related at the 95 % level to variations in El Niño simulation quality. Overall, recent versions of earlier models have improved in their ability to simulate El Niño teleconnections. For instance, the average model skills of temperature and precipitation for the Tropics, Northern Hemisphere and North America for 11 CMIP5 models are all larger than those for prior versions.

Description: In the eastern Mediterranean in general and in Turkey in particular, temperature reconstructions based on tree rings have not been achieved so far. Furthermore, centennial-long chronologies of stable isotopes are generally also missing. Recent studies have identified the tree species Juniperus excelsa as one of the most promising tree species in Turkey for developing long climate sensitive stable carbon isotope chronologies because this species is long-living and thus has the ability to capture low-frequency climate signals. We were able to develop a statistically robust, precisely dated and annually resolved chronology back to AD 1125. We proved that variability of δ 13 C in tree rings of J. excelsa is mainly dependent on winter-to-spring temperatures (January–May). Low-frequency trends, which were associated with the medieval warm period and the little ice age, were identified in the winter-to-spring temperature reconstruction, however, the twentieth century warming trend found elsewhere could not be identified in our proxy record, nor was it found in the corresponding meteorological data used for our study. Comparisons with other northern-hemispherical proxy data showed that similar low-frequency signals are present until the beginning of the twentieth century when the other proxies derived from further north indicate a significant warming while the winter-to-spring temperature proxy from SW-Turkey does not. Correlation analyses including our temperature reconstruction and seven well-known climate indices suggest that various atmospheric oscillation patterns are capable of influencing the temperature variations in SW-Turkey.

Description: The latest version of the state-of-the-art global land–atmosphere–ocean coupled climate forecast system of NCEP has shown considerable improvement in various aspects of the Indian summer monsoon. However, climatological mean dry bias over the Indian sub-continent is further increased as compared to the previous version. Here we have attempted to link this dry bias with climatological mean bias in the Eurasian winter/spring snow, which is one of the important predictors of the Indian summer monsoon rainfall (ISMR). Simulation of interannual variability of the Eurasian snow and its teleconnection with the ISMR are quite reasonable in the model. Using composite analysis it is shown that a positive snow anomaly, which is comparable to the systematic bias in the model, results into significant decrease in the summer monsoon rainfall over the central India and part of the Equatorial Indian Ocean. Decrease in the summer monsoon rainfall is also found to be linked with weaker northward propagation of intraseasonal oscillation (ISO). A barotropic stationary wave triggered by positive snow anomaly over west Eurasia weakens the upper level monsoon circulation, which in turn reduces the zonal wind shear and hence, weakens the northward propagation of summer monsoon ISOs. A sensitivity experiment by reducing snow fall over Eurasian region causes decrease in winter and spring snow depth, which in turn leads to decrease in Indian summer monsoon rainfall. Results from the sensitivity experiment corroborate with those of composite analysis based on long free run. This study suggests that further improvements in the snow parametrization schemes as well as Arctic sea ice are needed to reduce the Eurasian snow bias during winter/spring, which may reduce the dry bias over Indian sub-continent and hence predictability aspect of the model.

Description: We examine the influence of the South-American land-mass and its mountains on the significant cyclic diurnal and semidiurnal components of the average circulation in the adjacent area of the southeastern tropical Pacific (SEP). Our approach is based on a number of numerical simulations with the regional atmospheric model weather research and forecasting forced by the National Centers for Environmental Prediction’s final analysis operational analysis data. In the control simulation the model domain covers the SEP and a large part of South America. In several sensitivity experiments the domain is reduced to progressively exclude continental areas. We find that the mean diurnal cycle is sensitive to model domain in ways that reveal the existence of different contributions originating from the Chilean and Peruvian land-masses. The experiments suggest that diurnal variations in circulations and thermal structures over the SEP (mainly forced by local insolation) are influenced by convection over the Peruvian sector of the Andes cordillera, while the mostly dry mountain-breeze circulations force an additional component that results in semi-diurnal variations near the coast. A series of numerical tests, however, reveal sensitivity of the simulations to the choice of vertical grid, limiting the possibility of solid quantitative statements on the amplitudes and phases of the diurnal and semidiurnal components across the domain.

Description: The title compound, Sr0.6Ba0.4Nb2O6 (strontium barium niobium oxide), belongs to the group of strontium–barium niobates with varying composition of Sr and Ba. Their general formula can be written as SrxBa1 - xNb2O6. Below the Curie temperature, Tc, these materials indicate ferroelectric properties. The Curie temperature for SBN60 is equal to 346±0.5 K so the structure is in the ferroelectric phase at the measurement temperature of 100 K. Characteristic for this family of compounds is the packing along the z-axis. The NbO6 corner-sharing octahedra surround three types of vacancy tunnels with pentagonal, square and triangular shapes. The Sr2+ ions partially occupy two unique sites, the first one located inside the pentagon and the second one in the square tunnels. Consequently, they are situated on the mirror plane and the intersection of two glide planes, respectively. The site inside the pentagonal tunnel is additionally disordered so that the same position is shared by Ba2+ and Sr2+ ions whereas another part of the Ba2+ ion occupies a different position (relative occupancies 0.43:0.41:0.16). One of the NbV atoms and three of the O2− ions occupy general positions. The second NbV atom is located on the intersection of the mirror planes. Two remaining O2− ions are located on the same mirror plane. Only the NbV atom and one of the O2− ions which is located on the mirror plane are not disordered. Each of the remaining O2− ions is split between two sites, with relative occupancies of 0.52:0.48 (O2− ions in general positions) and 0.64:0.36 (O2− ion on the mirror plane).

Description: The monoclinic form of trilithium dichromium(III) tris(orthophosphate), Li3Cr2(PO4)3, was prepared by the reactive halide flux method. The structure of the title compound is composed of a three-dimensional anionic framework with composition ∞ 3[Cr2(PO4)3]3− and Li+ ions situated in the empty channels. The rigid framework built up from CrO6 octahedra and PO4 tetrahedra is the same as that found in other monoclinic Li3M2(PO4)3 (M = Fe, Sc, V) phases. The three Li+ cations of Li3Cr2(PO4)3 are unequally disordered over six crystallographically different sites. The classical charge balance of the title compound can be represented as [Li+]3[Cr3+]2[P5+]3[O2−]12. Solid-state UV/Vis spectra indicate that the crystal filed splitting (Δ0) of the Cr3+ ion is around 2.22 eV.

Description: In the title compound, [Zn(SO4)(C12H8N2)2]·C3H8O2, the ZnII ion is in a distorted square-pyramidal coordination environment composed of four N atoms from two chelating 1,10-phenanthroline ligands and one O atom from a monodentate sulfate ligand. The ZnII ion lies on a twofold rotation axis. The sulfate ligand and propane-1,2-diol molecules are disordered across the twofold rotation axis. The dihedral angle between the two chelating N2C2 groups is 83.26 (13)°. In the crystal, the complex molecule and the propane-1,2-diol molecule are connected through a pair of O—H...O hydrogen bonds.

Description: In the title compound, [N(C4H9)4][Sn(C4H9)Cl4], the SnIV atom of the stannate anion has a trigonal-bipyramidal coordination sphere by two Cl atoms and one butyl chain in the equatorial plane and by two Cl atoms in the apical positions. Two of the four butyl chains of the tetrabutylammonium cation are partially disordered, each with refined site occupancies of 0.691 (6):0.309 (6). Weak C—H...Cl hydrogen-bonding interactions help to consolidate the crystal packing, as well as a short Cl...Cl interaction of 3.295 (2) Å.

Description: The title compound, [Fe(C44H28N4)(C6HF4O)], is a porphyrin complex with iron(III) in fivefold coordination with a tetrafluorophenolate group as the axial ligand. The Fe atom and the phenolate ligand are disordered across the porphyrin ring with the two phenolates appearing to be roughly related by a center of symmetry. The occupancies of the two phenolate groups refined to 0.788 (3) for the major component and 0.212 (3) for the minor component. The structure shows extraordinary Fe displacements of 0.488 (4) (major) and 0.673 (4) Å (minor) from the 24-atom mean plane of the porphyrin. The Fe—Np distances range from 2.063 (4) to 2.187 (6) Å and the Fe—O distances are 1.903 (5) Å for major component and 1.87 (2) Å for minor component. The four phenyl groups attached to the porphyrin ring form dihedral angles of 63.4 (4), 49.6 (4), 62.4 (4), and 63.3 (4)° (in increasing numerical order) with the three nearest C atoms of the porphyrin ring. The major and minor component phenolate groups form dihedral angles of 24.9 (4)° and 24.8 (4)°, respectively, with the four porphyrin N atoms. The Fe...Fe distance between the two iron(III) atoms of adjacent porphyrin molecules is 6.677 (3) Å. No close intermolecular interaction was observed. The crystal studied was twinned by inversion, with a major–minor component ratio of 0.53 (3):0.47 (3).

Description: In the title compound, [Ir(C10H15)(C11H8N)(N3)], the IrIII ion is coordinated by three anionic ligands, namely, pentamethylcyclopentadienyl (Cp*−), 2-(pyridin-2-yl)phenyl (ppy−) and azide (N3−), and adopts a three-legged piano-stool geometry The coordination mode of N3− is typical for Cp*IrIII–N3 complexes, with an Ir—N(N3) bond length of 2.125 (2) Å and an Ir—N=N bond angle of 116.5 (2)°. The N3− ligand is almost linear [N=N=N = 176.0 (3)°], and the N=N bond length between the central and coordinating N atom and that between the central and non-coordinating terminal N atom are 1.194 (3) and 1.157 (3) Å, respectively. For the ppy− ligand, the Ir—C and Ir—N bond lengths are 2.066 (3) and 2.079 (3) Å, respectively, which are rather close to each other, compared to the related IrIII– or RhIII–ppy complexes. The Ir—C(Cp*) bond lengths vary in the range 2.163 (2)–2.232 (2) Å, indicating a strong trans influence of the cyclometallated C-donor atom of the ppy− ligand.

Description: The asymmetric unit of the title solvated molecular salt, (C5H6N)[Cr(C2O4)2(H2O)2]·CO(NH2)2, contains half a formula unit. Each component is completed by crystallographic twofold symmetry: in the cation, one C and the N atom lie on the rotation axis; in the anion, the CrIII ion lies on the axis; in the solvent molecule, the C and the O atom lie on the axis. The aqua ligands are in a trans disposition in the resulting CrO6 octahedron. In the crystal, the components are linked by O—H...O, N—H...O and N—H...(O,O) hydrogen bonds, generating a three-dimensional network.

Description: In the title hydrate, C17H18N2O5·H2O, the complete organic molecule is generated by a crystallographic mirror plane with one C and one O atom lying on the mirror plane. The O atom of the water molecule has m site symmetry. Two symmetry-related intramolecular O—H...O hydrogen bonds complete S(6) rings in the organic molecule. In the crystal, the components are linked into (010) sheets by O—H...O and N—H...O hydrogen bonds.

Description: In the crystal structure of Y4F2[Si2O7][SiO4], three fundamental building blocks are present, viz. anionic disilicate and orthosilicate units ([Si2O7]6− and [SiO4]4−) and cationic [F2Y4]10+ entities. The latter are built up by two [FY3]8+ triangles sharing a common edge. The four crystallographically independent Y3+ cations display coordination numbers of eight for one and of seven for the other three cations, provided by oxide and fluoride anions. The overall arrangement of the building blocks can be considered as layer-like parallel to the ac plane.

Description: The crystal structure of the title compound, [Cu(SO4)(C12H8N2)2]·C2H5OH, arises from the assembly of the neutral complex [Cu(SO4)(C12H8N2)2] and an ethanol solvent molecule. The CuII ion is five-coordinate, surrounded by two pairs of N atoms from two independent N,N′-chelating 1,10-phenanthroline ligands, and one O atom of monodentate sulfate ligand, in a distorted trigonal-bipyramidal fashion. Spatial orientation of the ligands and the assembly in the solid state are stabilized by the C—H...O hydrogen-bonding interactions, established between the O atoms (from the sulfate ligand and the ethanol molecule) and the neighbouring 1,10-phenanthroline molecules. There is also an offset face-to-face π–π stacking between the 1,10-phenanthroline ligands. The ethanol solvent molecule is disordered over two orientations in the ratio 0.663 (10):0.337 (10). The crystal examined was subject to racemic twinning and the refined twin fraction was 0.346 (19).

Description: The asymmetric unit of the title compound, (C8H12NO)2[Mn(H2P2O7)2(H2O)2]·2H2O, consists of half an MnII complex anion, a 2-methoxybenylammonium cation and a solvent water molecule. The MnII complex anion lies across an inversion center, and has a slightly distorted octahedral coordination environment for the MnII ion, formed by two bidentate dihydrogendiphosphate ligands and two water molecules. In the crystal, the components are linked by O—H...O and N—H...O hydrogen bonds, forming layers parallel to (100). An intramolecular N—H...O hydrogen bond is also observed.

Description: The title dinuclear complex, [Fe2Br4(C13H9N4)2], which lies on an inversion center, features two approximately planar bis(pyridin-2-yl)pyrazole (bpypz−) ligands [maximum deviation = 0.082 (3) Å] and four bromide ions. Each FeIII ion is octahedrally coordinated by four N atoms of two bpypz− ligands and two Br ions. π–π stacking interactions [centroid–centroid distances = 3.7004 (17)–4.0123 (18) Å] are observed between pyridyl and pyrazole rings, and between pyridyl and pyridyl rings of adjacent complex molecules.

Description: In the binuclear title compound, [Ag2(C11H11N3)2](ClO4)2·2C2H6SO, the complex cation is centrosymmetric, with the unique AgI cation coordinated by two pyridine N atoms from two symmetry-related N-(pyridine-2-ylmethyl)pyridine-3-amine ligands in a geometry slightly distorted from linear [N—Ag—N = 170.78 (9)°], resulting in the formation of a 16-membered cyclic dimer. The two pyridine rings coordinating to the AgI atom are almost perpendicular to each other [dihedral angle = 87.73 (10)°]. Intermolecular Ag...O interactions [3.149 (3) and 2.686 (3) Å], N—H...O and C—H...O hydrogen bonds and C—H...π interactions between the cyclic dimers and the anions or the solvent molecules lead to the formation of a three-dimensional supramolecular network.

Description: The title compound, {[ZnCl(C13H12F2N6O)2]Cl·2H2O}n, is a two-dimensional coordination polymer. The ZnII atom is six-coordinated by four N atoms from four 2-(2,4-difluorophenyl)-1,3-bis(1,2,4-triazol-1-yl)propan-2-ol (HFlu) ligands and by two Cl atoms in a distorted octahedral geometry. Two Cl atoms bridge two ZnII atoms, forming a centrosymmetric dinuclear unit. The HFlu ligands connect the dinuclear units into a 44 net parallel to (001) when the dinuclear unit is considered as a node. O—H...O and O—H...Cl hydrogen bonds link the cationic layer, free chloride anions and lattice water molecules. Intralayer π–π interactions between the triazole rings are observed [centroid–centroid distance = 3.716 (6) Å].

Description: In the title compound, [Cd(C8F4O4)(C2H5OH)2]n, the CdII cation sits on an inversion centre and is coordinated by six O atoms from four tetrafluorobenzene-1,4-dicarboxylate anions and two ethanol molecules in a distorted octahedral geometry. The anionic ligand is also located on an inversion centre, and connects four CdII cations, generating a two-dimensional polymeric layer parallel to the ab plane. Within the layer, the ethanol molecule links F and O atoms of the nearest anionic ligands via O—H...O and O—H...F hydrogen bonds. The ethyl group of the ethanol molecule is disordered over two positions with an occupancy ratio of 0.567 (10):0.433 (10).

Description: In the title compound, C24H27N5O2S·0.5H2O, the piperidine ring adopts a distorted boat conformation. The phenyl rings subtend dihedral angles of 69.7 (1) and 88.7 (1)° with the best plane through the piperidine moiety. In the crystal, symmetry-related molecules are linked through a network of C—H...O and C—H...N interactions, the former connecting them into zigzag chains along the c-axis direction and the latter forming an R22(4)motif. The dimer formation (C—H...N) and the repetition of symmetry-related molecules (C—H...O) along the b-axis direction stabilize the packing mode. The water molecule is located on a twofold rotation axis.

Description: The asymmetric unit of the title compound, C14H6O4, contains three independent molecules (A, B and C). In molecule C, there are two disordered sets of two carbonyl O atoms [occupancies = 0.643 (11) and 0.357 (11)]. All three molecules are non-planar due to repulsion between two O atoms in peri positions on the anthracene ring, showing a slight difference in deviation of the carbonyl O atoms. The intramolecular distances between the two nearest O atoms are in the range of 2.685 (10)–2.766 (10) Å. In the crystal, molecules are linked by C—H...O and π–π [centroid–centroid distances = 3.615 (2), 3.844 (2) and 3.921 (2) Å] interactions, which lead to the formation of a herringbone-like arrangement.

Description: The title compound, {(C6H21N4)[V3O9]·H2O}n, crystallizes as a salt with [trenH3]3+ cations [tren is tris(2-aminoethyl)amine], and one-dimensional anionic {[VVO3]−}n (metavanadate) chains along the c-axis direction. Three crystallographically distinct VV sites and one occluded water molecule are present for every [trenH3]3+ cation in the unit cell. The {[VVO3]−}n chains are composed of vertex-sharing [VO4] tetrahedra and have a repeat unit of six tetrahedra. Each tetrahedron in the chain contains two terminal and two μ2-bridging oxide ligands. The [trenH3]3+ cations, {[VVO3]−}n anions and occluded water molecules participate in an extensive three-dimensonal hydrogen-bonding network. The three terminal ammonium sites of the [trenH3]3+ cations each form strong N—H...O hydrogen bonds to terminal oxide ligands on the {[VVO3]−}n chain. Each occluded water molecule also donates two O—H...O hydrogen bonds to the terminal oxide ligands.

Description: The asymmetric unit of the title compound, C18H16F2N2·H2O, contains two independent molecules (A and B), and two independent water molecules of crystallization. In molecule A, the imidazole ring makes dihedral angles of 47.46 (7) and 60.98 (6)° with the 2,4-difluorophenyl and methylphenyl rings, respectively. The corresponding angles in molecule B are 45.85 (7) and 62.78 (7)°, respectively. The dihedral angle between the two benzene rings is 64.98 (7)° in molecule A and 65.53 (7)° in molecule B. In the crystal, the two independent molecules are linked by O—H...N and O—H...O hydrogen bonds, forming chains propagating along [100]. These chains are linked via C—H...F hydrogen bonds, forming slab-like two-dimensional networks lying parallel to (001).

Description: In the title compound, [Co(C12H12O4)(C5H5N)2]n, the CoII cation is coordinated by four O atoms from three 5-tert-butylbenzene-1,3-dicarboxylate anions and two N atoms from pyridine molecules in a distorted octahedral geometry. One carboxylate group of the anionic ligand chelates a CoII cation while another carboxylate group bridges two CoII cations, resulting in a polymeric layer parallel to (101). Weak C—H...O hydrogen bonds occur between adjacent polymeric layers. In the crystal, one of pyridine molecules is equally disordered over two positions.

Description: In the title compound, C12H16FNO2, the dioxane ring adopts a chair conformation with the methyl substituents and the C—N bond in equatorial orientations. Its mean plane subtends a dihedral angle of 40.17 (6)° with the benzene ring. In the crystal, weak N—H...F hydrogen bonds link the molecules into C(7) chains propagating in [100].

Description: In the title compound C26H25NO7, the mean plane through the lactone-substituted ring of the pyrrolizidine moiety forms dihedral angles of 78.46 (6) and 58.28 (8)° with the acenaphthylene moiety and the sugar based-lactone ring, respectively. The sum of the angles at the the N atom of the pyrrolizidine ring (335.0°) is in accordance with sp3 hybridization. Some atoms of the acetate group are disordered and were refined using a split model [occupancy ratio 0.673 (10):0.327 (10)].

Description: The asymmetric unit of the title salt, C12H14N22+·2C7H3N2O6−, comprises half a 4-[2-(pyridin-1-ium-4-yl)ethyl]pyridin-1-ium dication, being disposed about a centre of inversion, and a 2,6-dinitrobenzoate anion, in a general position. In the anion, the carboxylate group is inclined to the benzene ring [dihedral angle = 85.45 (9)°], whereas near-coplanar and twisted arrangements are found for the nitro groups [O—N—C—C torsion angles = 179.80 (14) and 20.2 (2)°]. In the crystal, three-component aggregates sustained by charge-assisted N+—H...O− hydrogen bonds are found and these are consolidated into a three-dimensional architecture by C—H...O and π–π [inter-centroid distances = 3.6796 (14) and 3.7064 (14) Å] interactions.

Description: The asymmetric unit of the title compound, C6H5N3·C7H6O3, comprises independent benzotriazole and 4-hydroxybenzoic acid molecules. The dihedral angle between the benzene ring and the benzotriazole ring system is 15.18 (7)°. The mean plane of the carboxyl group is twisted at an angle of 18.55 (1)° with respect to the benzene ring. The crystal structure is stabilized by weak intermolecular N—H...N, O—H...N, O—H...O and C—H...O interactions, forming a three-dimensional network.

Description: The asymmetric unit of the title compound, C10H9N3O2, contains two independent molecules linked by a C—H...N hydrogen bond. Each molecule has a similar conformation, being built up from fused five- and six-membered rings, each linked to an ally and nitro group, respectively. The indazole ring system makes dihedral angles of 2.7 (2) and 2.2 (2)°, respectively, with the plane through the nitro group. The allyl group is nearly perpendicular to the indazole system, as indicated by the N—N—C—C torsion angles of −75.3 (2) and −82.2 (2)°, this being the most important difference between the conformations of the two molecules. In the crystal, molecules are linked by C—H...O and π–π [inter-centroid distance = 3.6225 (8) Å] interactions to form a three-dimensional network.

Description: The title thiacalix[4]arene derivative, C72H80O4S8, adopts a 1,3-alternate conformation, where the four 4-methylsulfanylbenzyl groups are located alternately at the two sides of a virtual plane defined by the four bridging S atoms. In the crystal, there are no significant intermolecular interactions present. Some of the peripheral tert-butyl and methylsulfanyl groups are disordered over two positions. A region of disordered electron density, occupying voids of ca 700 Å3 for an electron count of 124, was treated using the SQUEEZE routine in PLATON [Spek (2009). Acta Cryst. D65, 148–155].

Description: In the title compound, C16H19ClN4O3, the cyclohexane ring displays a chair formation and the tetrahydropyridine ring displays an envelope conformation with the methylene C atom as the flap; the imidazolidine ring also displays an envelope conformation with a methylene C atom as the flap. In the crystal, O—H...N hydrogen bonds between hydroxy groups and pyridine rings link inversion-related molecules into dimers. Weak C—H...O hydrogen bonds further link the dimers into supramolecular chains running along the c axis.