Crystal structure and Hirshfeld surface analysis of 4,4'-di-meth-oxy-biphenyl-3,3',5,5'-tetra-carb-oxy-lic acid dihydrate

In the crystal of the title compound, C18H14O10·2H2O, the arene rings of the biphenyl moiety are tilted at an angle of 24.3 (1)°, while the planes passing through the carboxyl groups are rotated at angles of 8.6 (1) and 7.7 (1)° out of the plane of the benzene ring to which they are attached. The crystal structure is essentially stabilized by O-H⋯O bonds. Here, the carboxyl groups of neighbouring host mol-ecules are connected by cyclic R 2 2(8) synthons, leading to the formation of a three-dimensional network. The water mol-ecules in turn form helical supra-molecular strands running in the direction of the crystallographic c-axis (chain-like water clusters). The second H atom of each water mol-ecule provides a link to a meth-oxy O atom of the host mol-ecule. A Hirshfeld surface analysis was performed to qu-antify the contributions of the different inter-molecular inter-actions, indicating that the most important contributions to the crystal packing are from H⋯O/O⋯H (37.0%), H⋯H (26.3%), H⋯C/C⋯H (18.5%) and C⋯O/O⋯C (9.5%) inter-actions.

Crystal structure and Hirshfeld surface analysis of ethyl 2-[9-(2-hy-droxy-phen-yl)-3,3,6,6-tetra-methyl-1,8-dioxo-2,3,4,4a,5,6,7,8a,9,9a,10,10a-dodeca-hydro-acridin-10-yl]acetate

In the title compound, C27H33NO5, a 3,3,6,6-tetra-methyl-tetra-hydro-acridine-1,8-dione ring system carries an ethyl acetate substituent on the acridine N atom and an o-hy-droxy-phenyl ring on the central methine C atom of the di-hydro-pyridine ring. The benzene ring is inclined to the acridine ring system at an angle of 80.45 (7)° and this conformation is stabilized by an intra-molecular O-H⋯O hydrogen bond between the hy-droxy substituent on the benzene ring and one of the carbonyl groups of the acridinedione unit. The ester C=O oxygen atom is disordered over major and minor orientations in a 0.777 (9):0.223 (9) ratio and the terminal -CH3 unit of the ethyl side chain is disordered over two sets of sites in a 0.725 (5): 0.275 (5) ratio. In the crystal, C-H⋯O hydrogen bonds combine to link the mol-ecules into a three-dimensional network. van der Waals H⋯H contacts contribute the most to the Hirshfeld surface (66.9%) followed by O⋯H/H⋯O (22.1%) contacts associated with weak hydrogen bonds.

Crystal structures of three N-(aryl-sulfon-yl)-4-fluoro-benzamides

The crystal structures of three N-(aryl­sulfon­yl)-4-fluoro­benzamides, namely 4-fluoro-N-(2-methyl­phenyl­sulfon­yl)­benzamide, (I), N-(2-chloro­phenyl­sulfon­yl)-4-fluoro­benzamide, (II), and N-(4-chloro­phenyl­sulfon­yl)-4-fluoro­benzamide monohydrate, (III), are described and compared with related structures. The conformation of the three mol­ecules is very similar with the aromatic rings being inclined to one another by 82.83 (11) and 85.01 (10)° in the two independent mol­ecules of (I), 89.91 (10)° in (II) and 81.82 (11)° in (III).

The crystal structures of three N-aryl­sulfonyl-4-fluoro­benzamides, namely 4-fluoro-N-(2-methyl­phenyl­sulfon­yl)benzamide, C₁₄H₁₂FNO₃S, (I), N-(2-chloro­phenyl­sulfon­yl)-4-fluorobenzamide, C₁₃H₉ClFNO₃S, (II), and N-(4-chloro­phenyl­sulfon­yl)-4-fluoro­benzamide monohydrate, C₁₃H₉ClFNO₃S·H₂O, (III), are described and compared with related structures. The asymmetric unit of (I) contains two independent mol­ecules (A and B), while that of (II) contains just one mol­ecule, and that of (III) contains a mol­ecule of water in addition to one main mol­ecule. The dihedral angle between the benzene rings is 82.83 (11)° in mol­ecule A and 85.01 (10)° in mol­ecule B of (I), compared to 89.91 (10)° in (II) and 81.82 (11)° in (III). The crystal structure of (I) features strong N—H⋯O hydrogen bonds between the A and B mol­ecules, resulting in an R₄⁴(16) tetra­meric unit. These tetra­meric units are connected into sheets in the bc plane by various C—H⋯O inter­actions, and adjacent sheets are further inter­linked via C—H⋯π_ar­yl inter­actions, forming a three-dimensional architecture. The crystal structure is further stabilized by π_ar­yl–π_ar­yl and S=O⋯π_ar­yl inter­actions. In the crystal of (II), mol­ecules are connected into R₂²(8) and R₂²(14) dimers via N—H⋯O hydrogen bonds and C—H⋯O inter­actions, respectively; the dimers are further inter­connected via a weak C=O⋯π_ar­yl inter­action, leading to the formation of chains along [1-10]. In the crystal of (III), N—H⋯O and O—H⋯O hydrogen bonds involving both the main mol­ecule and the solvent water mol­ecule results in the formation of sheets parallel to the bc plane. The sheets are further connected by C—H⋯O inter­actions and weak C—Cl⋯π_ar­yl, C—F⋯π_ar­yl and S=O⋯π_ar­yl inter­actions, forming a three-dimensional architecture.

Crystal structure of N,N,N',N',N'',N''-hexa-methyl-guanidinium cyanate 1.5-hydrate

The title hydrated salt, C7H18N3 (+)·OCN(-).1.5H2O, was synthesized starting from N,N,N',N',N'',N''-hexa-methyl-guanidinium chloride by a twofold anion-exchange reaction. The asymmetric unit contains two cations, two cyanate anions and three water mol-ecules. One cation shows orientational disorder and two sets of N-atom positions were found related by a 60° rotation, with an occupancy ratio of 0.852 (6):0.148 (6). The C-N bond lengths in both guanidin-ium ions range from 1.329 (2) to 1.358 (10) Å, indicating double-bond character, pointing towards charge delocalization within the NCN planes. Strong O-H⋯N hydrogen bonds between the crystal water mol-ecules and the cyanate ions and strong O-H⋯O hydrogen bonds between the water mol-ecules are present, resulting in a two-dimensional hydrogen bonded network running parallel to the (001) plane. The hexa-methyl-guanidinium ions are packed in between the layers built up by water mol-ecules and cyanate ions.

Crystal structure of (5-chloro-2-hy-droxy-phen-yl)(3-methyl-isoxazolo[5,4-b]pyridin-5-yl)methanone

In the title compound, C₁₄H₉ClN₂O₃, the fused pyridine and isoxazole rings are approximately planar, making a dihedral angle of 1.14 (16)°. The mol­ecule is twisted with the benzene ring and the mean plane through the fused pyridine-isoxazole ring system being inclined to one another by 47.03 (13)°. There is an intra­molecular O—H⋯O hydrogen bond forming an S(6) ring motif. In the crystal, mol­ecules are linked by C—H⋯N hydrogen bonds, forming chains propagating along [001]. The chains are linked by slipped parallel π–π inter­actions, involving inversion-related benzene rings, forming slabs lying parallel to the bc plane {inter-centroid distance = 3.770 (2) Å].

Crystal structure of 16-hy-droxy-4,4,10,13,14-penta-methyl-17-(6-methyl-hept-5-en-2-yl)-4,5,6,9,10,11,12,13,14,15,16,17-dodeca-hydro-1H-cyclo-penta-[a]phenanthren-3(2H)-one

The title compound, C30H48O2, contains a fused four-ring triterpenoid system. In the mol-ecule, the two cyclo-hexane rings adopt a chair conformation and a twist boat conformation, respectively, the central cyclo-hexene ring adopts a half-chair conformation whereas the five membered ring adopts an envelope conformation. In the crystal, O-H⋯O hydrogen bonds between the hy-droxy and carbonyl groups of adjacent mol-ecules link the mol-ecules into supra-molecular chains propagating along the b-axis direction.

Cystal structre of 5-hy-droxy-2-nitro-benzaldehyde

In the title compound, C₇H₅NO₄, the nitro group and the aldehyde group are inclined to the benzene ring by 16.6 (3) and 15.6 (3)°, respectively. In the crystal, mol­ecules are linked via O—H⋯O hydrogen bonds, forming chains along [100]. The chains are linked by C—H⋯O hydrogen bonds, forming a three-dimensional structure.

Crystal structure of rac-3-hy-droxy-2-(p-tol-yl)-2,3,3a,4,7,7a-hexa-hydro-1H-4,7-methano-isoindol-1-one

In the title compound, C₁₆H₁₇NO₂, the cyclo­hexene ring adopts a boat conformation, and the five-membered rings have envelope conformations with the bridging atom as the flap. Their mean planes are oriented at a dihedral angle of 86.51 (7)°. The mol­ecular structure is stabilized by a short intra­molecular C—H⋯O contact. In the crystal, mol­ecules are linked by O—H⋯O hydrogen bonds forming chains propagating along [100]. The chains are linked by C—H⋯π inter­actions, forming slabs parallel to (001).

Crystal structure of lead(II) tartrate: a redetermination

Single crystals of poly[μ4-tartrato-κ(6) O (1),O (3):O (1'):O (2),O (4):O (4')-lead], [Pb(C4H4O6)] n , were grown in a gel medium. In comparison with the previous structure determination of this compound from laboratory powder X-ray diffraction data [De Ridder et al. (2002 ▶). Acta Cryst. C58, m596-m598], the redetermination on the basis of single-crystal data reveals the absolute structure, all atoms with anisotropic displacement parameters and a much higher accuracy in terms of bond lengths and angles. It could be shown that a different space group or incorporation of water as reported for similarly gel-grown lead tartrate crystals is incorrect. In the structure, each Pb(2+) cation is bonded to eight O atoms of five tartrate anions, while each tartrate anion links four Pb(2+) cations. The resulting three-dimensional framework is stabilized by O-H⋯O hydrogen bonds between the OH groups of one tartrate anion and the carboxyl-ate O atoms of adjacent anions.

Crystal structure of ethyl (6-hy-droxy-1-benzo-furan-3-yl)acetate sesquihydrate

In the title hydrate, C12H12O4·1.5H2O, one of the water mol-ecules in the asymmetric unit is located on a twofold rotation axis. The mol-ecule of the benzo-furan derivative is essentially planar (r.m.s. deviation for the non-H atoms = 0.021 Å), with the ester group adopting a fully extended conformation. In the crystal, O-H⋯O hydrogen bonds between the water mol-ecules and the hy-droxy groups generate a centrosymmetric R 6 (6)(12) ring motif. These R 6 (6)(12) rings are fused, forming a one-dimensional motif extending along the c-axis direction.