metal-organic compounds
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The title compound,[FeCl2(C18H25N3O2)], has a distorted tetrahedral Cl2N2 coordination of the FeII atom as a result of the constraints imposed by the 2-[2,2-bis(4,4-dimethyl-4,5-dihydro-1,3-oxazol-2-yl)propyl]pyridine ligand. The pyridine ring is almost perpendicular to the six-membered chelated ring containing the metal atom [dihedral angle between their mean planes = 88.5 (1)°].
organic compounds
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The title compound, C14H10N2O3, is a π-conjugated molecule containing a benzoxazole aromatic fused heterobicycle. The benzoxazole ring system is planar within 0.01 Å. The molecule assumes an approximately flat conformation, the benzoxazole ring system forming dihedral angles of 6.52 (12) and 7.4 (3)° with the benzene ring and the nitro group, respectively. In the crystal, molecules are connected by very weak C—HO hydrogen interactions, forming chains running parallel to the a or c axes. The methyl H atoms are disordered over two sets of sites of equal occupancy rotated by 60°.
organic compounds
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The title compound, C17H15N7O4, is a push–pull non-linear optical chromophore containing a dialkylamino donor group and the dicyanoimidazolyl acceptor separated by a π-conjugated path. The benzene and imidazole rings are not coplanar, making a dihedral angle of 10.0 (2)°. In the crystal, molecules are linked by an extended set of hydrogen bonds and several motifs are recognized. Pairs of molecules are held together by hydrogen bonding between carboxy O—H donor groups and diazenyl N-atom acceptors, forming R22(24) ring patterns across inversion centres. Four-molecule R44(28) ring motifs are formed, again across inversion centres, through hydrogen bonding involving carboxy O—H donor groups and diazenyl and imidazole N-atom acceptors. Four-molecule R44(42) patterns are formed among molecules related by translation and involve carboxy O—H and imidazole N—H donor groups with carbonyl O-atom and imidazole N-atom acceptors.
organic compounds
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The title compound, C31H48O7·0.04CH3COOH, is a polyoxygenated steroid obtained by selective chemical oxidation of 7-dehydrocholesteryl acetate. The asymmetric unit comprises three molecules of the steroid (Z′ = 3) and a molecule of acetic acid which has occupancy factor 0.131 (5). The geometric parameters of the independent molecules do not reveal significant differences. In one molecule, the terminal isopropyl group is disordered over two sets of sites with occupancy ratio 0.869 (5):0.131 (5). The three molecules reveal different hydrogen-bonding patterns. Each of them is involved in an intramolecular S(6) hydrogen-bonding motif, involving hydroxy groups as donor and acceptor. In the crystal, two independent molecules form dimers through hydrogen bonding between an OH donor and an acetate carbonyl acceptor, giving rise to R22(16) ring patterns. A single hydrogen bond between the OH group and a ketone carbonyl group is observed between two symmetry-independent molecules.
organic compounds
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The title compound, C31H48O7, a polyoxygenated steroid, was obtained by chemical oxidation of 7-dehydrocholesteryl acetate. The molecular geometry features trans A/B and C/D junctions at the steroid core with the acetyl groups in the equatorial position and a fully extended conformation for the alkyl side chain. A chair conformation is observed for rings A and C while ring B adopts a half-chair conformation. The five-membered ring D has an envelope conformation, with the C atom bearing the methyl group at the flap. The terminal isopropyl group and one acetyl group are disordered over two sets of sites with 0.774 (8):0.226 (8) and 0.843 (7):0.157 (7) ratios, respectively. An intramolecular S(6) O—HO hydrogen-bonding motif involving a hydroxy donor and acceptor is observed. In the crystal, chains of molecules running along the b axis are formed via O—HO hydrogen bonds between hydroxy donors and carbonyl acceptors of the ordered acetyl group, giving rise to a C(14) motif. The chains are wrapped around the 21 screw axes.
organic compounds
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In the title adduct, C15H10N4·2C10H10N2, the pyrimidine ring is nearly co-planar with the heteroatomic perimidine ring, as indicated dihedral angle between their mean planes of 3.21 (11)°. The diaminonaphthalene molecules are slightly twisted [dihedral angles = 4.2 (2) and 3.0 (2)°] because of the steric encumbrance of NH2 groups. The perimidine and diaminonaphthalene molecules are linked by N—HN hydrogen bonds, forming an R44(12) graph-set motif across an inversion center. In the crystal, alternating layers of the perimidine and diaminonaphthalene molecules are formed along [100]. In the perimidine layer, molecules are π–π stacked along the c-axis direction with an interplane separation of approximately 3.4 Å.
organic compounds
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The title compound, C20H18O6, prepared from D-mannitol by a two-step procedure, is a functionalized fused bis-tetrahydrofuran. In the central fragment, consisting of two fused tetrahydrofuran rings, one O atom and its two adjacent C atoms, a methylene and a bridgehead C atom, are disordered over two sets of sites with an occupancy ratio of 0.735 (9):0.265 (9). In the major component, the ring containing the disordered O atom is a half-chair conformation with twisted methylene and benzoate-substituted C atoms, whereas the other ring has a half-chair or T-form conformation. In the minor component, the ring with the disordered O atom has an envelope conformation, with the O atom as the flap, and the other ring has a half-chair conformation, with the O atom and the other bridgehead CH atom being twisted. The two aromatic rings are inclined to one another by 20.00 (12)°. In the crystal, adjacent molecules are linked via C—Hπ interactions, forming chains propagating along [010].
organic compounds
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The title compound, C20H16O7, contains a cis-fused γ-lactone tetrahydrofuran ring system functionalized with two benzoyloxy groups. Both rings adopt an envelope conformation. The molecule assumes an elongated shape and exibits non-crystallographic C2 symmetry. The benzoyloxy groups are almost planar [maximum deviations of 0.0491 (15) and 0.0336 (17) Å for the O atoms] and their mean planes are inclined to one another by 16.51 (4)°. The crystal packing features weak C—HO interactions. The aryl groups of adjacent molecules are parallel shifted with face-to-face contacts and a shortest intermolecular CC distance of 3.482 (4) Å.
organic compounds
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The title compound, C22H28N2O6, crystallizes with one half-molecule in the independent unit, the molecule being located on an inversion centre. The penthyl groups are in the all-trans conformation and an almost planar conformation of the whole molecule is observed [maximum deviation from the least-squares plane through all non-H atoms is 0.0229 (17) Å for an N atom]. The amino groups are involved in intra- and intermolecular hydrogen bonds. Intramolecular hydrogen bonding involving the amino group and ester carbonyl helps to lock the syn conformation of the ester with respect to the amino group. In the crystal, N—HO hydrogen bonding involving the amino group and the furan and ester carbonyl O atoms self-assembles the molecules into a two-dimensional hydrogen-bonded network parallel to (010) that displays interdigital packing sustained by alkyl–alkyl interactions.