Biomedical subjects
Publications and source records attributed to R E Gerkin.
The title substance, C20H34, crystallized in the centrosymmetric space group C2/c with a single molecule as the asymmetric unit. The molecule is quite crowded intramolecularly, and has a notably non-planar benzene ring. There is, however, virtually no intermolecular crowding.
The title compound, C14H10O, crystallized in the centrosymmetric space group P2(1)/c with a single molecule in the asymmetric unit. The C-H...O interaction having the shortest C...O distance involves the ring-bridging C9 atom and one of its H atoms, and results in the formation of a cyclic dimer about a center of symmetry. The molecular core is nearly planar. The dihedral angle between the best-fit plane of the ring to which the aldehyde group is attached and the plane of the aldehyde group is 4.4 (9) degrees. In a number of respects the molecular disposition is similar to that previously determined for the geometrically similar dibenzofuran-4-carboxaldehyde molecule.
The title acid, C19H16O2, crystallized in space group P1. In this structure, a hydrogen bond of the 'cyclic dimer' type is formed about a center of symmetry. The O(donor)...O(acceptor) distance is 2.647 (1) A. The carboxylic H and O atoms are ordered. The dihedral angle between the best-fit naphthalene plane and the carboxylic acid group plane is 11.1 (2) degrees.
The title acid, C10H7NO2, crystallized in the centrosymmetric space group P2(1)/c with one molecule in the asymmetric unit. There is a single hydrogen bond. O-H...N, with a donor-acceptor distance of 2.596 (1) A. The carboxylic H atom is ordered. The dihedral angle between the best-fit quinoline core plane and the carboxyl plane is 45.9 (1) degrees. Structural comparisons are made with the closely related molecule 2-phenylquinoline-4-carboxylic acid.
The title acid, C16H14O4, crystallized in the centrosymmetric space group C2/c with 1.5 molecules in the asymmetric unit. Each of the three independent carboxylic H atoms is ordered, and each participates in hydrogen bonding. The OD...OA distances in the hydrogen bonds are 2.584 (2), 2.647 (2) and 2.722 (2) A. Three sets of cyclic dimer hydrogen bonds are formed within and between two asymmetric units, linking them into molecular trimers. The trimers lie on twofold axes which bisect the central C-C bond of one molecule and the COOH dimer connecting the other two. The two biphenyl twist angles are 68.1 (1) and 64.6 (1) degrees. The dihedral angles between the benzene-ring planes and the planes of the carboxyl groups attached to them are 0.7 (3), 23.3 (2) and 18.4 (2) degrees. Structural comparisons are made with the 'parent' compound, diphenic acid, and with the isomeric compound, 6,6'-dimethylbiphenyl-2,2'-dicarboxylic acid.
The title acid, C4H5NO2S2, crystallized in the noncentrosymmetric space group P2(1)2(1)2(1) with one molecule as the asymmetric unit. Two hydrogen bonds occur, namely, N--H...O, with a donor-acceptor distance of 2.850 (2) A, and O-H...S (resonance induced), with a donor-acceptor distance of 3.318 (2) A; both H atoms involved are ordered. These two types of bonds link a given molecule to four neighbors, the molecules linked being of space-group symmetry types 1 and 3, or 2 and 4. These two subsets of molecules alternate in layers along c. Three significant C-H...O interactions occur, one of which crosslinks the subsets just described to produce a three-dimensional network of linked molecules. The absolute structure is determined.
The title compound, C7H8NO3+.Cl-.H2O, crystallized in the centrosymmetric space group P2(1)/c in an ionic form, the proton from HCl having been transferred to the amino N atom. The three H atoms on N, the H atom on the carboxyl group, the H atom of the hydroxyl group and the H atoms of the water molecule, all of which are involved in hydrogen bonding, are ordered. The eight 'best' hydrogen bonds have the following donor-acceptor distances: O...O 2.681 (2) and 2.598 (2); O...Cl 3.367 (1), 3.345 (2) and 3.156 (2); N...O 2.995 (2); N...Cl 3.173 (2) and 3.114 (2) A. In this structure, the acid cations are not linked directly to each other by hydrogen bonds, but are linked indirectly, via hydrogen bonds involving chloride ions and water molecules, into a three-dimensional network. Through basic second-level graphs, finite patterns substantially outnumber chains and rings.
The title acid, C8H7NO4.0.5H2O, crystallized in the centrosymmetric space group C2/c in a zwitterionic form (5-ammonioisophthalate), with the water molecule on a twofold axis. The three ammonio H atoms and the H atom on the remaining carboxyl group, which are involved in hydrogen bonding, are ordered. Three intermolecular N-H...O hydrogen bonds have N...O distances ranging from 2.762 (2) to 2.905 (2) A and N-H...O angles ranging from 155 (2) to 163 (2) degrees. Two intermolecular O-H...O hydrogen bonds have O...O distances of 2.536 (2) and 2.746 (2) A, and O-H...O angles of 178 (2) and 176 (2) degrees. A three-dimensional network of hydrogen bonds is present. Through basic second-level graphs involving acid-to-acid hydrogen bonds, chains are more numerous than rings.
The title acid, C18H12O3, crystallized in the centrosymmetric space group C2/c and exhibits carboxyl group hydrogen bonding of the cyclic dimer type about a center of symmetry. The Odonor-Oacceptor distance in the hydrogen bond is 2.692 (2) A. In addition, seven C-H groups and the three O atoms in the molecule are involved in significantly attractive C-H...O interactions with 11 neighbors, forming a three-dimensional network. The carboxylic H atom is ordered, as are the carboxylic O atoms.
Phenanthrene-4-carboxylic acid, C15H10O2, crystallized in the centrosymmetric space group P2(1)/n, while 1,2-dihydrophenanthrene-4-carboxylic acid, C15H12O2, crystallized in the centrosymmetric space group Pbca. In each structure, there is a single type of hydrogen bond: it is of the cyclic dimer type about a center of symmetry. The Odonor...Oacceptor distances are 2.634 (2) and 2.651 (2) A, and the O-H...O angles are 176 (3) and 173 (2) degrees, respectively, for the two structures. In each structure, the carboxy H and O atoms are ordered. The phenanthrene core of the fully aromatic acid is roughly planar; the dihedral angle between the best-fit core plane and the carboxy group plane is 63.7 (1) degree. As expected, the hydrogenated ring of the second acid is much less nearly planar; the remaining naphthalenoid core is, however, roughly planar and the dihedral angle between this best-fit plane and the carboxy group plane is 60.4 (1) degree.
The title acid, 8-aminooctanoic acid, C8H17NO2, crystallized in the centrosymmetric space group P2(1)/n in the zwitterionic form. The three H atoms involved in hydrogen bonding are ordered. The five intermolecular N-H...O hydrogen bonds have N...O distances ranging from 2.752 (2) to 3.258 (2) A and N-H...O angles ranging from 131 (2) to 165 (2) degrees. Each molecule is linked to six neighboring molecules by a total of ten hydrogen bonds. A complex network of hydrogen bonds ensues in which chains predominate.
The title acid, 3-amino-2-methylpropanoic acid monohydrate, C4H9NO2.H2O, crystallized in the centrosymmetric space group Pbca in the zwitterionic form. The three H atoms on N, which are involved in hydrogen bonding, are ordered. The three intermolecular N-H...O hydrogen bonds have N...O distances ranging from 2.758 (2) to 2.809 (2) A and N-H...O angles ranging from 149 (2) to 171 (1) degrees. The two intermolecular O-H...O hydrogen bonds have O...O distances 2.739 (2) and 2.755 (2) A, and O-H...O angles 170 (2) and 175 (2) degrees. Each acid molecule and its associated water molecule are directly hydrogen bonded to five acid molecules and two water molecules; the structure comprises two subsets of molecules which are not cross-linked by these hydrogen bonds. Through basic second-level graphs, approximately two-thirds of the hydrogen-bonding patterns are finite and one-third are chains; there is a single ring pattern, which occurs about a center of symmetry.
The title acid, C13H10O2, crystallized in the centrosymmetric space group P2(1)/c with four molecules in the asymmetric unit. These four molecules form two pairs of cyclic hydrogen-bonded dimers of the usual sort, but these are not formed about centers of symmetry. The Odonor...Oacceptor distances in these hydrogen bonds are 2.660(3), 2.638(3), 2.676(3) and 2.634(3) A. The carboxylic H atoms and the carboxylic O atoms are ordered. The biphenyl twist angles range from 46.5(2) to 52.5(2) degrees. The dihedral angles between the carboxyl group planes and the planes of the rings to which they are attached range from 43.6(3) to 50.9(3) degrees. In the two latter respects, this structure differs appreciably from the structures of the other two biphenyl monocarboxylic acids. The structure is layered parallel to the ab plane.
The title molecule, C12H18O3, crystallized in the centrosymmetric space group P2(1)/c with two molecules in the asymmetric unit. Each molecule donates three, and accepts three, hydrogen bonds. The Od...Oa distances in these bonds range from 2.687(3) to 2.787(2) A. The hydroxyl H atoms are ordered. A three-dimensional network of hydrogen-bond chains is formed which is 'decorated' with sets of cyclic hydrogen bonds and numerous finite hydrogen-bond patterns. This structure shows both similarities and differences with respect to the structures of the related molecules benzene-1,3,5-triacetic acid and benzene-1,3,5-trimethanol.
Phenolphthalein, C20H14O4, crystallized in the noncentrosymmetric space group Pna2(1) with two crystallographically inequivalent molecules. Each of these is linked to four others of its own type by four hydrogen bonds having Odonor...Oacceptor distances ranging from 2.631 (4) to 2.787 (4) A. While chains of hydrogen bonds propagate in a number of directions in this structure, cyclic hydrogen bonding is not observed. 3',3"-Dinitrophenolphthalein, C20H12N2O8, crystallized in the centrosymmetric space group Pbcn with a single molecule in the asymmetric unit. Each molecule is linked to three others by four hydrogen bonds having Odonor...Oacceptor distances ranging from 2.572 (4) to 3.274 (3) A. Although chains of hydrogen bonds are prominent in this structure, cyclic hydrogen bonding also occurs and forms dimers. As expected on the basis of the excess of potential acceptor O atoms over donors in both structures, significant C-H...O interactions are also abundant.
3-Aminopyrazole-4-carboxylic acid, C4H5N3O2, crystallized in the non-centrosymmetric space group P21 in the zwitterionic form. Intermolecular N--H...O hydrogen bonds with N...O distances of 2.768 (2) and 2.747 (2) A link molecules into two sets of chains propagating along [110] and [110]. The two sets of chains are crosslinked by strong hydrogen bonds. A complex network of hydrogen bonds ensues. There is a single intramolecular hydrogen bond. The pyrazole core is closely planar; the dihedral angle between the best-fit core planes of the molecules making up the two chains is 82.2 (1) degrees. The dihedral angles between the core plane and the planes of the carboxylate group and the amino group are in the region of 2 and 37 degrees, respectively.
The title compound, (+/-)-cis-2-phenylcyclopropanecarboxylic acid, C10H10O2, crystallized in the centrosymmetric space group P2(1)/n. The hydrogen bonding is of the cyclic dimer type about a center of symmetry; the Odonor...Oacceptor distance is 2.645 (2) A. The carboxylic H atom is ordered, as are the O atoms. The cyclopropane ring is asymmetric; the values found for the asymmetry parameters are delta(COOH) = -0.045 (4) A and delta(phenyl) = -0.027 (4) A.
The title compound, C14H12O6, crystallized in the centrosymmetric space group Pbca but does not exhibit hydrogen bonding of the usual cyclic dimer type about a center of symmetry or otherwise. Each molecule is linked to six neighbors by eight hydrogen bonds, which leads, in this structure, to a rich pattern of chains. Of the nine patterns of chains described, six propagate along the a direction, while three propagate along the c direction. The Odonor...Oacceptor distances in these hydrogen bonds are 2.683 (2), 2.706 (2), 3.011 (2) and 3.218 (3) A. In addition, each C-H group in the molecule is involved in one or more significantly attractive C-H...O interactions, while every O atom is involved in two or more. The two carboxylic H atoms are ordered, as are the carboxylic O atoms.