Biomedical subjects

S Athimoolam

Publications and source records attributed to S Athimoolam.

3 recordsLinked to original sources

PubMed2006

Hydrogen-bonding motifs in 4-carboxyphenylammonium nitrate and perchlorate monohydrate, and in bis(4-carboxyphenylammonium) sulfate.

In the title compounds, C7H8NO2+.NO3-, (I), C7H8NO2+.ClO4-.H2O, (II), and 2C7H8NO2+.SO4(2-), (III), the carboxyl planes of the 4-carboxyphenylammonium cations are twisted from the aromatic plane. A homonuclear C(8) hydrogen-bonding motif of 4-carboxyphenylammonium cations is observed in both (I) and (II), leading to ;head-to-tail' layers. The cations in (III) form carboxyl group dimers, making a graph-set motif of R2(2)(8). In all the structures, anions connect the cationic layers and an infinite chain running along the c axis is observed, having the C2(2)(6) graph-set motif. Interestingly, in (II), the anions are connected through weak hydrogen bonds involving the water molecules, leading to a graph-set motif of R4(4)(12). Alternate hydrophobic and hydrophilic layers are observed in all three compounds as a result of the column-like arrangement of the aromatic rings of the cations and the anions. Furthermore, in (I), head-to-tail N-H...O interactions and interactions linking the cations and anions form an R6(4)(16) hydrogen-bonding motif, resulting in a pseudo-inversion centre at (1/2, 1/2, 0).

4-Aminobenzoic Acid↗

PubMed2006

L-prolinium picrate and 2-methylpyridinium picrate.

In the structure of L-prolinium picrate, C5H10NO2+.C6H2N3O7-, the Cgamma atom of the pyrrolidine ring has conformational disorder. Both the major and minor conformers of the pyrrolidine ring adopt conformations intermediate between a half-chair and an envelope. Both the cation and anion are packed through chelated three-centred N-H...O hydrogen bonds. The prolinium cation connects two different picrate anions, leading to an infinite chain running along the b axis. In 2-methylpyridinium picrate, C6H8N+.C6H2N3O7-, the cations and anions are packed separately along the a axis and are interconnected by N-H...O hydrogen bonds. Intramolecular contacts between phenolate O atoms and adjacent nitro groups are identified in both structures. A graph-set motif of R1(2)(6) is observed in both structures.

Journal Article↗

PubMed2006

Pyridoxinium picrate.

The title compound [systematic name: 3-hydroxy-4,5-bis(hydroxymethyl)-2-methylpyridinium 2,4,6-trinitrophenolate], C(8)H(12)NO(3)(+)xC(6)H(2)N(3)O(7)(-), is a complex of picric acid with pyridoxine. The asymmetric part of the unit cell contains one pyridoxinium cation and one picrate anion. The aromatic rings of the picrate anion and the pyridoxinium cation are inclined with a dihedral angle of 83.19 (7) degrees . An intramolecular hydrogen bond between OH and a nearby CH(2)OH group is observed in the cation. The hydrophobic layers at y = {1/2} are packed between the hydrophilic layers at y = 0.

Anions↗