Crystal structure of o-aminopyridinium dihydrogenmonophosphate, (NH2C5H4NH)[H2PO4]

Abstract

Source of materialThe hybrid compound was prepared by adding orthophosphoric acid to water, followed by the addition of 2-aminopyridine. The mixture was heated and stirred for two hours to attain homogeneity. The resulting solution was slowly evaporated at room temperature for several days, led to colorless single crystals, stable for long time under normal conditions of temperature and moisture. DiscussionThe asymmetric unit of the structure of (2-NH2CsH4NH)H2P04 consists of one phosphate anion and one organic cation ( (2) A is approximately equal to C=N double bond length, indicating that N2 atom of the amino group must be sp 2 hybridized. This is also supported by the C5-N2-H6 angle of 119.6°, and by the fact that atoms C5, N2, H5 and H6 lie almost in the pyridine plane. Main bond lengths and angles of these entities are as expected. The o-aminopyridinium cations are anchored onto the anionic three-dimensional network with similar direction, by framing hydrogen bonds with the oxygen atoms with N-H-O distances in the range 2.739(2) A -2.979(2) A. These hydrogen bonds contribute to the stability of the network of the crystal structure. This latter is additionally stabilized by π-π interactions considered as weak intermolecular interactions, between organic molecules stacked in opposition to each other along the a axis (d= 3.51 A).

A tetrachlorocobaltate(II) salt with 2-amino-5-picolinium: Synthesis, theoretical and experimental characterization

“…Optimized molecular structure gives a comparison between the optimized geometric parameters and experimental X-ray crystallographic parameters. From this table, the C-C linkages in the pyridine of the 2-amino-5-picolinium group were calculated at the range of 1.384 Å-1.512 Å which is compatible with other pyridine rings [36]. The average value of calculated bond length of C-H an N-H is equal to 1.1 Å relative to the mean value observed by experimentally of 1.01.…”