engleski

3-Acetylanilinium bromide, nitrate and dihydrogen phosphate: hydrogen-bonding motifs in one, two and three dimensions

In the title compounds, namely 3-acetylanilinium bromide, C_8H_10NO^+.Br^-, (I), 3-acetylanilinium nitrate, C_8H_10NO^+.NO_3^-, (II), and 3-acetylanilinium dihydrogen phosphate, C_8H_10NO^+.H_2PO_4^-, (III), each asymmetric unit contains a discrete cation, with a protonated amino group, and an anion. In the crystal structure of (I), the ions are connected via N-H...Br and N-H...O hydrogen bonds into a chain of spirofused R_2^2(14) and R_4^2(8) rings. In compound (II), the non-H atoms of the cation all lie on a mirror plane in the space group Pnma, while the nitrate ion lies across a mirror plane. The crystal structures of compounds (II) and (III) are characterized by hydrogen-bonded networks in two and three dimensions, respectively. The ions in (II) are connected via N-H...O hydrogen bonds, with three characteristic graph-set motifs, viz. C_2^2(6), R_1^2(4) and R_6^4(14). The ions in (III) are connected via N-H...O and O-H...O hydrogen bonds, with five characteristic graph-set motifs, viz. D, C(4), C_2^1(4), R_3^3(10) and R_6^4 (12). The significance of this study lies in its illustration of the differences between the supramolecular aggregations in the bromide, nitrate and dihydrogen phosphate salts of a small organic molecule. The different geometry of the counter-ions and their different potential for hydrogen-bond formation result in markedly different hydrogen-bonding arrangements.

hydrogen-bonding motifs; 3-acetylanilinium bromide; 3-acetylanilinium

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