Variation in supramolecular arrangements of hydrazones, o-H2NC6H4CMe[dbnd]NNHC6H4X (X[dbnd]H, o-, m- and p-NO2), derived from o-aminoacetophenone and phenylhydrazines

Abstract

The crystal structures of four hydrazones, 1, derived from phenylhydrazines, XC6H4NHNH2 (XH, o-NO2, m-NO2 or p-NO2) with 2-aminoacetophenone are reported, as is the mono hydrochloride, (2: Xm-NO2), of (1: Xm-NO2). Consistent strong intramolecular hydrogen bonds in 1 are of the type, NH(amino)⋯N(hydrazono), while (1: Xm-NO2) portrays an additional NH(hydrazono)⋯O(nitro), intramolecular hydrogen bond. Of interest, different sets of strong intermolecular interactions are found even among the nitro derivatives, 1. In (1: Xo-NO2), the strongest intermolecular interactions are NH(amino)⋯O(nitro) hydrogen bonds, while in (1: Xm-NO2 and p-NO2), both NH(hydrazono)⋯O(nitro) and NH(amino)⋯N(amino) are present. These strong intermolecular hydrogen bonds coupled with different combinations of some of CH⋯O, ππ stacking interactions and NO⋯π generate different supramolecular arrays for (1: X=nitro): 2-D, 2-D and 3-D, respectively for (1: Xo-NO2), for (1: Xm-NO2) and (1: Xp-NO2). In (1: XH), the major intermolecular interactions are NH(hydrazono)⋯N(amino hydrogen bonds: these, supplemented by weaker NH⋯π and CH⋯π interactions, generate a two-dimensional array.While significant changes in the intermolecular interactions result on formation of the salt, (2: Xm-NO2) from (1: Xm-NO2), the strong NH(amino)⋯N(hydrazono) intramolecular hydrogen bonds persist. Strong intermolecular hydrogen bonds found in (2: Xm-NO2) are of the types NH⋯Cl (both hydrazone and amine), NH(amino)⋯O(nitro): these coupled with weaker CH⋯O, NO⋯π, and ππ generate a three dimensional array.