Crystal structures and Hirshfeld surfaces of differently substituted (E)-N′-benzylidene-N-methyl-2-(thiophen-2-yl)acetohydrazides

Abstract

The syntheses and crystal structures of (E)-N′-(3-cyanobenzylidene)-N-methyl-2-(thiophen-2-yl)acetohydrazide, C15H13N3OS, (I), and (E)-N′-(4-methoxybenzylidene)-N-methyl-2-(thiophen-2-yl)acetohydrazide, C15H16N2O2S, (II), with different substituents in themetaandparaposition of the benzene ring are described. Compounds (I) and (II) both crystallize with two molecules in the asymmetric unit, with generally similar conformations [r.m.s. overlay fits for (I) and (II) of 0.334 and 0.280 Å, respectively] that approximate to L-shapes. The thiophene rings in (I) are well ordered, whereas those in (II) exhibit `flip' rotational disorder [occupancies 0.662 (2) and 0.338 (2) for molecule 1, and 0.549 (3) and 0.451 (3) for molecule 2]. The packing for (I) features short C—H...O interactions arising from the C—H grouping adjacent to the cyanide group and C—H...Nc(c = cyanide) links arising from the methine groups to generate [110] double chains. Weak C—H...π interactions interlink the chains into a three-dimensional network. The packing for (II) features numerous C—H...O and C—H...π interactions arising from different donor groups to generate a three-dimensional network. Hirshfeld fingerprint plots indicate significant differences in the percentage contact surfaces for (I) and (II).