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

The syntheses and crystal structures of (E)-N′-(3-cyano­benzyl­idene)-N-methyl-2-(thio­phen-2-yl)acetohydrazide, C(15)H(13)N(3)OS, (I), and (E)-N′-(4-meth­oxy­benzyl­idene)-N-methyl-2-(thio­phen-2-yl)acetohydrazide, C(15)H(16)N(2)O(2)S, (II), with different substituents in the meta and para position 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⋯N(c) (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).