Synthesis, mol­ecular and crystal structure of 1-(1,2-di­hydro­phthalazin-1-yl­idene)-2-[1-(thio­phen-2-yl)ethyl­idene]hydrazine

The title compound, C(14)H(12)N(4)S, was synthesized by the condensation reaction of hydralazine and 2-acetyl­thio­phene and during the reaction, a proton transfer from the imino nitro­gen atom to one of the endocylic nitro­gen atoms occurred. The compound crystallizes in the monoclinic crystal system with two independent mol­ecules (mol­ecules 1 and 2) in the asymmetric unit. In each mol­ecule, there is a slight difference in the orientation of the thio­phene ring with respect to phthalazine ring system, mol­ecule 1 showing a dihedral angle of 42.51 (1)° compared to 8.48 (1)° in mol­ecule 2. This implies an r.m.s deviation of 0.428 (1) Å between the two mol­ecules for the 19 non-H atoms. The two independent mol­ecules are connected via two N—H⋯N hydrogen bonds, forming dimers which inter­act by two bifurcated π–π stacking inter­actions to build tetra­meric motifs. The latter are packed in the ac plane via weak C—H⋯π inter­actions and along the b axis via C—H ⋯N and C—H⋯π inter­actions. This results a three-dimensional architecture with a tilted herringbone packing mode.