Experimental and computational evidence for stabilising parallel, offset π[C(O)N(H)NC]⋯π(phenyl) interactions in acetohydrazide derivatives

Abstract

Parallel, offset π[C(O)N(H)NC]⋯π(phenyl) interactions are observed in the crystal of (2-thienyl)CH₂CON(H)–NC(H)Ph, along with more conventional non-covalent interactions. All notable interactions were analysed using Hirshfeld surface analysis, NCI plots and QTAIM analysis. The π[C(O)N(H)NC]⋯π(phenyl) interactions, whereby the (H) atom lies over the ring centroid and the N and C atoms on either side of the (H) atom closely overlay the 1,3-carbon atoms of the phenyl ring, are shown to be attractive. Theory suggests the energy of association provided by the π[C(O)N(H)NC]⋯π(phenyl) interaction to the molecular packing to be about 15 kJ mol⁻¹, a value similar to that provided by similarly oriented benzene and pyridine rings. A survey of related structures in the literature suggests that comparable interactions occur in approximately 5–6% of crystals where they can potentially occur.