Impact of the complementary electronic nature of C-X and M-X halogens and intramolecular X•••O interaction on supramolecular assemblies of Zn(II) complexes of o-halophenyl substituted hydrazides

The disparity in the electronic nature of organic (C-X) and inorganic (M-X) halogens in a supramolecular context has been demonstrated herein. Metal complexes [Zn(hyd-X)Cl-2] center dot nDMF of three o-halophenyl substituted hydrazide based ligands hyd-X (hyd = hydrazide, X = F, Cl and Br) have been synthesized and characterized by single crystal XRD. The C-X halogen atom in these complexes is involved in either intramolecular X. O interaction (when X = Cl/Br) or intramolecular N-H center dot center dot center dot X (when X = F) hydrogen bonding. Supramolecular networks propagated via intermolecular C-X center dot center dot center dot N halogen bonds and N-H center dot center dot center dot X(M) hydrogen bonds are observed in crystal structures of the complexes. Intramolecular X center dot center dot center dot O interaction and intramolecular N-H center dot center dot center dot F hydrogen bonds exert decisive roles in locking the molecular conformation of these compounds. DFT, AIM and NBO studies have been employed to acquire quantitative accounts of the halogen mediated non-covalent interactions.