Formation of a New CuII-Triazole Ester Complex From 1,2-Cyclohexanedione Compound as a Consequence of Copper(II)-Catalyzed Click Reaction

Abstract

Reaction of 1,2-cyclohexanedione-bis(p-bromobenzohydrazone) (CBB) as a bis-aroyl-hydrazone derivative with copper(II) nitrate trihydrate in acetonitrile under ambient conditions produced a mononuclear Cu(II) complex [Cu(TE)(NO3)(2)] (TE: triazole-ester) (1). TE is an intermediate which is formed in situ during the oxidation of CBB by Cu(II) ion based on so-called copper(II)-catalyzed click reaction. CBB and 1 are characterized with various techniques. On the basis of single-crystal X-ray crystallography, compound 1 is confirmed as a 4-coordinate mononuclear Cu(II) complex with a distorted square planner geometry. In this compound, copper is bound to the 1-N of two monodentate triazole ester molecules and two monodentate nitrate ions. Moreover, the antimicrobial activity of CBB and 1 against some selected pathogenic bacteria was investigated. Due to this study, these compounds showed a good antibacterial activity. In addition, the Hirshfeld surface analysis (d(norm) surface and two-dimensional fingerprint plots) was performed to reveal the nature of intermolecular interactions in CBB and 1. The most important contributions for the crystal packing of CBB are mainly from H horizontal ellipsis H (28.8%), Br horizontal ellipsis H/H horizontal ellipsis Br (23.2%) and C horizontal ellipsis H/H horizontal ellipsis C (19.5%) interactions, while the most important contributions for the crystal packing of 1 are found to be from H horizontal ellipsis H (27%), O horizontal ellipsis H/H horizontal ellipsis O (23.7%) and Br horizontal ellipsis H/H horizontal ellipsis Br (19%) interactions.