Nickel(II)-azido/thiocyanato complexes of 1-alkyl-2-(arylazo) imidazole: single crystal X-ray structure of [Ni(Pai-Me)₂(N₃)₂] (Pai-Me=1-methyl-2(phenylazo)imidazole)

Abstract

Abstract Reaction of Ni(ClO4)2 · 6H2O with 1-alkyl-2-(arylazo)imidazole (RaaiR/) and sodium azide (NaN3) or ammonium thiocyanate (NH4SCN) (1 : 2 : 2 molar ratio) in methanol gives [Ni(RaaiR/)2(X)2] (X=N3 (3, 4) and SCN (5, 6). All these complexes are characterized by elemental analyses, UV–Vis and IR spectral data, thermal and magnetic moment measurements. The X-ray structure is confirmed by single crystal measurement of [Ni(Pai-Me)2(N3)2] (3a). Cyclic voltammetry exhibits quasireversible response at >0.80 V corresponding to Ni(III)/Ni(II) couple along with ligand reductions at negative potential (<−0.5 V) to SCE reference. The electronic structure, spectral and redox properties are explained by DFT (Gaussian03) calculation. Keywords: Nickel(II)-azido/thiocyanato complexesArylazoimidazolesX-ray structureElectrochemistryDFT calculation Acknowledgement Financial support from UGC, New Delhi is gratefully acknowledged.