Thioether Bonded Nickel(II)‐Azoimidazole Complexes: Structures, Spectra and Electrochemical Oxidation to the Nickel(III) State

Abstract

Abstract Nickel(II) complexes of 1‐alkyl‐2‐[( o ‐thioalkyl)phenylazo]imidazole (SRaaiNR′) are described in this article. SRaaiNR′ has imidazole‐N, azo‐N and thioether‐S donor centres. Counter ions ClO 4 – , pseudohalides [azide (N 3 – ), thiocyanate (CNS – )] are used in the syntheses of complexes. One of the structures of [Ni(SRaaiNR′) 2 ](ClO 4 ) 2 has suggested meridional binding of tridendate chelator with cis‐trans‐cis configuration in the sequence of cis ‐N(imidazole), trans ‐N(azo) and cis ‐S(thioether). Structural study of Ni II ‐azido‐SRaaiNR′ defines μ 1,1 ‐N 3 bridged Ni II dimer, [Ni(NNS)(N 3 ) 2 ] 2 and thus show interesting intramolecular ferromagnetic coupling. The best fit gave the results: J = 38.13 ± 0.6 cm –1 , g = 2.24 ± 0.002, D = 8.1 ± 0.4 cm –1 and R = 2.1 × 10 –4 . DFT computation has attempted to explain spectral, redox and magnetic properties of the complexes.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)