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

Nickel(II) complexes of 1-alkyl-2-[(o-thioalkyl)phenylazojimidazole (SRaaiNR') are described in this article. SRaaiNR' has imidazole-N, azo-N and thioether-S donor centres. Counter ions CIO4, pseudohalides [azide (N-3(-)), thiocyanate (CNS-)] are used in the syntheses of complexes. One of the structures of [Ni(SRaaiNR')(2)](CIO4)(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 Nil'-azido-SRaaiNR' defines mu(1), (1)-N-3 bridged Ni' dimer, [Ni(NNS)(N-3)(2)](2) and thus show interesting intrarnolecular 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 X 10(1). DFT computation has attempted to explain spectral, redox and magnetic proper-ties of the complexes. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)