Square planar bis{3,6-bis(trimethylsilyl)benzene-1,2-dithiolato}metal complexes of Cr(II), Co(III), and Rh(II): an experimental and density functional theoretical study.

The three square planar complexes N(n-Bu)(4)[Cr(II)L(2)] x 4 CH(3)CN (S = 2; 1), [N(n-Bu)(4)][Co(III)L(2)] (S = 1; 3), and N(n-Bu)(4)[Rh(II)L(2)] x 4 CH(3)CN (S = 1/2; 4) have been prepared and structurally characterized by X-ray crystallography (L(2-) represents the 3,6-bis(trimethylsilyl)benzene-1,2-dithiolate(2-)). Aerial oxidation of CH(2)Cl(2) solutions of 1 produced purple crystals of [N(n-Bu)(4)][Cr(V)OL(2)] x 2 CH(2)Cl(2) (S = 1/2; 2), the structure of which has also been determined by X-ray crystallography. The electro- and magnetochemistry of all species has been studied. Their electronic structures have been experimentally investigated by recording their electronic and EPR spectra; solid-state temperature-dependent magnetic susceptibility measurements have been performed. Density functional theoretical calculations at the ZORA-B3LYP level have been carried out for all four species in order to obtain a better understanding of the electronic structure of the square planar complexes and the one-electron reduced Rh(I)L(2) species. The reactivity of the latter with CH(3)I has been studied, and two products have been identified: cis-[Rh(III)I(2)(L'')(L')] and cis-[Rh(III)(CH(3))(I)(L'')(L')] where (L')(-) represents the S-methylated monoanion of L(2-) and (L'')(0) is the neutral, twice-S-methylated form of (L)(2-).