Structural characteristics of dithiolene and nitronyl nitroxide salts: a unique oxygenation?deoxygenation process

Abstract

Slow interdiffusion of acetonitrile solutions of [TBA][Ni(bdt)₂] (bdt = 1,2-denzenedithiol) and [MPYNN][I] (MPYNN = 4,4,5,5-tetramethyl-2-(1-methyl-4-pyridinio)-3-oxide-4,5-dihydro-1H-1-imidazolyloxyl) resulted in two sets of crystals suitable for X-ray analysis. One of these showed a 2 : 1 salt comprising 1-methyl-4(1H-4,5-dihydro-4,4,5,5-tetramethylimidazol-2-yl)pyridinium, resulting from double deoxygenation of [MPYNN]⁺, and [Ni(bdt)₂]^? with two oxygen atoms bonded to two of the sulfur atoms in a trans configuration suggesting an oxygen-transfer reaction between the two components. The salt packed with mixed stacks of anions and cations. The second structure showed the starting complex [TBA][Ni(bdt)₂], only the second structural characterisation of the radical [Ni(bdt)₂]^?. Strong interactions between the complexes are prevented by alkyl arms of the countercation