Novel oxidation and reduction products of the neutral nickel-dithiolene [Ni(Pri2timdt)2] (Pri2timdt is the monoanion of 1,3-diisopropylimidazolidine-2,4,5-trithione)

[Ni(Pr(2)(i)timdt)(2)] (1) (Pr(2)(i)timdt is the monoreduced form of 1,3-diisopropylimidazolidine-2,4,5-trithione), which belongs to a new class of nickel-dithiolenes showing remarkably high absorption in the near-IR (lambda approximate to 1000 nm), is reduced by use of 1,4-phenylenediamine to the monoanion [Ni(Pr(2)(i)timdt)(2)](-1). This is isolated in the solid state as Bu4N[Ni(Pr(2)(i)timdt)(2)] (2), and exhibits in CH3CN solution the near-IR absorption at lambda = 1384 nm. By reaction of 1 with IBr (1:4 molar ratio between reagents in CHCl3-CH3CN mixtures), a solid, whose analytical and spectral results suggest it to be an adduct of 4,5,9,10-tetrathiocino[1,2-b:5,6-b']diimidazolyl-1,3,6,8-tetraisopropane-2,7-dithione with I-2 and IBr (3), is isolated. The same reaction performed with a large excess of IBr (1:60 molar ratio) gives on standing (three weeks) orange-red crystals (4) formed by the dication 4,5,9,10-tetrathiocino[1,2-b:5,6-b']diimidazolium-1,3,6,8-tetraisopropane-2,7-diiodo containing IBr2- counterions. Spectroscopic and X-ray diffraction studies of 2 (monoclinic, space group P2(1)/c, a = 18.396(5), b = 13.553(6), c = 17.582(5) Angstrom, beta = 96.59(2)degrees, Z = 4) and 4 (monoclinic, space group P2(1)/c, a = 9.304(7), b = 8.202(7), c = 23.289(5) Angstrom, beta = 100.93(2)degrees, Z = 2), are given. (C) 1998 Elsevier Science S.A. All rights reserved.