NOVEL OXIDATION AND REDUCTION PRODUCTS OF THE NEUTRAL NICKEL-DITHIOLENE [NI(PR(2)(I)TIMDT)(2)] (PR(2)(I)TIMDT 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 c lass of nickel-dithiolenes showing remarkably high absorption in the n ear-IR (lambda approximate to 1000 nm), is reduced by use of 1,4-pheny lenediamine to the monoanion [Ni(Pr(2)(i)timdt)(2)](-1). This is isola ted 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 reac tion of 1 with IBr (1:4 molar ratio between reagents in CHCl3-CH3CN mi xtures), a solid, whose analytical and spectral results suggest it to be an adduct of ]diimidazolyl-1,3,6,8-tetraisopropane-2,7-dithione wit h I-2 and IBr (3), is isolated. The same reaction performed with a lar ge excess of IBr (1:60 molar ratio) gives on standing (three weeks) or ange-red crystals (4) formed by the dication ']diimidazolium-1,3,6,8-t etraisopropane-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)de grees, 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), a re given. (C) 1998 Elsevier Science S.A. All rights reserved.