SYNTHESIS, CRYSTAL-STRUCTURE AND ELECTROCHEMISTRY OF BIS(N,N-DIMETHYLAMMONIUM) TRIS(1,2-BENZENEDITHIOLATO)TITANATE(IV)

Synthesis, electrochemical and structural data for [NH2(CH3)2]2[Ti(S2C6H4)3] (1) are described. Treating Ti{N(CH3)2}4 with 1,2-(HS)2C6H4 in a 1:3 ratio affords 1 in 94% isolated yield. Dark red single crystals of 1, suitable for X-ray crystallography, were obtained from CH3CN-Et2O mixtures. The molecular structure of the anion of 1, [Ti(S2C6H4)3]2-, provides a rare example of a homoleptic thiolate complex of titanium, but more importantly, the titanium centre contains the unusual TiS6 coordination of a skew-trapezoidal bipyramid (S-TzBP) with angular coordinates phi(A) = 60-degrees, phi(B) = 140-degrees and phi(E), = 75-degrees. The S6 polyhedron in 1 can be alternatively described as a pentagonal bipyramid with an equatorial vertex missing. A spectropotentiostatic experiment for 1 verified that a reversible one-electron reduction occurs at -1.51 V (vs Ag/AgCl, DMF). The electrochemical product was characterized by UV-vis (347, 414 and 434 nm) and ESR (77 K, rhombic: g1 = 2.18, g2 = 2.04 and g3 = 2.00) spectroscopies.