Synthesis, crystal structure and electrochemistry of bis( N,N-dimethylammonium) tris(1,2-benzenedithiolato)titanate(IV)

Abstract

Synthesis, electrochemical and structural data for [NH 2(CH 3) 2] 2[Ti(S 2C 6H 4) 3] ( 1 are described. Treating Ti{N(CH 3) 2} 4 with 1,2-(HS) 2C 6H 4 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 CH 3CNEt 2O mixtures. The molecular structure of the anion of 1, [Ti(S 2C 6H 4) 3] 2−, provides a rare example of a homoleptic thiolate complex of titanium, but more importantly, the titanium centre contains the unusual TiS 6 coordination of a skew-trapezoidal bipyramid (S-TzBP) with angular coordinates φ A = 60°, φ B = 140 E = 75°. The S 6 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: g 1 = 2.18 g 2 = 2.04 and g 3 = 2.00) spectroscopies.