Monocyclopentadienyl-Titanium Aryloxide Sulfide Complexes.

Abstract

In this report we extend titanium-sulfide chemistry, describing the syntheses, structures, and chemistry of monocyclopentadienyl-titanium aryloxide sulfide complexes. Reduction of Cp'Ti(OC(6)H(3)-2,6-i-Pr(2))Cl(2) (Cp' = Cp (1), Cp (3)) with n-BuLi affords the Ti(III) compounds [CpTi(OC(6)H(3)-2,6-i-Pr(2))(&mgr;-Cl)](2) (2) and [CpTi(OC(6)H(3)-2,6-i-Pr(2))(&mgr;-Cl)](2) (4). Compound 2 is oxidized by moisture, giving [CpTi(OC(6)H(3)-2,6-i-Pr(2))Cl](2)(&mgr;-O) (5). Oxidation of 4 by sulfur led to a mixture of uncharacterized products; however, reaction of 3 with 2 equiv of n-BuLi followed by subsequent addition of sulfur afforded a new diamagnetic species, CpTi(OC(6)H(3)-2,6-i-Pr(2))S(5) (6). Oxidation of 2 by S(8) yields [CpTi(OC(6)H(3)-2,6-i-Pr(2))](2)(&mgr;-S)(&mgr;-S(2)) (7). Reaction of the known sulfide-bridged dimer [CpTi(OC(6)H(3)-2,6-i-Pr(2))(&mgr;-S)](2) (8) with sulfur provides an alternative route to 7. The conversion of 7 to 8 is reversible as reaction of 7 with PPh(3) yields SPPh(3) and 8 quantitatively. Reaction of 1 with Li(2)S proceeds cleanly to give 8. Reduction of CpTi(OC(6)H(3)-2,6-i-Pr(2))(SPh)Cl (9) with n-BuLi affords the diamagnetic product [CpTi(OC(6)H(3)-2,6-i-Pr(2))(&mgr;-SPh)](2) (10), which reacts with phenylpyridine to generate the paramagnetic species CpTi(OC(6)H(3)-2,6-i-Pr(2))(SPh)(NC(5)H(4)Ph) (11). Attempts to isolate a monosulfide-bridged complex are described. Isolation of a monosulfide-bridged species, [CpTi(OC(6)H(3)-2,6-i-Pr(2))(2)](2)(&mgr;-S) (14), is achieved via reaction of [CpTi(OC(6)H(3)-2,6-i-Pr(2))(2)Cl (13) with Li(2)S. Structural data for 2, 4-7, 10, and 14 are reported. Comparisons are made with the related titanocene-sulfide systems, and the implications are considered.