Chemistry of Oxophilic Transition Metals. 2. Novel Derivatives of “Titanocene” and “Zirconocene”

Reduction of dichlorobis(175-cyclopentadienyl)titanium(IV) (3) with 1.5 equiv of sodium amalgam (Na/Hg) gives the dinuclear η5:η6-fulvalene complex 4 of composition and the 5 in 40% yield each; both compounds represent Ti(III) species. The chloro-bridged complex 4 undergoes quick oxidation upon exposure to air, thus yielding the Ti(IV) derivative (6). Reduction of 4 with lithium triethylhydridoboranate cleanly gives “titanocene” 5, with the latter compound representing a good starting material for the synthesis of the sulfido-bridged fulvalene complex (7). Compound 7 in turn undergoes a sulfur/oxygen exchange reaction when treated with molecular oxygen; in this case, the oxo-/sulfido-bridged derivative (8) is formed. © 1986, American Chemical Society. All rights reserved.