REACTIONS OF TITANIUM(III) AND ZIRCONIUM(III) COMPLEXES WITH UNSATURATED ORGANIC-SYSTEMS - X-RAY STRUCTURE OF ([(ETA-5-C5H5)ZR(CH3)]2[MU-ETA-1-ETA-2-CN(ME2C6H3)](MU-ETA-5-ETA-5-C10H8))

The reaction of {[Me2Si(C5H4)2]TiCl}2 with LiC = CPh takes place with C-C coupling of the acetylide ligand to give a dimeric titanium(IV) complex containing a bridging 1,4-diphenyl-1,3-butadiene group. Two intermediates were isolated from this reaction, one containing sigma-C = CPh units and the other consisting of two bridging -C = CPh groups-sigma and pi-bound to both metal centers. In a similar reaction of {[(eta(5)-C5H5)Zr(mu-Cl)]2(mu-eta(5)-eta(5)-C10H8)} with LiC = CPh only the compound with-sigma,pi-C = CPh groups was isolated. This complex shows a high Zr = C alkylidene character with what are essentially Zr(IV) centers. The same zirconium(III) derivative also reacts with 2,6-dimethylphenyl isocyanide, leading to the oxidative addition of the isocyanide ligand to give an imine dimeric complex containing bridging eta(1)-eta(2) groups with C and N coordinated to both zirconium atoms, {[(eta(5)-C5H5)ZrCl]2[mu-eta(1)eta(2)-CN(2,6-Me2C6H3)](mu-eta(5)-eta(5)-C10H8)}. The alkylation of this compound with MeLi produces the dimethyl derivative which was studied by X-ray diffraction methods, and its crystal structure is reported. The compound crystallizes in the monoclinic space group P2(1)/n, with Z = 8, a = 14.739 (4) angstrom, b = 20.583 (7) angstrom, c = 17.535 (5) angstrom, and beta = 103.77 (1)-degrees. Anisotropic refinement of all atoms, except hydrogen, converged to the residuals R = 0.053, R(w) = 0.058 for 6448 observed reflections. The two zirconium atoms are bonded together by fulvalene and isocyanide groups.