(C(5)H(5-N)ME(N))(2)TICL2/MG/ME(3)SNC-CSNME(3) (N=0, 2-5) SYSTEMS - FORMATION AND CRYSTAL-STRUCTURES OF (C(5)ME(5))(2)TI(ETA(2)-ME(3)SNC-CSNME(3)) AND [(C(5)H(5-N)ME(N))(2)TI(MU-ETA(2)ETA(1)-C-CSNME(3))](2) (N=0,2) COMPLEXES

The reduction of (C(5)H(5-n)Me(n))(2)TiCl2 (n = 0, 2-5) by Mg in THF and in the presence of bis(trimethylstannyl)acetylene affords mainly single products for n = 0, 2, and 5, which were isolated and characterized. X-ray structure analyses proved the compounds to be the monomeric Ti(II) complex (C(5)Me(5))(2)Ti[eta(2)-C-2(SnMe(3))(2)] (1; monoclinic, C2/c, No. 15 (Z = 4), a = 15.879(15) Angstrom, b = 11.851(11) Angstrom, c = 17.555(13) Angstrom, and beta = 109.60(5)degrees), and the diamagnetic dimeric Ti(III) compounds [(C5H5)(2)Ti(mu-eta(2):eta(1)-C double bond CSnMe(3))](2) (2;, orthorhombic, Pbca, No. 61 (Z = 4), a = 14.846(2) Angstrom, b = 13.119(2) Angstrom, and c = 15.107(2) Angstrom) and [(C(5)H(3)Me(2))(2)Ti(mu-eta(2):eta(1)-C double bond CSnMe(3))](2) (3; monoclinic, P2(1)/n, No. 14 (Z = 2), a = 10.789(3) Angstrom, b = 9.976(2) Angstrom, c = 17.289(2) Angstrom, and beta = 98.98(1)degrees). Compounds 2 and 3 arise from the oxidative addition of C-2(SnMe(3))(2) to a titanocene(II) species followed by thermal elimination of the SnMe(3) radical, yielding Sn(2)Me(6) The molecular structures of all the compounds are very similar to those of analogous trimethylsilyl-substituted compounds. The systems for n = 3 and 4 afford mixtures of unidentified products which are different from structural types of 1 and 2 or 3, as indicated by the infrared data.