BENZENE 1,2,4,5-TETRATHIOLATO DINUCLEAR COMPLEXES OF 1,1'-BIS(TRIMETHYLSILYL)METALLOCENES OF TITANIUM TRIADS - SYNTHESIS AND STRUCTURAL DETERMINATION OF [(ETA-5-ME3SIC5H4)2TIS2]2C6H2 AND [(ETA-5-ME3SIC5H4)2HFS2]2C6H2

The reaction of tetrasodium 1,2,4,5-tetramercaptobenzene with the 1,1'-bis(trimethylsilyl)metallocene dichlorides M(eta-5-C5H4R)2Cl2 (R = Si(CH3)3; M = Ti, 1a; Zr, 1b; Hf, 1c) gives the new dinuclear chelate-bridged complexes (eta-5-C5H4R)2MS2C6H2S2M(eta-5-C5H4R)2 (R = Si(CH3)3; M = Ti, 3a; Zr, 3b; Hf, 3c), which were characterized by IR, H-1 NMR and mass spectroscopy. The structures of 3a and 3c have been determined by X-ray diffraction analyses. The bridging MS2C6H2S2M moieties are in chair-like conformations with the MS2 planes inclined by 47-degrees for 3a and 52-degrees for 3c with respect to the S2C6S2 plane. Both compounds crystallize triclinic, space group P1BAR, with two crystallographically independent centrosymmetric molecules in the unit cell; lattice parameters for 3a are a 1174.7(5), b 1355.9(7), c 1475.9(11) pm, alpha 90.67(8), beta 97.13(8), gamma 98.03(5)-degrees; for 3c a 1188.6(3), b 1363.9(7), c 1519.6(9) pm, alpha 91.14(6), beta 98.37(5), gamma 98.68(3)-degrees.