ZIRCONIUM-SULFUR CHEMISTRY - SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF THE ZR3S3(TBUS)2(BH4)4(THF)2, ZR6S6(TBUS)4(BH4)8(THF)2, ZR3(S)(TBUS)10, AND (MG(THF)6)[ZR2(SPH)7.2(CH2PH)1.8]2-CENTER-DOT-THF CLUSTERS - ACTIVATION AND CLEAVAGE OF THE C-S BOND IN ZIRCONIUM-COORDINATED ALKANETHIOLATE LIGANDS

New zirconium thiolate complexes have been obtained by the acidification of either the Zr(BH4)4 or the Zr(CH2Ph)4 complexes by RSH molecules in reactions that produce either B2H6 or toluene as byproducts. The polynuclear clusters Zr3S3(tBuS)2(BH4)4(THF)2, 1, and Zr6S6(tBuS)4(BH4)8(THF)2, II, are obtained from (t)BuSH and Zr(BH4)4. The Zr3(S)(tBuS)10 cluster, III, is obtained from (t)BuSH and Zr(CH2Ph)4. The sulfido ligands in these clusters are obtained from the zirconium-coordinated (t)BuS- ligands as a result of C-S bond activation followed by what appears to be mainly a heterolytic bond cleavage reaction. The(Mg(THF)6)[Zr2(SPh)7.2(CH2Ph)1.8]2.3THF cluster, IV, was obtained from Zr(CH2Ph)4 and PhSH in the presence of H2CPhMgCl. The absence of S2- ligands in IV is attributed to a stronger C-S bond in the Z-coordinated PhS- ligands. The compounds I-IV crystallize all in the space group P2(1)/c. The cell dimensions are a = 11.545(3) angstrom, b = 16.481(4) angstrom, c = 18.118(4) angstrom, and beta = 91.23(2)-degrees for I, a = 12.443(1) angstrom, beta = 15.197(2) angstrom, c = 18.365(2) angstrom, and beta = 70.214(7)-degrees for II, a = 22.009(8) angstrom, b = 11.372(4) angstrom, c = 26.980(7) angstrom, and beta = 101.93(3)-degrees for III, and a = 14.352(6) angstrom, b = 22.307(14) angstrom, c = 23.554(8) angstrom, and beta = 95.46(3)-degrees for IV. The data for all structures were obtained on an automatic diffractometer employing Mo Kalpha radiation. Full matrix refinement of 235 parameters on 2169 data for I, 278 parameters on 3102 data for II, 315 parameters on 3966 data for III, and 387 parameters on 2582 data for IV gave final R(W) values of 0.050, 0.043, 0.069, and 0.070, respectively. The structures of III are closely related and contain the [Zr3(mu3-S)2(mu2-S)3]n+ core, with a distorted hexagonal bipyramidal structure, as a structural feature. In I and II the Zr3 subunits (n = 4) show two mu2-tBu thiolates and a mu2-sulfide ligands bridging the Zr atoms in the equatorial plane and two mu3-sulfido ligands serving as 'capping'' ligands on the axial positions. In III (n = 6) three mu2-tBu thiolates bridge the Zr atoms in the equatorial plane and mu3-sulfido and mu3-thiolato ligands serve as ''capping'' ligands on the axial positions. The coordination geometries of the Zr atoms are distorted octahedral, and in I and II BH4- and THF ligands are involved in coordination. Only sulfur ligands are coordinated to the zirconium atoms in III.