COORDINATION BEHAVIOR OF VINYL AND ALKYNY L SUBSTITUTED CHLOROSILANES

The coordination ability of vinyl and alkynyl substituted chlorosilane s of type (H2C=CH)(R)SiCl2 (1a R = Cl, Ib R = CH3, 1c R = C=CPh), (H2C =CH)(PhC=C)(R)SiCl [1d R = N(SiMe(3))(2), 1e R = C=CPh], as well as of the disiloxane [(H2C=CH)(PhC=C)(2)Si]O-2 (11) towards different organ ometallic compounds, such as Fe-2(CO)(9) (2), MnCp(CO)(3) (4, Cp = eta (5)-C5H5) and Co-2(CO)(8) (6) is discussed. Treatment of the vinylchlo rosilanes 1a and 1b with Fe-2(CO)(9) (2) or MnCp(CO)(3) (4) in n-penta ne or n-hexane produces the compounds [(eta(2)-H2C=CH)ML(n)](R)SiCl2 [ 3a ML(n) = Fe(CO)(4), R = Cl; 3b ML(n) = Fe(CO)(4), R = CH3; 5a ML(n) = MnCp(CO)(2), R = Cl; 5b ML(n) = MnCp(CO)(2), R = CH3] in which the v inyl unit is eta(2)-coordinated to an Fe(CO)(4) or MnCp(CO)(2) moiety. While compounds la or Ib do not react with Co-2(CO)(8) (6) under simi lar applied reaction conditions, it is found that the alkynyl substitu ted chlorosilanes 1c-1e yield on addition of Co-2(CO)(8) the complexes [(eta(2)-C=CPh)Co-2(Co)(6)](H2C=CH)(R)SiCl [7a R = Cl, 7b R = N(SiMe( 3))(2), 7e R = C=CPh] or [(eta(2)-C=CPh)Co-2(CO)(6)](2)(H2C=CH)SiCl (7 d) respectively. In these compounds, the phenylethinyl ligands are eta (2)-coordinated to a Co-2(CO)(6) fragment, thus forming bulky dicobalt a-tetrahedrane units. Hydrolysis of compound 7c produces the disiloxan e {[(eta(2)-C=CPh)Co-2(CO)(6)](H2C=CH)(PhC=C)Si}O-2 (9). Additionally, this compound can be synthesized by the reaction of [(H2C=CH)(PhC=C)( 2)Si]O-2 (11) with two equivalents of Co-2(CO)(8) (6). On treatment of 6 with one equivalent of the disiloxane 11 the formation of compound -2(CO)(6)](H2C=CH)(PhC=C)Si-O-Si(HC=CH2)(C=CPh)(2) (12) is obtained. A ll compounds were characterized by analytical and spectroscopic data ( IR, H-1, C-13, Si-29 NMR, MS). The solid state structures of compounds [(eta(2)-C=CPh)Co-2(CO)(6)](H2C=CH)SiCl2 (7a) and [(eta(2)-C=CPh)Co-2 (CO)(6)](H2C=CH)(PhC=C)SiCl (7c) are reported. Complexes 7a and 7c cry stallize in the triclinic space group <P(1)over bar> with the followin g cell parameters: 7a a = 816.8(3), b = 1597.5(9), c = 1601.5(8) pm, a lpha = 101.49(4), beta = 100.01(4), gamma = 96.55(4)degrees, V = 2003( 1) x 10(6) pm(3) and Z = 4; 7c a = 827.6(2), b = 914.0(2), c = 1696.7( 5) pm, alpha = 89.35(2), beta = 76.75(2), gamma = 84.05(2)degrees, V = 1242(1) x 10(6) pm(3) and Z = 2.