Article abstract of DOI:10.1016/0022-328X(96)06287-0

The coordination ability of vinyl and alkynyl substituted chlorosilanes of type (H₂C=CH)(R)SiCl₂ (1a R = Cl, lb R = CH₃, 1c R = C≡CPh), (H₂C=CH)(PhC≡C)(R)SiCl [1d R = N(SiMe₃)₂, 1e R = C≡CPh], as well as of the disiloxane [(H₂C=CH)(PhC≡C)₂Si]₂O (11) towards different organometallic compounds, such as Fe₂(CO)₉ (2), MnCp(CO)₃ (4, Cp = η⁵-C₅H₅) and Co₂(CO)₈ (6) is discussed. Treatment of the vinylchlorosilanes 1a and 1b with Fe₂(CO)₉ (2) or MnCp(CO)₃ (4) in n-pentane or n-hexane produces the compounds [(η²-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 vinyl unit is η-coordinated to an Fe(CO)₄ or MnCp(CO)₂ moiety. While compounds 1a or 1b do not react with Co₂(CO)₈ (6) under similar applied reaction conditions, it is found that the alkynyl substituted chlorosilanes 1c-1e yield on addition of Co₂(CO)₈ the complexes [(η²-C=CPh)Co₂(CO)₆](H₂C=CH)(R)SiCl [7a R = Cl, 7b R = N(SiMe₃)₂, 7c R = C≡CPh] or [(η²-C≡CPh)Co₂(CO)₆]₂(H₂C=CH)SiCl (7d) respectively. In these compounds, the phenylethinyl ligands are η²-coordinated to a Co₂(CO)₆ fragment, thus forming bulky dicobalta-tetrahedrane units. Hydrolysis of compound 7c produces the disiloxane {[(η²-C=CPh)Co₂(CO)₆](H₂C=CH)(PhC≡C)Si}₂O (9). Additionally, this compound can be synthesized by the reaction of [(H₂C=CH)(PhC≡C)₂Si]₂O (11) with two equivalents of Co₂(CO)₈ (6). On treatment of 6 with one equivalent of the disiloxane 11 the formation of compound [(η²-C≡CPh)Co₂(CO)₆](H₂C=CH)(PhC≡C)Si-O-Si(HC=CH₂)(C=CPh)₂ (12) is obtained. All compounds were characterized by analytical and spectroscopic data (IR, ¹H, ¹³C, ²⁹Si NMR, MS). The solid state structures of compounds [(η²-C≡CPh)Co₂(CO)₆](H₂C=CH)SiCl₂ (7a) and [(η²-C≡CPh)Co₂(CO)₆](H₂C=CH)(PhC≡C)SiCl (7c) are reported. Complexes 7a and 7c crystallize in the triclinic space group P1 with the following cell parameters: 7a a = 816.8(3), b = 1597.5(9), c = 1601.5(8) pm, α = 101.49(4), β = 100.01(4), γ = 96.55(4)°, V = 2003(1) × 10⁶ pm³ and Z = 4; 7c a = 827.6(2), b = 914.0(2), c = 1696.7(5) pm, α = 89.35(2), β = 76.75(2), γ = 84.05(2)°, V = 1242(1) × 10⁶ pm³ and Z = 2. Alle Verbindungen wurden durch die Elementaranalyse und spektroskopisch (IR, ¹H-, ¹³C-, ²⁹Si-NMR, MS) vollstaendig charakterisiert. Von den Komplexen [(η²-C≡CPh)Co₂(CO)₆](H₂C=CH)SiCl₂ (7a) und [(η²-C≡CPh)Co₂(CO)₆](H₂C=CH)(PhC≡C)SiCl (7c) wurde eine Kristallstruktur angefertigt. Die Verbindungen 7a und 7c kristallisieren in der triklinen Raumgruppe P1 mit folgenden Zellparametern: 7a a = 816.8(3), b = 1597.5(9), c = 1601.5(8) pm, α = 101.49(4), β = 100.01(4), γ = 96.55(4)°, V = 2003(1) × 10⁶ pm³ und Z = 4; 7c a = 827.6(2), b = 914.0(2), c = 1696.7(5) pm, α = 89.35(2), β = 76.75(2), γ = 84.05(2)°, V = 1242(1) × 10⁶ pm³ und Z = 2.