- Formation and X-ray crystal structure determination of the novel triplatinum cluster [(Ph3P)Pt(μ-SiC12H8)]3 from reaction of silafluorene with (Ph3P)2Pt(η2-C2H4
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The formation and x-ray crystal structure determination of the novel triplatinum cluster were studied. The trinuclear platinum complex containing bridging silylene units was formed from mononuclear silicon and platinum precursors. Dinuclear and especially
- Braddock-Wilking, Janet,Corey, Joyce Y.,Dill, Kimberly,Rath, Nigam P.
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- Spectroscopic and reactivity studies of platinum-silicon monomers and dimers
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Mononuclear Pt-Si-containing complexes with the general formulas (Ph 3P)2Pt(H)(SiAr2H) and (Ph3P) 2-Pt(SiAr2H)2 were produced at low temperature from the reaction of the secondary arylhydrosilanes Ph2-SiH 2, C12H8SiH2 (silafluorene), and C20H24SiH2 (3,7-di-tert-butylsilafluorene) with (Ph3P)2Pt(η2-C2H4). When solutions of the mononuclear complexes were run at low temperature and then warmed to room temperature, or when the reactions were run at room temperature or above, dinuclear Pt-Si-containing complexes were produced, [(Ph 3P)Pt(μ-η2-HSiAr2)]2 (Ar = Ph (4)) and [(Ph3P)2Pt(H)(μ-SiAr2)(μ- η2-HSiAr2)Pt(PPh3)] (Ar2 = C12H8 (8), C20H24 (15); both fluxional). A mechanism is proposed for the formation of the unsymmetrical dinuclear complexes (8 and 15) that involves a bimolecular reaction between two mononuclear species, (Ph3P)2Pt(H)(SiAr2H) and (Ph3P)Pt(H)(SiAr2H). VT-NMR studies of complexes 8 and 15 illustrate that a fluxional process occurs which can be explained by elimination and recoordination of a PPh3 ligand. Complex 15 reacted with added P(p-Tol)3 to produce a mixture of dinuclear products consistent with the presence of both types of phosphines in the dinuclear complexes. Reaction of the dinuclear complex 8 with the mononuclear complex 16 as well as the elevated-temperature reaction between 8 and 15 will be described.
- Braddock-Wilking, Janet,Corey, Joyce Y.,Trankler, Kevin A.,Xu, Huan,French, Lisa M.,Praingam, Ngamjit,White, Colin,Rath, Nigam P.
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p. 2859 - 2871
(2008/10/09)
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- Reaction of silafluorenes with (Ph3P) 2Pt(η2-C2H4): Generation and characterization of Pt-Si monomers, dimers and trimers
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The reaction of silafluorene (1; H2SiC12H 8) with (Ph3P)2Pt(η2-C 2H4) (2) at room temperature in C7D8 initially provided the mononuclear complex (Ph3P) 2Pt(H)[Si(H)C12H8] (3), followed by the appearance of the unsymmetrical dinuclear complex (Ph3P) 2(H)Pt(μ-SiC12H8)(μ-η2- HSiC12H8)Pt(PPh3) (4) and finally the novel trinuclear complex [(Ph3P)Pt(μ-SiC12H 8)]3 (5). The three complexes were characterized by multinuclear NMR spectroscopy and by X-ray crystallography (5). The molecular structure of 5 exhibits a nonplanar Pt3Si3 core. When the reaction was conducted at low temperature until the silafluorene was consumed and the mixture then warmed to room temperature, the dinuclear complex 4 could be isolated. The related substituted silafluorene system 3,7-di-tert- butylsilafluorene (6; H2SiC20H24) also reacted with 2 to provide both mono- and dinuclear complexes (7 and 8) analogous to 3 and 4. The dinuclear complex 8 was isolated and crystallographically characterized. Each of the two Pt centers in complex 8 exhibits a unique environment. In solution at low temperature 8 is best described as having one platinum center with a terminal hydride, [Pt(H)(PPh3)2], and the second platinum with a nonclassical [Si...H...Pt(PPh 3)] unit. However, in the solid state, the two hydrides may both adopt a bridging environment. Heating a sample of the unsymmetrical dimer 8 led to the formation of several products, one of which was the trimer 9, analogous to 5.
- Braddock-Wilking, Janet,Corey, Joyce Y.,Trankler, Kevin A.,Dill, Kimberly M.,French, Lisa M.,Rath, Nigam P.
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p. 4576 - 4584
(2008/10/09)
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