Synthesis and Study of Cationic,Two‐Coordinate Triphenylphosphine– Gold–π Complexes |
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Authors: | Rachel E M Brooner Dr Timothy J Brown Prof Ross A Widenhoefer |
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Institution: | Department of Chemistry, Duke University, French Family Science Center, Durham, NC 27708 (USA), Fax: (+1)?919‐660‐1605 |
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Abstract: | Cationic, two‐coordinate triphenylphosphine–gold(I)–π complexes of the form (PPh3)Au(π ligand)]+ SbF6? (π ligand=4‐methylstyrene, 1? SbF6), 2‐methyl‐2‐butene ( 3? SbF6), 3‐hexyne ( 6? SbF6), 1,3‐cyclohexadiene ( 7? SbF6), 3‐methyl‐1,2‐butadiene ( 8? SbF6), and 1,7‐diphenyl‐3,4‐heptadiene ( 10? SbF6) were generated in situ from reaction of (PPh3)AuCl], AgSbF6, and π ligand at ?78 °C and were characterized by low‐temperature, multinuclear NMR spectroscopy without isolation. The π ligands of these complexes were both weakly bound and kinetically labile and underwent facile intermolecular exchange with free ligand (ΔG≠≈9 kcal mol?1 in the case of 6? SbF6) and competitive displacement by weak σ donors, such as trifluoromethane sulfonate. Triphenylphosphine–gold(I)–π complexes were thermally unstable and decomposed above ?20 °C to form the bis(triphenylphosphine) gold cation (PPh3)2Au]+SbF6? ( 2? SbF6). |
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Keywords: | alkene ligands allenes diene ligands gold π complexes |
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