Platinum Complexes of a Borane‐Appended Analogue of 1,1′‐Bis(diphenylphosphino)ferrocene: Flexible Borane Coordination Modes and in situ Vinylborane Formation |
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Authors: | Bradley E. Cowie Prof. David J. H. Emslie |
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Affiliation: | Department of Chemistry and Chemical Biology, McMaster University, 1280 Main St. West, Hamilton, Ontario, L8S 4M1 (Canada) |
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Abstract: | A bis(phosphine)borane ambiphilic ligand, [Fe(η5‐C5H4PPh2)(η5‐C5H4PtBu{C6H4(BPh2)‐ortho})] (FcPPB), in which the borane occupies a terminal position, was prepared. Reaction of FcPPB with tris(norbornene)platinum(0) provided [Pt(FcPPB)] ( 1 ) in which the arylborane is η3BCC‐coordinated. Subsequent reaction with CO and CNXyl (Xyl=2,6‐dimethylphenyl) afforded [PtL(FcPPB)] {L=CO ( 2 ) and CNXyl ( 3 )} featuring η2BC‐ and η1B‐arylborane coordination modes, respectively. Reaction of 1 or 2 with H2 yielded [PtH(μ‐H)(FcPPB)] in which the borane is bound to a hydride ligand on platinum. Addition of PhC2H to [Pt(FcPPB)] afforded [Pt(C2Ph)(μ‐H)(FcPPB)] ( 5 ), which rapidly converted to [Pt(FcPPB′)] ( 6 ; FcPPB′=[Fe(η5‐C5H4PPh2)(η5‐C5H4PtBu{C6H4(BPh‐CPh=CHPh‐Z)‐ortho}]) in which the newly formed vinylborane is η3BCC‐coordinated. Unlike arylborane complex 1 , vinylborane complex 6 does not react with CO, CNXyl, H2 or HC2Ph at room temperature. |
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Keywords: | boranes coordination modes donor‐acceptor systems ligand design phosphane ligands |
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