182817-98-7Relevant academic research and scientific papers
Synthesis, structure, and reactivity of (tBu2PC2H4PtBu 2)Ni(CH3)2 and {(tBu2PC2H4PtBu 2)Ni}2(μ-H)2
Bach, Ingrid,Goddard, Richard,Kopiske, Carsten,Seevogel, Klaus,P?rschke, Klaus-Richard
, p. 10 - 20 (1999)
Oxidative addition of CH3I to (dtbpe)Ni(C2H4) (dtbpe = tBu2PC2H4PtBu 2) affords (dtbpe)-Ni(I)CH3 (1). The reaction of (dtbpe)NiCl2 or 1 with the stoichiometric quantity of (tmeda)-Mg(CH3)2 yields (dtbpe)Ni(CH3)2 (2). (dtbpe)Ni(I)CD3 (1-d3) and (dtbpe)Ni(CD3)2 (2-d6) have been prepared analogously. Thermolysis of 2 in benzene affords {(dtbpe)Ni}2(μ-η2:η 2-C6H6) (4). The reaction of either 2 or 4 with hydrogen (H2, HD, D2) gives {(dtbpe)Ni}2(μ-H)2 (3) and the isotopomers {(dtbpe)Ni}2(μ-H)(μ-D) (3-d) and {(dtbpe)Ni}2(μ-D)2 (3-d2). According to the NMR spectra, the structure of 3 is dynamic in solution. The crystal structures of 2 and 3 have been determined by X-ray crystallography. Solution thermolysis of 2 or reduction of (dtbpe)NiCl2 with Mg* in the presence of alkanes probably involves σ-complex-type intermediates [(dtbpe)Ni(η2-R′H)] (R′ = e.g. C2H5, A). While the nonisolated [(dtbpe)Ni0] σ-complexes A are exceedingly reactive intermediates, isolated 3 and 4 represent easy to handle starting complexes for [(dtbpe)Ni0] reactions. Partial protolysis of 2 with CF3SO3H affords (dtbpe)Ni(CH3)(OSO2CF3) (5). Complex 5 reacts slowly with 2 equiv of ethene to give equimolar amounts of [(dtbpe)Ni(C2H5)]+(OSO 2CF3-) (6) and propene. The reaction is thought to be initiated by an insertion of ethene into the Ni-CH3 bond of 5 to form the intermediate [(dtbpe)Ni(C3H7)(OSO2CF 3)] (G), followed by elimination of propene to give the hydride intermediate [(dtbpe)Ni(H)(OSO2CF3)] (H), which on insertion of ethene into the Ni-H bond affords 6.
