General Route to Halide-Bridged Organopalladium A-Frame Complexes and Studies of Reductive Elimination from These Bimetallic Systems
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- 作者：Robert A. Stockland ; Jr. ; Mesfin Janka ; Gretchen R. Hoel ; Nigam P. Rath ; and Gordon K. Anderson
- 刊名：Organometallics
- 出版年：2001
- 出版时间：November 26, 2001
- 年：2001
- 卷：20
- 期：24
- 页码：5212 - 5219
- 全文大小：126K
- 年卷期：v.20,no.24(November 26, 2001)
- ISSN：1520-6041
文摘
Reactions of [Pd2Cl2(
-dppm)2] with RMgX (R = Me, Et, Bu, Ph, C6H4Me-4) at lowtemperature, followed by addition of CBr4 and excess NH4PF6 or 1 equiv of TlPF6, providedhalide-bridged organopalladium A-frame complexes of the form [Pd2R2(-X)(-dppm)2]PF6.Mixed metal complexes were obtained similarly starting from [PdPtCl2(-dppm)2]. Unsymmetrical A-frames of the type [Pd2(C6H2Me3-2,4,6)R(-Cl)(-dppm)2]+ were generated byreaction of [Pd(C6H2Me3-2,4,6)(dppm)2]+ (obtained by treatment of [PdCl2(cod)] with mesitylmagnesium bromide at low temperature, followed by 2 equiv of dppm) with [Pd2R2(-Cl)2(AsPh3)2]. The organopalladium A-frames did not react readily with CO, but thecorresponding acyl derivatives [Pd2(COR)2(-Cl)(-dppm)2]PF6 were produced by carbonylation of [Pd2R2(-Cl)2(AsPh3)2] followed by addition of dppm (R = Me, Et, Bn). Thermaldecomposition of [Pd2(CH2Ph)2(-Cl)(-dppm)2]Cl was found to be first order in A-frame andresulted in quantitative formation of [Pd2Cl2(-dppm)2] and 1,2-diphenylethane. The methyland aryl complexes underwent both reductive elimination and hydrogen abstraction reactions.[Pd2Et2(-Br)(-dppm)2]PF6 decomposed by 
-hydride elimination and subsequent reductiveelimination to yield ethene and ethane, whereas the butyl derivative gave both 1- and2-butene. Acetic acid was formed when [Pd2(COMe)2(-Cl)(-dppm)2]PF6 was heated in dmso-d6 solution, but decarbonylation was the predominant process in dioxane. The molecularstructures of [Pd2(CH2Ph)2(-Br)(-dppm)2]PF6·H2O,2C6H6 and [Pd2Cl2(-Cl)(-dppm)2]OH·0.5(CH3)2CO are also described.
-dppm)2] with RMgX (R = Me, Et, Bu, Ph, C6H4Me-4) at lowtemperature, followed by addition of CBr4 and excess NH4PF6 or 1 equiv of TlPF6, providedhalide-bridged organopalladium A-frame complexes of the form [Pd2R2(-X)(-dppm)2]PF6.Mixed metal complexes were obtained similarly starting from [PdPtCl2(-dppm)2]. Unsymmetrical A-frames of the type [Pd2(C6H2Me3-2,4,6)R(-Cl)(-dppm)2]+ were generated byreaction of [Pd(C6H2Me3-2,4,6)(dppm)2]+ (obtained by treatment of [PdCl2(cod)] with mesitylmagnesium bromide at low temperature, followed by 2 equiv of dppm) with [Pd2R2(-Cl)2(AsPh3)2]. The organopalladium A-frames did not react readily with CO, but thecorresponding acyl derivatives [Pd2(COR)2(-Cl)(-dppm)2]PF6 were produced by carbonylation of [Pd2R2(-Cl)2(AsPh3)2] followed by addition of dppm (R = Me, Et, Bn). Thermaldecomposition of [Pd2(CH2Ph)2(-Cl)(-dppm)2]Cl was found to be first order in A-frame andresulted in quantitative formation of [Pd2Cl2(-dppm)2] and 1,2-diphenylethane. The methyland aryl complexes underwent both reductive elimination and hydrogen abstraction reactions.[Pd2Et2(-Br)(-dppm)2]PF6 decomposed by -hydride elimination and subsequent reductiveelimination to yield ethene and ethane, whereas the butyl derivative gave both 1- and2-butene. Acetic acid was formed when [Pd2(COMe)2(-Cl)(-dppm)2]PF6 was heated in dmso-d6 solution, but decarbonylation was the predominant process in dioxane. The molecularstructures of [Pd2(CH2Ph)2(-Br)(-dppm)2]PF6·H2O,2C6H6 and [Pd2Cl2(-Cl)(-dppm)2]OH·0.5(CH3)2CO are also described.