Magill Alison M, Yates Brian F, Cavell Kingsley J, Skelton Brian W, White Allan H
School of Chemistry, University of Tasmania, Private Bag 75, Hobart, Tasmania, Australia 7001.
Dalton Trans. 2007 Aug 21(31):3398-406. doi: 10.1039/b706053j. Epub 2007 Jun 26.
Methylpalladium(II) carbene complexes of the type [Pd(NHC)Me(P-P)]BF(4) (NHC = N-heterocyclic carbene, P-P = chelating phosphine) have been synthesised, the complex [Pd(tmiy)Me(dcype)]BF(4) (tmiy = 1,3,4,5-tetramethylimidazol-2-ylidene, dcype = 1,2-bis(dicyclohexylphosphino)ethane) being characterised crystallographically. Complexes bearing the tmiy ligands were shown to decompose in an analogous manner to complexes bearing monodentate phosphine ligands, with the rate of decomposition being nominally linked to the size of the chelate ring. The decomposition of these complexes in the presence of aryl halides-expected to yield Pd(Ar)X(P-P)-was studied and shown instead to yield PdX(2)(P-P) and [Pd(tmiy)X(P-P)]BF(4). Additionally, Pd(Me)X(P-P) and Pd(Ar)X(P-P) were observed in some cases. Intermolecular cross-over reactions between the starting complex and Pd(Ar)X(P-P) were found to be the source of these unexpected products.
已合成了[Pd(NHC)Me(P-P)]BF₄类型的甲基钯(II)卡宾配合物（NHC = N-杂环卡宾，P-P = 螯合膦），对配合物[Pd(tmiy)Me(dcype)]BF₄（tmiy = 1,3,4,5-四甲基咪唑-2-亚基，dcype = 1,2-双（二环己基膦基）乙烷）进行了晶体学表征。结果表明，带有tmiy配体的配合物与带有单齿膦配体的配合物以类似方式分解，分解速率名义上与螯合环的大小有关。研究了这些配合物在芳基卤化物存在下的分解情况——预期会生成Pd(Ar)X(P-P)——结果表明生成的是PdX₂(P-P)和[Pd(tmiy)X(P-P)]BF₄。此外，在某些情况下还观察到了Pd(Me)X(P-P)和Pd(Ar)X(P-P)。发现起始配合物与Pd(Ar)X(P-P)之间的分子间交叉反应是这些意外产物的来源。
