Intermolecular Aklkynyl Ligand Transfer in Palladium(II) and Platinum(II) Complexes with -C(ident to)CCOOR and -C(ident to)CPh Ligands. Relative Stability of the Alkynyl Complexes and Conproportionation of Dialkynyl and Diiodo Complexes of These Met

摘要

An equimolar reaction of transf-Pd(C(ident to)CCOOMe)_2(PEt_3)_2 with trans-PdI_2(PEt_3)_2 catalyzed by CuI causes conproportionation of the complexes at room temperature, producing trans-PdI(C(ident to)_COOMe)(PEt_3)_2 in 88% yield, while the reaction without CuI catlayst gives the monoalkynylpalladium complex in approximately 2% yield after a prolonged period. Similar reactions of trans-Pd(C(ident to)CPh)_2(PEt_3)_2 with trans-PdI_2(PEt_3)_2 with and without CuI catalyst give the alkynyl ligand transfer reaction product trans-PdI(C(ident to)CPh)(PEt_3)_2 in 95% and 33% yields respectively. CuI-catalyzed conproportionation of trans-Pt(C(ident to)CPh)_2(PEt_3)_2 and trans-Pt(C(ident to)CCOOMe)_2(PEt_3)_2 does not react with the diiodoplatinum complex even int e presence of CuI. The alkynyl ligand transfer reaction from trans-Pd(C(ident to)CCOOMe)_2(PEt_3)_2 to trans-PtI_2(PEt_3)_2 occurs in the presence of CuI catalyst, affording a mixture of several organopalladium and -platinum complexes. The main Pd complex in the reaction mixture is trans-PdI(C(ident to)CCOOMe)(PEt_3)_2, while the Pt-containing product is ocmposed of trans-Pt(C(ident to)CCOOMe)_2(PEt_3)_2, trans-PtI(C(ident to)CCOOMe(PEt_+3)_2, and trans-PtI_2(PEt_3)_2 in an approximate 1:2:1 molar ratio. Mixing of trans-Pd(C(ident to)CCOOMe)_2(PEt_3)_2, trans-PdI_2(PEt_3)_2, and trans-PtI_2(PEt_3)_2 results in the formation of trans-PdI(C(ident to)CCOOMe)(PEt_3)_2 in a high yield, while the alkynyl ligand transfer from Pd to Pt complexes is almost negligible. trans-PtI_2(PEt_3)_2 catalyzes the alkynyl lighand transfer between the dialkynyl- and diiodopalladium(II) complexes and remains unchanged in the reation mixture.