Novel reactions of metal-metal bonds. Reactions of Pd2{(C6H5)2PCH2P(C 6H5)2}2Cl2 with acetylenes, olefins, and isothiocyanates

Article abstract of DOI:10.1021/ic50222a026

Acetylenes with electron-withdrawing substituents react with Pd₂(dpm)₂X₂ (dpm = (C₆H₅)₂PCH₂P(C₆H ₅)₂; X = Cl, Br, I) to form Pd₂(dpm)₂(μ-acetylene)X₂ (acetylene = C₂(CF₃)₂, C₂(CO₂CH₃)₂, C₂(CO₂C₂H₅)₂, HC₂CO₂H, HC₂CO₂CH₃) which have been characterized by infrared and ³¹P{¹H} and ¹H NMR spectroscopy. These acetylene adducts are resistant to acetylene exchange and to protonation. Reaction with methyl isocyanide yields [Pd₂(dpm)₂(μ-C₂{CO₂CH ₃}₂)-(CNCH₃)₂][[PF₆] ₂ which is also formed by reaction of [Pd₂(dpm)₂(μ-CNCH₃)(CNCH₃) ₂][PF₆]₂ with dimethyl acetylenedicarboxylate. Pd₂(dpm)₂Cl₂ is a catalyst for the cyclotrimerization of dimethyl acetylenedicarboxylate and Pd₂-(dpm)₂(μ-C₂{CO₂CH ₃}₂)Cl₂ is formed during the reaction. The reaction of Pd₂(dpm)₂I₂ with maleic anhydride results in the formation of Pd(dpm)I₂ and two other incompletely characterized products which can also be obtained through the addition of maleic anhydride to Pd₂(dpm)₃. Ethylene, norbornadiene, and chlorotrifluoroethene are unreactive toward Pd₂(dpm)₂Cl₂. Phenyl and methyl isothiocyanate react with Pd₂(dpm)₂Cl₂ to yield Pd₂(dpm)₂(μ-CNR)Cl₂ in 50% isolated yield; some Pd₂(dpm)₂(μ-S)Cl₂ is formed in the process.