Phosphinoalkylnitrile: Synthese und Koordinationsverhalten an Palladiumzentren / Phosphinoalkylnitnles: Synthesis and Coordination Behaviour at Palladium Centres

Abstract

Phosphinoalkylnitriles R2P-(CH2)n-CN {R = isopropyl (ipr), phenyl (ph), cyclohexyl (chex), n = 3, 6, 10} have been prepared starting from the corresponding secondary phosphines in an easy three step synthesis. All new compounds were characterized by their 1H -, 13C and 31P NMR data. Some of these new P, N ligands were used to prepare complexes [{R2P- (CH2)n-CN}2PdCl2] which were also identified by their NMR data. In addition the crystal structures of three derivatives, [{ipr2P-(CH2)3-CN}2PdCl2] 7a, [{ph2P-(CH2)3-CN}2PdCl2) 7b and [{ph2P-(CH2)6-CN}2PdCl2] 8b were determined by X-ray analysis. The coordination mode of the phosphinoalkylnitriles in these complexes was found to be P-bonded resulting in a trans configuration. Palladium catalysts with 5a as ligand show high activies in the co-oligomerization of butadiene and carbon dioxide. The δ-lactone 11a is formed under very mild conditions.