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

Abstract

Phosphinoalkylnitriles R 2 P-(CH 2 ) n -CN {R = isopropyl ( i pr), phenyl (ph), cyclohexyl ( c hex), 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 1 H -, 13 C and 31 P NMR data. Some of these new P, N ligands were used to prepare complexes [{R 2 P- (CH 2 ) n -CN} 2 PdCl 2 ] which were also identified by their NMR data. In addition the crystal structures of three derivatives, [{ i pr 2 P-(CH 2 ) 3 -CN} 2 PdCl 2 ] 7a, [{ph 2 P-(CH 2 ) 3 -CN} 2 PdCl 2 ) 7b and [{ph 2 P-(CH 2 ) 6 -CN} 2 PdCl 2 ] 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.