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

Abstract

Phosphinoalkylnitriles R2P-(CH2)"-CN {R = isopropyl ('pr), phenyl (ph), cyclohexyl (' 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 'H -, i3C and 31P NMR data. Some of these new P, N ligands were used to prepare complexes [{R2P-(CH2)"-CN}2PdCl2] which were also identified by their NMR data. In addition the crystal structures of three derivatives, [{'pr2P-(CH2)3-CN }2PdCl2] 7a, [{ph2P-(CH2)3-CN }2PdCl2) 7b and [{ph2P-(CH 2)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 ^-lactone 11a is formed under very mild conditions.

Synthesis and Coordination Chemistry of Cyano-Substituted Phosphines

“…Similarly, trans-L2PdX2 complexes were obtained by the reaction of (2-cyanoethyl)phosphines 83 with bis(benzonitrile)palladium dichloride and for R = Ph and c Hex the stereochemical configuration was firmly confirmed by the X-ray study (Scheme 60) [33].…”

“…In another approach, a two-step method comprising the alkylation of metal phosphides by unsymmetrical , -dihaloalkanes, followed by the substitution of the terminal chlorine atom by the cyano group was applied (Scheme 11) [33].…”

Homogeneously catalysed reduction of carbon dioxide with silanes: a study on solvent and ligand effects and catalyst recycling

“…The pre-catalyst Ru 2 Cl 5 (MeCN) 7 4 was prepared according to the method developed earlier [5]. The hemilabile co-ligands (see Table 3) of the types R 2 P(CH 2 ) n CN and 2-[R 2 P(CH 2 ) m ]C 5 H 5 N were prepared according to published procedures [11,12].…”

“…The tested ligands differ in their basicity at the phosphorus, their distance between both donor groups, and their N-donor group, e.g. nitrile or 2-pyridyl (Scheme 4) [11,12].…”

“…Also with Ph 2 P(CH 2 ) 6 CN as co-ligand an effective catalyst is formed (entry 7). Higher P/Ru ratios result in a significantly decreased activity (entries 4,5,8,11,14,17), even more than by use of monodentate phosphines ( Table 2). Effects due to the presence of additional N-donor groups in the ligand backbone cannot be noted.…”