914670-66-9Relevant articles and documents
Acrylonitrile insertion reactions of palladium alkyl complexes that contain neutral or anionic bidentate phosphine ligands
Wu, Fan,Jordan, Richard F.
, p. 5631 - 5637 (2008/10/09)
The reactions of acrylonitrile (AN) with palladium alkyl complexes that contain bisphosphine ligands, P∧P = Ph2P(CH2) 3PPh2 (a, dppp), Me2P(CH2) 2PMe2 (b, dmpe), [Ph2B(CH2PPh 2)2]- (c, Ph2BP2), were studied. (P∧P)PdMeCl (1a.b) reacts with [Li(Et2O) 2.8][B(C6F5)4] and AN to form N-bound AN adducts (P∧P)PdMe(NCCH=CH2)+ (3a,b). 3b inserts AN to form [(dmpe)Pd(CHEtCN)]nn+ (4b). Sequential reaction of [ASN][(Ph2BP2)PdMe2] (1c, ASN = 5-azoniaspiro[4.4]nonane) with [HNMe2Ph] [B(C6F 5)4] and AN affords the N-bound adduct (Ph 2BP2)PdMe(NCCH=CH2) (3c), which reacts to form [(Ph2NP2)-Pd(CHEtCN)]n (4c). IR data suggest that the Pd units of 4b,c are aggregated by PdCHEtCN...Pd bridges. 4b reacts with PPh3 to form (dmpe)Pd(CHEtCN)(PPh3) + (5b). 4c reacts with PMe3 and with pyridine (py) to form (Ph2BP2)Pd(CHEtCN)(L) (L = PMe3 (6c), py (7c)). The characterization of 5b, 6c, and 7c confirms the 2,1 AN insertion of 3b,c. The rate constants for AN insertion (kobs,AN, 23°C) vary in the order 3c (1.12(3) × 10-3 s-1) > 3b (3.33(5) × 10-5 s-1) > 3a (no reaction). Electron-rich metal centers and incorporation of an anionic charge in the P∧P ligand promote insertion, probably by favoring formation of a reactive π-bound AN complex.
