182625-37-2Relevant articles and documents
Allosteric Effects in Ethylene Polymerization Catalysis. Enhancement of Performance of Phosphine-Phosphinate and Phosphine-Phosphonate Palladium Alkyl Catalysts by Remote Binding of B(C6F5)3
Wilders, Alison M.,Contrella, Nathan D.,Sampson, Jessica R.,Zheng, Mingfang,Jordan, Richard F.
, p. 4990 - 5002 (2018/02/07)
Remote binding of B(C6F5)3 to (PPO)PdMeL (L = pyridine or lutidine) or {(PPO)PdMe}2 ethylene polymerization catalysts that contain phosphine-arenephosphinate or phosphine-arenephosphonate ligands (PPO- = [1-PAr2-2-PR′O2-Ph]-: Ar = R′ = Ph (1a); Ar = Ph, R′ = OEt (1b); Ar = Ph, R′ = OiPr (1c); Ar = 2-OMe-Ph, R′ = OiPr (1d)) significantly increases the catalyst activity and the molecular weight of the polyethylene (PE) product. In the most favorable case, in situ conversion of (1d)PdMe(py) to the base-free adduct {1d·B(C6F5)3}PdMe increases the ethylene polymerization activity from 9.8 to 5700 kg mol-1 h-1 and the Mn of the PE product from 9030 to 99 200 Da (80 °C, 410 psi). X-ray structural data, trends in ligand lability, and comparative studies of BF3 activation suggest that these allosteric effects are primarily electronic in origin. The B(C6F5)3 binding enhances the chain growth rate (Rgrowth) by increasing the degree of positive charge on the Pd center. This effect does not result in the large increase in the chain transfer rate (Rtransfer) and concomitant reduction in PE molecular weight seen in previous studies of analogous (PO)PdRL catalysts that contain phosphine-arenesulfonate ligands, because of the operation of a dissociative chain transfer process, which is inhibited by the increased charge at Pd.
Novel palladium complexes employing mixed phosphine phosphonates and phosphine phosphinates as anionic chelating [P,O] ligands
Reisinger, Corinna M.,Nowack, Ruediger J.,Volkmer, Dirk,Rieger, Bernhard
, p. 272 - 278 (2007/10/03)
A route to various substituted phosphine phosphonic acid compounds of the general form Ar2PC6H4PO(OH)2 (Ar = Ph, o-MeC6H4, o-MeOC6H4) has been investigated. These comp
Platinum(n), palladiuni(n) and rhodium(i) complexes of o-, m- And P-Ph2PC6H4PO(OEt)2. PtCl2-SnCl2 Hydroformylation catalysts modified with phosphonated triarylphosphines
Ellis, Dianne D.,Harrison, Gayle,Guy Orpen,Phctmung, Hirihattaya,Pringle, Paul G.,Dcvries, Johannes G.,Oevering, Henk
, p. 671 - 675 (2007/10/03)
An improved route to the bulky phosphine o-Ph2PC6H4PO(OEt)2 o-l has been elaborated. The isomers [PtCl2L2], L = o- (2), m- (3) or p-l (4), were made by treatment of [PtCl2(cod)] with the appropriate phosphine. Complex 2 has a trans configuration whereas the m and p isomers, 3 and 4 are cis, reflecting the greater bulk of the o isomer. Crystal structure analyses of o-1 and its platinum complex 2 indicated normal dimensions for the tertiary phosphine in both and the considerable asymmetric steric bulk of o-l. Abstraction of the chloro ligands in 2 occurs upon addition of AgSbF6 and the resulting dicationic bis P,O-chelate 5 has a cis geometry. The palladium complexes [PdCl2L2], L = o- (6), m- (7), orp-1 (8) were made by treatment of [PdCl2(NCPh)J with the appropriate phosphine but, in contrast to the platinum analogues, the o isomer 6 has a cis configuration and the 7 and p isomers 7 and 8 are predominantly trans. Complex 6 is fluxional: variable temperature 31P NMR spectroscopy is consistent with hemilabile behaviour of the ligand with reversible co-ordination of the P=O of the phosphonate functionality. Treatment of [Rh2Cl2(CO)4] with o-1 gave the mononuclear chelate [RhCl(CO)(o-1)] (9) which upon addition of further o-l gave predominantly the fluxional species trans-[RhCl(CO)(o-l)J. The platinum complexes 2,3 and 4 when combined with SnCl2 catalyse the hydroformylation of but-2-ene and but-1-ene. The Royal Society of Chemistry 2000.
