Structural and chemical relationships in metal phosphine complexes relevant to homogeneous catalysis

[摘要] English: The aim of this research work was to improve the fundamental understandingof the role selected tertiary bicyclic and conventional phosphine ligands playin modified cobalt-catalyzed hydroformylation.Selected bicyclic ligands were synthesized by radical addition of 1-alkenes tothe 2° phosphines shown in Figure 1 (see in full text PDF).The following ligands were synthesized in this way: Phoban-Q (Q = CH2CH3(C2), (CH2)4CH3 (Cs), (CH2)3N(CH3)2 (C3NMe2), Lim-Cs, VCH-Cs and PA-Cs.Phoban-Cy was made from the reaction between a diene and a 1° phosphine,H2PCy, with a radical initiator at 100°C.the second set ranging from PnBu3 to the Lim family with hydrogenationranging from 9 - 15% respectively.Crystal structures of the cobalt dimers of the following ligands; Phoban[3.3.1]-C21Phoban[3.3.1]-C5, Phoban[3.3.1]-C3NMe2, Phoban[3.3.1]-Cy, PA-C5,PCy3, and PCp3 were obtained and characterised by X-ray crystallography.A series of [Rh(acac)(CO)(P-Ph)] complexes where P-Ph = Phoban[3.3.1]-Ph,Phoban[4.2.1]-Ph, a mixture of 4R, 8S- and 4S, 8S-Lim-Ph, a mixture ofVCH[3.3.1]-Ph and VCH[3.2.2]-Ph and PA-Ph were successfully synthesizedand characterised by NMR and IR spectrophotometers.The crystal structures of [Rh(acac)(CO)(4R, BS-Lim-Ph)] and[Rh(acac)(CO)(PA-Ph)] were obtained and characterised by X-raycrystallography.The oxidative addition and CO-insertion reactions of the rhodium complexesof these ligands were carried out and the results indicate that the Lim-Phsystems were the most active among the bicyclic ligands included in thestudy.The general reactivity trend for the oxidative addition was found to be: 4S,8S-Lim-Ph > 4R, 8S-Lim-Ph > VCH-Ph > Phoban[3.3.1]-Ph > Phoban[4.2.1]Ph>PPh3 - PCy3 >PA-Ph.The overall reactivity trend for the CO-insertion reaction was determined as4S, 8S-Lim-Ph > 4R, 8S-Lim-Ph > Phoban[4.2.1]-Ph > VCH-Ph >Phoban[3.3.1]-Ph > PA-Ph.

[发布机构] University of the Free State