663952-89-4Relevant academic research and scientific papers
The synthesis and late transition metal chemistry of 7-aza-N-indolyl phosphines and the activity of their palladium complexes in CO-ethene co-polymerisation
Burrows, Andrew D.,Mahon, Mary F.,Varrone, Maurizio
, p. 4718 - 4730 (2007/10/03)
The 7-aza-N-indolyl phosphine ligands PR2(N2C7H5) (L1, R = Ph; L2, R = NC4H4) were prepared in a two-step process involving treatment of 7-azaindole with BuLi, followed by reaction of the lithium salt with PClR2. L1 and L2 react with [MCl2(cod)] (M = Pd, Pt) to give [PdCl2(L-κ2P,N)] (1a, L = L1; 1b, L = L2) or [PtCl2(L-κ2P,N)] (2a, L = L1; 2b, L = L2) and with [Rh(μ-Cl)(cod)]2 in the presence of CO to give [RhCl(CO)(L-κ2P,N)] (3a, L = L1; 3b, L = L2). Crystal structures for 1a,b and 3a,b are reported, and structural and spectroscopic evidence confirm that L2 is a poorer σ-donor/better π-acceptor than L1. The complexes [PdClMe(L-κ2P,N)] (4a, L = L1; 4b, L = L2), prepared from [PdClMe(cod)], react with AgOTf to yield [PdMe(OTf)(L-κ2P,N)] (5a, L = L1; 5b, L = L2). Complexes 5a,b are active catalysts for the co-polymerisation of CO and ethene, with activities similar to previously reported catalysts containing P,N-donor ligands. From the stepwise insertion reactions of CO and ethene with 5a,b, the acyl complexes [Pd{C(O)Me}(OTf)(L-κ2P,N)] (7a, L = L1; 7b, L = L2) and alkyl complexes [Pd{CH2CH2C(O)-Me-κ2C,O} (L-κ2P,N)]OTf (8a, L = L1; 8b, L = L2) have been isolated and crystallographically characterised, and the acyl complexes [Pd{C(O)CH2CH2C(O)Me-κ2C,O} (L-κ2P,N)]OTf (9a, L = L1; 9b, L = L2) have been spectroscopically characterised. Reactions of 7a and 9a with MeOH gave methyl acetate and methyl 4-ketopentanoate respectively, with formation of palladium metal and conversion of the remaining palladium to [Pd(L1-κ2P,N)2](OTf)2 10 which has been crystallographically characterised.
