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The 7-aza-N-indolyl phosphine ligands PR2N2C7H5L1, 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. L1and L2react with MCl2cod M Pd, Pt to give PdCl2L-κ2P,N1a, L L1; 1b, L L2 or PtCl2L-κ2P,N2a, L L1; 2b, L L2 and with Rhμ-Clcod2in the presence of CO to give RhClCOL-κ2P,N3a, L L1; 3b, L L2. Crystal structures for 1a,band 3a,bare reported, and structural and spectroscopic evidence confirm that L2is a poorer σ-donorbetter π-acceptor than L1. The complexes PdClMeL-κ2P,N4a, L L1; 4b, L L2, prepared from PdClMecod, react with AgOTf to yield PdMeOTfL-κ2P,N5a, L L1; 5b, L L2. Complexes 5a,bare 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 PdCOMeOTfL-κ2P,N7a, L L1; 7b, L L2 and alkyl complexes PdCH2CH2COMe-κ2C,OL-κ2P,NOTf 8a, L L1; 8b, L L2 have been isolated and crystallographically characterised, and the acyl complexes PdCOCH2CH2COMe-κ2C,OL-κ2P,NOTf 9a, L L1; 9b, L L2 have been spectroscopically characterised. Reactions of 7aand 9awith MeOH gave methyl acetate and methyl 4-ketopentanoate respectively, with formation of palladium metal and conversion of the remaining palladium to PdL1-κ2P,N2OTf210which has been crystallographically characterised.

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.