Reactions of palladium complex of N, N-dimethylbenzylamine with aromatic phosphines bearing the methoxy groups at the 2,6-positions

Abstract

Reactions of [(C 6H 4CH 2NMe 2- C 2, N)PdCl] 2 ( 1) with (2,6-dimethoxyphenyl)diphenylphosphine (MDMPP), bis(2,6-dimethoxyphenyl)phenylphosphine (BDMPP), and tris(2,6-dimethoxyphenyl)phosphine (TDMPP) gave the corresponding complexes [(C 6H 4CH 2NMe 2- C 2,N)PdCl(L)] ( 2a: L=MDMPP; 2b: L=BDMMP; 2c: L=TDMPP). Reactions of 2 with NaPF 6 led to replacement of the Cl atom with the methoxy-O atom to form the corresponding complexes [(C 6H 4CH 2NMe 2- C 2, N)Pd(L)](PF 6) ( 3). On treatment of 3 with HCl (aq), protonation occurred at the N atom in 3 to give [(C 6H 4CH 2NHMe 2- C 2)PdCl(L)] ( 5). Based on X-ray structural analyses of 2c, 3a, 3b, 5a and 5c, complexes ( 2b, 2c, 3b, 3c, 5b and 5c) bearing BDMPP and TDMPP ligands have square-pyramidal structures with a P–O coordination in the axial position and complexes ( 2a, 3a and 5a) bearing MDMPP have square planar structures. When a complex bearing triphenylphosphine [(C 6H 4CH 2NMe 2- C 2, N)PdCl(PPh 3)] was treated with NaPF 6, [(C 6H 4CH 2NMe 2- C 2, N)Pd(PPh 3)(O 2H)](PF 6) ( 4) bearing a H 2O ligand was obtained. The reaction with HCl (aq) led to a cleavage of a Pd–C bond to give [PdCl 3(PPh 3)][PhCH 2NHMe 2] ( 6). X-ray analyses of 4 and 6 were also carried out. Reactions of 1 or 2a with mesityl isocyanide (MesNC) proceeded with replacement of a Cl atom with isocyanide and insertion of isocyanide to produce [(C 6H 4CH 2NMe 2- C 2, N)PdCl(MesNC)] ( 7) and [C 6H 4CH 2NMe 2- C 2)PdCl(MesNC) 2] ( 8).