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

Article abstract of DOI:10.1016/S0022-328X(00)00586-6

Reactions of [(C₆H₄CH₂NMe₂-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 [(C₆H₄CH₂NMe₂-C ²,N)PdCl(L)] (2a: L = MDMPP; 2b: L = BDMMP; 2c: L = TDMPP). Reactions of 2 with NaPF₆ led to replacement of the Cl atom with the methoxy-O atom to form the corresponding complexes [(C₆H₄CH₂NMe₂-C ²,N)Pd(L)]-(PF₆) (3). On treatment of 3 with HCl (aq), protonation occurred at the N atom in 3 to give [(C₆H₄CH₂NHMe₂-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 [(C₆H₄CH₂NMe₂-C ²,N)PdCl(PPh₃)] was treated with NaPF₆, [(C₆H₄CH₂NMe₂-C ²,N)Pd(PPh₃)(O₂H)](PF₆) (4) bearing a H₂O ligand was obtained. The reaction with HCl (aq) led to a cleavage of a Pd-C bond to give [PdCl₃(PPh₃)][PhCH₂NHMe₂] (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 [(C₆H₄CH₂NMe₂-C ²,N)PdCl(MesNC)] (7) and [C₆H₄CH₂NMe₂-C ²)PdCl(MesNC)₂] (8).