Interaction of Palladium(II) Acetate with Substituted Pyridines, including a Cyclometallation Reaction and the Structure of [Pd{meso-[(py)PhMeC]2C5H3N}(02CMe)][02CMe].3H2O

The reactivity of meso- and rac- diastereoisomers of 2,6-bis[l-phenyl-1-(pyridin-2-yl)ethyl]pyridine {[(py)PhMeC]2C5H3N}, 2,6-bis[l,l-bis(pyridin-2-yl)ethyl]pyridine {[(py)2MeC]2C5H3N}, and the pyridin-2-ylmethanes (py)2Ph3-nCH (n = 1-3), (py)nCH4-n, (n = 2 or 3), and (py)3PhC toward palladium(II) acetate in refluxing glacial acetic acid and at ambient temperature in organic solvents has been investigated. The nitrogen donor ligands form co-ordination derivatives in organic solvents. All except alpha-phenyl-alpha-(pyridin-2-yl)toluene [(py)Ph2CH] form identical complexes in glacial acetic acid, with (py)Ph2CH undergoing cyclometallation to form [{Pd[(py)PhHCC6H4](mu- O2CMe)}2]. meso-[(py)PhMeC]2C5H3N, which binds as a tripodal tridentate ligand to methylmercury(II), has been shown by a single crystal X-ray study to act as a planar tridentate ligand to palladium(II) in [Pd{meso-[(pyPhMeC]2C5H3N}(O2CMe)][O2CMe].3H2O with square-planar co-ordination being completed by a unidentate acetate group. Syntheses of the new ligand [(py)2MeC]2C5H3N, with five pyridine donor groups, and alpha,alpha,alpha-tris(pyridin-2-y1)toluene [(py)3PhC] are described.