Towards thermally robust homogeneous catalysts: Re, Ir and W complexes of the highly thermally stable ligand, tri-2-pyridylamine

Article abstract of DOI:10.1016/0020-1693(95)04837-5

The ligand tri-2-pyridylamine (tripyam (1)), which was expected to be highly resistant to thermal degradation, forms a variety of stable complexes with rhenium, tungsten and iridium. Reaction of 1 with ReCl₃(PPh₃) (benzil), WCl₄(PPh₃)₂ and (NH₄)₂IrCl₆ yields the chloride complexes ReCl₃(tripyam) (2), WCl₄(tripyam) (3) and IrCl₃(tripyam) (4), respectively. In addition, the first tripyam supported hydride, [IrH₂(PPh₃)₂(η²-tripyam)]BF ₄ (5), was synthesized by reaction of 1 with the dihydride [IrH₂(PPh₃)₂(acetone)₂]BF ₄. The principal characteristic of 2, 4 and 5 is their very high thermal stability: they survive thermolysis at temperatures up to 270°C. Finally, the high oxidation state complexes [ReO₃(tripyam)]ReO₄ (6) and [ReO(OCH₂CH₂O) (PPh₃) (tripyam)]Cl (7) were also synthesized.