TOWARDS THERMALLY ROBUST HOMOGENEOUS CATALYSTS - RE, IR AND W COMPLEXES OF THE HIGHLY THERMALLY STABLE LIGAND, TRI-2-PYRIDYLAMINE

The ligand tri-2-pyridylamine (tripyam (1)), which was expected to be highly resistant to thermal degradation, forms a variety of stable com plexes with rhenium, tungsten and iridium. Reaction of 1 with ReCl3(PP h3) (benzil), WCl4(PPh3)(2) and (NH4)(2)IrCl6 yields the chloride comp lexes ReCl3(tripyam) (2), WCl4(tripyam) (3) and IrCl3(tripyam) (4), re spectively. In addition, the first tripyam supported hydride, [IrH2(PP h3)(2)(eta(2)-tripyam)]BF4 (5), was synthesized by reaction of 1 with the dihydride [IrH2(PPh3)(2)(acetone)(2)]BF4. The principal characteri stic of 2, 4 and 5 is their very high thermal stability: they survive thermolysis at temperatures up to 270 degrees C. Finally, the high oxi dation state complexes [ReO3(tripyam)]ReO4 (6) and [ReO(OCH2CH2O)(PPh3 ) (tripyam)]Cl (7) were also synthesized.