Synthesis of Platinum(II) Complexes of a Pyridyl Azafluoranthene Ligand

Abstract

Pyridyl azafluoranthene ligand (LH, 2) was prepared by a Diels- Alder cycloaddition reaction between 2-cyanopyridine and bis(4-tertbutylphenyl)- 8H-cyclopenta[l]acenaphthylen-8-one (1). Treatment of (2) with [PtCl2(dmso)2] (dmso = dimethyl sulfoxide) in the presence of triethylamine in chloroform afforded the cyclometallated square-planar platinum(II) complex [(L)PtCl] (3) containing an anionic terdentate (C^N^N) ligand. The reaction of (2) with 0.5 equivalent of [(η3- methallyl)Pt(μ-Cl)]2 in dichloromethane and subsequent addition of NH4PF6 in methanol resulted in the formation of the salt[(η3- methallyl)Pt(2)]PF6 (4). The chloride ligand in (3) can be replaced by iodide and trifluoroacetate to yield [(L)PtI] (5) and [(L)PtO2CCF3] (6), respectively. Treatment of (3) with HC≡CC6H4But-4 in the presence of triethylamine and CuI yielded the acetylide [(L)PtC≡CC6H4But-4] (7). Treatment of (3) with PPh3 in dichloromethane and subsequent addition of NH4PF6 in methanol gave the salt [(L)Pt(PPh3)]PF6 (8). Similarly, the salt [(L)Pt(DMAP)]PF6 (9) was prepared by the reaction between (3) and 4-dimethylaminopyridine (DMAP). All the complexes were characterized by elemental analysis, IR, Mass and NMR spectroscopy