A mixed-valent cyclodiphosphazane: Transition metal chemistry and cis/trans isomerisation

Abstract

The hydrolysis of cis-{ClP(μ-N t Bu) 2 P(NH t Bu)} (1) produced a mixed P III /P V derivative of cyclodiphosphazane, cis-{( t BuNH)P(μ-N t Bu) 2 P(O)H} (2). The treatment of 2 with elemental selenium resulted in the formation of the monoselenide, trans-dichloromethane afforded corresponding mononuclear complexes, [(η 3 -C 3 H 5 )PdCl{( t BuNH)P(μ-N t Bu) 2 P(O)H}] (4) and [((η 6 -p-cymene)RuCl 2 ){( t BuNH)P(μ-N t Bu) 2 P(O)H}] (5). The treatment of 2 with M(COD)Cl 2 (M = Pd and Pt) in dichloromethane at room temperature gave [MCl 2 {( t BuNH)P(μ-N t Bu) 2 P(O)H} 2 ] (6 M = Pd; 7 M = Pt) in good yield.Owing to the cis/trans isomerisation of the cyclodiphosphazane rings, the complexes 6 and 7 exist as a mixture of two isomers. Various NMR spectroscopic techniques were employed for structural elucidation. The molecular structures of 5 and 7 were established by single crystal X-ray crystallographic studies.