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

Research paper by GUDDEKOPPA S ANANTHNAG, JOEL T MAGUE, MARAVANJI S BALAKRISHNA

Indexed on: 19 Aug '15Published on: 19 Aug '15Published in: Journal of Chemical Sciences



Abstract

The hydrolysis of cis-{ClP(μ-N tBu)2P(NHtBu)} (1) produced a mixed PIII/P V derivative of cyclodiphosphazane, cis-{(tBuNH)P(μ-N tBu)2P(O)H} (2). The treatment of 2 with elemental selenium resulted in the formation of the monoselenide, trans-{(tBuNH)P(Se)(μ-N tBu)2P(O)H} (3) in good yield. The reactions of two equivalent of 2 with [Pd(μ-Cl)(η3-C3H5)]2 or [Ru(η6-p-cymene)(μ-Cl)Cl]2 in dichloromethane afforded corresponding mononuclear complexes, [(η3-C3H5)PdCl{(tBuNH)P(μ-N tBu)2P(O)H}] (4) and [((η6-p-cymene)RuCl2){(tBuNH)P(μ-NtBu)2P(O)H}] (5). The treatment of 2 with M(COD)Cl2 (M = Pd and Pt) in dichloromethane at room temperature gave [MCl2{(tBuNH)P(μ-N tBu)2P(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.Transition metal complexes of a mixed-valent cyclodiphosphazane are described.