Notes. Synthesis and crystal structures of [PPh4][MN{ButNC(O)NBut}Cl2](M = Ru or Os); a new reaction of tert-butyl isocyanate. Synthesis of W[ButNC(O)NBut]2(NHBut)2

Abstract

The interaction of the tetraphenylphosphonium salts of the ruthenium- and osmium-(VI) anions [RuO₂Cl₃]^–, [RuO₂Cl₄]^2– and [OsO₂Cl₄]^2– with excess of tert-butyl isocyanate in acetonitrile forms the salts of the anions [MN{Bu^tNC(O)NBu^t}Cl₂]^–, M = Ru or Os. X-Ray diffraction studies have shown the anions to have distorted square-pyramidal geometry with nitrido groups in axial positions. The metal nitrido groups have been shown to arise by C–N bond cleavage of unisolated tert-butylimido intermediates accompanied by cycloelimination of Me₂CCH₂ and HCl. Similar reactions using other aryl and alkyl isocyanates gave intractable products. The compound W[Bu^tNC(O)NBu^t]₂(NHBu^t)₂ is formed on reaction of W(NBu^t)₂(NHBu^t)₂ with Bu^tNCO.