Studies on transition–metal oxo and nitrido complexes. Part 10. New oxo–ruthenium and oxo–osmium pyridine complexes, and use of the former as catalysts for oxidation of alcohols

Abstract

The new complexes trans-[RuO₂(py)₄]²⁺, trans-[OsO₂(py)₃(H₂O)]²⁺, trans-[MO₂(py)₂X₂](M = Ru or Os; X = Cl or Br, py = pyridine) and trans-[Ru₂O₆(py)₄] are reported. Both trans-[RuO₂(py)₄]²⁺ and trans-[Ru₂O₆(py)₄] in CH₂Cl₂ are efficient oxidants for primary alcohols to aldehydes and secondary alcohols to ketones, and function catalytically, with N-methylmorpholine N-oxide (mmo) or [NBuⁿ₄][IO₄] as co-oxidants. A simple preparation of trans-[Ru(py)₄Cl₂] and the isolation of [OsO₄·L], [OsO₂L₂(O₂C₂H₄)], and [OsO₂L₂(O₂C₆H₁₀)](L = pyridine N-oxide) are also reported. Complexes were characterised by Raman, i.r. and ¹H n.m.r. spectroscopy.