Microwave methods for the synthesis of paddlewheel diruthenium compounds with N,N-donor ligands

Abstract

Microwave irradiation can lead to easy and fast synthesis methods in the obtention of paddlewheel diruthenium complexes with N,N-donor ligands. Microwave assisted substitution of acetate groups on [Ru₂Cl(O₂CMe)₄] by three different types of N,N-donor ligands gives rise to [Ru₂(DPhT)₄] (1), (DPhT⁻ = 1,3-diphenyltriazenide); [Ru₂(DFPhT)₄] (2), (DFPhT⁻ = 1,3-bis(p-fluorophenyl)triazenide); [Ru₂Cl(DPhF)₄] (3), (DPhF⁻ = 1,3-diphenylformamidinate); [Ru₂Cl(DAniF)₄] (4), (DAniF⁻ = 1,3-bis(p-methoxyphenyl)formamidinate); and [Ru₂Cl₂(hpp)₄] (5), (hpp⁻ = 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-α]pyrimidinate). In addition, the selective replacement of the acetate group on [Ru₂Cl(DPhF)₃(O₂CMe)] by [1,3,5-(O₂C)₃C₆H₃]³⁻ under microwave irradiation produces {[Ru₂Cl(DPhF)₃]₃(O₂C)₃C₆H₃}·3H₂O, (6). The experimental conditions have been optimised in every case to obtain better yields and more environmentally friendly reaction conditions than the ones reported by other conventional methods of synthesis.