Highly active ruthenium complexes with bidentate phosphine ligands for the solvent-free catalytic synthesis of N,N-dimethylformamide and methyl formate

Abstract

Complexes of the type [RuCl ₂ L ₂ ] [L = Ph ₂ P(CH ₂ ) _n PPh ₂ (n = 1–3), Me ₂ P(CH ₂ ) ₂ PMe ₂ ] are shown to be highly active and selective catalysts for the synthesis of formic acid derivatives from carbon dioxide, hydrogen and dimethylamine or methanol–triethylamine, respectively, without any additional solvent, affording at 373 K with [RuCl ₂ (dppe) ₂ ] an extremely high turnover frequency (TOF) of 360000 h ^{- 1} in N,N-dimethylformamide synthesis and a TOF of 830 h ^{- 1} in methyl formate synthesis.