Silica xerogels containing bidentate phosphine ruthenium complexes: textural properties and catalytic behaviour in the synthesis of N, N-dimethylformamide from carbon dioxide

Abstract

Ruthenium complexes having bidentate phosphine ligands were incorporated into an amorphous silica matrix via chemical anchoring using a silylether bridge. The integrity of the complexes after immobilisation was confirmed by CP/MAS 31P NMR. Amorphous hybrid gels with pores smaller than 4 nm exhibited outstanding catalytic activity in the synthesis of N, N-dimethylformamide from supercritical carbon dioxide, hydrogen and dimethylamine. At 100°C a turnover frequency of 970 h −1 was achieved with 100% selectivity to dimethylformamide. The incorporated ruthenium complexes are stable in air, making them particularly suitable for technical applications.