Transfer Hydrogenation Reactions Catalyzed by Free or Silica‐Immobilized [RuCl₂(ampy){RN(CH₂PPh₂)₂}] Complexes

Abstract

The complexes cis-[RuCl 2 (ampy){R 1 N(CH 2 PPh 2 ) 2 }] [ampy = (2-aminomethyl)pyridine, R 1 = C 6 H 5 or (CH 3 CH 2 O) 3 Si-(CH 2 ) 3 ] showed very high catalytic activity in the homogeneous transfer hydrogenation of acetophenone (TOF Ͼ 300000 h -1 ) with the use of 2-propanol as the hydrogen donor and in the presence of sodium isopropoxide. The ligand (CH 3 CH 2 O) 3 Si(CH 2 ) 3 N(CH 2 PPh 2 ) 2 (ATM) was prepared in high yield by reacting (3-aminopropyl)triethoxysilane, paraformaldehyde, and diphenylphosphane in toluene heated at 80°C. The -N(CH 2 PPh 2 ) 2 function was attached to the surface of three different kinds of silica by means of two alternative methods. Thus, MA-Si-150 and mesoporous MA-Si-MCM-41 were prepared by the reaction of the inorganic matrix with ATM, whereas MA-Si-60 was synthesized by reaction of the commercially available 3-aminopropyl-function-

Ruthenium and osmium complexes containing 2-(aminomethyl)pyridine (Ampy)-based ligands in catalysis

“…Attempts were also made to prepare heterogeneous TH catalysts based on Ampy [23]. The preparation of the model silicon containing diphosphine (CH 3 CH 2 O) 3 Si(CH 2 ) 3 N(CH 2 PPh 2 ) 2 (ATM) was prepared in high yield by reacting (3-aminopropyl) [26].…”

1‐(Pyridin‐2‐yl)methanamine‐Based Ruthenium Catalysts for Fast Transfer Hydrogenation of Carbonyl Compounds in 2‐Propanol

“…Attempts were also made to prepare heterogeneous TH catalysts based on Pyme. The best results were obtained using a silica‐immobilized complex of the type [RuCl 2 {RN(CH 2 PPh 2 ) 2 }(Pyme)] ( 13 ), prepared by reaction of trans , cis ‐[RuCl 2 (PPh 3 ) 2 (Pyme)] with a diphosphane covalently bound to silica, synthesized by reaction of a 3‐aminopropyl‐functionalized silica with formaldehyde and PHPh 2 [Equation (5)] 46 …”