Cooperative interplay between a flexible PNN-Ru(II) complex and a NaBH4 additive in the efficient catalytic hydrogenation of esters
Zheng Wang
Xiangyang Chen
Bo Liu
Qing-Bin Liu
Gregory A. Solan
Xinzheng Yang
Wen-Hua Sun
2381/40149
https://figshare.le.ac.uk/articles/journal_contribution/Cooperative_interplay_between_a_flexible_PNN-Ru_II_complex_and_a_NaBH4_additive_in_the_efficient_catalytic_hydrogenation_of_esters/10208360
A catalyst loading of between 0.001–0.05 mol% of the PNN-bearing ruthenium(II) complex [fac-PNN]RuH(PPh3)(CO) (PNN = 8-(2-diphenylphosphinoethyl)amidotrihydroquinoline), in combination with 5 mol% NaBH4, efficiently catalyzes the hydrogenation of esters to their corresponding alcohols under mild pressures of hydrogen. Both aromatic and aliphatic esters can be converted with high values of TON or TOF achievable. Mechanistic investigations using both DFT calculations and labeling experiments highlight the cooperative role of NaBH4 in the catalysis while the catalytically active species has been established as trans-dihydride [mer-PNHN]RuH2(CO) (PNHN = 8-(2-diphenylphosphinoethyl)aminotrihydroquinoline). The stereo-structure of the PNHN-ruthenium species greatly affects the activity of the catalyst, and indeed the cis-dihydride isomer [fac-PNHN]RuH2(CO) is unable to catalyze the hydrogenation of esters until ligand reorganization occurs to give the trans isomer.
2017-08-10 15:34:27
Science & Technology
Physical Sciences
Chemistry, Physical
Chemistry
RUTHENIUM PINCER COMPLEXES
TRANSITION-ELEMENTS
CHIRAL ALCOHOLS
REDUCTION
METHANOL
TRANSFORMATIONS
ACTIVATION
CARBONATES
FORMATES
BIOMASS