870641-29-5Relevant academic research and scientific papers
Experimental and Theoretical Study of CO2 Insertion into Ruthenium Hydride Complexes
Ramakrishnan, Srinivasan,Waldie, Kate M.,Warnke, Ingolf,De Crisci, Antonio G.,Batista, Victor S.,Waymouth, Robert M.,Chidsey, Christopher E. D.
, p. 1623 - 1632 (2016)
The ruthenium hydride [RuH(CNN)(dppb)] (1; CNN = 2-aminomethyl-6-tolylpyridine, dppb = 1,4-bis(diphenylphosphino)butane) reacts rapidly and irreversibly with CO2 under ambient conditions to yield the corresponding Ru formate complex 2. In contrast, the Ru hydride 1 reacts with acetone reversibly to generate the Ru isopropoxide, with the reaction free energy δG°298 K = 3.1 kcal/mol measured by 1H NMR in tetrahydrofuran-d8. Density functional theory (DFT), calibrated to the experimentally measured free energies of ketone insertion, was used to evaluate and compare the mechanism and energetics of insertion of acetone and CO2 into the Ru-hydride bond of 1. The calculated reaction coordinate for acetone insertion involves a stepwise outer-sphere dihydrogen transfer to acetone via hydride transfer from the metal and proton transfer from the N-H group on the CNN ligand. In contrast, the lowest energy pathway calculated for CO2 insertion proceeds by an initial Ru-H hydride transfer to CO2 followed by rotation of the resulting N-H-stabilized formate to a Ru-O-bound formate. DFT calculations were used to evaluate the influence of the ancillary ligands on the thermodynamics of CO2 insertion, revealing that increasing the acidity of the ligand cis to the hydride ligand and increasing the σ basicity of the ligand trans to it decreases the free energy of CO2 insertion, providing a strategy for the design of metal hydride systems capable of reversible, ergoneutral interconversion of CO2 and formate.
Dynamic Kinetic Resolution of Alcohols by Enantioselective Silylation Enabled by Two Orthogonal Transition-Metal Catalysts
Oestreich, Martin,Seliger, Jan
supporting information, p. 247 - 251 (2020/10/29)
A nonenzymatic dynamic kinetic resolution of acyclic and cyclic benzylic alcohols is reported. The approach merges rapid transition-metal-catalyzed alcohol racemization and enantioselective Cu-H-catalyzed dehydrogenative Si-O coupling of alcohols and hydrosilanes. The catalytic processes are orthogonal, and the racemization catalyst does not promote any background reactions such as the racemization of the silyl ether and its unselective formation. Often-used ruthenium half-sandwich complexes are not suitable but a bifunctional ruthenium pincer complex perfectly fulfills this purpose. By this, enantioselective silylation of racemic alcohol mixtures is achieved in high yields and with good levels of enantioselection.
Formic Acid Dehydrogenation by a Cyclometalated κ3-CNN Ruthenium Complex
Beller, Matthias,Junge, Henrik,Léval, Alexander
supporting information, (2020/04/02)
Hydrogen utilization as a sustainable energy vector is of growing interest. We report herein a cyclometalated ruthenium complex [Ru(κ3-CNN)(dppb)Cl], originally described by Baratta, to be active in the selective dehydrogenation (DH) of formic
PRODUCTION METHOD OF OPTICALLY ACTIVE SECONDARY ALCOHOL
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Paragraph 0119; 0122, (2016/11/14)
PROBLEM TO BE SOLVED: To provide a chemical catalytic method allowing efficient production of a corresponding optically active secondary alcohol from an aromatic ketone having a substituent at each of two β-positions in an aromatic ring to the carbonyl site, so that both enantiomers can be separately made. SOLUTION: A production method of optically active secondary alcohol is characterized by reacting a ketone compound such as acetophenone derivatives with hydrogen in the presence of a ruthenium complex catalyst having an optically active diphosphine ligand. COPYRIGHT: (C)2015,JPO&INPIT
