Highly efficient hydrogenation of carbon dioxide to formate catalyzed by iridium(iii) complexes of imine-diphosphine ligands

Insight into the electronic effect of phosphine ligand on Rh catalyzed CO2 hydrogenation by investigating the reaction mechanism

The effect of the outer coordination sphere of the diphosphine ligand on the catalytic efficiency of [Rh(PCH₂X^RCH₂P)₂]⁺ (X^R = CH₂, N–CH₃, CF₂) catalyzed CO₂ hydrogenation was studied. It was found that the hydricity of the metal hydride bond determined the activation energy of the rate determining step of the reaction.

Insertion of CO2 into the carbon–boron bond of a boronic ester ligand

We report the first example of CO₂ insertion into a C–B bond.

Rechargeable Hydrogen Storage System Based on the Dehydrogenative Coupling of Ethylenediamine with Ethanol

A novel and simple hydrogen storage system was developed, based on the dehydrogenative coupling of inexpensive ethylenediamine with ethanol to form diacetylethylenediamine. The system is rechargeable and utilizes the same ruthenium pincer catalyst for both hydrogen loading and unloading procedures. It is efficient and uses a low catalyst loading. Repetitive reversal reactions without addition of new catalyst result in excellent conversions in both the dehydrogenation and hydrogenation procedures in three cycles.

Highly selective hydrogenation of CO2 into C2+ alcohols by homogeneous catalysis

Methanol, ethanol, propanol, 2-methyl propanol, butanol, and 2-methyl butanol were produced in homogeneous CO₂ hydrogenation with a selectivity for C₂₊ alcohols of 96.4%.

The hydrogenation of CO₂ to produce alcohols with two or more carbons (C₂₊ alcohols) is of great importance, but is challenging. In this work, we found that a Ru₃(CO)₁₂/Rh₂(CO)₄Cl₂–LiI system could catalyze the reaction effectively in 1,3-dimethyl-2-imidazolidinone (DMI) under mild conditions. Methanol, ethanol, propanol, 2-methyl propanol, butanol, and 2-methyl butanol were produced in the homogeneous catalytic reaction. The C₂₊ alcohols could be generated at 160 °C, which is the lowest temperature reported so far for producing C₂₊ alcohols via CO₂ hydrogenation. The selectivity for the C₂₊ alcohols could be as high as 96.4% at the optimized conditions, which is higher than those reported in the literature. In addition, the catalytic system could be easily recycled. The route of the reaction for forming the C₂₊ alcohols was discussed on the basis of control experiments.