Thermal-reductive transformations of carbon dioxide catalyzed by small molecules using earth-abundant elements

Catalytic reduction of carbon dioxide by a zinc hydride compound, [Tptm]ZnH, and conversion to the methanol level

The zinc hydride compound, [Tptm]ZnH, may achieve the reduction of CO₂ by (RO)₃SiH (R = Me, Et) to the methanol oxidation level, (MeO)_xSi(OR)_4-x, via the formate species, HCO₂Si(OR)₃. However, because insertion of CO₂ into the Zn-H bond is more facile than insertion of HCO₂Si(OR)₃, conversion of HCO₂Si(OR)₃ to the methanol level only occurs to a significant extent in the absence of CO₂.

Zn(ii)@TFP-DAQ COF: an efficient mesoporous catalyst for the synthesis of N-methylated amine and carbamate through chemical fixation of CO2

Selective N-methylation and carbamate formation reactions were demonstrated via the chemical incorporation of CO₂ using a Zn-loaded TFP-DAQ COF (covalent organic framework) as an active catalyst under mild reaction conditions.

Scalable direct N-methylation of drug-like amines using 12CO2/13CO2 by simple inorganic base catalysis

With the growing urgency of potential catastrophic climate changes due to anthropogenic CO₂ emissions, numerous efforts have been devoted to development of synthetic protocols using CO₂ as a building block in organic reactions, but the general applicability to complex drug-like substrates remains a challenge. We develop a general protocol for scalable direct N-methylation of a wide-scope drug-like amines using CO₂ and polymethylhydrosiloxane-a nontoxic, aerobically-stable hydrosilane considered as an industrial waste-via simple inorganic base catalysis. A rare application of the Sabatier principle in organic chemistry led to the discovery of cheap, nontoxic K₃PO₄ as an efficient catalyst. Preparations of a wide-scope drug-like amines with carbon-isotope label were also successfully achieved, enabling direct use of CO₂ in studies of drug absorption, distribution, metabolism and excretion.

Highly Efficient Synthesis of Functionalizable Polymers from a CO2/1,3-Butadiene-Derived Lactone

Making polymers from CO₂ and olefins has been long sought and is of particular significance for chemical utilizations of CO₂. Herein, high molecular-weight polymers with 29 wt % CO₂ were obtained by polymerizing a δ-lactone (L) synthesized from a C-C coupling reaction between CO₂ and 1,3-butadiene, an economical large-volume chemical that can also be derived from top biomass platform chemicals. Although L has been known for many years, little was investigated in its polymerization. We found that L's polymerizability can be vitalized upon simply heating in the presence of O₂. The polymerization is additive/solvent-free with abundant preserved olefins and up to full monomer conversion, providing a convenient, economical, and scalable avenue to obtain CO₂-derived polymers with potentially tailorable properties via the readily modifiable olefins.