Energyless CO2 Absorption, Generation, and Fixation Using Atmospheric CO2.

From an economic and ecological perspective, the efficient utilization of atmospheric CO2 as a carbon resource should be a much more important goal than reducing CO2 emissions. However, no strategy to harvest CO2 using atmospheric CO2 at room temperature currently exists, which is presumably due to the extremely low concentration of CO2 in ambient air (approximately 400 ppm=0.04 vol%). We discovered that monoethanolamine (MEA) and its derivatives efficiently absorbed atmospheric CO2 without requiring an energy source. We also found that the absorbed CO2 could be easily liberated with acid. Furthermore, a novel CO2 generator enabled us to synthesize a high value-added material (i.e., 2-oxazolidinone derivatives based on the metal catalyzed CO2-fixation at room temperature) from atmospheric CO2.

Air-stable cationic gold(I) catalyst featuring a Z-type ligand: promoting enyne cyclizations.

An air-stable cationic Au(I) complex featuring a Z-type ligand (boron atom) as a σ-acceptor was developed for elucidating the effect of B on catalytic reactions. An enyne cyclization in the presence of either [Au→B](+) or [Au](+) showed that [Au→B](+) promotes the reactivity, which enabled the effective construction of not only five- and six-membered rings, but also seven-membered rings.