From an economic and ecological perspective, the efficient utilization of atmospheric CO 2 as a carbon resource should be a much more important goal than reducing CO 2 emissions. However, no strategy to harvest CO 2 using atmospheric CO 2 at room temperature currently exists, which is presumably due to the extremely low concentration of CO 2 in ambient air (approximately 400 ppm 0.04 vol%). We discovered that monoethanolamine (MEA) and its derivatives efficiently absorbed atmospheric CO 2 without requiring an energy source. We also found that the absorbed CO 2 could be easily liberated with acid. Furthermore, a novel CO 2 generator enabled us to synthesize a high value-added material (i.e., 2-oxazolidinone derivatives based on the metal catalyzed CO 2 -fixation at room temperature) from atmospheric CO 2 .Key words carbon dioxide absorption; carbon dioxide generation; carbon dioxide fixation; cyclization; atmospheric chemistryIn 2014, the Intergovernmental Panel on Climate Change (IPCC) reported 1) that warming of the climate is unequivocal and that the largest contribution is a result of increasing atmospheric CO 2 since 1750. In the previous year, the National Oceanic and Atmospheric Administration (NOAA) in Mauna Loa, Hawaii, observed that the concentration of atmospheric CO 2 surpassed 400 ppm for the first time since measurements began in 1958. This value is approximately 120 ppm higher than that of the pre-industrial atmosphere (approximately 280 ppm).2) Global CO 2 emissions from fuel combustion in 2012 reached a record of 31.7 gigatons (GtCO 2 ) based on calculations performed by the International Energy Agency (IEA).3) On the other hand, there are many reports that CO 2 is not an essential source for Climate Change.4-10) The experimental fact can only prove the answer of these discussions. Thus, techniques for reduction of CO 2 must be globally important.Current efforts for CO 2 reduction include CO 2 capture and storage (CCS) 11) and artificial photosynthetic systems (APSs).12,13) CCS involves the capture of CO 2 using chemical absorbent (i.e., monoethanolamine, MEA 1 etc.) [14][15][16][17][18][19][20] in highdensity areas, such as industrial facilities and power stations, and transporting CO 2 to deep subsurface rock formations or the bottom of the ocean via pipelines. This is a useful and efficient technique that can prevent the release of large quantities of CO 2 . However, this technology does not provide any immediate economic benefit, and the captured CO 2 is not chemically altered. In the projects of CCS, the liberation of CO 2 gas from chemical absorbent requires heating at high temperature, which uses high amount of electricity. This means that introducing CCS plants spends one part of electricgenerating capacity in power station. The limited number of sites is also problematic because CCS plants must be constructed near areas with high CO 2 densities. In contrast, APSs use solar light and a metal catalyst. In this approach, CO 2 is transformed into HCO 2 H 12) or CO, 13) whereby the products c...

Gold­(I) complexes featuring Z-type ligands introducing electron-withdrawing groups (EWG), Au­(DPBF)Cl (4a) and Au­(DPBCl)Cl (4b) (DPB = diphosphine-boron), have been synthesized and structurally characterized. These studies suggest that increasing the electron-withdrawing properties of the boron phenyl substituent only results in minor structural changes of the gold complexes. These complexes can be converted into Au­(DPBF)­SbF6 and Au­(DPBCl)­SbF6 by treatment of 4a,b with AgSbF6. The cationic complexes show interesting catalytic properties and readily promote the cyclization of yne-diols into unprecedented dioxabicyclo[3.2.2] derivatives.

The metal‐catalyzed carboxylation of propargylamines with aerial CO2 at room temperature to form 5‐methyleneoxazolidin‐2‐one derivatives has been developed. In this reaction, the catalyst [Au(dpbF)]X featuring a Z‐type ligand gave the best results, presumably due to the σ‐acceptance of the borane atom.