Activation of Metal-Catalyzed Reaction Using Z-type Ligand​ 

Ligands of transition metal catalysts are classified into three types. L type: two electrons are supplied from a ligand to the central metal X type: one electron from the ligand and the central metal form a covalent bond Z type: the ligand receives two electrons from the central metal Most ligands are classified into L type and X type, and examples of Z type ligand are few, and catalytic reaction utilizing a complex having Z type ligand has hardly been reported. Therefore, we have focused on the development of new reactivity featuring Z type ligands.

An air-stable cationic Au(I) complex 1 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.

Air-Stable Cationic Gold(I) Catalyst Featuring a Z-Type Ligand: Promoting Enyne Cyclizations
Inagaki, F.; Matsumoto, C.; Okada, Y.; Maruyama, N.; Mukai, C.
Angew. Chem. Int. Ed. 201554, 818-822.
DOI: 10.1002/anie.201408037

 Utilization of Atmospheric CO2 

Our research has focused on the utilization of atmospheric CO2 at room temperature.

General CO2 adsorbents/absorbents react with both CO2 and moisture, which is a problematic for the separation. We found that the m-xylylenediamine (MXDA) worked as a CO2-selective absorbent under air to form MXDA·CO2 without hydration. The generation of dry CO2 from MXDA·CO2 was accomplished under heating, which enabled us to use atmospheric CO2 in moisture-sensitive CO2-fixation by the Grignard reaction without any dewatering processes.

CO2-Selective Absorbents in Air: Reverse Lipid Bilayer Structure Forming Neutral Carbamic Acid in Water without Hydration.
Inagaki, F.; Matsumoto, C.; Iwata, T.; Mukai, C.
J. Am. Chem. Soc. 2017139, 4639-4642.
DOI: 10.1021/jacs.7b01049