Profile

I conduct chemistry research focusing on the synthesis of sulfur-containing metal complexes and the analysis of their electrochemical behavior using voltammetry. My consistent research theme is the “development of redox catalysts based on unique coordination and dimensional structures,” with a particular emphasis on metal complexes with sulfur-containing ligands.

Development of homogeneous redox catalysts with thiacarbanion ligands
To date, I have synthesized metal complexes of first-row transition metals using ligands containing thiacarbanion groups, and investigated their electrocatalytic properties—especially those of iron (Fe) and nickel (Ni). This work was conducted in collaboration with Professor Isamu Kinoshita and Professor Akio Ichimura at the Graduate School of Science, Osaka City University.

Synthesis of metal complexes with sulfur-containing amino acid ligands and construction of supramolecular assemblies
I am also studying the coordination behavior and properties of metal complexes using natural amino acids such as cysteine and penicillamine as ligands. This research is in collaboration with Professor Takumi Konno at the Graduate School of Science, Osaka University.

Electrocatalytic function of sulfur-bridged multinuclear metal complexes with sulfur-containing amino acid ligands
Through electrochemical analysis of the above complexes, I have discovered their catalytic activity for both water oxidation and reduction. Recently, I successfully synthesized and structurally characterized a coordination polymer incorporating all Group 10 metal ions—platinum(II), palladium(II), and nickel(II)—within a single molecule. The polymer exhibited significantly enhanced heterogeneous catalytic activity for hydrogen evolution, depending on the number of different metal ions incorporated. Additionally, using the same ligands, coordination polymers containing copper(II), zinc(II), and platinum(II) were synthesized. In these systems, the coordination environment and dimensional structure of copper(II) could be tuned by the choice of counterion, and the oxygen evolution reaction (OER) catalytic performance was found to dramatically increase with the number of vacant coordination sites on the copper(II) centers.

Exploration of catalytic activity through the hybridization of dithiolene complexes with inorganic materials
Dithiolene complexes have long been studied for their redox-active properties and are known to act as proton reduction catalysts in solution. We discovered that when combined with graphene oxide, these complexes function as heterogeneous catalysts for hydrogen evolution. We also reported that the catalytic activity varies depending on the oxidation degree, size, and dispersion of the graphene oxide. This study was conducted in collaboration with Professor Hideki Hashimoto of Kogakuin University.

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