Toma Kunikubo (Graduate School of Science)’s paper has been accepted for the Chemical Science.
Congratulations!
Authors
Toma Kunikubo, Raúl Castañeda, Muralee Murugesu, Jaclyn L. Brusso,
Kosei Yamauchi, Hironobu Ozawa, Ken Sakai
Affiliation
Graduate School of Science, Department of Chemistry
Manuscript Title
Enhanced red-light-driven hydrogen evolution by a diplatinum photocatalyst by the larger wavefunction leakage of iodide coordinated to the platinum center
Abstract
The single-molecular photocatalyst Pt2(bpia)Cl3 (bpia = bis(2-pyridylimidoyl)amido), recently proven to promote red-light-driven hydrogen evolution reaction (HER) in water via singlet-to-triplet (S–T) transitions (Toma Kunikubo, et al., Angew. Chem. Int. Ed., 2025, 64, e202418884), is shown to gain a significantly improved photocatalytic performance upon ligating iodide instead of chloride to give Pt2(bpia)I3. Upon iodide ligation, the absorption and emission energies both show a red shift basically due to destabilization of the HOMO by mixing of the iodide orbitals having essentially higher orbital energies compared to those of chloride. Consequently, the triplet lifetime and the luminescence quantum yield both decrease by obeying the energy gap law. The unique S–T transition features of Pt2(bpia)Cl3 are preserved in Pt2(bpia)I3 with the excited-state redox properties remaining unchanged. In spite of apparently disadvantageous photophysical features induced by the iodide ligation, Pt2(bpia)I3 is ascertained to promote the photocatalytic HER at a considerably higher rate in comparison with Pt2(bpia)Cl3, primarily attributed to the higher reductive quenching efficiency for the triplet excited state of Pt2(bpia)I3. The observations are rationalized due to the substantially more excellent acceptor characteristics of iodide, in which its larger wavefunction leakage significantly contributes to a larger electronic coupling factor in driving the outer-sphere electron transfer from the sacrificial electron donor.
Journal name
Chemical Science
Relevant SDGs
SDGs 7 (Affordable and clean energy)
Comments
Our research, which aimed to develop a single-molecular photocatalyst capable of evolving hydrogen even under low-energy light, has finally come to fruition after much trial and error. The results of this study have been published in Chemical Science, the flagship journal of the Royal Society of Chemistry (RSC). Building on insights gained from our previous work, we challenged ourselves to design a single-molecular photocatalyst that can utilize longer-wavelength light, and successfully achieved a significant enhancement in the hydrogen-evolving activity of a diplatinum complex under red-light irradiation. Although there were times when it was difficult to obtain results, I feel that our perseverance has finally paid off. I hope this achievement will contribute to the advancement of next-generation sustainable energy conversion research. Moving forward, I will continue to pursue the development of more efficient and sustainable energy conversion systems. I would like to express my deepest gratitude to my supervisors and all collaborators for their invaluable guidance and insightful discussions.
