Seminar CEMES/LCC, Prof. Garry HANAN

Prof. Garry HANAN

Chemistry department, Université de Montréal
Montréal, Québec H2V 0B3, Canada
e-mail: garry.hanan@umontreal.ca

Developing New Photosensitizers based on Transition Metal Ions for Green Energy Applications

Rising global population and increased CO₂ levels in the atmosphere have focused attention on developing alternative and widely available carbon-free energy sources.^1,2 Our research focuses on harnessing the unique properties of excited states in metal complexes to drive self-assembly processes and develop innovative energy applications. By leveraging the photophysical and photochemical behaviors of these complexes, we explore how light-induced excitations can be utilized to control molecular organization and energy transfer at the nanoscale. The parallels with Natural Photosynthesis are evident: light energy is captured by self-assembled Light Harvesting Complexes and is channeled to a reaction centre which induces electron transfer and the eventual production of chemical energy.³

Our approach involves the synthesis of polypyridyl-based metal complexes, which are known for their stability and tunable electronic properties. By manipulating the excited states of these complexes, we demonstrate how light can act as a stimulus to induce self-assembly (Figure 1), leading to the formation of well-defined nanostructures with potential applications in catalysis, sensing, and optoelectronics.⁴ Additionally, we extend our approach to the development of photoactive molecular devices capable of storing and transferring electrons, offering insights into the design of next-generation photosensitizers for chemical energy production.⁵ We have also moved from second- and third-row transition metal ions to the first row, and explore energy applications of these abundant, inexpensive and relatively non-toxic metal ions.⁶

Figure 1. X-Ray crystal structure of a tetraruthenium square assembled by light irradiation. Solvent, hydrogen atoms, and anions are removed for clarity.⁴

References

1. https://ourworldindata.org/world-population-growth (01-04-2026).
2. https://www.iea.org/world (01-04-2026).
3. Balzani, A. Credi, M. Venturi, Chem Sus Chem 2008, 1, 26.
4. Laramée-Milette, F. Puntoriero, F. Nastasi, S. Campagna, G. S. Hanan, Chem. Eur. J., 2017 23, 16497.
5. M. Mercier, E. Rousset, I. Oubaha, K. Bandyopadhyay, A. K. Pal, I. Ciofini, L.-M. Chamoreau, V. Marvaud, G. S. Hanan, Chem. Commun. 2025 61 (77), 14911-14914.
6. Saha, G. Turner, M. Cibian, S. Serroni, S. Genovese, S. Campagna, G. S. Hanan, F. Nastasi, submitted for publication.