Abstract

Porphyrin derivatives and their analogs show great potential as near-infrared (NIR) chromophores, paving the way for innovative optical materials across various fields, including light-harvesting, sensing, and therapeutic applications. Structural modifications, such as core expansion, peripheral fusion, and chromophore array, have shifted the light-responsive wavelength into the NIR window while maintaining high photo- and chemical stability. Since the discovery of the porphyrin isomer known as N-confused porphyrin, our research group has focused on developing a series of π-conjugated porphyrin analogs incorporating “N-confused” pyrrole rings. These unique structures enhance metal coordination ability, which is crucial for triggering molecular orbital mixing and tuning in N-confused porphyrinoids. This leads to remarkable NIR optical properties and controlled excited-state dynamics.

This presentation will highlight the recent advancements in bis-metal complexes of N-confused porphyrinoids that exhibit NIR functionality, following a brief overview of the chemistry of N-confused porphyrin and its contracted or expanded analogs.[1, 2] Unique properties—including distinct emission and photoacoustic signals in the second and third NIR regions, stable π radicals, an exceptionally high twophoton absorption cross-section upon second NIR pulse irradiation, and numerous metal-ligand chargetransfer transitions via d-π orbital interactions—are all attributed to the molecular orbital features.[3]

[1] Toganoh, M.; Furuta, H. Chem. Rev. 2022, 122 , 8313–8437.

[2] Białek, M. J.; Hurej, K.; Furuta, H.; Latos-Grażyński, L. Chem. Soc. Rev. 2023, 52 , 2082–2144.

[3] Ghosh, A.; Bhandari, S.; Furuta, H.; Ishida, M. ChemPlusChem 2025, accepted Article

(https://doi.org/10.1002/cplu.202500090).

Biography

Hiroyuki Furuta received his B.Sc. (1980), M.Sc. (1982), and Ph.D. (1986) degrees from Kyoto University. After postdoctoral research at the MitsubishiKasei Institute of Life Sciences, Tokyo, and the University of Texas, Austin, he started his independent academic career in 1992 as an Associate Professor at Oita University. In 1997, he moved to Kyoto University as an Associate Professor. In 2002, he was named a Full Professor in Chemistry at Kyushu University. In 2022, he became Professor Emeritus. He has been a Distinguished Professor at Shanghai University and VAJRA Professor at IIT Kanpur since 2025. His current research focuses on the synthesis of N-confused porphyrinoids with novel functionality.