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Investigation of Excited-State Intramolecular Proton Transfer and Structural Dynamics in Bis-Benzimidazole Derivative (BBM)

The bis-benzimidazole derivative (BBM) molecule, consisting of two 2-(2′-hydroxyphenyl) benzimidazole (HBI) halves, has been synthesized and successfully utilized as a ratiometric fluorescence sensor for the sensitive detection of Cu(2+) based on enol–keto excited-state intramolecular proton transfe...

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Detalles Bibliográficos
Autores principales: Xie, Junhan, Wang, Ziyu, Zhu, Ruixue, Jiang, Jiaming, Weng, Tsu-Chien, Ren, Yi, Han, Shuhua, Huang, Yifan, Liu, Weimin
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10253469/
https://www.ncbi.nlm.nih.gov/pubmed/37298391
http://dx.doi.org/10.3390/ijms24119438
Descripción
Sumario:The bis-benzimidazole derivative (BBM) molecule, consisting of two 2-(2′-hydroxyphenyl) benzimidazole (HBI) halves, has been synthesized and successfully utilized as a ratiometric fluorescence sensor for the sensitive detection of Cu(2+) based on enol–keto excited-state intramolecular proton transfer (ESIPT). In this study, we strategically implement femtosecond stimulated Raman spectroscopy and several time-resolved electronic spectroscopies, aided by quantum chemical calculations to investigate the detailed primary photodynamics of the BBM molecule. The results demonstrate that the ESIPT from BBM-enol* to BBM-keto* was observed in only one of the HBI halves with a time constant of 300 fs; after that, the rotation of the dihedral angle between the two HBI halves generated a planarized BBM-keto* isomer in 3 ps, leading to a dynamic redshift of BBM-keto* emission.