Donor‐Controlled Intramolecular Charge Transfer in Multi‐Modular Push‐Pull Conjugates Containing Competing Electron Acceptors

作者：Chamari V. Ileperuma, Pankaj K. Gupta, Rajneesh Misra, Francis D’Souza · 发表于：Chemistry - A European Journal · 年份：2026 · DOI：10.1002/chem.71635 · 研究领域：Synthesis and Properties of Aromatic Compounds、Fullerene Chemistry and Applications、Organic Electronics and Photovoltaics

ABSTRACT The superior electron‐accepting behavior of fullerene (C 60 ), even in the presence of strong electron acceptor entities, is demonstrated in a series of multi‐modular push‐pull systems carrying a donor, phenothiazine, and C 60 , coupled with strong electron acceptors, tetracyanobutadiene or dicyanoquinodimethane, between the donor and phenothiazine entities. Owing to the strong push‐pull nature of the closely spaced entities, strong intramolecular charge transfer was observed, extending the optical coverage into the near‐infrared region. Electrochemical studies revealed multiple redox processes (up to ten) owing to the presence of four redox‐active molecular entities. DFT and TD‐DFT studies helped assess the electronic structures and the excited states responsible for charge transfer, and, importantly, the role of molecular segment(s) within the multi‐modular system as electron push or pull groups. Femtosecond pump‐probe spectroscopy confirmed the occurrence of excited‐state charge transfer and separation, with C 60 as the terminal electron acceptor. Additionally, the terminal electron donor is shown to influence the lifetime of the final charge‐separated state. The unique findings reported here provide new opportunities for modular systems for the next generation of efficient energy‐harvesting, photocatalytic, and optoelectronic applications.