Early bird or night owl? Controlling the ultrafast photodynamics of triphenylamine substituted 2,2′:6′,2′′-terpyridine

• Published in: Physical chemistry chemical physics : PCCP 2024-02, Vol.26 (7), p.6265-6276
• Main Authors: Maro, Anna Maria, Cannelli, Oliviero, Socie, Etienne Christophe, Lodowski, Piotr, Oppermann, Malte, Machura, Barbara, Chergui, Majed
• Format: Article
• Language: English
• Subjects: Fluorescence; Knobs; Night; Organic chemistry; Quantum mechanics; Solvents
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d3cp04492k

Controlling the ultrafast photodynamics of metal-free organic molecules has great potential for technological applications. In this work, we use solvent polarity and viscosity as "external knobs" to govern the photodynamics of an electron-donating derivative of 2,2′:6′,2′′-terpyridine ( terpy ), namely 4′-(4-(di(4- tert -butylphenyl)amine)phenyl)-2,2′:6′,2′′-terpyridine ( t BuTPAterpy ). We combine femtosecond fluorescence upconversion (FlUC), transient absorption (TA) and quantum mechanical calculations to provide a comprehensive description of the t BuTPAterpy 's photodynamics. Our results demonstrate that, by changing the solvent, the time scale of light-induced conformational changes of the system can be tuned over two orders of magnitude, controlling the t BuTPAterpy fluorescence spectral region and yield. As a result, depending on the local environment, t BuTPAterpy can act either as an "early bird" or a "night owl", with a tunability that makes it a promising candidate for metal-free sensors. 4′-(4-(di(4- tert -butylphenyl)amine)phenyl)-2,2′,6′,2′′-terpyridine presents a complex photodynamics tuned by the local environment, making it either an 'early bird' or a 'night owl'.