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In this article, we present several organic synthetic way to synthesize a family of five polyaromatic molecules based on a cyclophane core. Our strategies revolves around palado-catalyzed substitution on a [2.2]paracyclophane (pCp) building block. Direct formation of a cyclophane was also employed for two molecules. The polyaromatic nature of the cyclophane library we synthetized made them good fluorophores candidate, we hence performed full photophysical characterization (Absorption, Emission, TCSPC) in different solvent as well as embed in polystyrene films. We evaluate how the cyclophane moiety influence their photo physical properties compared to their corresponding homologues without pCp core, demonstrating greater stoke shift and intramolecular exciplex behavior. The general behavior among cyclophanes was also compared and show solvent dependent properties as well as consistency of the photophysics between toluene and polystyrene matrix., (© 2024 The Authors. ChemistryOpen published by Wiley-VCH GmbH.)

A new class of photoswitches and the corresponding elementary photoinduced reaction, the so-called Excited-State Cation Transfer (ESCT), are investigated. This reaction relies on an intramolecular photo-release/photo-complexation of cation: after irradiation, the cation is translocated from a complexation site 1 to a site 2 during the excited state lifetime. Our purpose is thus to develop a computational strategy based on Density Functional theory (DFT) and its time-dependent counterpart (TD-DFT) to improve the different properties of the ESCT photoswitches, namely (i) the ground state complexation constant K , (ii) the excited state complexation constant K *, (iii) the photoejection properties and (iv) the population of the triplet states from a singlet state via intersystem crossing to increase the lifetime of the excited state. In this work, we are interested in optimizing the ESCT properties of a betaine pyridinium chromophore substituted by a 15-aza-5-crown, that was previously shown to efficiently photoeject a Ca 2+ cation from the site 1 but no photo-recapture was observed in the site 2 [Aloïse et al. , Phys. Chem. Chem. Phys ., 2016, 22 , 15384]. To this purpose, we have investigated the impact of the modification of the site 1 on the ESCT properties by introducing different substituents (EDG groups, halogen atoms) at different positions. So far, promising systems have been identified but a simultaneous improvement of all the ESCT photoswitches properties has yet not been achieved.