Magnifying the ESIPT process in tris(salicylideneanilines) the steric effect - a pathway to the molecules with panchromatic fluorescence

• Published in: Physical chemistry chemical physics : PCCP 2023-05, Vol.25 (17), p.125-12514
• Main Authors: Gawrys, Pawel, Morawski, Olaf, Banasiewicz, Marzena, Barboza, Cristina A
• Format: Article
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d3cp00638g

Four tris(salicylideneanilines) (TSANs) with gradually increased steric interactions between the keto-enamine moiety and neighbouring phenyl substituent are presented. The steric interactions are induced by placing two alkyl groups at the ortho position in the N -aryl substituent. The impact of the steric effect over the radiative channels of deactivation of the excited state was evaluated through spectroscopic measurements and theoretical calculations using ab initio techniques. Our results show that the emission occurring after excited state intramolecular proton transfer (ESIPT) is favoured by placing the bulky groups in the ortho position of the N -phenyl ring of the TSAN. However, our TSANs seem to offer the opportunity to obtain a pronounced emission band at higher energy, significantly increasing the coverage of the visible spectrum, resulting in the enhancement of the dual emissive properties of tris(salicylideneanilines). Thus, TSANs may be promising molecules capable of white-like emission for use in organic electronic devices such as white OLEDs. The twist of the phenyl rings of tris(salicylideneanilines) facilitates the ESIPT emission, significantly increases coverage of the visible spectrum and enables spectrally wide tuning of luminescence chromaticity.