3-Ethynyltriimidazo[1,2- a :1',2'- c :1″,2″- e ][1,3,5]triazine Dual Short- and Long-Lived Emissions with Crystallization-Enhanced Feature: Role of Hydrogen Bonds and π-π Interactions

• Published in: Molecules (Basel, Switzerland) Vol. 29; no. 9; p. 1967
• Main Authors: Malpicci, Daniele, Maver, Daniele, Rosadoni, Elisabetta, Colombo, Alessia, Lucenti, Elena, Marinotto, Daniele, Botta, Chiara, Bellina, Fabio, Cariati, Elena, Forni, Alessandra
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 25-04-2024
• Subjects: Crystallization; crystallization-enhanced emission; dual emission; Energy; Fluorescence; Hydrogen; Hydrogen bonding; Hydrogen bonds; organic room temperature phosphorescence; supramolecular interactions; organic room temperature phosphorescence; supramolecular interactions; crystallization-enhanced emission; dual emission
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules29091967

Organic room temperature phosphorescent (ORTP) materials with stimuli-responsive, multicomponent emissive behaviour are extremely desirable for various applications. The derivative of cyclic triimidazole (
) functionalized with an ethynyl group,
, is isolated and investigated. The compound possesses crystallization-enhanced emission (CEE) comprising dual fluorescence and dual phosphorescence of both molecular and supramolecular origin with aggregation-induced components highly sensitive to grinding. The mechanisms involved in the emissions have been disclosed thanks to combined structural, spectroscopic and computational investigations. In particular, strong CH⋯N hydrogen bonds are deemed responsible, for the first time in the
family, together with frequently observed π⋯π stacking interactions, for the aggregated fluorescence and phosphorescence.