Understanding the Driving Mechanisms of Enhanced Luminescence Emission of Oligo(styryl)benzenes and Tri(styryl)‐s‐triazine. Issue 15 (19th February 2020)

• Record Type: Journal Article
• Authors: Domínguez, Rocío; Moral, Mónica; Fernández‐Liencres, M. Paz; Peña‐Ruiz, Tomás; Tolosa, Juan; Canales‐Vázquez, Jesús; García‐Martínez, Joaquín C.; Navarro, Amparo; Garzón‐Ruiz, Andrés
• Is Part Of: Chemistry. Volume 26:Issue 15(2020)
• Page Start: 3373
• Page End: 3384
• Publication Date: 2020-02-19
• Subjects: aggregation -- luminescence -- photochemistry -- self-assembly -- styrylbenzenes; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201905336
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: This work is focused on unraveling the mechanisms responsible for the aggregation‐induced enhanced emission and solid‐state luminescence enhancement effects observed in star‐shaped molecules based on 1, 3, 5‐tris(styryl)benzene and tri(styryl)‐ s ‐triazine cores. To achieve this, the photophysical properties of this set of molecules were analyzed in three states: free molecules, molecular aggregates in solution, and the solid state. Different spectroscopy and microscopy experiments and DFT calculations were conducted to scrutinize the causative mechanisms of the luminescence enhancement phenomenon observed in some experimental conditions. Enhanced luminescence emission was interpreted in the context of short‐ and long‐range excitonic coupling mechanisms and the restriction of intramolecular vibrations. Additionally, we found that the formation of π‐stacking aggregates could block E / Z photoisomerization through torsional motions between phenylene rings in the excited state, and hence, enhancing the luminescence of the system. Abstract : Stars vs. crosses : Aggregation‐induced enhanced emission and solid‐state luminescence enhancement is observed in star‐shaped molecules based on 1, 3, 5‐tris(styryl)benzene and tri(styryl)‐ s ‐triazine cores, but not in cross‐shaped structures, such as 1, 2, 4, 5‐tetra(styryl)benzene. The mechanisms for these processes are investigated experimentally and theoretically.