Solid state thiazole-based fluorophores: Promising materials for white organic light emitting devices

• Published in: Dyes and pigments Vol. 187; p. 109077
• Main Authors: Godugu, Kumar, Shaik, Sultana, Mohinuddin Pinjari, Mohammad Khaja, Gundala, Trivikram Reddy, Chellappa Subramanyam, Dwaraka Viswanath, Loka, Subramanyam Sarma, Divi, Haranath, Venkatramu, Vemula, Reddy Nallagondu, Chinna Gangi
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-03-2021
• Subjects: 2-(3-pyridyl)/2-aminothiazoles; Silica-supported HClO4; Solvent-free mechanochemical synthesis; White organic light emitting devices; Silica-supported HClO4; Solvent-free mechanochemical synthesis; 2-(3-pyridyl)/2-aminothiazoles; White organic light emitting devices
• ISSN: 0143-7208; 1873-3743
• DOI: 10.1016/j.dyepig.2020.109077

A facile and more efficient solvent-free mechanochemical synthetic route has been developed for the synthesis of a series of solid state white light emissive thiazole-based donor-acceptor (D-A) type fluorophores, 2-(3-pyridyl)/2-aminothiazoles from ω-bromomethylketones and pyridine-3-carbothioamide/thiourea in the presence of silica-supported HClO4 as a reusable solid Brønsted acid catalyst at RT. The photophysical and electrochemical properties of these compounds have been derived. Most of the studied D-A type solid thiazole-based fluorophores emitted white light and it can be tuned from warm - ideal - cold white light by introduction of a variety of substituents at 4th position of 2-(3-pyridyl)/2-aminothiazoles. Further, HOMO and LUMO energy levels of the titled compounds are found to be in the range −5.52 eV to −5.72 eV and −1.84 eV to −2.45 eV, respectively. The lifetimes of these levels of thiazole-based fluorophores have been determined through luminescence decay curves and are found to be in the range of 7.7–11 μs. The photophysical and electrochemical properties of the synthesized thiazole-based fluorophores indicate that the compounds could be promising materials for white organic light emitting devices.
Solvent-free mechanochemical route has been developed for the synthesis of a series of solid state white light emissive (tunable from warm-ideal-cold) and hole transporting D-A type 2-(3-pyridyl)/2-aminothiazoles (3/5). [Display omitted]
•HClO4-SiO2 catalyzed solvent-free mechanochemical synthesis of 2-(3-pyridyl)/2-aminothiazoles.•The photophysical and electrochemical properties of D-A type 2-(3-pyridyl)/2-aminothiazoles have been investigated.•Thiazole-based fluorophores exhibited tunable white light emission (warm–ideal–cold) in the solid state.•The HOMO and LUMO values of synthesized thiazoles are in good agreement with the reported hole transporting materials.