Discovery of full color emissive thiazole fluorophores in solution and solid states: The core is central and regulating torsional barrier does the trick!

Abstract

The rare class of full color tunable molecules from 5-(hetero-2-yl)-1,3-thiazole core with solid and solution state emissions were designed. Stable conformers were predicted computationally and C4 substituent on the 1,3-thiazole ring emerged crucial as multifunctional stacking modulator in the multidirectional charge transfer donor-acceptor systems. Seven novel molecules were synthesized, and their emissions with very good quantum yield both in solution and solid states were reported along with very rare full color dual emission (solution:469–672 nm, solid:466–614 nm). These full color dual state emissive (FCDSE) molecules also displayed solvatochromism and large Stokes shift (solution: 78–210 nm, solid: 90–106 nm). Further, absorption and emission wavelengths were calculated using TDDFT-PBE0/6-31G(d,p) by accounting the solvent effects using Poisson Boltzmann solvation model and the experimental results were well reproduced. The accurate prediction of absorption-emission trend in this homologous series is expected to guide the design of custom-emissive fluorophores and the facile synthetic route can provide diverse compounds for desired technological applications.