AIEgens-NLOphores coumarin-triphenylamine chalcone derivatives: Synthesis, photophysical properties and DFT computational study

Three coumarin-triphenylamine chalcone derivatives (5a-c) with push-pull structures of type A-pi-D and D -pi-A-pi-D were synthesized, varying the substituent at position 7 of coumarin. The characterization of the final compounds as for the intermediates was conducted using( 1) H and (13) C NMR, FT-IR, and HRMS. The study of the photophysical properties of 5a-c revealed a strong solvatochromism, mainly in fluorescent emission, due to the formation of a twisted intramolecular charge transfer (TICT) state. Moreover, aggregation-induced emission (AIE) in MeCN -H2O mixtures was notably observed, as well as a strong red emission in the solid state. Computational studies by DFT methods allowed to elucidate the molecular geometries of the ground (S-0 ) and excited states (S-1 ), assign vibrational modes and electronic transitions of IR and UV-Vis spectra, respectively, to describe the reactivity and the electronic distribution from the molecular electrostatic potential (MEP) and the HOMO-LUMO orbitals. Computationally calculated first and second-order hyperpolarizabilities show chalcones 5a-c as potential NLO materials. (C) 2022 Elsevier B.V. All rights reserved.