Pyrrole-thiazole based push-pull chromophores: An experimental and theoretical approach to structural, spectroscopic and NLO properties of the novel styryl dyes

- Thiazole based styryl (push-pull) fluorophores are made and spectroscopic properties are investigated.
- NLO properties are evaluated using spectroscopic and DFT methods.
- BLA index and generalized Mulliken-Hush (GMH) analysis are performed to understand the charge transfer.
- The chromophores possesses very high thermal decomposition temperatures (Td).

Novel push-pull fluorophores constituted by two donors (substituted pyrrole and morpholine) linked to acceptor through thiazole electron spacer have been synthesized. The fluorophores are investigated for linear and non-linear optical properties by UV-VIS absorption and fluorescence spectroscopies, and by means of TD-DFT (B3LYP/6-31G(d)) method, with the aim of elucidating the ability of the morpholine/pyrrole-donor-thiazole-spacer based D-π-A fluorophores as organic NLO materials. The bond length alternation and generalized Mulliken-Hush (GMH) analysis is performed to understand the involvement of the donor in effective transfer of the charge to acceptor. Values of first-order hyperpolarizabilities (βCT or β0), obtained by the solvatochromic method (Lippert Mataga model), and the transition dipole moments (μeg) used to characterize and evaluate the non-linear optical performances of the D-π-A fluorophores in various microenvironments. The D-π-A fluorophores possess good values of βCT or β0 in different organic solvents and hold high thermal stabilities therefore can be used as potential organic NLO materials.

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