Computational Design, Synthesis, and Structure Property Evaluation of 1,3-Thiazole-Based Color-Tunable Multi-heterocyclic Small Organic Fluorophores as Multifunctional Molecular Materials

Abstract

Probing the chemical space of luminescent organic materials built on novel cores is highly imperative for its potential to expand the horizons of advanced functional materials. Small organic fluorophores possessing therapeutic traits can contribute to theranostics. We coupled computational and classical synthetic chemistry strategies for the rational design of 5-(hetero-2-yl)-1,3-thiazoles as color-tunable fluorophore core. With the aid of DFT and TD-DFT, we prove that the multi-heterocyclic system is built on a thiazole-het core with three inherent tunable sites on thiazole (C2, C4, and C5) capable of accommodating a panoply of substituents as a multifunctional molecular materials' platform. This de novo design offered unprecedented freedom to control strength and direction of charge transfer by varying donor-acceptor fragments. A 30-member fluorophore library built on thiazole-thiophene/furan core was accomplished using commercial reagents by a simple [4 + 1] synthesis. Structure-photophysical property studies revealed large Stokes shift, positive solvatochromism, acidochromism, and color tunability in different solvents and were rationalized using computational calculations. In vitro studies indicated 1a to be active against HL-60 cell lines, suggesting the possibility of expanding the core for theranostics. The lower values of computed hole reorganization energies indicated their potential as hole transporting materials in optoelectronics and widen the scope of these molecules as advanced functional materials.

Coumarin-Based Dual Chemosensor for Colorimetric and Fluorescent Detection of Cu2+ in Water Media

“…The optimized geometries of compounds were determined at the PBE0/6-31+G­(d) level of theory, − using the Gaussian 09 program package. , The structures and the nature of the bonds in these compounds have also been investigated through the atoms in molecules (AIM) topological analysis, using the AIM2000 software . The calculated results, including the electron density (ρ­( r )), Laplacian ∇ 2 (ρ­( r )), the bond critical points (BCPs), and the ring critical points (RCPs), were used to evaluate the stability of bonds, the characteristics of bonds, the presence of bonds, and ring structure. ,− The electronic properties of compounds were investigated by the natural bond orbital (NBO) analysis, using the NBO 3.1 program available in Gaussian 09 package, at the PBE0/6-31+G­(d) level of theory.…”

Triphenylamine/4,4′-Dimethoxytriphenylamine-Functionalized Thieno[3,2-b]thiophene Fluorophores with a High Quantum Efficiency: Synthesis and Photophysical Properties

“…It is well recognized that fluorescent materials have been immensely popular in display technologies due to their unique advantages in energy economy with low driving voltage, high brightness, and high contrast display for full-color fluorescence. − Conjugated organic molecules are one of the most popular materials used in display technologies along with other applications such as light-emitting diodes, lighting lasers, photovoltaics, nonlinear optical (NLO) materials, security marking, and biomedical imaging. − Organic fluorophores with high quantum efficiency, strong brightness, , long-lasting fluorescence lifetime, chemical and thermal robustness, and color tunability − are potential compounds for fluorescence applications. An important advantage is that fluorescence properties can be finely tuned through chemical modification of their structures. − In particular, the geometrical design and conformation of the fluorophores have a crucial influence on their fluorescence and electroluminescence properties. − Thiophene-derived conjugated compounds, such as thienothiophenes (TTs), have particular importance as they are easy to modify in addition to their electron-rich, flat, and good electron delocalized structures.…”

Investigation on Photophysical, Solvatochromism and Biological Significance of Substituted 2H‐Indazole Derivatives

“…N-heterocylic molecules are being extensively utilized as building blocks [30] for the construction of luminescent probes because of their interesting electron withdrawing properties upon photoexcitation. [31,[32][33][34] Moreover, these molecules known to exhibit reversible protonation behavior, resulting in induced photoluminescence in solution and solid phase, paving way for the development of colorimetric sensors. [35] Similarly, phosphorous and nitrogen containing pyrenes exhibit redox properties with tunable multi-color photoluminescence.…”

“…Till date, 2 H ‐indazole is considered as a starting molecule or a building block for many drug discoveries and still lot of novel activities yet remain unexplored. N‐heterocylic molecules are being extensively utilized as building blocks for the construction of luminescent probes because of their interesting electron withdrawing properties upon photoexcitation . Moreover, these molecules known to exhibit reversible protonation behavior, resulting in induced photoluminescence in solution and solid phase, paving way for the development of colorimetric sensors .…”