Quantum Computational and Spectroscopic Investigation of 3-aminosalicylic Acid.

Quantum chemical calculations of 3-aminosalicylic acid (3ASA) (monomer and dimer forms) have been performed using DFT and TD-DFT theories with B3LYP/6-311 G(d,p) functional level in the ground and excited states. Using TD-DFT with IEF-PCM model, the electronic spectra of 3ASA in solvents were computed and correlated with the experimental data. The theoretically calculated absorption and emission maxima of 3ASA (monomer) are observed in the range of 343 - 347 nm (S → S transition) and 429 - 448 nm (S → S transition), respectively.

Excited-state properties of 6-methoxyflavone in the presence of halide ions in aqueous media.

The present work investigated the influence of different halides on the excited state dynamics of 6-methoxyflavone (6MF) in an aqueous solution with steady-state and time-resolved techniques. On successive addition of Iand Brions, the fluorescence of 6MF quenched significantly, whereas the respective ions do not change the maximum fluorescence band. Fluorescence of 6MF was quenched 66% by Iions and 34% by Brions.

Effect of halide ions on the fluorescence properties of 3-aminoquinoline in aqueous medium.

Fluorescence (FL) quenching of 3-aminoquinoline (3AQ) by halide ions has been explored in an aqueous acidic medium using the steady-state and time-domain FL measurement techniques. The halide ions showed no significant change in the absorption spectra of 3AQ in an aqueous acidic medium. The FL intensity was strongly quenched by ions and the order of FL quenching by halide ions was .

Solvatochromism and estimation of ground and excited state dipole moments of 6-aminoquinoline.

The spectral behaviour of 6AQ was investigated using fluorescence spectroscopy in several polar and non-polar solvents. Both the absorption and fluorescence spectra displayed solvatochromism. The Stokes shift increased significantly with increasing solvent polarity and signifies a more polar excited state with possible change in the excited state (ES) geometry.

Structural, Electronic and NLO Properties of 6-aminoquinoline: A DFT/TD-DFT Study.

A computational study based on the DFT/TD-DFT approach was performed to explore various properties of 6-aminoquinoline (6AQ). The geometrical parameters, molecular orbitals (MOs), electronic spectra, electrostatic potential, molecular surface, reactivity parameters and thermodynamic properties of 6AQ were explored. The absorption and emission spectra of 6AQ in solvents have been estimated by TD-DFT coupled with the PCM model and correlated with the available experimental results.

Reinvestigation of the photophysics of 3-aminobenzoic acid in neat and mixed binary solvents.

The present study elucidates the reinvestigation of the photophysical behavior of 3-aminobenzoic acid (3ABA) in solvents of different polarities using the steady-state spectroscopic techniques. Kamlet-Taft and Catalan solvatochromic models have been used to analyze the solvatochromic changes in neat solvents. The hydrogen bond donating ability of the solvent was found to be the main parameter affecting the spectral behavior of 3ABA.

Flavones Fluorescence-Based Dual Response Chemosensor for Metal Ions in Aqueous Media and Fluorescence Recovery.

Responsiveness of sensing materials 3-hydroxyflavone (3HF) towards metal ions in aqueous medium has been explored following photoexcitation. 3HF exhibited both colorimetric and fluorescence (FL) turn-off response towards Cu and Fe with high sensitivity and selectivity. Meanwhile, the distinct colour change and the rapid quenching of FL intensity provide naked-eye detection.