Role of Substituent Position in Coumarin Derivatives during their Interaction with TiO Nano Particles.

The effect of position of benzo group in coumarin derivatives, 5,6 benzo-4-azidomethyl coumarin (5BAMC) and 7,8 benzo-4-azidomethyl coumarin (7BAMC) during their interaction with TiO nanoparticles in ethyl acetate, tetrahydrofuran, butan-1-ol and acetonitrile solvents has been studied using different spectroscopic methods and electrochemical analysis. Benesi-Hildebrand plots indicate that nature of interaction between 7BAMC and TiO is 1:2 in solvent with low dielectric constant whereas for 5BAMC and TiO, it is 1:1 in all the solvents. From the fluorescence quenching study and binding equilibria analysis, it is observed that interaction between 5BAMC and TiO depends on the dielectric constant of the solvent.

Study of Photophysical Properties on Newly Synthesized Coumarin Derivatives.

Herein, we have studied the photophysical properties for three newly synthesized coumarin derivatives; 4-((2,6-dibromo-4-methylphenoxy)methyl)-2H-benzo[h]chromen-2-one (DMB), 4-((3,4-dihydro-6,7-dimethoxyisoquinolin-1-yl)methyl)-6-methyl-2H-chromen-2-one (DIM) and 4-((p-tolyloxy)methyl)-6-methoxy-2H-chromen-2-one (TMC). The absorption and emission spectra for above said molecules were recorded in different solvents at room temperature in order to calculate their ground and excited state dipole moments. The ground (μ ) and excited state dipole (μ ) moments of these coumarin derivatives were calculated using Lippert's, Bakshiev's and Kawski-Chamma-Viallet's equations by the solvatochromic shift method, which involves a variation of Stokes shift with the solvent dielectric constant and refractive index.

Photophysical Properties of a Novel and Biologically Active 3(2H)-Pyridazinone Derivative Using Solvatochromic Approach.

Herein, we report photophysical properties of a novel and biologically active 3(2H)-pyridazinone derivative 5-(4-chloro-2-hydoxy-phenyl)-2-phenyl-2H-pyridazin-3-one [CHP] molecule using solvatochromic approaches. Absorption and fluorescence spectra of CHP molecule have been measured at room temperature in various solvents of different polarities. From this, it is observed that the positions, intensities and shapes of the absorption and emission bands are usually modified.

Analysis of Fluorescence Quenching for Newly Synthesized Biologically Active 3(2H)-pyridazinone Derivative by Aniline.

Herein, we have studied the analysis of fluorescence quenching for newly synthesized biologically active 3(2H)-pyridazinone derivative 5-(5-bromo-2-hydroxy-phenyl)-2-phenyl-2H-pyridazin-3-one [BHP] by various concentrations of aniline using UV-Visible spectroscopy, fluorescence spectroscopy and time-correlated single photon counting technique in five different solvents namely, methanol, ethanol, propan-2-ol, dimethylsulfoxide and ethyl acetate at room temperature. The fluorescence intensity of BHP molecule decrease with increasing in the aniline concentration and it is studied using the Stern-Volmer relation. The obtained Stern-Volmer plots were found to be linear in all the five solvents.

Solvent Effects on the Electronic Absorption and Fluorescence Spectra of HNP: Estimation of Ground and Excited State Dipole Moments.

We report the effect of solvents on absorption and fluorescence spectra of biologically active 3(2H)-pyridazinone namely 5-(2-hydroxy-naphthalen-1-yl)-2-phenyl-2H-pyridazin-3-one (HNP) in different solvents at room temperature. The ground and the excited state dipole moments of HNP molecule was estimated from Lippert's, Bakshiev's and Kawski-Chamma-Viallet's equations using the solvatochromic shift method. The ground state dipole moment (μ g ) was also estimated by Guggenheim and Higasi method using the dielectric constant and refractive index of solute at different concentrations, the μ g value obtained from these two methods are comparable to the μ g value obtained by the solvatochromic shift method.