Studies of solvation in homogeneous and heterogeneous media by electronic spectroscopic method

Synthesis of a Polymer Bearing Several Coumarin Dyes along the Side Chain and Study of its Fluorescence in Pure and Binary Solvent Mixtures as well as Aqueous Surfactant Solutions

“…The deviation from linearity of spectroscopic transition in energy has often been explained in terms of preferential solvation of the solute by one of the solvents. 36,37 The results obtained in the present case suggest that the free fluorophore is preferentially solvated by water, particularly in the mole fraction range X(water) = 0.0−0.6. The preference of water over 1,4-dioxane can be rationalized in view of the H-bond formation between the carbonyl group of the coumarin derivative and water.…”

“…A linear variation of E ( F ) with solvent composition has often been explained by assuming that the local composition of the solvent mixture around the solute is similar to that in the bulk (ideal solvation). , The “ideal” line for the case of the free fluorophore is shown in Figure a as a continuous straight line. The deviation from linearity of spectroscopic transition in energy has often been explained in terms of preferential solvation of the solute by one of the solvents. , The results obtained in the present case suggest that the free fluorophore is preferentially solvated by water, particularly in the mole fraction range X (water) = 0.0–0.6. The preference of water over 1,4-dioxane can be rationalized in view of the H-bond formation between the carbonyl group of the coumarin derivative and water.…”

Origin of Strong Synergism in Weakly Perturbed Binary Solvent System: A Case Study of Primary Alcohols and Chlorinated Methanes

“…The spectroscopic studies of molecules and clusters have crossed the boundaries of homogeneous medium and a lot of concern is being devoted to understand the behavior in micro heterogeneous systems. − Recently, solvent mixtures made attract a lot of attention because of its unique behavior compared to its constituent counterpart and explained in terms of differential interaction leading to the formation of micro heterogeneous environment. − The use of solvent mixtures provide the means of modification of solute–solvent interactions by virtue of its composition. The solute–solvent interaction is generally monitored in terms of the stabilization of its electronic energy level and this interaction depends on the proportion of either of the constituting solvents and is known for several years. − The behavior of molecules in binary solvent mixture depends on either one or both solvent component by specific interactions, e.g., hydrogen bonding, self-association or by nonspecific interactions such as dipole–dipole, dipole–induced dipole interactions. ,− In binary solvent mixtures, the deviation from ideality is believed to originate from the nature and extent of solute–solvent interactions, locally developed in the immediate vicinity of the solute molecules, which has an impact on the spectroscopic properties of the molecules. Generally, solvent polarizability, H-bond donating ability (HBD) and H-bond accepting ability (HBA) or solvent basicity are three parameters which have been characterized to represent the variation of solute–solvent interactions. , All these parameters are solvatochromic parameter (represented like as π*, α, and β respectively, the Kamlet–Taft parameters) and provide information about the different mode of solvent interaction with the probe molecules in pure solvents and also in solvent mixtures. − Characterization of solvation behavior has been done employing various methods like conductance or transfer measurements, NMR chemical shifts, − vibrational spectroscopy, , UV–vis spectroscopy, − solvation dynamics, , etc.…”

Targeting the heme proteins hemoglobin and myoglobin by janus green blue and study of the dye–protein association by spectroscopy and calorimetry

“…The protein induced spectral changes may be rationalized in terms of a lowering in the polarity of the immediate environment around the dye, being very high in the presence of Mb. 29 The spectral titration data were analysed by Benesi-Hildebrand plot to determine the equilibrium constants using the following relation, 30…”