Solvation dynamics of 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl) 4H-pyran (DCM) in aqueous solution of a protein, human serum albumin (HSA), is studied using picosecond time-resolved emission spectroscopy. The solvation dynamics of DCM bound to HSA is found to be biexponential with one component of 600 ( 100 ps (25%) and a very long component of 10 ( 1 ns (75%). This indicates that the motion of the water molecules in the vicinity of the protein is highly constrained.

Corrosion inhibition performance of 2-(2-hydroxybenzylideneamino)phenol (L(1)), 2-(5-chloro-2-hydroxybenzylideneamino)phenol (L(2)) and 2-(2-hydroxy-5-nitrobenzylideneamino)phenol (L(3)) on the corrosion behaviour of mild steel surface in a 1 M hydrochloric acid (HCl) solution is investigated by sophisticated analytical methods like potentiodynamic polarization, electrochemical impedance spectroscopy and weight loss measurements. Polarization studies showed that all the compounds are mixed type (cathodic and anodic) inhibitors and the inhibition efficiency (η%) increased with increasing inhibitor concentration. The inhibition actions of these Schiff base molecules are discussed in view of blocking the electrode surface by means of adsorption of the inhibitor molecule obeying the Langmuir adsorption isotherm. Scanning electron microscopy (SEM) studies of the metal surfaces confirmed the existence of an adsorbed film. Density functional theory (DFT) and molecular dynamics (MD) simulation have been used to determine the relationship between molecular configuration and their inhibition efficiencies. The order of inhibition performance obtained from experimental results is successfully verified by DFT and MD simulation.

The fluorescence anisotropy decay of two dyes merocyanine 540 and oxazine 1 has been studied in a polymer−surfactant aggregate containing poly(vinylpyrrolidone) (PVP) and sodium dodecyl sulfate (SDS). The results are analyzed in terms of the necklace model of the polymer−surfactant aggregate. The rotational motion of the probe is assumed to involve “wobbling-in-cone” along with translational motion along the micellar surface. It is observed that the presence of the polymer chains around the spherical SDS micelles causes significant retardation of both the wobbling motion as well as the translational motion of the two dyes. As a result, the wobbling and translational diffusion of the dyes in the PVP−SDS aggregate are slower than those in SDS micelle.

Solvation dynamics of Coumarin 480 (C-480) in a tetraethyl orthosilicate (TEOS) sol-gel matrix has been studied using time-resolved emission spectroscopy. In the macroscopically solid TEOS matrix the solvation dynamics of C-480 is described by a major (85%) component of 120 ( 20 ps and a minor (15%) component of 800 ( 100 ps. These components are substantially slower than the solvation dynamics in bulk water. The rotational relaxation time of C-480 in this matrix is found to be very short (<80 ps).

In order to evaluate the effect of the functional group present in the ligand backbone towards corrosion inhibition performances, three Schiff-base molecules namely, (E)-4-((2-(2,4-dinitrophenyl)hydrazono)methyl)pyridine (L(1)), (E)-4-(2-(pyridin-4-ylmethylene)hydrazinyl)benzonitrile (L(2)) and (E)-4-((2-(2,4-dinitrophenyl)hydrazono)methyl)phenol (L(3)) were synthesized and used as corrosion inhibitors on mild steel in 1 M HCl medium. The corrosion inhibition effectiveness of the studied inhibitors was investigated by weight loss and several sophisticated analytical tools such as potentiodynamic polarization and electrochemical impedance spectroscopy measurements. Experimentally obtained results revealed that corrosion inhibition efficiencies followed the sequence: L(3) > L(1) > L(2). Electrochemical findings showed that inhibitors impart high resistance towards charge transfer across the metal-electrolyte interface and behaved as mixed type inhibitors. Scanning electron microscopy (SEM) was also employed to examine the protective film formed on the mild steel surface. The adsorption as well as inhibition ability of the inhibitor molecules on the mild steel surface was investigated by quantum chemical calculation and molecular dynamic (MD) simulation. In quantum chemical calculations, geometry optimized structures of the Schiff-base inhibitors, electron density distribution in HOMO and LUMO and Fukui indices of each atom were employed for their possible mode of interaction with the mild steel surfaces. MD simulations revealed that all the inhibitors molecules adsorbed in parallel orientation with respect to the Fe(110) surface.