Influence of Chain Length and Concentration-Dependent Morphological Switching on Oxidation of Aromatic Alcohols in a Micellar Environment

Catalytic oxidation of benzyl alcohol (BA), p-chlorobenzyl alcohol (p-ClBA) and p-anisyl alcohol (p-OMeBA) in aqueous media has been investigated in the presence of two cationic surfactants, viz. cetylpyridinium chloride (CPCl) and dodecylpyridinium chloride (DPCl). The chromium(VI)-governed oxidations of such aromatic compounds exhibit an unusual kinetics depending upon the concentration of CPCl and DPCl. Both the cationic surfactants catalyzed the oxidations at lower concentrations while retardation was noticed at higher concentrations. The catalytic and inhibitory functions of both the surfactants at the sub- and postmicellar levels have been enlightened based on the kinetic CMC (critical micellization concentration). The chain length of the two surfactants influences the kinetic profiles of the oxidation processes. Herein, the π–π interaction and the cation−π interaction play important roles in the solubilization process and therefore encourage the reaction rate. These strong interactions result in a maximum 12-fold catalytic enhancement for the oxidation of p-anisyl alcohol in the CPCl micellar environment, while the inhibitory effect of CPCl and DPCl on the oxidation kinetics have been analyzed based on the dilution effect. The morphological alteration of aggregates during the oxidation aids the interpretation of the inhibitory activity of both micelles produced by CPCl and/or DPCl. Berezin’s model has been employed to reveal the inhibition caused by cationic micelles. Morphological alteration of both the cationic surfactants from spherical-to-cylindrical shape at variable concentrations in the absence and presence of substrate was supported by SAXS (small-angle X-ray scattering), TEM (transmission electron microscopy), and FE-SEM (field emission scanning electron microscopy) analysis

Structural Insights into In Situ Disulfide Bond Formation for Enhancing Schottky Diode Behavior of a Paddle-Wheel Zn-Based Coordination Polymer

In the present study, a one-dimensional (1D) Zn­(II)-based paddle-wheel coordination polymer [Zn­(2,2′-dsb)­(4-phpy)] (1) [H22,2′-dsba = 2,2′-disulfanediyldibenzoic acid and 4-phpy = 4-phenylpyridine] has been fabricated using a slow diffusion method at room temperature. Here, the monomeric ligand 2-mercaptobenzoic acid (2-mba) produces in situ dimeric 2,2′-dsba ligand via S–S bond formation, which ultimately generates a 1D cyclic loop chain structure. The structural feature originating from the formation of S–S bond significantly influences the electrical conductivity of the material, which exhibits semiconducting nature and reveals Schottky barrier diode behavior. Semiconducting nature of the compound is documented by density functional theory calculation and current density–voltage (I–V) characteristics