Activity

Circular dichroism spectral studies give information about the conformational changes of HSA in the absence and presence of GO when it forms complex with 7-DCA. The fluorescence lifetime imaging study shows the presence of the 7-DCA/HSA complex on the GO sheet. Molecular docking simulation shows that the closest distance between 7-DCA and HSA is 11.9 Å, and the protein interacted with the ligand through hydrogen bonding, hydrophobic interaction, and so forth.Triflyl nitrate is easily generated from tetra-n-butylammonium nitrate in CH2Cl2 solution and serves as an effective nitrating agent for a wide range of unsaturated substrates to form nitro olefins.Molybdenum dithiocarbamates (MoDTCs) are a class of lubricant additives widely employed in automotives. Most of the studies concerning MoDTC take into account the dimeric structures because of their industrial relevance, with the mononuclear compounds usually neglected, because isolating and characterizing subgroups of MoDTC molecules are generally difficult. However, the byproducts of the synthesis of MoDTC can impact the friction reduction performance at metallic interfaces, and the effect of mononuclear MoDTC (mMoDTC) compounds in the lubrication has not been considered yet in the literature. In this study, we consider for the first time the impurities of MoDTC consisting of mononuclear compounds and combine experimental and computational techniques to elucidate the interaction of these impurities with binuclear MoDTC in commercial formulations. click here We present a preliminary strategy to separate a commercial MoDTC product in chemically different fractions. These fractions present different tribological behaviors depending on the relative amount of mononuclear and binuclear complexes. The calculations indicate that the dissociation mechanism of mMoDTC is similar to the one observed for the dimeric structures. However, the different chemical properties of mMoDTC impact the kinetics for the formation of the beneficial molybdenum disulfide (MoS2) layers, as shown by the tribological experiments. These results help to understand the functionality of MoDTC lubricant additives, providing new insights into the complex synergy between the different chemical structures.The fluorescence spectrum measurement of a fluorescence pH probe, C. SNARF-4F, was performed for monitoring the interfacial pH of aqueous electrolytes between mica or silica surfaces while varying the surface separation (D) using surface force apparatus (SFA) fluorescence spectroscopy. The pH of the aqueous CsCl between mica exponentially decreased with decreasing D. The order of the decay lengths of the interfacial pH obtained from the exponential fitting (L) at various electrolyte concentrations was L1mM > L0.1mM ≈ L0.4mM > L10mM. For studying the mechanisms of these changes, we performed the electric double layer (EDL) model calculation of the interfacial pH based on the surface potentials, which were evaluated from the EDL forces between the substrates in aqueous electrolytes using the same SFA. The calculated pH value for the 0.1 mM aqueous electrolyte corresponded to the values obtained from fluorescence spectroscopy, indicating that the interfacial pH was attributed to only the general EDL effect. On the other hand, the measured pH value for the higher concentrations of aqueous electrolytes (0.4-10 mM) decreased in the longer D ranges than the values calculated from the model, indicating that there was an additional factor affecting the interfacial pH for those concentrations. We also studied the effects of the cationic species of the electrolytes (Cs+, Na+, and Li+) and of the silica substrate on the interfacial pH. The systematic studies of the interfacial pH revealed that it depended on all three factors studied here, that is, the electrolyte concentration, electrolyte species, and the substrates. The results also suggested that the interfacial pH was not only due to the simple EDL theory but could also be affected by an additional factor due to the ion adsorption at the interface and chemical states of the substrates.Exploring active and ecological materials for the restoration of complex pollution system is highly desired. This study presents a facile defect-tailoring strategy for combined pollutants purification with BiVO4 photocatalysis in which the jointed synchronous reaction of oxidation and reduction is integrated instead of the sequential reaction in two individual systems. XPS and EPR reveal that BiVO4 with a suitable oxygen vacancies (OVs) concentration and distribution exhibits superior photocatalytic activity under the coexistence of TC-HCl and Cr(VI) with Cr(VI) reduction efficiency increased by 71 times compared with the individual Cr(VI) system along with TC-HCl removal efficiency comparable to a single TC-HCl system. The mechanism of synchronous redox reactions mediated by surface OVs is revealed by comprehensive characterization together with reaction kinetic analysis, and the electronic band structure adjustment induced by the OVs variation is confirmed. Active species identification tests and intermediate product analysis confirm that singlet oxygen (1O2) accounts for the selective oxidation of TC-HCl, while electrons dominate the reduction of Cr(VI), under a coexistent environment. The influence of water quality parameters (e.g., pH, cations, anions, and organic substances) on the photocatalytic activity is investigated considering the complexity of the real aquatic environment. Importantly, toxicity assessment with Gram-negative strain E. coli as a model bacterium validates that the toxicity of the intermediates can be reduced to low or even ultralow levels. This work is dedicated to the mechanistic study of defect photocatalysis over BiVO4 and provides a jointed synchronous reaction system for combined pollutant purification.We report on the synthesis and structural characterization of four arylarsonate- and phosphonate-capped polyoxomolybdates that exhibit different organic substituents in the para position of the phenyl group. The reaction of arylarsonates (RAsO3, wherein R = 4-BrC6H4 or 4-N3C6H4) with molybdate in aqueous pH 3.5 media resulted in the cyclic hexamolybdates [(BrC6H4As)2Mo6O24]4- (Mo6As2La) and [(N3C6H4As)2Mo6O24]4- (Mo6As2Lb), whereas the reaction of arylphosphonates (R’PO3, wherein R’ = 4-O2CC6H4 or 4-O2CC6H4CH2) with molybdate in aqueous pH 3 media resulted in the cyclic pentamolybdates [(O2CC6H4P)2Mo5O21]6- (Mo5P2Lc) and [(HO2CC6H4CH2P)2Mo5O21]4- (Mo5P2Ld), respectively. Polyanions Mo6As2La and Mo6As2Lb comprise a ring of six MoO6 octahedra that is capped on either side by an organoarsonate group, whereas Mo5P2Lc and Mo5P2Ld consist of a ring of five MoO6 octahedra that is capped on either side by an organophosphonate group, with the organic arms protruding away from the metal-oxo core of the polyanions. All four polyanions Mo6As2La, Mo6As2Lb, Mo5P2Lc, and Mo5P2Ld have been characterized in the solid state by single-crystal X-ray diffraction, IR spectroscopy, and thermogravimetric and elemental analysis and in solution by multinuclear NMR (31P, 13C, and 1H).