Meltonpennington7489

Consistent with this conclusion, the frontier molecular orbitals of the Ni-CH3 species indicate a ligand-centered LUMO, with a d9 population on the metal center, rather than the d7 population expected for a typical metal-alkyl species generated by oxidative addition. Collectively, these data support the presence of an inverted ligand field configuration for the Ni-CH3 Az species, in which the lowest unoccupied orbital is centered on the ligands rather than the more electropositive metal. These analyses provide the first evidence for an inverted ligand field within a biological system. The functional relevance of the electronic structures of both the Ni-CO and Ni-CH3 species are discussed in the context of native ACS, and an inverted ligand field is proposed as a mechanism by which to gate reactivity both within ACS and in other thiolate-containing metalloenzymes.Heterogeneous electro-Fenton (HEF) reaction has been considered as a promising process for real effluent treatments. However, the design of effective catalysts for simultaneous H2O2 generation and activation to achieve bifunctional catalysis for O2 toward •OH production remains a challenge. Herein, a core-shell structural Fe-based catalyst (FeNC@C), with Fe3C and FeN nanoparticles encapsulated by porous graphitic layers, was synthesized and employed in a HEF system. The FeNC@C catalyst presented a significant performance in degradation of various chlorophenols at various conditions with an extremely low level of leached iron. Electron spin resonance and radical scavenging revealed that •OH was the key reactive species and FeIV would play a role at neutral conditions. Experimental and density function theory calculation revealed the dominated role of Fe3C in H2O2 generation and the positive effect of FeN x sites on H2O2 activation to form •OH. Meanwhile, FeNC@C was proved to be less pH dependence, high stability, and well-recycled materials for practical application in wastewater purification.The structural elucidation of chiral molecules with more than one stereocenter is usually a tricky problem. In this paper, efficient 1H NMR spectroscopic approaches for assigning the erythro and threo configurations of 1-oxygenated 1,2-diarylpropan-3-ols were developed. By analysis of the chemical shift differences of diastereotopic methylene H2-3 (Δδ3) in CDCl3 or the chemical shift differences of H-1 and H-2 (Δδ1,2) in methanol-d4, deuterated dimethyl sulfoxide, and acetone-d6, the configurations of 1-oxygenated 1,2-diarylpropan-3-ols can be rapidly and conveniently determined.Constructed wetlands (CWs) are of great socioeconomic significance because they can remove anthropogenic compounds from aquatic environments. selleck However, no information is available about the removal of persistent chlorinated paraffins by CWs. This study investigates the occurrences, fates, and mass balances of short-chain chlorinated paraffins (SCCPs), medium-chain chlorinated paraffins (MCCPs), and long-chain chlorinated paraffins (LCCPs) in a CW ecosystem. MCCPs were the predominant compounds in water, sediments, and plants within the system. The amounts of SCCPs, MCCPs, and LCCPs entering the wetland were 3.3, 6.8, and 3.4 g/day, respectively. Overall removal efficiencies were 51-78%, 76-86%, and 76-91% for SCCPs, MCCPs, and LCCPs, respectively, and the greatest reduction in CPs was observed in the subsurface flow wetland unit. CPs were predominantly adsorbed onto the sediment and bioaccumulated in the plants, and their organic carbon-water partitioning and plant-water accumulation increased as the carbon and chlorine numbers increased. Sediment sorption (12-38%) and degradation (12-50%) contributed the most to the removal of CPs, but bioaccumulation of CPs in plants (3.8-12%) should not be neglected. Wetlands can economically remove large amounts of CPs, but sediment in the wetland systems could be a sink for CP pollutants.Cellulose nanofibrils, which attract extensive attention as a bio-based, sustainable, high-performance nanofibril, are believed to be predominantly hydrophilic. This study aimed to prove the presence of an amphiphilic "Janus-type fiber surface" in water with hydrophobic and hydrophilic faces in a cellulose nanofibril (ACC-CNF) that was prepared by the aqueous counter collision method. We clarified the surface characteristics of the ACC-CNF by confocal laser scanning microscopy with a carbohydrate-binding module and congo red probes for the hydrophobic planes on the cellulose fiber surfaces and calcofluor white as hydrophilic plane probes. The results indicated the presence of both characteristic planes on a single ACC-CNF surface, which verifies an amphiphilic Janus-type structure. Both hydrophobic probes adsorbed onto ACC-CNFs for the quantitative evaluation of the degree of ACC-CNF surface hydrophobicity by Langmuir's adsorption theory based on the optimal maximum adsorption amounts for various starting raw material types.We present an efficient and versatile visible light-driven methodology to transform aryl aldehydes and ketones chemoselectively either to alcohols or to pinacol products with CdSe/CdS core/shell quantum dots as photocatalysts. Thiophenols were used as proton and hydrogen atom donors and as hole traps for the excited quantum dots (QDs) in these reactions. The two products can be switched from one to the other simply by changing the amount of thiophenol in the reaction system. The core/shell QD catalysts are highly efficient with a turn over number (TON) larger than 4 × 104 and 4 × 105 for the reduction to alcohol and pinacol formation, respectively, and are very stable so that they can be recycled for at least 10 times in the reactions without significant loss of catalytic activity. The additional advantages of this method include good functional group tolerance, mild reaction conditions, the allowance of selectively reducing aldehydes in the presence of ketones, and easiness for large scale reactions. Reaction mechanisms were studied by quenching experiments and a radical capture experiment, and the reasons for the switchover of the reaction pathways upon the change of reaction conditions are provided.