Tuning Selectivity in the Visible-Light-Promoted Coupling of Thiols with Alkenes by EDA vs TOCO Complex Formation

The visible-light-promoted catalyst-free condition has been demonstrated for self- and cross-coupling reactions of thiols in an ambient atmosphere. Further, synthesis of β-hydroxysulfides is accomplished under very mild conditions involving the formation of an electron donor-acceptor (EDA) complex between a disulfide and an alkene. However, the direct reaction of thiol with alkene via the formation of a thiol-oxygen co-oxidation (TOCO) complex failed to produce the desired compounds in high yields. The protocol was successful with several aryl and alkyl thiols for the formation of disulfides. However, the formation of β-hydroxysulfides required an aromatic unit on the disulfide fragment, which supports the formation of the EDA complex during the course of the reaction. The approaches presented in this paper for the coupling reaction of thiols and the synthesis of β-hydroxysulfides are unique and do not require toxic organic or metal catalysts.

Enhanced Photo-Catalytic and Antibacterial Properties of Ni-Doped Cd0.9Zn0.1S Nanostructures

The present work describe the synthesis of Cd_0.9Zn_0.1S and Cd_0.87Zn_0.1Ni_0.03S nanostructures by chemical co-precipitation method. The XRD profile proved the cubic crystal structure of the samples without any impurity related phases. The reduced size from 63 to 51 Å and the dissimilarities in lattice parameters and micro-strain has been discussed by Ni addition in Cd_0.87Zn_0.1Ni_0.03S structure. The noticed anomalous optical studies and the elevated transmittance at Ni doped sample suggested them for the fabrication of efficient opto-electronic devices. The energy gap reduction during the substitution of Ni = 3% is explained by the generation of extra energy levels associated with defects within the two bands. The release of additional charge carriers, improved optical property, reduced particle size and more defect generation are responsible for the enhanced photo-catalytic performance of Ni doped Cd_0.9Zn_0.1S. The enhanced anti-bacterial capacity in Cd_0.87Zn_0.1Ni_0.03S is described by the collective response of reduced particle size and higher reactive oxygen species (ROS) like O₂^⋅−, H₂O₂ and OH^⋅ generating capacity.

Unprecedented Isomerism-Activity Relation in Molecular Electrocatalysis

The role of electrocatalysts in energy storage/conversion, biomedical and environmental sectors, green chemistry, and much more has generated enormous interest in comprehending their structure-activity relations. While targeting the surface-to-volume ratio, exposing reactive crystal planes and interfacial modifications are time-tested considerations for activating metallic catalysts; it is primarily by substitution in molecular electrocatalysts. This account draws the distinction between a substituent's chemical identity and isomerism, when regioisomerism of the -NO₂ substituent is conferred at the "α" and "β" positions on the macrocycle of cobalt phthalocyanines. Spectroscopic analysis and theoretical calculations establish that the β isomer accumulates catalytically active intermediates via a cumulative influence of inductive and resonance effects. However, the field effect in the α isomer restricts this activation due to a vanishing resonance effect. The demonstration of the distinct role of isomerism in substituted molecular electrocatalysts for reactions ranging from energy conversion to biosensing highlights that isomerism of the substituents makes an independent contribution to electrocatalysis over its chemical identity.

Synthesis of cobalt nanoparticles by pyrolysis of vitamin B12: a non-noble-metal catalyst for efficient hydrogenation of nitriles

A facile preparation of vitamin B₁₂-derived carbonaceous cobalt particles supported on ceria is reported.

Synthesis and characterization of benzilic alcohol metalloporphyrin and its nanocomposite with graphene oxide (GO–CoTHMP) and investigation of their efficiency in the removal of environmental pollutants

5,10,15,20-Tetrakis-(4-hydroxymethylphenyl)porphyrin (THMP), metalloporphyrin [(Co(iii)THMP)] and its nanocomposites with graphene oxide (GO–CoTHMP) were synthesized for the first time.