Luminescence mechanism in hydrogenated silicon quantum dots with a single oxygen ligand

Upon excitation, electrons are strongly localized near the SiO site, which induces a faster radiative transition.

The subatomic resolution study of laccase inhibition by chloride and fluoride anions using single-crystal serial crystallography: insights into the enzymatic reaction mechanism

Laccases are enzymes that catalyze the oxidation of a wide range of organic and inorganic substrates accompanied by the reduction of molecular oxygen to water. Here, a subatomic resolution X-ray crystallographic study of the mechanism of inhibition of the laccase from the basidiomycete fungus Steccherinum murashkinskyi by chloride and fluoride ions is presented. Three series of X-ray diffraction data sets were collected with increasing doses of absorbed X-ray radiation from a native S. murashkinskyi laccase crystal and from crystals of complexes of the laccase with chloride and fluoride ions. The data for the native laccase crystal confirmed the previously deduced enzymatic mechanism of molecular oxygen reduction. The structures of the complexes allowed the localization of chloride and fluoride ions in the channel near the T2 copper ion. These ions replace the oxygen ligand of the T2 copper ion in this channel and can play the role of this ligand in the enzymatic reaction. As follows from analysis of the structures from the increasing dose series, the inhibition of laccases by chloride and fluoride anions can be explained by the fact that the binding of these negatively charged ions at the position of the oxygen ligand of the T2 copper ion impedes the reduction of the T2 copper ion.

Heterobimetallic cerium(iv) oxo clusters supported by a tripodal oxygen ligand

Heterometallic CeIV/M (M = MoVI, ReVII, VV) oxo clusters supported by the Kläui tripodal oxygen ligand [(η5-C5H5)Co{P(O)(OEt)2}3]− (LOEt−) have been synthesized and the catalytic activity of the CeIV/VV oxo cluster in the oxidation of thioanisoles has been studied.

l-Carnitine is a calcium chelator: a reason for its useful and toxic effects in biological systems

Investigation of the direct link betweenThe chemical structure of LC, which contains oxygen ligand atoms, prompted to measure its activity as a CaThe effect of LC was measured as a free entity in solution and when added to human serum. Our results showed a significant decrease (p<0.05) in the average absorbance of Ca-CPC in the presence of LC compared to the control.In conclusion, LC exhibits a significant Ca

Multi-Electron-Transfer Catalysts Needed for Artificial Photosynthesis

ABSTRACTWe report a study on catalytic water oxidation by cobalt in oxygen ligand environments because such systems are as promising as any in the water oxidation component of solar fuel production. We have re-examined the catalytic activity of Co(II) in aqueous solution using either [Ru(bpy)3]3+ as a stoichiometric oxidant or in visible-light-driven reactions with persulfate as a sacrificial electron acceptor. In both systems a distinctive induction period is observed. A simple kinetic model is proposed that describes the experimental data well. The presence of an induction period is explained by relatively slow formation of the true catalyst from aquacobalt(II).