Redox-inactive metal ions can modulate the reactivity of redox-active metal ions in a variety of biological and chemical oxidations. Many synthetic models have been developed to help address the elusive roles of these redox-inactive metal ions. Using a non-heme manganese(II) complex as the model, the influence of redox-inactive metal ions as a Lewis acid on its catalytic efficiency in oxygen at...

Two polynuclear mixed-valence manganese clusters, [Mn(13)] and [Mn(16)], containing mixed chelating ligands were synthesized and structurally characterized. The alternating current (AC) susceptibilities of both complexes reveal nonzero frequency-dependent out-of-phase (χ(M)'') signals.

Most intracellular Mn is found in mitochondria. We have used the shift in the manganese absorption edge in x-ray absorption near edge structure (XANES) spectroscopy to determine the oxidation state of Mn in brain, heart, and liver mitochondria, as well as in PC12 cells. We compared the XANES spectra of Mn in brain, heart, and liver mitochondria over a range of Mn concentrations with those of Mn...

In Iraq. the municipalities are responsible for the production and delivery of drinking water (DW) .The quality of DW in Iraq is greatly deteriorated because of the war operation in this country Objective to study the effects of manganese chloride on histological testes, epididymis and kidney of rats and explore the dose –effects and time effects .The rats are randomly divided into six treatmen...

Electron spin echo electron-nuclear double resonance (ESE-ENDOR) experiments performed on a broad radical electron paramagnetic resonance (EPR) signal observed in photosystem II particles depleted of Ca2+ indicate that this signal arises from the redox-active tyrosine YZ. The tyrosine EPR signal width is increased relative to that observed in a manganese-depleted preparation due to a magnetic i...

The deposition of manganese in a water distribution system with manganese-related "dirty water" problems was studied over a 1-year period. Four monitoring laboratories with Robbins biofilm sampling devices fitted to the water mains were used to correlate the relationship among manganese deposition, the level of manganese in the water, and the chlorination conditions. Manganese deposition occurr...

Oxidative tissue damage is considered an early sign of cadmium (Cd) toxicity and has been linked with carcinogenesis. Manganese(II)-at low doses, was found to act as a potent antioxidant against oxidative stress in different in vitro systems producing lipid peroxidation conditions. The present study investigates in vivo antioxidant effects of Mn(2+) pretreatment in acute Cd intoxication with re...

Manganese (Mn) is an essential trace element that is required for maintaining the proper function and regulation of many biochemical and cellular reactions. Despite its essentiality, at excessive levels Mn is toxic to the central nervous system. The overdose accumulation of Mn in specific brain areas, such as the substantia nigra, the globus pallidus and the striatum, triggers neurotoxicity res...

Three new manganese oxy-bis(benzoate) compounds, synthesized by increasing the reaction temperature, with increasing dimensionality and decreasing Mn-Mn distances, indicate a possible pathway through an entropy driven dehydration route.

Mn-(III)-chlorin, Photosynthesis, Photoreduction, Photooxidation, Hydroxylamine K3(Mn-(III)-chlorin e6)acetate, a water-soluble chlorophyll derivative with manganese as central atom was prepared. The influence of reducing agents, light, and bicarbonate on the oxida­ tion states of manganese in the chlorin complex was investigated. In alkaline solutions the central Mn3+ was reducible to Mn2+. Th...