Nickel Complexes as Antioxidants. Inhibition of Aldehyde Autoxidation by Nickel(II) Tetraazamacrocycles

Photocatalytic asymmetric epoxidation of trans-stilbene with manganese–porphyrin/graphene-oxide nanocomposite and molecular oxygen: axial ligand effect

An efficient, visible light-driven manganese–porphyrin photocatalyst was developed for the asymmetric epoxidation of trans-stilbene by molecular oxygen under mild conditions.

An efficient approach for enhancing the catalytic activity of Ni-MOF-74 via a relay catalyst system for the selective oxidation of benzylic C–H bonds under mild conditions

A facile and efficient approach for enhancing the catalytic activity of Ni-MOF-74 via a relay catalysis strategy with [bmim]Br was developed, which is excellent for the selective oxidation of benzylic C–H bond under mild conditions.

Oxoiron(iv)-mediated Baeyer–Villiger oxidation of cyclohexanones generated by dioxygen with co-oxidation of aldehydes

Mechanistic studies on the Fe(ii)-catalyzed Baeyer–Villiger oxidation are described, including the formation and the reactivity of the trapped oxoiron(iv) intermediate.

Blockade of peroxynitrite-mediated astrocyte death by manganese(III)-cyclam

Under glucose-deprived conditions, astrocytes rapidly underwent death due to their increased susceptibility to endogenously produced peroxynitrite (Gila 31, 155-164; J. Neuroimmunol. 112, 55-62; J. Neurochem. 74, 1989-1998). In the present study, the cell membrane-permeable synthetic superoxide dismutase (SOD) mimetic cyclam manganese(III) 1,4,8,11-tetraazacyclodecane (Mn(III)-cyclam) completely inhibited the death of glucose-deprived immunostimulated astrocytes. However, the structurally related compounds Ni(II)-cyclam, Co(II)-cyclam, and H(2)-cyclam, which lacks metals, had no or a little cytoprotective effect. Of the cyclams used in this study, only Mn(III)-cyclam completely scavenged the peroxynitrite produced in glucose-deprived immunostimulated astrocytes and significantly blocked the depolarization of mitochondrial transmembrane potential in those cells. The present results suggest that cell membrane-permeable synthetic SOD mimetics such as Mn(III)-cyclam may be potential therapeutic agents for various diseases associated with the endogenous production of peroxynitrite.

Hydrogen Peroxide Bleaching of Amaranth Catalysed by Nickel(II) Nitrilotriacetic Acid

The complex of NiII with nitrilotriacetic acid (NTA) (but not other aminocarboxylate complexes) autocatalyses the hydrogen peroxide bleaching of amaranth, although the reaction is inhibited by the absence of light or presence of alcohol, suggesting a radical-based mechanism.