Oxygen binding and cleavage are important for both molecular recognition and catalysis. Mn-based porphyrins in particular are used as catalysts for the epoxidation of alkenes, and in this study the homolytic cleavage of O2 by a surface-supported monolayer of Mn porphyrins on Ag(111) is demonstrated by scanning tunneling microscopy, X-ray absorption, and X-ray photoemission. As deposited, {5,10,...

Supplementary Material Available: Preparative methods for the starting materials, stereochemical assignments of 1,3-diols listed in Table I, and 400-M Hz 'H N M R spectra of acetonides of 1-3 and 7 (6 pages). Ordering information is given on any current masthead page. The Cytochrome P-450 dependent monooxygenases are mem­ brane-bound enzymes that catalyze a great variety of reactions, among whi...

Alkene monooxygenase (AMO) from Rhodococcus rhodochrous B-276 is a 3-component enzyme system encoded by the 4-gene operon amoABCD, which catalyzes the stereoselective epoxidation of aliphatic alkenes yielding primarily the R enantiomer. With propene as the substrate, wild-type AMO yields R-epoxypropane with an enantiomeric excess (e.e.) of 83%. The presumed site of alkene oxidation is a dinucle...

A facile and one-pot multicomponent synthesis of novel 1,4-disubstituted-1H-1,2,3-triazoles from alkenes at room temperature is reported. At the first step, in the presence of I2/NaN3 reagents, various alkenes were converted to the corresponding azido iodides and in the next step, the reaction of these compounds with phenylacetylene in the presence of catalytic amount of sodium ascorbate/ CuSO4...

The FeII complexes of two isomeric pentadentate bispidine ligands in the presence of H2O2 are catalytically active for the epoxidation and 1,2-dihydroxylation of cyclooctene (bispidine = 3,7-diazabicyclo[3.3.1]nonane; the two isomeric pentadentate bispidine ligands discussed here have two tertiary amine and three pyridine donors). The published spectroscopic and mechanistic data, which include ...

A treatment of the diatom Phaeodactylum tricornutum with high light (HL) in the visible range led to the conversion of diadinoxanthin (Dd) to diatoxanthin (Dt). In a following treatment with HL plus supplementary ultraviolet (UV)-B, the Dt was rapidly epoxidized to Dd. Photosynthesis of the cells was inhibited under HL + UV-B. This is accounted for by direct damage by UV-B and damage because of...

Polyoxomolybdates were generated in situ by treating a carboxylic acid-functionalized ionic liquid with an aqueous solution of sodium molybdate. This reaction mixture was applied in the catalytic epoxidation of olefins using hydrogen peroxide as oxidant. The influence of acid and catalyst concentration as well as of the reaction temperature was investigated. The system showed a good performance...