No abstract

Current examples of photoredox catalytic processes for CO, CN, CHal and CC bond formation are described with emphasis on the basic mechanistic scenarios. The focus is on the special aspects of photochemical redox catalysis especially on the electron transfer energetics, the use of electron transfer (ET) sensitizers and mediators as well as sacrificial reagents.magnified image

The most efficient and commonly used electrochemiluminescence (ECL) emitters are luminol, [Ru(bpy) ] , and derivatives thereof. Luminol stands out due to its low excitation potential, but applications are limited by its insolubility under physiological conditions. The water-soluble m-carboxy luminol was synthesized in 15 % yield and exhibited high solubility under physiological conditions and afforded a four-fold ECL signal increase (vs. luminol). Entrapment in DNA-tagged liposomes enabled a DNA assay with a detection limit of 3.2 pmol L , which is 150 times lower than the corresponding fluorescence approach. This remarkable sensitivity gain and the low excitation potential establish m-carboxy luminol as a superior ECL probe with direct relevance to chemiluminescence and enzymatic bioanalytical approaches.

No abstract

Biradicals have been postulated as intermediates in many organic reactions and described in excellent articles.2 Even ground-state transformations allowed from the Wood war d-Hoffmann orbital symmetry rules have been discussed as proceeding via l,n-biradicals.3The latter assumptions usually originate from calculations rather than from experimental facts. In the