A new facile synthesis of tertiary dithioesters

Thermal decomposition of tertiary azo compounds in the presence of a triphenylmethyl dithioester results in the formation of the corresponding tertiary dithioesters. This procedure is especially useful for the synthesis of tertiary phosphoryldithioformates, but also represents an easy synthetic methodology of general applicability.     

Solar cells based on a fullerene-azothiophene dyad

A power conversion efficiency of 0.37%, under white light of 80 mW cm-2 intensity, was obtained when a fullerene-azothiophene dyad was used as the active layer of a photovoltaic cell.     

Temperature dependent reaction pathways in the addition of silyl, germyl, stannyl and plumbyl radicals to maleic anhydride and related compounds: an ESR study

The addition of Group IVB organometallic radicals to maleic anhydride, maleic thioanhydride, maleimide and N-methyl maleimide has been investigated by ESR spectroscopy. For Si and Ge centred radicals the reaction pathway has been found to be temp dependent, the addition of the organometallic radical occurring at the CC double bond at lower temps at either of the two CO groups at higher temps. For Sn and Pb centred radicals only the latter spin adducts could be detected even at low temp.     

EPR characterization of new phosphavinyl σ radicals

A number of radicals have been added to 1,3-bis(2,4,6-tri-tert-butylphenyl)diphospha-allene at low temperature in cyclopropane solution. Addition of thiyl and alkoxyl radicals occurs regiospecifically to one of the phosphorus atoms leading to new phosphavinyl radicals, isoelectronic with vinyl radicals, which have been characterised by means of EPR spectroscopy. The results of ab initio calculations are in agreement with the experimentally determined spectral parameters and suggest that these radicals are bent, with a PCP bond angle of ca. 150°. In contrast, silyl and germyl radicals appear to add to the carbon atom of the phosphaallene.     

Steady-state fully noninductive current driven by electron cyclotron waves in a magnetically confined plasma

A steady-state, fully noninductive plasma current has been sustained for the first time in a tokamak using electron cyclotron current drive only. In this discharge, 123 kA of current have been sustained for the entire gyrotron pulse duration of 2 s. Careful distribution across the plasma minor radius of the power deposited from three 0. 5-MW gyrotrons was essential for reaching steady-state conditions. With central current drive, up to 153 kA of current have been fully replaced transiently for 100 ms. The noninductive scenario is confirmed by the ability to recharge the Ohmic transformer. The dependence of the current drive efficiency on the minor radius is also demonstrated.     

Probing the reactivity of nebularine N1-oxide. A novel approach to C-6 C-substituted purine nucleosides

A novel approach to the synthesis of purine nucleoside analogues, featuring the reaction of the C6-N1-O⁻ aldonitrone moiety of 9-ribosyl-purine (nebularine) N1-oxide with some representative dipolarophiles, as well as Grignard reagents, is reported. Addition of Grignard reagents to the electrophilic C-6 carbon of the substrate allows a facile access to C-6 C-substituted purine nucleosides without using metal catalysts. 1,3-Dipolar cycloaddition processes lead to novel nucleoside analogues via opening, degradation or ring-enlargement of the pyrimidine ring of the base system of the first-formed isoxazoline or isoxazolidine cycloadduct.