Search

An array of semiconducting oligoselenophenes (n and p types), up to hexamer units, has been synthesized by the double Stille coupling methods using tetrakis(triphenylphosphine)palladium(0) as a catalyst. A series of semiconducting oligomers (n and p types) containing mixed hetero-units (hexamers of thiophene and selenophene) have been also synthesized using the Stille coupling reaction. Their thermal properties are systematically studied and compared with those of π-conjugated thiophene based oligomers using DSC and TGA. The field-effect mobility of synthesized n and p type oligomers is analyzed. [ABSTRACT FROM AUTHOR]

Assesses the commercial potential of the Russian space industry in the world space market. Structure of the global market in space products; Effectiveness of space activities at the state, sectoral and regional levels; Classification of the market in space products; Sectors of the world space market and the relative shares of countries engaged in it; World accomplishments and leaders in space activities.

Absorption, ESR and photoluminescence of hexakis(pentamethyldisilyl)disilane [(Me3SiMe2Si)3Si]2 1 were studied. Two branched polysilyl radicals were observed by ESR spectroscopy under UV irradiation of 1. The smaller ‘star’ radical (Me3SiMe2Si)3Si⋅ 2 has half-lifetime 1 s whereas the bigger one (Me3SiMe2Si)3Si(Me3SiMe2Si)2Si⋅ 3 has a half-lifetime about 50 min. During irradiation the reaction 1 → 2 + 3 followed by 2 + 3 → products (P) occur. The behavior of the 300 nm absorption of radical 3 during the irradiation was found to be similar to the radical 3 appearance measured by ESR. The silane (Me3SiMe2Si)3SiH was found as main product (∼50% yield) of the photo-cleavage of the disilane 1. [Copyright &y& Elsevier]