Lifetimes of ortho-positronium in benzene solutions of .BETA.-diketonates of iron(III) and cobalt(III).

概要

論文の詳細を見る
The lifetimes of ortho-positronium (o-Ps) have been measured in benzene solutions of β-diketonates of iron(III) and cobalt(III). A trend in substituent effect on the acceleration of o-Ps decay has been found. A substituent such as trifluoromethyl, that tends to withdraw electrons from the chelate ring, greatly accelerated o-Ps decay; the greatest rate constant observed was 33.8×109 M−1 s−1 for tris(hexafluoroacetylacetonato)iron(III). An electron-releasing substituent such as t-butyl accelerated o-Ps decay to a lesser extent, e.g. 10.5×109 M−1 s−1for tris(dipivaloylmethanato)iron(III). The extent to which a complex accelerated o-Ps decay was largely related to the redox potential, which was observed by cyclic voltammetry. Complexes with phenyl substituents in the ligand showed slightly smaller effects than that suggested by their redox potentials.
公益社団法人日本化学会の論文