Neutral mixed-valence organic monoradicals

With the aim of examining the possibility of synthesizing and utilizing neu tral organic radicals exhibiting intramolecular electron transfer, cyclic m ono-radicals consisting formally of one neutral and paramagnetic NO. and on e cationic and diamagnetic NO+, connected by an anionic BH2- and one or mor e CH2 groups, have been studied with emphasis placed on their stabilities a nd distribution of the lone electron. Accurate energy estimates suggest tha t, except for strained rings, the cyclic forms are stable with respect to r ing opening and therefore represent a reasonable synthetic target for neutr al mixed-valence compounds, the electron transfer rates of which should not critically depend on the environmental conditions. (C) 1999 Elsevier Scien ce B.V. All rights reserved.