M. Lucarini et al., SPONTANEOUS AND PHOTOINDUCED FORMATION OF RADICAL-ANIONS IN THE REACTION OF BOROHYDRIDES WITH UNSATURATED-COMPOUNDS, Perkin transactions. 2, (11), 1993, pp. 2083-2087
The spontaneous and photoinduced reactions of tetrabutylammonium boroh
ydride, Bu4NBH4, with a number of quinones, ketones, cyano derivatives
and nitrogen-containing heteroaromatic bases have been studied by mea
ns of EPR spectroscopy in benzene and in ethereal solvents. In the abs
ence of UV irradiation, formation of radical anions resulting from ele
ctron transfer from the borohydride negative ion, BH4-, to the organic
substrate has been detected with compounds having reduction potential
s less negative than -1.5 V vs. SCE. With the less easily reducible co
mpounds, UV irradiation leads in some cases to radical anions produced
by photoinduced ET and in other cases to radical adducts of the boran
e radical anion, BH3.-.