Despite this variation, regardless of the employed conditions, we always observe an EPR signal that can be assigned to an unpaired electron (g = 2.004) interacting with at least one nuclear spin of multiplicity I=1 with a hyperfine coupling constant of ca 11 Gauss, pointing to the consistent presence of a nitro radical. The broad signals correlate with the appearance of a suspension in solution, and in an effort to avoid aggregation and gain spectral resolution, we tried one, or a combination, of the following: i) decreasing the concentration of nitrobenzene, ii) changing the molar ratio between nitrobenzene and anionic organic base ( [1]:[B -X + ]), and iii) increasing the polarity of the medium by mixing THF and benzene with DMSO. This resulted in much more resolved signals, as exemplified nicely by LDA (Figure ), whose spectrum with 25% of DMSO could be perfectly fitted to [1 •-], i.e., using one nuclear spin of I=1, assigned to the nitrogen of the nitro, plus one and two sets of equivalent nuclear spins of I=1/2, assigned to the para, meta and ortho hydrogen atoms, respectively (Figure , Table ) -a similar behaviour is observed with t BuLi and LiHMDS, using even smaller amounts of DMSO (Figure and).