Ricerc@Sapienza

N-Heterocyclic olefin (NHO) can be generated by simple
cathodic reduction of BDMImBF
4
-DMF solution or neat
BDMImBF
4
(BDMImBF
4
=
1-butyl-2,3-dimethyl-1
H
-imidazolium
tetrafluoroborate; DMF
=
dimethylformamide). In the latter case,
the use of any organic solvent and chemical base is avoided. To
prove the presence of NHO, its adduct with benzaldehyde was
isolated. The electrochemical behavior of NHO is very similar to
that of the corresponding N-heterocyclic carbene (NHC, from 1-
butyl-3-methyl-1
H
-imidazolium tetrafluoroborate), showing that
it is electroactive at the anode, and this peculiarity can be
exploited to verify its presence in a solution. The main differ-
ence between NHO and NHC is in the nucleophilic site
(exocyclic for NHO, endocyclic for NHC). Electrogenerated NHO
stability (evaluated by cyclic voltammetry) and its catalytic
ability (evaluated in the transesterification reaction) were
compared with those of electrogenerated NHC.