Compounds with (NHC)→E coordination bond are being generated and their
chemistry is being explored over the past 15 years (NHC=
N-heterocyclic carbenes, E = main group elements). Many examples
of species with N-heterocyclic olefins (NHOs) are known, which
exhibit umpolung chemistry. Increasing number of chemical species, which
carry NHC as a functional unit, are being reported. There is a need to
understand their electronic structure. Alkylated imidazole oximes
(cationic, found useful in medicinal chemistry) ((NHC)-C(H)=N-OH(+))
carry NHC unit as a functional group. Similarly, the corresponding
nitroso-N-heterocyclic olefins ((NHC)=C(R)-N=O) also carry NHC as
a functional unit. It is important to establish the interaction between
the NHC unit and the rest part of the molecule in these species. Density
functional (DFT) study has been carried out to explore the electronic
structure details of a few oximes and nitroso NHOs. The results indicate
that a structure with NHC→C coordination interaction can be considered
as one of the resonance structures of these species.
NHC Ligated Oximes: Exploring the Electronic Structure and Properties
