Mh. Voges et al., Synthesis and characterization of 14-electron cyclopentadienyl chromium(II) complexes containing a heterocyclic carbene ligand, ORGANOMETAL, 18(4), 1999, pp. 529-533
Chromocene reacts with 1,3-dimesitylimidazolium chloride in THF to yield cy
clopentadiene and CpCrCl(1,3-dimesitylimidazolin-2-ylidene) (1), which cont
ains an N,N-heterocyclic carbene ligand. This new complex is a relatively r
are example of a CpCr(II) complex containing four unpaired electrons. The r
eaction of 1 with phenylmagnesium bromide yields CpCrPh(1,3-dimesitylimidaz
olin-2-ylidene) (2). An X-ray crystallographic investigation of 2 reveals a
two-legged piano stool structure with a planar central Cr atom.