The First Phenanthrene-Fused Imidazol-2-ylidene and Its Transition-Metal Complexes
Chemistry and Biochemistry
A new phenanthrene-fused N-heterocyclic carbene was generated and characterized in soln. The synthesis of air-stable Rh, Ir, and Ag complexes, supported by the new phenanthrene-fused 1,3-dibutylimidazol-2-ylidene ligand, is described. Deprotonation of phenanthrene-fused imidazolium salt 4 in the presence of [M(COD)Cl]2 (M = Rh, Ir) afforded complexes 6 and 7 in excellent yields. The Ag complex was obtained by reaction of 4 with Ag2O. The solid state mol. structures of these complexes were detd. by x-ray diffraction studies. The fluorescence emission spectra of 4, 6, and 7 are compared to that of phenanthrene.