Influence of anellation in N-heterocyclic carbenes: Novel quinoxaline-anellated NHCs trapped as transition metal complexes

Abstract
The synthesis, NMR-, and crystal structure data of novel electron-deficient quinoxaline anellated imidazol-2-ylidene precursors and complexes thereof are reported and compared with related less electron-withdrawing or non-anellated N-heterocyclic carbenes and complexes to illustrate anellation effects.