First chelated chiral N-heterocyclic bis-carbene complexes

[formula: see text] First chiral bidentate bis-carbene complex of Pd(II) prepared from a bis-imidazolium salt derived from (S)-2,2'-bromomethyl-1,1'-binaphthyl exists in both cis- and trans-square planar geometry. These and the corresponding trans-Ni(II) complexes are remarkably resistant to high temperature, air, water, and silica gel chromatography. The Pd complexes catalyze Heck reactions.