Finally, we tested the same approach with a N,N,N-tridentate ligand (1 2 ,2 2 :2 6 ,3 2 -terpyridine, terpy in the following). The precursor gold(III) complexes had a [(terpy)Au III X2] + speciation. As the gold(III) complexes prefer square planar coordination and the complex retains two halogen ligands, the terpy ligand initially coordinates probably only as a bidentate ligand. The complex easily eliminates one of the halogen atoms and forms [(terpy)Au II X] + . Presumably, the ligand changes the coordination mode and fills in the vacant coordination site after the elimination of X. For more detailed information, we studied bond dissociation energies (BDEs) for the halogen eliminations.