Calculating Electronic Optical Activity of Coordination Compounds

The theory underlying calculations of electronic optical activity (circular dichroism (CD) and optical rotation (OR)) is discussed. A brief survey of computations of CD and OR for metal complexes and metal clusters using first-principles theory (specifically: time-dependent density functional theory) is provided. Emphasis is placed on the origin of the optical activity of ligand-field transitions and ligand-to-metal charge transfer excitations for complexes of the type ML₃ where L is a bidentate ligand. The strong exciton coupling CD in chiral metal complexes with nonchiral ligands with π chromophores such as 1,10-phenanthroline or 2,2'-bipyridine is analyzed with the help of an exciton dipole coupling model and by comparisons of experiment and first-principles calculations.