OPTICAL ROTATORY POWER OF METAL CHELATE COMPOUNDS CONTAINING ORGANIC UNSATURATED MOLECULES AS LIGANDS

Rotational strengths due to the π-electron transitions of optically active dihedral metal complexes containing organic unsaturated molecules as ligands were theoretically studied by calculating directly magnetic transition dipole moments. The observed CD bands due to the π-π transitions within the ligand π-electron systems could well be explained by the present theoretical treatment which used the wave functions evaluated by the composite-system method. The absolute configuration of optical isomers could be determined by comparing the theoretical results with the observed CD signs of the ligand π-π* transitions. The rotational strengths due to the metal-ligand charge-transfer transitions appearing in certain α,α’-dipyridyl and o-phenanthroline complexes were also examined from the theoretical point of view. Two of the three charge-transfer transitions at the 500-mμ region were shown to have large rotational strengths corresponding to the observed two CD bands with opposite signs, though these two transitions gave a small contribution to the electronic absorption spectrum. © 1969, American Chemical Society. All rights reserved.