Circular dichroism of trigonal dihedral chromium(III) complexes: a theoretical study based on open-shell time-dependent density functional theory.

Spin-unrestricted time-dependent density functional theory has been applied to the electronic circular dichroism spectra of Cr(III) complexes with an open-shell ground state, that is, [Cr(L-L)(3)](n+) with L-L = en(ethylenediamine), acac(acetylacetonate), ox(oxalate), mal(malonate), and Thiox(dithiooxalate). The simulated CD spectra are analyzed in details and compared with experimental data, as well as previous calculations on similar Co(III) complexes where available. The theoretical results serve as a tool for elucidating the absolute configuration of similar complexes, by pointing to transitions for which the sign of the rotatory strength can be used as fingerprint for one particular configuration.