Computational study of [(phenanthroline)2FeII/III–(terephthalate)–CoIII/II(phenanthroline)2]3+ binuclear complex

Abstract

Bistability of the proposed [(phenanthroline)2FeII/III–(terephthalate)–CoIII/II(phenanthroline)2]3+ binuclear complex, arising from intramolecular FeII/III ↔ CoIII/II charge transfer, is investigated based on energetics, geometries, atomic charges, electric polarizabilities, and IR and UV-Vis spectra obtained computationally at (TD)DFT-B3LYP/LANL2DZ level of theory. Two distinct stable states are obtained which have different characteristics, including structures, charge distributions, and spectroscopic properties. Also, the well-defined first-order saddle point obtained between these two states using the QST3 search method, having a 1.182 eV activation (barrier) energy for the FeIICoIII → FeIIICoII reaction, furthermore approves bistability in this complex. This value of activation energy suggests that switching between the two charge distribution states FeII–CoIII and FeIII–CoII in this complex may be induced by electric field and/or infrared radiation, and thus, it can be candidate as an infrared radiation- or electric field-driven molecular two-state switch.