A. I. Panin

Electronic structure, spectrum, and intramolecular electron transfer model of [(NH3)5Ru-(4,4’-bipy)-Ru(NH3)5]5+

The electronic structure of the ground and excited states of the binuclear mixed-valence complex [Ru(NH3)5]2(4,4’-bipy)5+ is calculated by the semiempirical INDO + CI method, and an electronic spectrum assignment is given. A theoretical model of electron transfer between the Ru(II) and Ru(III) metal centers is constructed on the basis of many-electron wave functions. The dependence of the electron transfer characteristics on the angles between the planes of the pyridine rings and also between the pyridine rings and the planes of cis(NH3)-Ru-cis(NH3) is analyzed.

Indo calculation of electronic spectra for transition metal complexes in the extended approximation of singly excited configurations

Semiempirical INDO-E/S calculations of [RuX6]q (X=NH3, q=+2, +3; X=CN−, q=−4, −3) complexes are performed to demonstrate that the MO relaxation in the electronically excited state can be taken into account by introducing certain double excitations into the configuration interaction matrix; the principles of selection of the excitations are discussed. The calculation results are compared with the experimental electronic absorption spectra.

Intramolecular electron transfer in mixed-valence complexes [(NH3)5Ru-L-Ru(NH3)5]5+ (L = N2, pyz, pym, 4,4′-bipy, bpa)

The dynamics of the intramolecular electron transfer from Ru(II) to Ru(III) in binuclear mixedvalence complexes [(NH3)5Ru-L- Ru(NH3)5]5+ (L = N2,pyz, bipy, pym, bpa) is analyzed by the semiempirical CINDO +CI method.

Semiempirical calculations of the electronic spectra of organometallic compounds: Estimation of solvent and counterion effects

The electronic spectra of the [Ru(NH3)5pz]2+, [Ru(NH3)5pz]3+, and [Ru(CN)5pz]3− complexes are calculated by the CI INDO method. The effect of solvation on the spectra is considered in a point charge approximation and in terms of the parametric model of a charged sphere enveloping the metal fragment. Interrelation of these approaches is discussed. Data on the molecular electrostatic potentials created by the complexes are presented to substantiate the models.

SEMIEMPIRICAL CALCULATIONS OF THE ELECTRONICALLY EXCITED STATES OF ORGANOMETALLIC COMPOUNDS: SELECTION OF CONFIGURATION INTERACTION BASIS SETS

Semiempirical INDO-E/S+RCIP calculations of the electronic structures of the ground and excited states of the pyrazine (pz) molecule and [Ru(NH3)5pz]q (q=+1, +2, +3) complexes were performed to analyze the dependence of the calculation results on the active MO space and configuration basis set. Recommendations for the construction of the {Фk} basis sets and formation of the {ϕk} sets are given.

CONSTRUCTION OF MOLECULAR ORBITALS LOCALIZED ON POLYATOMIC FRAGMENTS

A simple method of localizing molecular orbitals on polyatomic molecular fragments is proposed; the method allows one to separate orbitals in the structural units of extended molecules. The method is illustrated by semiempirical calculations of the binuclear bridged complexes [(NH3)5Ru-py-(C2H2)n- py-Ru(NH3)5]5+ (n = 0,1,2,3). One of possible application is construction of orbital bases for calculations by the configuration interaction method with limited sets of active MOs.

Structural-dynamic approach and path analysis of the intramolecular electron transfer in the bridged complexes [(NH3)5Ru-py-(C2H2)n-py-Ru(NH3)5]5+ withn = 0,1,2,3

The electron interaction transfer paths in the mixed-valence complexes[(NH3)5Ru-py-(C2H2)n-py-Ru(NH3)5]5+ are analyzed in the framework of perturbation theory. A structural-dynamic approach to treatment of the intramolecular electron transfer is proposed. This approach is based on the solution of the nonstationary Schrödinger equation in a basis of many-electron functions describing separate structural sites of the electron-transport chain RyII→pyridyl→ C2H2)n→pyridyl→RuIII.

Quantum chemical study of the magnetic properties and electronic structure of the Creutz-Taube ion [(NH3)5Ru-pyz-Ru(NH3)5]5+

A method is developed of calculating the g-tensor from the results of quantum chemical calculations by semiempirical methods in a many-electron approximation. Calculations are performed for the g-tensors of the ruthenium complexes [(NH3)5Ru-pyz-Ru(NH3)5]5+ and [NH3Ru-pyz]3+. A comparison between the experimental and calculated g-factors of the Creutz-Taube ion [(NH3)5Ru-pyz-Ru(NH3)5]5+ allows one to conclude that the electronic structure of this ion is localized.

Electronic structure and spin bonds in the [(NH3)5Cr-O-Cr(NH3)5]4+ complex

The electronic structure of the lowest singlet, triplet, quintet, and septet states of the binuclear complex [Cr(NH3)5]2O4+ are calculated by the semiempirical MC SCF method in the INDO approximation. Schemes of spin coupling of Cr-O-Cr in these states are analyzed.

Intramolecular electron transfer in mixed-valence complexes [(NH3)5Ru-L-Ru(NH3)5]5+ (L = N2, pyz, pym, 4,4’-bipy, bpa)

The dynamics of the intramolecular electron transfer from Ru(II) to Ru(III) in binuclear mixed-valence complexes [NH3)5Ru -L-Ru(NH3)5]5+(L = N2, pyz, bipy, pym, bpa) is analyzed by the semiempirical CINDO + CI method.