Chemistry of Polypyridine Ruthenium Complexes: VII. Electronic Structure and Photochemistry of cis-[Ru(2,2'-bpy)2(L)(Cl)]+ Complexes

The electronic absorption spectra and photochemical behavior of the complexes of cis-[Ru(bpy)₂ · (L)(Cl)]⁺ (bpy is 2,2'-bipyridyl) with pyridine (L = py) and 4-substituted pyridines [L = methyl-, amino-, and cyanopyridine, and 4,4'-bipyridyl (bipy)]. Photoirradiation of acetonitrile solutions of the complexes results in substitution of ligand L by a solvent molecule. A correlation was revealed between the photolysis quantum yield and the coordination-induced ligand L-to-metal charge transfer.     

Ru(II) Chloro-Bis(bipyridyl) Complexes with Substituted Pyridine Ligands: Interpretation of Their Electronic Absorption Spectra

A number of complexes were synthesized with the general formula cis-[Ru(Bipy)₂(L)(Cl)](BF₄), where Bipy is 2,2"-bipyridine, L is pyridyne (Py), 4-aminopyridine (4-NH₂py), 4-picoline (4-Mepy), nicotin-amide (3-CONH₂py), isonicotinamide (4-CONH₂py), 3- and 4-cyanopyridine (3-CNpy, 4-CNpy), 4,4"-bipyridine (4,4"-Bipy), trans-1,2-bis(4-pyridyl)ethylene (Bpe), 4,4"-azopyridine (Azpy), pyrazine (Pyz), imidazole (Imid), and NH₃. The semiempirical CINDO-CI method was used to calculate the energies and intensities of transitions in the electronic absorption spectra. The differences observed in the spectra of these compounds are mainly due to the positions of the charge-transfer transitions d (Ru) *(L). Depending on the positions of these transitions, ligands L can be divided into three groups: 1) transitions Ru L lie in the region of the first long-wavelength band d (Ru) *(Bipy) (L = Azpy, Pyz); 2) transitions Ru L lie between the first and second bands due to the charge transfer to Bipy (L = 3-CONH₂py, 4-CONH₂py, 4,4"-Bipy, Bpe, 4-CNpy), and 3) transitions Ru L lie in the region of the second band d (Ru) *(Bipy) (L = Py, 4-Mepy, 3-CNPy, 4-NH₂py, Imid).     

Electronic structure and polarizability of ortho-benzoquinonediimine and its singly and doubly charged anions

The results of electronic structure calculations for o-benzoquinonediimine and its singly and doubly charged anions are presented. The variation of the geometrical and valence structures due to electron addition to the molecule is analyzed, and electron affinity is estimated. Polarizabilities of the neutral molecule and singly charged anion are calculated. The influence of the basis on the results of polarizability calculations for molecular anions is investigated. Translated from Zhumal Struktumoi Khim ii, Vol. 41, No. 1, pp. 34-41, January–February, 2000.