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.     

Chemistry of Electronically Excited Ruthenium Polypyridine Complexes: III.1 Electronic Structure of Complexes cis-[Ru(2,2'-bpy)2(4,4'-bipy)(X)]q

The results of ab initio quantum-chemical calculations of isolated ruthenium(II) complexes cis- [Ru(bpy)₂(bipy)(X)]⁴4q (bpy is 2,2'-bipyridyl, bipy is 4,4'-bipyridyl; X = NH₃, Cl^-, Br^-, CN^-, NO^- ₂, ONO^-, MeCN, and NO⁺) are presented. Analysis of the charge distributions and the orbital structures of the complex ions points to absence of strong -acceptor bonds Ru-bpy, Ru-bipy, and Ru-X (X = NO⁺), to delocalization of -electron density under the action of strong donors X, to localized nature of lowest unoccupied molecular orbitals, and to special position of the nitrosyl complexes in this series.     

Synthesis and Properties of Platinum(II) 2-(2-Pyridyl)thiophenide Complexes and Ruthenium(II) Bisbipyridyl Complexes with 1,2-Bis(diphenylphosphino)ethene

Russian Journal of General Chemistry -     

Chemistry of Ruthenium Polypyridine Complexes: IV. Quantum-Chemical Simulation of the Effect of Solvation Shell on the Electronic Structure of Ru(II) Complexes with Nitrogen-containing Ligands

Ab initio quantum-chemical calculations of Ru(II) complexes have been fulfilled with consideration for solvation within the framework of the polarized continuum model. Energy levels of fragments of Ru(II) complexes with organic ligands are shifted relative to each other by electrostatic interactions with the solvation shells.     

Quantum-Chemical Study of the Electronic Structure of the Complex Ions [Ru(NH3)5pyz]2 + and [Ru(CN)5pyz]3 - in Solution

The hydration shell of the complex ions [Ru(NH₃)₅pyz]^{2 +} and [Ru(CN)₅pyz]^{3 -} was simulated on the basis of ab initio Hartree-Fock calculations in the supermolecular approximation, within the framework of the multicavity polarizable continuum model. In calculations of the spectral characteristics of complexes with a pronounced nonuniformity of electron density distribution, it is primarily necessary to take into account the shift of energy levels of particular fragments under the action of the electrostatic potential produced by the solvation surrounding. Consideration of the charge transfer between the complex and the outer-sphere water molecules has no significant effect on the calculated electronic spectrum; the transferred electron density is below 1e.     

Chemistry of Ruthenium Polypyridine Complexes: VIII. Electronic Structure and Reactivity of cis-[Ru(2,2'-Bpy)2(L)Cl]+ Complexes in Excited States

Ab initio and semiempirical CINDO/CI calculations of free ligands L and complexes cis-[Ru(bpy)₂(L)Cl]⁺ [bpy = 2,2'-bipyridyl, L = pyridine, 3-cyanopyridine, 4-picoline, nicotinamide, isonicotinamide, 4-picoline, 4-aminopyridine, 4,4'-bipyridyl (bipy), trans-1,2-bis(4-pyridyl)ethene, 4,4'-azopyridine, pyrazine (pyz), and imidazole] were used to study the interrelation between the electronic structures of the ligands and the complexes in the ground and electronically excited states and to interpret the electronic absorption spectra of the complexes. The quantum yields for photosubstitution of a solvent molecule for a ligand L were measured; for L = pyz and bipy, photolysis quantum yields as a function of irradiation wave-length were studied. The possibility of population of ligand-field photoactive states from overlying charge-transfer states and the associative mechanism of ligand photosubstitution were discussed.     

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).     

Chemistry of Ruthenium Polypyridine Complexes: VI. Synthesis and Photochemistry of cis-[Ru(bpy)2(bipy)X]q Complexes

Complexes cis-[Ru(bpy)₂(bipy)(X)] ^{n +} [bpy = 2,2'-bipyridyl, bipy = 4,4'-bipyridyl, X = Br^-, ONO^-, CN^- (n = 1); MeCN, PPh₃ (n = 2), and NO⁺ (n = 3)] were synthesized. Irradiation of acetonitrile solutions of the complexes with X = Cl^-, Br^-, ONO^-, NO₂-, CN^-, NH₃, MeCN, and PPh₃ by visible light results in photosubstitution of 4,4'-bipyridyl by a solvent molecule. The electronic absorption spectra of the complexes were assigned on the basis of quantum-chemical calculations. A correlation was revealed between photolysis quantum yields and charges transferred from ligands X upon their coordination.