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In this article we study the anchoring of cis-[Ru(bpyC 4 pyr)(CO) 2 (CH 3 CN) 2 ] 2+ , cis-[Ru(bpy) 2 (CO) 2 ] 2+ and cis-[Ru(bpyac)(CO) 2 Cl 2 ], onto nanoporous TiO 2 employing electropolymerization, electrostatic interaction and chemical bonding. Also, the [Re(bpyac)(CO) 3 Cl] rhenium(I) complex for chemical anchorage was analyzed. The characterization of TiO 2 /Ru(II) and TiO 2 /Re(I) nanocomposite films was performed by field emission scanning electron microscopy (FESEM), electron dispersive X-ray spectroscopy (EDS) and Raman spectroscopy. In addition, for the more stable nanocomposites obtained, the catalytic properties (solar energy conversion and CO 2 reduction) were evaluated. The efficiency improvement in redox process derived from the (photo)electrochemical evidence indicates that modified nanoporous TiO 2 structures enhance the rate of charge transfer reactions. [ABSTRACT FROM AUTHOR]

Photophysics of the MLCT excited-state of [Ru(bpy)(tpy)(OH2)]2+ (1) and [Ru(bpy)(tpy)(OD2)]2+ (2) (bpy = 2,2'-bipyridine and tpy = 2,2':6',2'-terpyridine) have been investigated in room-temperature H2O and D2O using ultrafast transient pump-probe spectroscopy. An inverse isotope effect is observed in the ground-state recovery for the two complexes. These data indicate control of excited-state lifetime via a pre-equilibrium between the ³MLCT state that initiates H-bond dynamics with the solvent and the ³MC state that serves as the principal pathway for nonradiative decay. [ABSTRACT FROM AUTHOR]

To study the fate of a molecular di-μ-oxo-bridged trinuclear ruthenium complex, [(NH3)5Ru-O-Ru(NH3)4-O-Ru(NH3)5]6+, also known as Ru-red, during the electro-driven water oxidation reaction, electrochemical in situ surface enhanced Raman spectroscopy (SERS) investigations have been conducted on an electrochemically roughened gold surface in acidic condition. It was previously described that on a basal plane pyrolitic graphite electrode in 0.1 M H2SO4 aqueous solution, Ru-red undergoes one electron oxidative conversion into a stable higher oxidation state ruthenium complex, Ru-brown, at <1.0 V ( vs normal hydrogen electrode (NHE)), and this leads to water oxidation and dioxygen release, but the fate of Ru-red during electrochemistry was not studied in much detail. In this investigation, Ru-red dispersed in acid electrolyte and immobilized on a roughened gold electrode without Ru-red in solution has been subjected to anodic controlled potential experiments, and in situ SERS was carried out at various potentials in succession. The electrochemical SERS data obtained for Ru-red are also compared with in situ SERS results of an electrodeposited ruthenium oxide thin film on the Au disk. Our study suggests that on a gold electrode in sulfuric acid solution containing Ru-red, one electron oxidative conversion of Ru-red to a higher oxidation state ruthenium compound, Ru-brown, occurs at ca. 0.74 V ( vs NHE), as supported by the electrochemical in situ SERS experiments. Moreover, at higher potentials and on Au disk, the Ru-red / Ru-brown are not stable and slowly decompose or electro-oxidize leading to deactivation of the tri-ruthenium catalytic system in acidic medium. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Highlights: [•] 35Cl NQR of (NH4)2RuCl6, (ND4)2RuCl6, (NH4)2SnCl6, and (ND4)2SnCl6 was measured. [•] Isotope effect on the spatial distribution of hydrogen atoms is discussed. [•] Tunneling splittings of torsional ground state of ammonium ions were estimated. [•] Origin of T 1Q anomaly previously reported in (NH4)2SnCl6 and (ND4)2SnCl6 was revealed. [ABSTRACT FROM AUTHOR]

Ruthenium(II) polypyridyl complexes pro- mote the efficient radical cation Diels-Alder cycloaddition of electron-rich dienophiles upon irradiation with visible light. These reactions enable facile [4 + 2] cycloadditions that would be electronically mismatched under thermal conditions. Key to the success of this methodology is the availability of ligand-modified ruthenium complexes that enable rational tuning of the electrochemical properties of the catalyst without significantly perturbing the overall photophysical properties of the system. [ABSTRACT FROM AUTHOR]

The treatment of [Ru(LOEt)(N)Cl2] (1; LOEt- = [Co(η5-C5H5){P(O)(OEt)2}3]-) with Et3SiH affords [Ru(LOEt)Cl2(NH3)] (2), whereas that with [Ru(LOEt)(H)(CO)(PPh3)] (3) gives the dinuclear imido complex [(LOEt)Cl2Ru(μ-NH)Ru(CO)(PPh3)(LOEt)] (4). The imido group in 4 binds to the two ruthenium atoms unsymmetrically with Ru-N distances of 1.818(6) and 1.952(6) Å. The reaction between 1 and 3 at 25 °C in a toluene solution is first order in both complexes with a second-order rate constant determined to be (7.2 ± 0.4) × 10-5 M-1 s-1. [ABSTRACT FROM AUTHOR]

The cationic complex [(pymox-Me2)RuCl2]+BF4−was found to be a highly effective catalyst for the C−H bond oxidation reaction of arylalkanes in water. For example, the treatment of ethylbenzene (1.0 mmol) with t-BuOOH (3.0 mmol) and 1.0 mol % of the Ru catalyst in water (3 mL) cleanly produced PhCOCH3at room temperature. Both a large kinetic isotope effect (kH/kD= 14) and a relatively large Hammett value (ρ = −1.1) suggest a solvent-caged oxygen rebounding mechanism via a Ru(IV)-oxo intermediate species. [ABSTRACT FROM AUTHOR]

The article offers a description of a ruthenium/chiral diimino-diphosphine (PNNP)-catalyzed asymmetric Diels-Alder reaction. It notes that the PNNP complexes promote the enantioselective Diels-Alder reaction of α-methylene &#03B2;-keto esters to give tetrahydro-1-indanones. It explains that the diene attacks the open re enantioface of metal-bound dienophile in highly enantioselective fashion.