A structural model of the O2-evolving center in photosystem II is provided by complex 1. The two ruthenium – hydroxo units play a key role oxidation water to O2. Deposition on an indium tin-oxide electrode has enabled 15.0 mL O2 (turnover 6730) be evolved from controlled-potential electrolysis at +1.7 V.

Tanaka and co-workers reported a novel dinuclear Ru complex, [Ru2(OH)2(3,6-Bu2Q)2(btpyan)](SbF6)2 (3,6-Bu2Q = 3,6-di tert-butyl-1,2-benzoquinone, btpyan 1,8-bis(2,2':6',2''-terpyrid-4'-yl)anthracene), that contains redox active quinone ligands has an excellent electrocatalytic activity for water oxidation when immobilized on indium-tin-oxide electrode (Inorg. Chem., 2001, 40, 329-337). The features of the related mononuclear species with ligands, comparison their properties to those...

The novel bridging ligand 1,8-bis(2,2':6',2"-terpyridyl)anthracene (btpyan) is synthesized by three reactions from 1,8-diformylanthracene to connect two [Ru(L)(OH)]+ units (L = 3,6-di-tert-butyl-1,2-benzoquinone (3,6-tBu2qui) and 2,2'-bipyridine (bpy)). An addition of tBuOK (2.0 equiv) a methanolic solution [RuII2(OH)2(3,6-tBu2qui)2(btpyan)](SbF6)2 ([1](SbF6)2) results in the generation [RuII2(O)2(3,6-tBu2sq)2(btpyan)]0 (3,6-tBu2sq 3,6-di-tert-butyl-1,2-semiquinone) due reduction quinone...

A bis-hydroxo-bridged dinuclear CoIII-pyridylmethylamine complex (1) was synthesized and the crystal structure determined by X-ray crystallography. Complex 1 acts as a homogeneous catalyst for visible-light-driven water oxidation persulfate (S2O82–) an oxidant with [RuII(bpy)3]2+ (bpy = 2,2′-bipyridine) photosensitizer affording high quantum yield (44%) large turnover number (TON 742) O2 formation without forming catalytically active Co-oxide (CoOx) nanoparticles. In water-oxidation process,...

Role model: The photochemical and electrochemical properties of a polypyridylruthenium complex with an NAD+/NADH (NAD+=nicotinamide adenine dinucleotide) model ligand, [Ru(bpy)2(pbn)]2+ ([1]2+; bpy=2,2′-bipyridine, pbn=2-(2-pyridyl)benzo[b]-1,5-naphthyridine), were investigated. When solutions containing [1]2+ triethylamine are irradiated visible light, [(1)HH]2+ is produced cleanly (see scheme). Supporting information for this article available on the WWW under...

The redox states of Ru(OH2)(Q)(tpy)2+ (Q = 3,5-di-tert-butyl-1,2-benzoquinone, tpy 2,2′:6′,2″-terpyridine) are investigated through experimental and theoretical UV-vis spectra Pourbaix diagrams. electrochemical properties reported for the species resulting from deprotonation processes in aqueous solution. formal oxidation couples various intermediate complexes systematically assigned using electronic structure theory. controversy over assignment ferromagnetic vs. antiferromagnetic coupling...

The ruthenium oxyl radical complex, [RuII(trpy)(Bu2SQ)O•-] (trpy = 2,2':6',2' '-terpyridine, Bu2SQ 3,5-di-tert-butyl-1,2-benzosemiquinone) was prepared for the first time by double deprotonation of aqua ligand [RuIII(trpy)(Bu2SQ)(OH2)](ClO4)2. [RuIII(trpy)(Bu2SQ)(OH2)](ClO4)2 is reversibly converted to [RuIII(trpy)(Bu2SQ)(OH-)]+ upon dissociation proton (pKa 5.5). Deprotonation hydroxo gave rise intramolecular electron transfer from resultant O2- Ru−dioxolene. showed antiferromagnetic...

Calming the radicals: Aminyl radicals may one day be useful oxidation catalysts if their thermodynamic instability can overcome, for example, through complexation with a metal. The semiquinone–anilino-radical and catechol–anilino-radical complexes 1 2 have now been prepared anilino-radical character of tetradentate amine ligand proved by electron paramagentic resonance Raman spectroscopy, as well DFT calculations. Supporting information this article is available on WWW under...

Abstract A bis(ruthenium–bipyridine) complex bridged by 1,8‐bis(2,2′:6′,2′′‐terpyrid‐4′‐yl)anthracene (btpyan), [Ru 2 (μ‐Cl)(bpy) (btpyan)](BF 4 ) 3 ([ 1 ](BF ; bpy=2,2′‐bipyridine), was prepared. The cyclic voltammogram of [ in water at pH 1.0 displayed two reversible II ,Ru ] 3+ /[Ru III 4+ and 5+ redox couples E 1/2 (1)=+0.61 (2)=+0.80 V (vs. Ag/AgCl), respectively, an irreversible anodic peak around =+1.2 followed a strong currents as result the oxidation water. controlled potential...

A polypyridylruthenium complex with an NAD+/NADH model ligand, [Ru(bpy)2(pbn)]2+ [bpy = 2,2′-bipyridine; pbn 2-(2-pyridyl)benzo[b]-1,5-naphthyridine] in a D2O/CH3CN/triethylamine solution, undergoes stereospecific hydrogenation to give Δ-(S)- and Λ-(R)-[Ru(bpy)2(pbnDD)]2+ [pbnDD 5,10-dideutero-2-(2-pyridyl)benzo[b]-1,5-naphthyridine] upon visible-light irradiation. This result clearly indicates the pathway via π-stacked dimer of deuterated one-electron-reduced species. The reduction Na2S2O4...

4,5-Bis(terpyridyl)-2,7-di-tert-butyl-9,9-dimethylxanthene (btpyxa) was prepared to serve as a new bridging ligand via Suzuki coupling of terpyridin-4'-yl triflate and 2,7-di-tert-butyl-9,9-dimethylxanthene-4,5-diboronic acid. The reaction btpyxa with either 1 equiv or an excess PtCl(2)(cod) (cod = 1,5-cyclooctadiene) followed by anion exchange afforded mono- dinuclear platinum complexes [(PtCl)(btpyxa)](PF(6)) ([1](PF(6))) [(PtCl)(2)(btpyxa)](PF(6))(2) ([2](PF(6))(2)), respectively. X-ray...

Abstract A ruthenium–dioxolene–amine complex, [RuIII(NH2-L)(Bu2sq)](PF6)2·0.5H2O (NH2-L = bis(2-pyridylmethyl)-2-aminoethylamine, Bu2sq− 3,5-di-tert-butylsemiquinonate), was newly prepared. The complex undergoes spontaneous one-electron reduction under basic conditions in MeOH and works as an electrocatalyst the oxidation of benzyl alcohol to benzaldehyde electrolysis at +0.4 V (vs SCE).

The bridging ligand, 1,8-bis(2,2':6',2''-terpyrid-4'-yl)anthracene (btpyan) was synthesized by the Miyaura-Suzuki cross coupling reaction of anthracenyl-1,8-diboronic acid and 4'-triflyl-2,2':6'-2''-terpyridine in presence Pd(PPh(3))(4) (5 mol%) with 68% yield. Three ruthenium-dioxolene dimers, [Ru(2)(OH)(2)(dioxolene)(2)(btpyan)](0) (dioxolene = 3,6-di-tert-butyl-1,2-benzosemiquinone ([1](0)), 3,5-dichloro-1,2-benzosemiquinone ([2](0)) 4-nitro-1,2-benzosemiquinone ([3](0))) were prepared...

The ruthenium complexes [Ru(bpy)(pbn)2](PF6)2 ([2]2+; bpy = 2,2′-bipyridine, pbn 2-(2-pyridyl)benzo[b]-1,5-naphthyridine) and [Ru(pbn)3](PF6)2 ([3]2+) were synthesized. Photoirradiation (λ > 420 nm) of [2]2+ [3]2+ in CH3CN/triethanolamine (TEOA) brought about proton coupled four- six-electron reduction the to produce [Ru(bpy)(pbnH2)2](PF6)2 ([2·H4]2+; pbnH2 5,10-dihydro-2-(2-pyridyl)benzo[b]-1,5-naphthyridine) [Ru(pbnH2)3](PF6)2 ([3·H6]2+), respectively. photoexcited...

Abstract Hexamethyldigermane, Me3GeGeMe3, reacted with various alkynes in the presence of platinum complexes at 120 °C to afford Z–1,2-bis(germyl)ethenes moderate good yields. Terminal exhibit higher reactivities than internal ones. [Pt(acac)2] and [Pt(dba)2] serve as efficient catalysts, while [Pt(PPh3)4], [PtCl2(PPh3)2], [Pt(dba)2]-phosphite were found be inactive. Four- six-membered cyclic oligogermanes, such dodecamethylcyclohexagermane, (Me2Ge)6, catalysts yield...

The synthesis and electrochemical properties of a Ru(II) complex having redox active ligand, 1,10-phenanthroline-5,6-dione, [Ru(trpy)(PD-N,N′)Cl](PF6) ([1](PF6)), mixed-metal complexes [(PPh3)2Pd(O,O′-PD-N,N′)Ru(trpy)Cl](PF6) ([2](PF6)) [(PPh3)2Pt(O,O′-PD-N,N′)Ru(trpy)Cl](PF6) ([3](PF6)) (trpy = 2,2′:6′,2″-terpyridine, PD 1,10-phenanthroline-5,6-dione) are presented. [1]+, which was prepared by the reaction Ru(trpy)(DMSO)Cl2 with in hot ethanol, underwent two reversible reductions PD-based...

A series of ruthenium complexes [Ru(OAc)(dioxolene)(terpy)] having various substituents on the dioxolene ligand (dioxolene = 3,5-t-Bu2C6H2O2 (1), 4-t-BuC6H3O2 (2), 4-ClC6H3O2 (3), 3,5-Cl2C6H2O2 (4), Cl4C6O2 (5); terpy 2,2':6'2' '-terpyridine) were prepared. EPR spectra these in glassy frozen solutions (CH2Cl2:MeOH 95:5, v/v) at 20 K showed anisotropic signals with g tensor components 2.242 > g1 2.104, 2.097 g2 2.042, and 1.951 g3 1.846. An value, Deltag - g3, an isotropic [(g1(2) + g2(2)...

Aminylradikale könnten nützliche Oxidationskatalysatoren werden, wenn ihre thermodynamische Unbeständigkeit beherrschbar würde – etwa indem man sie an ein Metallzentrum bindet. Der Semichinon- 1 und der Catechol-Anilinoradikal-Komplex 2 wurden nun hergestellt. Dass vierzähnige Aminligand über Anilinoradikal-Charakter verfügt, bestätigen EPR- Resonanz-Raman-Spektroskopie sowie DFT-Rechnungen. Supporting information for this article is available on the WWW under...

The four-electron oxygen reduction reaction (4e–-ORR) is the mainstay in chemical energy conversion. Elucidation of factors influencing catalyst's rate and selectivity important development more active catalysts 4e–-ORR. In this study, we investigated electrochemical 4e–-ORR catalyzed by Co2(μ-O2) complexes bridged xanthene (1) anthracene (3) a Co2(OH)2 complex anthraquinone (2). ORR using Fe(CpMe)2 as reductant acidic PhCN, found that 1 showed highest initial turnover frequency (TOFinit =...

A ruthenium complex bearing a phenolic moiety inspired by the OEC of photosystem II exhibits high catalytic activity for electrochemical water oxidation, clearly indicating promoting influence on activity.

Dinuclear cobalt-1,10-phenanthroline (1) and 2,2'-bipyridine (2) complexes bridged by 1,8-bis(2,2':6',2''-terpyrid-4'-yl)anthracene (btpyan) were prepared. Both of the selectively catalysed electrochemical four-electron reduction dioxygen to H2O without generation H2O2 as a two-electron product.

Ein Strukturmodell des O2-generierenden Zentrums vom Photosystem II stellt der Komplex 1 dar. Die beiden Ruthenium-Hydroxo-Einheiten Verbindung spielen eine wichtige Rolle bei Oxidation von Wasser zu O2. Nach Abscheidung Komplexes auf einer Indium-/Zinnoxid-Elektrode konnten 15.0 mL O2 (Umsatzzahl 6730) unter Spannungskontrolle (+1.7 V) durchgeführten Elektrolyse erzeugt werden.

Abstract The new Ru–dioxolene–ammine complexes, [RuII(NH3)(sq)(trpy)](ClO4) (1, sq = 3,5-di-tert-butyl-1,2-benzosemiquinone, trpy 2,2′:6′,2″-terpyridine) and [RuIII(NH3)(sq)(trpy)](ClO4)2 (2), were prepared. They have an ability to oxidize MeOH i-PrOH catalytically under very mild conditions such as the electrolysis at 0 V (vs SCE) in CH2Cl2.

Four by four: The mononuclear ruthenium(II) complex [1]2+ is reversibly converted into the four-electron-reduced form [1-H4]2+ through electrochemical and photochemical redox reactions in aqueous solution. 2,6-bis(benzo[b]-1,5-naphthyridin-6-yl)-4-tert-butylpyridine ligand acts alteratively as a reservoir/source of four electrons or protons.