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A new neutral diruthenium(III) complex coordinated with benzamidinato (bam) ligands, [Ru 2 (bam) 4 Cl 2 ]·H 2 O ( 1 ), was synthesized and characterized, and its electronic structure was closely investigated via magnetic susceptibility, absorption spectrum, cyclic voltammetry, and density functional theory (DFT) calculations. Single crystal X-ray diffraction analysis revealed that complex 1 has a typical paddlewheel-type structure with a Ru Ru bond (bond length: 2.342(1) Å), in which the diruthenium (Ru 2 ) core is coordinated by four equatorially μ-bridging bam ligands and two axial Cl − ions. The magnetic study and DFT calculations proved that complex 1 has a triplet spin state ( S = 1) and a unique electronic structure (π 4 δ 2 π *2 σ 2 ). Absorption spectral feature and electrochemical property of complex 1 were also carefully investigated both experimentally and theoretically in this study. [ABSTRACT FROM AUTHOR]

• Isomericdiruthenium complexes with bis(ethynyl)pyridine as bridge core 1 – 3 were synthesized and characterized. • Compared with compounds 1 and 2 , compound 3 with linear conjugate structure has higher charge-beneficial capacity. • IVCT band parameters (H ab = 387 cm−1 and Г = 0.08) revealed that 3 + belongs to a weakly coupled class II system. Isomeric diruthenium complexes with bis(ethynyl)pyridine as bridge core [2,6-bis(ethynyl)pyridine (1), 3,5-bis(ethynyl)pyridine (2), 2,5-bis(ethynyl)pyridine (3)] were successfully prepared and characterized by 1H NMR, 13C NMR and elemental analysis. The electrochemical properties of complexes 1–3 were investigated by cyclic voltammetry (CV) and square-wave voltammetry (SWV), and different potential difference values were revealed and affected by N atom position and distance between redox metal centers. Electron absorption spectra showed that the absorption of the linear molecule 3 displayed a red shift relative to that of complexes 1 and 2. The broad near-infrared absorption characteristic of the singly-oxidized complex 3 + revealed the existence of a mixed-valence state, which can be classified as a class II mixed-valence system according to the intervalence charge transfer (IVCT) absorption parameter H ab and Г. These results indicated that 3 has higher conjugation and charge delocalization ability than isomers 1 and 2. Density functional theory (DFT) calculations spin density distribution analysis further confirmed the above results, and time-dependent DFT showed the NIR multi-absorption of complex 3+ , and effectively attributed to Ru–C C→Ru IVCT absorption characteristics. [Display omitted] [ABSTRACT FROM AUTHOR]

A new bridging agent, 4-amino-2-anilinopyridine (aap), was synthesized and used as an equatorial ligand in the preparation of a diruthenium complex (4,0) Ru2(aap)4Cl. Both the ligand and the diruthenium complex were characterized by thermal analysis, MALDI-TOF mass spectrometry, IR and NMR (1H and13C) spectroscopy, and X-ray crystallography. The structural analysis revealed that the complex existed as a (4,0) isomer, in which the amino group on the pyridyl moiety was not involved in chemical bonding. [ABSTRACT FROM AUTHOR]

Three new diruthenium(III) complexes, [Ru2O(2-sb)2(2,2′-bipy)2(H2O)2]·2.5H2O (1), [Ru2O(3-sb)2(2,2′-bipy)2(H2O)2]·9H2O (2), and [Ru2O (4-sb)2(2,2′-bipy)2(H2O)2]·9H2O (3), where sb2−is sulfobenzoate dianion and 2,2′-bipy is 2,2′-bipyridine, were synthesized using hydrothermal methods and characterized by IR, elemental analysis, thermogravimetric analysis, UV–vis, and fluorescence spectra. The single crystal X-ray analysis showed that each of these complexes has a dinuclear core stabilized by two bridging carboxylates and one bridging O2−. Variable sb2−ligands (2-sb, 3-sb, and 4-sb) in these complexes lead to diverse electronic spectroscopic behavior. The efficiency of activating methyl phenyl sulfide oxidation utilizing H2O2in 3 equiv. was studied at 23 ± 2 °C. The effect of the amount of catalyst and solvents on activities was investigated. Under optimized reaction conditions, the major product was sulfoxide. Complex1gave significant conversion of 100 and 98% selectivity for sulfoxide after 4 h. [ABSTRACT FROM AUTHOR]

Abstract: Reaction of [Ru(2,2′-bipyridine)(2,2′:6′,2″-terpyridine)Cl]PF6 (abbreviated to [Ru(bipy)(terpy)Cl]PF6) with 0.5equiv of the bidentate ligand L produces the dinuclear complexes [{Ru(bipy)(terpy)}2(μ-L)](PF6)4 (L=4,4′-bipyridine 1, 1,4-diisocyanobenzene 2 and pyrazine 3) in moderate yields. Treating [Ru(bipy)(terpy)Cl]PF6 with equal molar of 1,4-diisocyanobenzene affords [Ru(bipy)(terpy)(CNC6H4NC)](PF6)2 (2a). These new complexes have been characterized by mass, NMR, and UV–Vis spectroscopy, and the structures of 1–3 determined by an X-ray diffraction study. Cyclic voltammetric studies suggest that metal communication between the two ruthenium ions increases from 1 to 2 to 3. [ABSTRACT FROM AUTHOR]

Abstract: A DFT study was carried out to investigate the reaction mechanisms of a model μ-benzoquinone diruthenium complex {CpRu(μ-H)}2(μ-η2:η2-C6H4O2), derived from the experimental compound {Cp*Ru(μ-H)}2(μ-η2:η2-C6H3RO2) (R=H or R=Me, Cp*=η5-C5Me5), with acetylene both in aprotic and protic solvents. Results of calculations show that the influence of the solvent methanol on the reaction is mainly on the step of acetylene coordination. Enhanced hydrogen bonding is the reason for acceleration of the reaction in protic solvent, which is supported by NBO charge analysis. [Copyright &y& Elsevier]

We prepared a new Ru2(III, IV) complex containing a pyrophosphate as the dinucleating component, by the reaction between the mononuclear complex [Ru(Me3tacn)Cl3] and Na4P2O7 µ 10H2O in aqueous solution. Cyclic voltammetric measurement for the complex [{Ru(Me3tacn)}2(μ-O)(μ-P2O7)]PF6 (1) in aqueous solution revealed the formation of two species with higher oxidation states, such as [O=Ru(IV)Ru(IV)=O] and [O=Ru(IV)Ru(V)=O]+. Furthermore, this complex showed activity for water oxidation reaction with Ce(NH4)2(NO3)6 as the chemical oxidant in acidic aqueous solution. [ABSTRACT FROM AUTHOR]

Density functional theory and ab initio calculations are used to study the activation of dinitrogen by diruthenium cofacial diporphyrin complex [Ru2DPB(Im)2] (DPB= diporphyrinato-biphenylene tetraanion and Im= imidazole). The calculated equilibrium geometry of the formed complex [(μ-N2)Ru2DPB(Im)2] was found to involve the flaring out of the diporphyrin's rings with a nearly linear dinitrogen bridge. The subsequent detailed analysis of the molecular orbitals (MOs) of this complex allows one to conclude that the dinitrogen activation is realized due to both the donation from the dinitrogen occupied bonding δ-MO to unoccupied d-AOs of the Ru atoms and the two-orbital back donation from two occupied MOs of the complex [Ru2DPB(Im)2] to the two splitting components of the unoccupied antibonding π*-MO of N2. [ABSTRACT FROM AUTHOR]

Abstract: Dynamic properties of a diruthenium complex with ligand-unsupported Ru–Ru triple bonds, Na2[Ru2(3,6-DTBCat)4] (1), were studied using variable-temperature 1H NMR. Structural freedom derived from the ligand-unsupported structure leads to torsional motion about the Ru–Ru bonds in THF and in DMF. The observed solvent dependency corresponds to the electrostatic interactions between the diruthenium complex and Na+ counter cations, which are sensitive to the polarity of solvents. In addition, a new diruthenium complex, [{Na(THF)2(H2O)}{Na(THF)0.5(H2O)}{Ru2(3,6-DTBCat)2(H4Cat)2}] (2·2.5THF·2H2O), with a ligand-unsupported Ru–Ru bond surrounded by two different kinds of catecholate derivatives, has been synthesized and crystallographically characterized. The complex, which was characterized by single-crystal structural analysis, will provide an opportunity to investigate not only static molecular structures but also dynamic physicochemical properties in comparison with analogues containing four identical catecholate derivatives. [Copyright &y& Elsevier]

Abstract: Hydrothermal treatment of RuCl3, hedpH4 [hedp = 1-hydroxyethylidenediphosphonate, CH3C(OH)(PO3)2] and NaOH at 180 °C gives a mixed valence diruthenium(II,III) compound Na3Ru2(hedp)2⋅4H2O (1). In this compound, the paddlewheel diruthenium units of are cross-linked into a square-grid layer. The layers are further connected through {NaO6} octahedra, forming a three-dimensional framework structure. Crystal data: monoclinic, space group C2/c, , , , , , . Ferromagnetic interactions are mediated between the dimers within the layer. [Copyright &y& Elsevier]

Abstract: Film electrochemistry of Ru2(2-CH3ap)4Cl (1), where 2-CH3ap is 2-(2-methylanilino)pyridinate anion, and their carbon monoxide (CO) binding ability were electrochemically investigated in three different cationic matrices at a basal plane pyrolytic graphite (BPG) electrode immersed in 0.5 M aqueous KCl solution under CO atmosphere. The matrices employed in this study were tetra-n-octylphosphonium bromide (4C8P+Br−), tetra-n-octylammonium bromide (4C8N+Br−), or tetra-n-heptylammonium bromide (4C7N+Br−). The complex 1 at the lipids modified electrodes was able to bind CO molecules in the Ru2 4+, Ru2 3+ and Ru2 2+ reduced forms. Regulation of CO binding reaction of the complex 1 was also examined in a cast film of an artificial lipid, di-n-hexadecyldimethylammonium poly(styrene sulfonate), 2C16N+PSS−, which has a phase transition between the crystalline and the liquid crystalline phase at 26.6 °C. Here, the Ru2 5+/Ru2 4+ and Ru2 4+/Ru2 3+ reactions under CO atmosphere showed a strong phase transition temperature dependence, suggesting the possibility of a temperature-driven regulation for the electrochemistry of complex 1 upon CO binding. [Copyright &y& Elsevier]

Abstract: Shvo''s diruthenium complex is an active catalyst in a considerable number of homogeneous reactions. Its catalytic activity is mainly due to the fact that it dissociates into two monomeric ruthenium species in solution under thermal conditions. We review the applications under three major headings i.e., oxidation, reduction and dynamic kinetic resolution. [Copyright &y& Elsevier]