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Corneal collagen crosslinking (CXL) is a commonly used minimally invasive surgical technique to prevent the progression of corneal ectasias, such as keratoconus. Unfortunately, riboflavin/UV-A light-based CXL procedures have not been successfully applied to all patients, and result in frequent complications, such as corneal haze and endothelial damage. We propose a new method for corneal crosslinking by using a Ruthenium (Ru) based water-soluble photoinitiator and visible light (430 nm). Tris(bipyridine)ruthenium(II) ([R u (bpy) 3 ]2+) and sodium persulfate (SPS) mixture covalently crosslinks free tyrosine, histidine, and lysine groups under visible light (400–450 nm), which prevents UV-A light-induced cytotoxicity in an efficient and time saving collagen crosslinking procedure. In this study, we investigated the effects of the Ru/visible blue light procedure on the viability and toxicity of human corneal epithelium, limbal, and stromal cells. Then bovine corneas crosslinked with ruthenium mixture and visible light were characterized, and their biomechanical properties were compared with the customized riboflavin/UV-A crosslinking approach in the clinics. Crosslinked corneas with a ruthenium-based CXL approach showed significantly higher young's modulus compared to riboflavin/UV-A light-based method applied to corneas. In addition, crosslinked corneas with both methods were characterized to evaluate the hydrodynamic behavior, optical transparency, and enzymatic resistance. In all biomechanical, biochemical, and optical tests used here, corneas that were crosslinked with ruthenium-based approach demonstrated better results than that of corneas crosslinked with riboflavin/ UV-A. This study is promising to be translated into a non-surgical therapy for all ectatic corneal pathologies as a result of mild conditions introduced here with visible light exposure and a nontoxic ruthenium-based photoinitiator to the cornea. Keratoconus, one of the most frequent corneal diseases, could be treated with riboflavin and ultraviolet light-based photo-crosslinking application to the cornea of the patients. Unfortunately, this method has irreversible side effects and cannot be applied to all keratoconus patients. In this study, we exploited the photoactivation behavior of an organoruthenium compound to achieve corneal crosslinking. Ruthenium-based organic complex under visible light demonstrated significantly better biocompatibility and superior biomechanical results than riboflavin and ultraviolet light application. This study promises to translate into a new fast, efficient non-surgical therapy option for all ectatic corneal pathologies. [Display omitted] [ABSTRACT FROM AUTHOR]

• Detail study of (η6-C 6 Me 6)Ru(Cl) 2 (P(OMe) 3) with AgOTf in different solvents. • A comparative study of counterions OTf− and BF 4 −in [(η6-C 6 Me 6)Ru(Cl)(P(OMe) 3) 2 ]X. • Formation of mono-, di- and trinuclear structures with (η6-C 6 Me 6)Ru(P(OMe) 3) moieties. • Complex sequence which undergoes coordinated trimethylphosphite ligands in solution. • A great preference to coordinate adventitious water and labile acetone adducts. An extensive study of the reactions of (η6-C 6 Me 6)Ru(Cl) 2 (P(OMe) 3) (1) with AgOTf in three different deuterated and non-deuterated solvents: chloroform, acetone and nitromethane is described. A series of compounds with the moiety (η6-C 6 Me 6)Ru(P(OMe) 3) is isolated and characterized, along with their crystalline structures. A simple associative step assisted by coordination of the silver cation to two molecules of 1 through the Cl-Ru-Cl bonds affords [{(η6-C 6 Me 6)Ru(Cl) 2 (P(OMe) 3)} 2 (μ-Ag)](OTf) (2), loss of AgCl from 2 gives 1 and (η6-C 6 Me 6)RuCl(OTf)(P(OMe) 3) (3), meanwhile 3 dimerizes to [(η6-C 6 Me 6)Ru(μ-Cl)(P(OMe) 3)] 2 (OTf) 2 (4) which in presence of P(OMe) 3 gives [(η6-C 6 Me 6)RuCl(P(OMe) 3) 2 ](OTf) (11OTf). A comparative study of the influence of the counterions OTf− and BF 4 − was carried out with the analogue [(η6-C 6 Me 6)RuCl(P(OMe) 3) 2 ](BF 4) (11BF4), as well as the corresponding demethylation of the coordinated trimethylphosphite ligands by the classical Michaelis-Arbuzov reactions. The resulting "quasi-chelate" (η6-C 6 Me 6)RuCl(P(O)(OMe) 2)(P(OH)(OMe) 2) (17) where a bridging proton in the phosphinito-phosphinous acid ligands is replaced by BF 2 affords (η6 - C 6 Me 6)RuCl({P(OMe) 2 (O)} 2 BF 2) (18) which contains the chelating structure [Me 2 POBF 2 OPMe 2 ]. The chemistry in solution at room temperature of 1 with AgOTf shows non-selective reactions, as can be determined by multinuclear NMR spectroscopy (1H, 13C{1H}, 31P, 19F). The mixture of products shows a great preference to coordinate water, even when it is in traces, as observed for the formation of [(η6-C 6 Me 6)RuCl(H 2 O)(P(OMe) 3)](OTf) (5), [(η6-C 6 Me 6)Ru(H 2 O)(OTf)(P(OMe) 3)]OTf (6) and [(η6-C 6 Me 6)Ru(H 2 O) 2 (P(OMe) 3)](OTf) 2 (7), being the latter 7 the "sink" product. Also, in presence of anhydrous AgOTf compound 1 can be transformed into the highly hygroscopic (η6-C 6 Me 6)Ru(OTf) 2 (P(OMe) 3) (8) which readily replaces triflate ligands by trace water. Structural characterization by single crystal X-ray diffraction of trinuclear compound 2 , dinuclear 4 and mononuclear 7, 11X (X = OTf, BF4), 18 and nitrile derivatives [(η6-C 6 Me 6)Ru(NCR) 2 (P(OMe) 3)](OTf) 2 (R = Et, 9 ; Me, 10) is discussed. The chemical transformations of AgOTf with (η6-C 6 Me 6)Ru(Cl) 2 (P(OMe) 3) lead to a variety of organoruthenium compounds in a non-selective path. The competition between products depends on the stoichiometry, solvent, and largely on the silver triflate salt, whose hygroscopic capacity favors the coordination of water in several compounds under study. [Display omitted] [ABSTRACT FROM AUTHOR]

In recent years, extensive research efforts have been focused on loading metal complexes onto macromolecular systems such as nanoparticles. We report a ligand with a catechol group based on a picolinamide which allows for coordination to organoruthenium moieties while the catechol group remains available for loading on nanoparticles as delivery vehicles towards tumors. All the compounds were characterized with standard analytical methods and the molecular structure of the ligand 1 , and its Ru complexes 1a and 1b were determined by X-ray diffraction analysis. The crystal structure of 1a and 1b showed pseudo-tetrahedral geometry of the Ru center with "piano-stool" conformation and 1 coordinated as an N,O -bidentate ligand, however, the latter depending on the reaction conditions employed. The Ru complexes 1a – 1c were effectively loaded on magnetite nanoparticles as characterized by inductively-coupled plasma mass spectrometry (ICP-MS), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). The functionalization of a picolinamide-derived ligand with a catechol group led to organoruthenium compounds that could be loaded on iron oxide nanoparticles. Nanoparticle modification was characterized by inductively-coupled plasma mass spectrometry, transmission electron microscopy and Fourier transform infrared spectroscopy. Image 1 • Design of organometallic compounds for nanoparticle functionalization. • Preparation of organometallic compounds and characterization. • Loading of the organometallic compounds to the nanoparticles. • Characterization of the nanoparticles by TEM, ICP-MS and FTIR. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • New olefin-tethered organoruthenium carbene complexes have been synthesized and epitomized. • X-ray studies confirmed an octahedral geometry of the new complexes. • The newly synthesized complexes catalyze the hydrogenation of esters efficiently. Abstract A series of Ru(II) complexes encompassing imidazolylidene olefin arm have been designed. The newly synthesized ligands and complexes were fully characterized by 1H, 13C NMR, and elemental analyses. Structural geometry for one of the envoy Ru(II) carbene complexes 3a was confirmed by single-crystal X-ray diffraction studies. The complexes acquired a distorted octahedral geometry. The highly active [Ru(II)-NHC] complex 3b , showed excellent catalytic performance for the hydrogenation of esters in 1,4-dioxane medium. The effects of solvent, base, wingtip substituents, time and catalyst loading were also investigated. The reported catalyst performed exceptionally well for a range of esters and furnishes very good yield of hydrogenated products. [ABSTRACT FROM AUTHOR]

In this study we report the synthesis, characterization and a thorough biological evaluation of twelve organoruthenium–8-hydroxyquinolinato ( Ru-hq ) complexes. The chosen hqH ligands bear various halogen atoms in different positions which enables to study effect of the substituents on physico-chemical and biological properties. The determined crystal structures of novel complexes expectedly show the cymene ring, a bidentately coordinated deprotonated hq and a halide ligand (chlorido or iodido) coordinated to the ruthenium central ion. In previous studies the anticancer potential of organoruthenium complex with 8-hydroxyquinoline ligand clioquinol was well established and we have decided to perform an extended biological evaluation (antibacterial and antitumor activity) of the whole series of halo-substituted analogs. Beside the cytotoxic potential of studied compounds also the effect of two selected complexes ( 9 and 10 ) on apoptosis induction in MG-63 and A549 cells was also studied via externalization of phosphatidylserine at the outer plasma membrane leaflet. Both selected complexes that gave best preliminary cytotoxicity results contain bromo substituted hq ligands. Apoptosis induction results are in agreement with the cell viability assays suggesting the higher and more selective anticancer activity of complex 10 in comparison to complex 9 on MG-63 cells. [ABSTRACT FROM AUTHOR]

A series of four new, cyclometallated ruthenium (II) complexes was synthesized from 3-acetyl-8-methoxy-2H-chromen-2-one functionalized 4( N )- substituted thiosemicarbazones and characterized through various spectral and analytical methods. The molecular structures of the complexes 1 , 2 and 4 were determined by single-crystal X-ray diffraction analysis, which confirmed that the complexes possess a distorted octahedral geometry with the ligands coordinating in a dibasic tridentate fashion via C, N and S atoms. DNA [Calf Thymus DNA (CT-DNA)] and protein [Bovine Serum Albumin (BSA) and Human Serum Albumin (HSA)] binding studies indicated an intercalative mode of binding with DNA and static quenching mechanism with proteins. The compounds cleaved plasmid DNA (pBR322) without application of any external agent and acted well as free radical scavengers. A good spectrum of antimicrobial activity was observed against four bacterial and five fungal pathogens. Two cancerous cell lines, MCF-7 (human breast cancer) and A549 (human lung carcinoma) were employed to test their in vitro cytotoxic activity using MTT assay. The complexes ( 1–4 ) showed better activity with lower IC 50 values over cisplatin . Further non toxic nature of the complexes have been examined with human normal keratinocyte cell line HaCaT. Further, the results of Lactate dehydrogenase release (LDH) and Nitric Oxide (NO) release supported the cytotoxic nature of the compounds. The results of all the biological studies carried out implied that the complex 3 bearing an ethyl substituent was observed to be the best. [ABSTRACT FROM AUTHOR]

Treatment of metalloligand [Ni(tsalphen)] (tsalphen =  N , N ′-bis(2-thiobenzylidene)-1,2-phenylenediaminato) with [( η 6 - p -cymene)RuCl( μ -Cl)] 2 or [CpRu(PPh 3 ) 2 Cl] afforded cationic “Ni( μ -S) 2 Ru” bimetallic complexes [( η 6 - p -cymene)Ru{Ni(tsalphen)}(MeCN)](OTf) 2 ( 1 ) and [CpRu{Ni(tsalphen)}(PPh 3 )] 2 (NiCl 4 )⋅4MeOH ( 2 ), respectively, which are characterized by single-crystal X-ray diffraction, and their catalytic activity for acetalation of benzaldehyde in the presence of H 2 was also investigated. [ABSTRACT FROM AUTHOR]

Ru(II) and Os(II) complexes of 2-pyridinecarbothioamide ligands were introduced as orally administrable anticancer agents (S.M. Meier, M. Hanif, Z. Adhireksan, V. Pichler, M. Novak, E. Jirkovsky, M.A. Jakupec, V.B. Arion, C.A. Davey, B.K. Keppler, C.G. Hartinger, Chem. Sci. , 2013 , 4 , 1837–1846 ). In order to identify structure-activity relationships, a series of N -phenyl substituted pyridine-2-carbothiamides (PCAs) were obtained by systematically varying the substituents at the phenyl ring. The PCAs were then converted to their corresponding Ru II ( η 6 - p -cymene) complexes and characterized spectroscopically and by X-ray diffraction as well as in terms of stability in water and HCl. The cytotoxic activity of the PCA ligands and their respective organoruthenium compounds was evaluated in a panel of cell lines (HCT116, H460, SiHa and SW480). The lipophilic PCAs 1 – 4 showed cytotoxicity in the low micromolar range and 6 was the most potent compound of the series with an IC 50 value of 1.1 μM against HCT116 colon cancer cells. These observations were correlated with calculated octanol/water partition coefficient (clog P ) data and quantitative estimated druglikeness. A similar trend as for the PCAs was found in their Ru complexes, where the complexes with more lipophilic ligands proved to be more cytotoxic in all tested cell lines. In general, the PCAs and their organoruthenium derivatives demonstrated excellent drug-likeness and cytotoxicity with IC 50 values in the low micromolar range, making them interesting candidates for further development as orally active anticancer agents. [ABSTRACT FROM AUTHOR]

The two complexes Ru ( II ) containing 2,6-bis(benzimidazol-2-yl)pyridine and 2-pyridine and 2-quinoline carboxylates were synthesized to fabricate organic photodiodes. The electrical properties of Au / Ru ( II ) complex ( I ) / n − Si / Al and Au / Ru ( II ) complex ( II ) / n − Si / Al diodes were investigated by current-voltage and capacitance-voltage measurements. The fabricated devices give a high rectification behavior with rectification ratio of 2.4 × 10 4 −2.1 × 10 3 at ± 4 V. The diodes exhibited a high photoconductivity based on trap levels within band gap. The series resistance and barrier height were calculated from ( C − V ) measurements and compared to other of ( I − V ) . The obtained results indicate that the prepared photodiodes can be used as photosensor for optoelectronic applications. [ABSTRACT FROM AUTHOR]

One pot synthesis of three structurally different ruthenium(II) carbonyl complexes [Ru(N,S-H-Nap-mtsc)(CO)Cl(PPh 3 ) 2 ]( 1a) , [Ru(N,N,S-H-Nap-mtsc)(CO)Cl(PPh 3 ) 2 ]( 1b) and [Ru(Nap-mtsc)(CO)(PPh 3 ) 2 ] ( 1c ) were prepared from a reaction of 2-hydroxy-1-naphthaldehyde-4( N )-methylthiosemicarbazone and [RuHCl(CO)(PPh 3 ) 3 ] in benzene. However, the same reaction in ethanol, methanol and DMF afforded only 1a and 1c . The new complexes were characterized by various spectro analytical techniques. The structure of the complexes 1a and 1c were solved by X-ray crystallography. In 1a the ligand behaved as bidentate monobasic by forming an unusual four member chelate ring. However, in 1c the ligand behaved as tridentate bibasic (ONS) donor by forming five and six member chelate rings. Attempts to crystallize 1b were unsuccessful due to the structural conversion of 1b to 1c . DFT studies were carried out to know more on the structural aspects of these new complexes. From the results, it is inferred that ONS chelate ( 1c ) has comparatively lesser energy than NS five ( 1b ) and four ( 1a ) member chelates. The structural conversion of 1b to 1c in polar solvents at room temperature prevents 1b to introduce for biological investigation. From the DNA binding studies, it is found that the complexes 1a and 1c bind through intercalative mode. In addition, they had a strong binding affinity with bovine serum albumin (BSA) through static quenching. The complexes 1a and 1c were subjected to in vitro cytotoxicity studies against human lung cancer cells (A549) and liver cancer cells (HepG2). The IC 50 values of the complexes 1a and 1c were found to be lower than cisplatin in A549 cell line. However, in HepG2 cell line; IC50 values were found in the following order 1c < cisplatin < 1a . Among the two metallates, 1c found to possess higher cytotoxicity and this may be due to the increase in electron delocalization within five and six member rings, which facilitates the reduction of electron density on ruthenium ion and subsequent increase in the cell permeability. [ABSTRACT FROM AUTHOR]

Three new ruthenium(II)–arene halido complexes of general formula [(η 6 - p -cymene)RuX(L)] ( C1 C3 ) were synthesised by reaction of [(η 6 - p -cymene)RuX 2 ] 2 (X − = Cl − , Br − , I − ) with 1 H -benzimidazole-2-carboxylic acid (HL) in ethanol. The complexes were characterised by elemental analysis, mass spectrometry, IR, 1 H and 13 C NMR spectroscopy. The 1 H -benzimidazole-2-carboxylate was found to act as a bidentate N,O–chelating ligand. Single-crystal X-ray diffraction analysis confirmed the “piano-stool” geometry of C3 . The cytotoxic activity of the ligand precursor and ruthenium complexes was tested in human cancer cell lines: cervical carcinoma (HeLa), breast carcinoma (MDA-MB-231), myelogenous leukemia (K562) as well as in one normal human fetal lung fibroblast cell line (MRC-5), by MTT assay. The results show that ruthenium(II)-arene complexes possess enhanced cytotoxicity when compared to that of HL. The latter was devoid of activity in the range of concentrations up to 300 μM. Complex C3 , carrying an iodido leaving ligand, exhibited moderate, but selective cytotoxicity toward HeLa, MDA-MB-231 and K562 cell lines, with IC 50 values: 73.7, 60.9 and 53.9 μM, respectively, being less toxic against MRC-5 cells (IC 50 = 175.9 μM). Complexes C1 and C2 showed moderate to low cytotoxicity in HeLa and K562 cells. [ABSTRACT FROM AUTHOR]

This article outlines the synthesis of an electrophilic organoruthenium carboxylic acid of the structure [(η 5 -Cp*)Ru(η 6 -C 6 H 5 CO 2 H)] + and explores the behavior of this molecule under a variety of nucleophilic substitution conditions using a range of oxygen and nitrogen based nucleophiles including alcohols, primary and secondary amines and aromatic sulfonamides. The resulting organoruthenium ester [(η 5 -Cp*)Ru(η 6 -C 6 H 5 COOR)] + and amide [(η 5 -Cp*)Ru(η 6 -C 6 H 5 CONHR)] + or [(η 5 -Cp*)Ru(η 6 -C 6 H 5 CONR)] + complexes are additionally reported. All prepared complexes have been fully characterized using Fourier-transform IR and NMR spectroscopy and electrospray mass spectrometry with single-crystal X-ray structural determinations reported for three complexes: 3[(η 5 -Cp*)Ru(η 6 -C 6 H 5 CO 2 H)]B(C 6 H 5 ) 4 .[(η 5 -Cp*)Ru(η 6 -C 6 H 5 CO 2 )].H 2 O, [(η 5 -Cp*)Ru(η 6 -C 6 H 5 CONHCH 2 Ph)]PF 6 and [(η 5 -Cp*)Ru(η 6 -C 6 H 5 CONHSO 2 C 6 H 4 COMe)]PF 6 . Complexes were also evaluated for in vitro cytotoxic activity against the MCF7 (hormone-dependant breast cancer), MDA-MD-231 (hormone-independent breast cancer), MM96L (human melanoma) tumourigenic cell lines and the normal NFF (neonatal foreskin fibroblasts) human cell line. [ABSTRACT FROM AUTHOR]

Herein we report investigation of the interactions between anticancer organoruthenium complexes, [(η 6 -arene)Ru(en)(Cl)]PF 6 (en = ethylenediamine, arene = p -cymene ( 1 ) or biphenyl ( 2 )), and the human copper chaperone protein Cox17 by mass spectrometry with cisplatin as a reference. The electrospray ionization mass spectrometry (ESI-MS) results indicate much weaker binding of the ruthenium complexes than that of cisplatin to apo-Cox17 2s-s , the functional state of Cox17. Up to tetra-platinated Cox17 adducts were identified while only mono-ruthenated and a little amount of di-ruthenated Cox17 adducts were detected even for the reactions with 10-fold excess of the Ru complexes. However, ESI-MS analysis coupled with liquid chromatography of tryptic digests of metalated proteins identified only three platination sites as Met4, Cys27 and His47 residues, possibly due to the lower abundance or facile dissociation of Pt bindings at other sites. Complexes 1 and 2 were found to bind to the same three residues with Met4 as the major site. Inductively coupled plasma mass spectrometry results revealed that ~ 7 mol Pt binding to 1 mol apo-Cox17 2s-s molecules, compared to only 0.17 ( 1 ) and 0.10 ( 2 ) mol Ru to 1 mol apo-Cox17 2s-s . This is in line with the circular dichroism results that much larger unfolding extent of α-helix of apo-Cox17 2s-s was observed upon cisplatin binding than that upon organoruthenium bindings. These results collectively indicate that Cox17 might not participate in the action of these anticancer organoruthenium complexes, and further verify the distinct anticancer mechanism of the organoruthenium(II) complexes from cisplatin. [ABSTRACT FROM AUTHOR]

Two previously isolated cytotoxic complexes [(η 6 - p -cymene)Ru(κ 2 -CF 3 C O CH C OC 5 H 3 O)L] n + (L = Cl ( 1 ); n = 0, pta ( 2 ) (pta = 1,3,5-triaza-7-phosphaadamantane); n = 1) were investigated for their selectivity and ability to interact with DNA G-quadruplex adopted by d[G 3 ATG 3 ACACAG 4 ACG 3 ] ( 3 ) whose topology exhibits diagonal, edge-type and double-chain reversal loops. Structural changes were followed using high-resolution NMR techniques in the presence of 1 and 2 . Results showed weak interaction between the organoruthenium complexes and G-quadruplex. Moreover, no significant changes in thermal stability were confirmed by a UV-melting assay for both 1 and 2 . These findings emphasize that anticancer activity of Ru(II) complexes may not be correlated with binding to nucleic acid like G-quadruplex. [ABSTRACT FROM AUTHOR]

The heterogeneous phase reaction of Ru( η 2 -RL)(PPh 3 ) 2 (CO)Cl, 1 with lithium acetylacetonate (Liacac) afforded the complexes of the type Ru( η 1 -RL)(PPh 3 ) 2 (CO)(acac), 2 in excellent yield where η 2 -RL is C 6 H 2 O-2-CHNHC 6 H 4 R( p )-3-Me-5 and η 1 -RL is C 6 H 2 OH-2-CHNC 6 H 4 R( p )-3-Me-5 and R is H, Me, Cl. The chelation of acac is attended with the cleavage of Ru–O and Ru–Cl bonds and iminium–phenolato → imine–phenol prototropic shift. A sterically controlled change in rotational conformation is involved in the 1 → 2 conversion. The conversion is irreversible and the type 2 species are thermodynamically more stable than the carboxylate, nitrite and nitrate complexes of 1 . The crystal structures of Ru( η 1 -MeL)(PPh 3 ) 2 (CO)(acac), 2 (Me) and Ru( η 1 -ClL)(PPh 3 ) 2 (CO)(acac), 2 (Cl) are reported. Spectral (UV–Vis, IR, 1 H NMR) and electrochemical data of the complexes are also reported. The electronic structure and the absorption spectra of the complexes are scrutinized by the density functional theory (DFT) and time-dependent density functional theory (TD-DFT) analyses. The complexes were also screened in vitro for their antiproliferative properties against the MCF-7 breast cancer cell lines by using the MTT assay. Flow cytometric analysis showed that the complexes arrested the cell cycle in the sub G0 phase. [ABSTRACT FROM AUTHOR]

The polyethyleneimine (PEI) wrapped multi-walled carbon nanotubes functionalized with a carboxylic acid group (CNTs–COOH) gold nanoparticle (AuNP)-modified gold (Au) electrode has been utilized as a platform to immobilize organoruthenium(II) complexes ( ORC ). The surface structure and composition of the sensor were characterized by scanning electron microscopy (SEM). Electrocatalytic reduction of iodate and nitrite on the surface of modified electrode was investigated with cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and hydrodynamic voltammetry methods. The cyclic voltammetric results indicated the ability of AuNPs / PEI / CNT – COOH / ORC modified Au electrode to catalyze the reduction of this compound. AuNPs / PEI / CNTs – COOH nanocomposite combined the advantages of PEI-well dispersed CNTs – COOH and in situ formed AuNPs. [ABSTRACT FROM AUTHOR]

Abstract: Two p-cymene ruthenium chlorido complexes containing isobutyl (C1) and isoamyl (C2) esters of (S,S)-ethylenediamine-N,N′-di-2-(3-cyclohexyl)propanoic acid as ligands were prepared from p-cymene ruthenium dichloride dimer and corresponding ester. All compounds have been characterized by elemental analysis, IR, ESI-MS, 1H and 13C NMR spectroscopy. Single crystal X-ray structure diffraction analysis of C1 shows the usual piano-stool geometry of complexes, with coordination of ester ligand via nitrogen donor atoms. Ligands exhibit moderate anticancer activity (IC50 > 50 μM), while the complexes were significantly more cytotoxic towards various cancer cell lines, including B16, A375, HCT116, A549 and MCF7 cells (IC50 min.–max. 2.9–8.0 μM). We stress that cisplatin resistant HCT116 cell line was highly sensitive to the treatment with C1 and C2 (IC50 values: 4.4 and 5.5 μM versus IC50 > 120 μM for cisplatin). In parallel, primary fibroblasts-MRC-5 were remarkably less affected by these compounds. [Copyright &y& Elsevier]

Abstract: Two new monofunctional ruthenium(II) arene complexes of the type [(η 6-arene)Ru(ethylenediamine)(X)] n+ where arene is substituted benzene (p-cymene), and X are halide (Br and Cl), [(η 6-p-cymene)Ru(en)Br]Br (1) and [(η 6-p-cymene)Ru(en)Cl]PF6 (2), have been investigated. The X-ray crystal structures of both organoruthenium(II) complexes are reported. Both two complexes have “piano stool” geometries with η 6 coordination of the arene ligand. RuO2 nanoparticles were simply synthesized by solid-state transformation of compounds 1 and 2 at 400°C under air atmosphere. The results show that the size and morphology of the RuO2 nanoparticles are dependent upon the starting organometallic ruthenium(II) complexes. [Copyright &y& Elsevier]

Abstract: The ruthenium(II)–cymene complexes [Ru(η6-cymene)(bha)Cl] with substituted halogenobenzohydroxamato (bha) ligands (substituents = 4-F, 4-Cl, 4-Br, 2,4-F2, 3,4-F2, 2,5-F2, 2,6-F2) have been synthesized and characterized by elemental analysis, IR, 1H NMR, 13C NMR, cyclic voltammetry and controlled-potential electrolysis, and density functional theory (DFT) studies. The compositions of their frontier molecular orbitals (MOs) were established by DFT calculations, and the oxidation and reduction potentials are shown to follow the orders of the estimated vertical ionization potential and electron affinity, respectively. The electrochemical E L Lever parameter is estimated for the first time for the various bha ligands, which can thus be ordered according to their electron-donor character. All complexes exhibit very strong protein tyrosine kinase (PTK) inhibitory activity, even much higher than that of genistein, the clinically used PTK inhibitory drug. The complex containing the 2,4-difluorobenzohydroxamato ligand is the most active one, and the dependences of the PTK activity of the complexes and of their redox potentials on the ring substituents are discussed. [Copyright &y& Elsevier]

Abstract: A series of p-cymene ruthenium dichloro complexes containing isonicotinic ester ligands, [(arene)RuCl2NC5H4-4-COO–C6H4–p-O-(CH2) n -CH3] (n = 1: 1, n = 3: 2, n = 5: 3, n = 7: 4, n = 9: 5, n = 11: 6, n = 13: 7, n = 15: 8), were prepared from p-cymene ruthenium dichloro dimer and the corresponding isonicotinic ester ligand. The single-crystal X-ray analysis of 1 shows the molecule to adopt the usual pseudo-tetrahedral piano-stool geometry, the isonicotinic ester ligand being coordinated through the nitrogen atom. The cytotoxicity of all complexes and of the free ligands was studied towards human ovarian cancer cells; high activities were observed only for n = 9 (presenting a chain with ten carbon atoms), both as far as the free ligands and the complexes are concerned. Based on this result, a new isonicotinic ester ligand with a C10 substituent containing a terminal alcohol function, NC5H4-4-COO–C6H4–p-O–(CH2)10–OH, was synthesized by a four-step method, and arene ruthenium complexes thereof, [(arene)RuCl2NC5H4-4-COO–C6H4–p-O–(CH2)10–OH] (arene = C6H6: 9a, arene = p-MeC6H4Pr i : 9b, arene = C6Me6: 9c) were prepared. The complexes 9a and 9b show indeed remarkable anticancer activities, the IC50 values for human ovarian cancer cells being in the submicromolar range. The highest cytotoxicity was observed for complex 9b, with IC50 values of 0.18 μM for A2780 and 3.04 μM for the cisplatin-resistant mutant A2780cisR. [Copyright &y& Elsevier]

Abstract: The compounds Ru4(CO)12(GePh3)2(μ-H)4, 1 and Ru4(CO)12(SnPh3)2(μ-H)4, 2 were obtained from the reactions of Ru4(CO)13(μ-H)2 with HGePh3 and HSnPh3, respectively. Both compounds contain a nearly planar butterfly structure for the four metal atoms with two GePh3/SnPh3 ligands and four bridging hydride ligands around the periphery of the cluster. When heated, 1 and 2 were converted into the complexes Ru4(CO)12(μ4-EPh)2, 3, E = Ge, and 4, E = Sn, by cleavage of two phenyl groups from each of the GePh3 ligands. Compounds 3 and 4 contain square planar arrangements of the four ruthenium atoms with quadruply bridging germylyne and stannylyne ligands on opposite sides of the square plane. The bonding and electronic transitions of 3 were analyzed by DFT computational analyses. [Copyright &y& Elsevier]

Abstract: The complex cis-[Ru(phpy)(phen)(CH3CN)2]+ (phpy=2-phenylpyridine, phen=1,10–phenanthroline) was investigated as a potential photodynamic therapy (PDT) agent. This complex presents desirable photochemical characteristics including a low energy absorption tail extending into the PDT window (600–850nm) and photoinduced exchange of the CH3CN ligands, generating a species analogous to the chemotherapy drug cisplatin. Furthermore, photochemical reactivity can be controlled through selective irradiation into the Ru-phen singlet metal-to-ligand charge transfer (1MLCT) band (λ irr =500nm) of [Ru(phpy)(phen)(CH3CN)2]+ in the presence of excess t-butylammonium chloride (TBACl) resulting in efficient photoinduced production of [Ru(phpy)(phen)(CH3CN)Cl] (Φ =0.25). This lower energy irradiation resulted in greater quantum yield of photosubstitution when compared to direct irradiation into the Ru-phpy 1MLCT peak (λ irr =450nm; Φ =0.08) in CH2Cl2. It was found that the lower quantum yield observed for irradiation into the Ru→phpy− 1MLCT band results from significant orbital mixing of the phpy− ligand with the t2g-type filled set in the metal, giving this state significant ligand-centered character. Lastly, this complex produced a decrease in the mobility of linearized ds-DNA when irradiated with λ irr ≥420nm, indicative of covalent binding by the transition metal complex similar to that observed for cisplatin. No change in mobility was found for the same samples kept in the dark indicating, unlike cisplatin, DNA binding of cis-[Ru(phpy)(phen)(CH3CN)2]+ only occurs with the activation of light. These observations support the use of cis-[Ru(phpy)(phen)(CH3CN)2]+ as a potential PDT agent by the photoinduced generation of a cisplatin analog. [Copyright &y& Elsevier]

Abstract: Reaction of RuH(Cl)(CO)(PPh3)3 with bidentate Schiffs base ligands, N-[(2-pyridyl)methyliden]-α/β-aminonaphthalene (L1 /L2 ) led to the formation of photoluminescence ruthenium carbonyl complexes formulated as [RuCl(CO)(PPh3)2(L1/L2)](PF6) (1a/1b) and [RuH(CO)(PPh3)2(L1/L2)](PF6) (2a/2b) [L1 =N-[(2-pyridyl)methyliden]-α-aminonaphthalene and L2 =N-[(2-pyridyl)methyliden]-β-aminonaphthalene]. The complexes have been characterized by analytical and spectroscopic (IR, UV–Vis and 1H NMR) techniques. The complexes exhibit a MLCT band in the visible region and are emissive in room temperature. The cyclic voltammetric study shows Ru(II)/Ru(III) quasi reversible one electron oxidation couple in the range 0.95–1.15V. The single crystal X-ray structure of 2a shows distorted octahedral geometry around ruthenium atom. DFT calculations are employed to study the structural and electronic features and to support the spectroscopic data. [Copyright &y& Elsevier]

Abstract: New ruthenium(II) carbonyl complexes bearing pyridine carboxamide and triphenylphosphine/triphenylarsine/pyridine have been prepared by direct reaction of ruthenium(II) precursors with some pyridine carboxamide ligands, N,N-bis(2-pyridinecarboxamide)-1,2-ethane (H2L1), N,N-bis(2-pyridinecarboxamide)-1,2-benzene (H2L2) and N,N-bis(2-pyridinecarboxamide)-trans-1,2-cyclohexane (H2L3). The organic ligands offering two Namide and two Npyridine donor sites to the metal centre. They have been characterized by elemental analyses, FT-IR, UV–Visible, NMR (1H, 13C and 31P) and ESI-MS techniques. Based on the above data, an octahedral structure has been assigned for all the complexes. The catalytic efficiency of the complexes in transfer hydrogenation of ketones in the presence of iPrOH/KOH and N-alkylation of amine in the presence of tBuOK was examined. Furthermore, the antioxidant activity of the ligands and its ruthenium(II) complexes were determined by DPPH radical, nitric oxide radical, hydroxyl radical and hydrogen peroxide scavenging methods, which indicates that the ruthenium(II) complexes exhibit more effective antioxidant activity than the ligands alone. [Copyright &y& Elsevier]

Abstract: The ionic multi-walled carbon nanotubes (IM-f-MWCNTs), which were covalently functionalized with imidazolium salt, have been utilized as support materials for the immobilization of Hoveyda-type Ru–carbene complex. The catalytic activity and recyclability of the ionic CNT-supported Ru–carbene complexes have been investigated for ring-closing metathesis of various dienes, and the recovered catalyst can be reused up to 10 times without any significant loss of catalytic activity. [Copyright &y& Elsevier]

Abstract: Heterometallic clusters containing a perpendicularly coordinated alkyne ligand, (Cp*Ru)2(Cp*Ir)(μ3–η2:η2(⊥)-PhCCR)(μ-H)2 (6a, R = Me; 6b, R = Ph), were prepared by the reaction of a trinuclear heterobimetallic tetrahydrido complex of ruthenium and iridium, (Cp*Ru)2(Cp*Ir)(μ-H)3(μ3-H) (2), with internal alkyne. X-ray diffraction studies clearly showed that the alkyne ligand was preferentially attached to the Ru–Ru bond in a perpendicular manner rather than to the Ru–Ir bond. Although no detectable changes were observed in a VT-NMR study on 6a, VT-NMR studies on 6b implied that the alkyne ligand underwent a switchback motion at the heterometallic site. The presence of the minor isomer 8b, in which the alkyne ligand was attached to the Ru–Ir bond, was also proposed by the density functional theory (DFT) calculations. The energy difference between 6b and 8b is estimated at 4.1 kcal mol−1. These results suggest that the coordination site of the alkyne ligand was determined thermodynamically. [Copyright &y& Elsevier]

Abstract: In this work, the preparation, characterization and investigation of catalytic activity ruthenium hydride catalyst, [RuHCl(CO)(PPh3)3], supported on MWCNT in the synthesis of β,γ-unsaturated ketones via carbon–carbon bond formation are reported. In the first reaction step, the MWCNTs were modified with 1,2-ethanedithiol, and in a second reaction step, the catalyst was attached to MWCNTs via this linker. The catalyst was characterized by diffuse reflectance UV–vis and FT-IR spectroscopic techniques, SEM, ICP and elemental analysis methods. The catalyst was reused several times without significant loss of its catalytic activity. [Copyright &y& Elsevier]

Abstract: The paper presents a combined experimental and computational study of a novel tricarbonyl rhenium(I) complex with benzothiazole ligand – [Re(CO)3(bt)2Cl]. The compound has been characterized by structural (single-crystal X-ray diffraction) and spectroscopic (IR, NMR, MS, UV–vis) methods. DFT and time-dependent DFT (TDDFT) calculations have been also carried out and the UV–vis spectrum of the complex has been discussed on this basis. [Copyright &y& Elsevier]

Abstract: The new complex cis-[Ru(phen)2(hesperidin)](PF6), complex 1, was synthesized and characterized by analytical (ESI-MS+, EA (C, H, N)) and spectroscopic (FTIR, UV–vis, 1H and 13C NMR) techniques and cyclic voltammetry. Complex 1 is chemically stable in the solid state and in organic solvents such as ethanol, methanol, acetone, and acetonitrile, as shown by spectrophotometric analysis. 1 is also photochemically and chemically stable (pH effects) and more hydrosoluble (518.83±0.91gmL−1) than free hesperidin (5.92gmL−1). In accordance with this, the lipophilicity value in aqueous-octanol solution for 1 was −1.28, indicating its high hydrophilic characteristic. Although complex 1 showed to be essentially noncytotoxic, IC50 >1.0mmolL−1 as evaluated in the human cervical cancer cells line HeLa, it exhibited a moderate capacity of inhibiting the catalytic activity of the acetylcholinaesterase enzyme, IC50 =63.6molL−1. The Lineweaver–Burk plot and the respective secondary replot indicated that the AChE inhibition was noncompetitive and reversible. These findings shows that complexation of the hesperidin improves physicochemical characteristics and increases the perspectives for development and medical applications of new bioactive-metal complexes. [Copyright &y& Elsevier]

The mononuclear arene-ruthenium(II) derivatives [RuCl2(η6-arene)(PTA-Me)] (arene=C6H6 (3a), p-cymene (3b), 1,3,5-C6H3Me3 (3c), C6Me6 (3d)), containing the ionic phosphine ligand 1-methyl-3,5-diaza-1-azonia-7-phosphaadamantane chloride (PTA-Me), have been synthesized and fully characterized. These complexes were evaluated as potential catalysts for the redox isomerization of allylic alcohols. Among them, best results in terms of activity were obtained with complex [RuCl2(η6-C6H6)(PTA-Me)] (3a) which, in combination with K2CO3 (2.5 equiv. per Ru), was able to selectively isomerize a number of allylic alcohols RCH(OH)CH ＝CH2 (R=H, aryl, alkyl or heteroaryl group) into the corresponding carbonyl compounds RC(＝O)CH2CH3 in refluxing THF (TOF values up to 800h−1). Complex [RuCl2(η6-C6H6)(PTA-Me)] (3a) was adsorbed onto the Montmorillonite K-10 clay, and the resulting solid proved also active in the isomerization of the model substrate 1-octen-3-ol. In addition, it could be easily separated from the reaction media by simple filtration and reused several times (up to 11 consecutive runs) with retention of its efficiency. [Copyright &y& Elsevier]

Abstract: DNA binding, cleavage and cytotoxicity characteristics of a novel Schiff base ligand 3-(benzothiazol-2-yliminomethyl)-naphthalen-2-ol and ruthenium(II) complexes have been investigated. The DNA interaction properties of the complexes have been investigated using absorption spectra, as well as gel electrophoresis studies. Intrinsic binding constant (K b) has been estimated under similar set of experimental conditions. Absorption spectral study indicate that the ligand and ruthenium(II) complexes has intrinsic binding constant in the range of 1.4–7.2×104 M−1. Ruthenium(II) complexes show more binding ability than the ligand. Further, in vitro cytotoxicity study of the ligand and the complexes exhibited antitumor activity against HeLa and HEp2 tumor cells. [Copyright &y& Elsevier]

Abstract: A series of p-cymene ruthenium(II) complexes with imidazol-2-yl phosphines as PN ligands was prepared. Depending on the number of imidazolyl substituents in the ligands Ph3−n P(im) n {1–3: n = 1–3, im = imidazol-2-yl (a), 1-methylimidazol-2-yl (b)} different coordination modes were observed: κP, κ2 N,N or κ3 N,N,N. The complexes were tested for their cytotoxicity in different cancer cell lines. Most of the compounds were found to be non-toxic; The compounds [(p-cymene)Ru(1a)Cl2] (4a) shows cytotoxicity towards A2780sens and Hct116 cells in the μM range but not in H4IIE cells. The cytotoxicity is decreased upon introduction of a methyl group as [(p-cymene)Ru(1b)Cl2] (4b) shows only modest toxicities in the cell lines investigated. The κP compound [(p-cymene)Ru(2a)Cl2] (5a) shows selective toxicity in H4IIE cells after 72 h whereas the κ2 N,N compound [(p-cymene)Ru(2a)Cl]OTf (5a′) showed no toxicity in the cell lines investigated which again. [Copyright &y& Elsevier]

Abstract: New air-stable, water-soluble Ru(II)–phosphane complexes were synthesized in high purity by the reaction of cis-[RuCl2(dmso)4] with 2 equivalents of 1,3,5-triaza-7-phosphaadamantane (pta) and its N-methyl and N-benzyl derivatives (pta-Me and pta-Bn, respectively). All new complexes were characterized by elementary analysis and spectroscopic methods (NMR, ESI-MS) and the molecular structures of cis-cis-trans-[RuCl2(dmso)2(pta)2], cis-cis-trans-[RuCl2(dmso)2(pta-H)2]Cl2 (obtained in acidic solutions) and that of cis-cis-trans-[RuCl2(dmso)2(pta-Me)2](CF3SO3)2 were determined by single crystal X-ray diffraction. Under mild conditions, cis-[RuCl2(dmso)4] actively catalyzed the transformation of allylic alcohols into the corresponding ketones with 100% selectivity while in the same reaction the new Ru(II)–pta complexes showed moderate activity and selectivity. [Copyright &y& Elsevier]

Abstract: New ruthenium(II) complexes containing η6-arene-η1-pyrazole ligands were synthesized and characterized by elemental analysis and spectroscopic methods. In addition, the molecular structure of dichloro-3,5-dimethyl-1-(pentamethylbenzyl)-pyrazole–ruthenium(II), [Ru]L3b , was determined by X-ray diffraction studies. These complexes were applied in the transfer hydrogenation of acetophenone by isopropanol in the presence of potassium hydroxide. The activities of the catalysts were monitored by NMR. [Copyright &y& Elsevier]

Abstract: The reaction of [Ru3(CO)12] with 1,4-benzoquinone, in a hydrogen atmosphere led to the formation of a product with the formula [(μ-H)Ru3(CO)10(μ2-O–C6H4OH)] which crystallizes with two molecules of free hydroquinone in the asymmetric unit with which it forms an arrangement of hydrogen bridges leading to a layered structure of trinuclear metallic and hydroquinone fragments. Electrochemical studies showed that electrode inhibition is obtained by cycling of the oxidation process of this compound. [Copyright &y& Elsevier]

Abstract: A series of oxo-centered triruthenium–acetate complexes with tetrathiafulvalene-fused ligands, [Ru3O(OAc)6(py)2(dtpy)](PF6) (2, py = pyridine, dtpy = 4′,5′-dimethyldithiotetrathiafulvenyl-4-pyridine), [Ru3O(OAc)5{μ-η1(C), η2(N,N)-L}(py)2](PF6) (L = dtpn, 3, L = btpn, 4; dtpn = 4′,5′-dimethyldithiotetrathiafulvenyl[4,5-f][1,10]phenanthroline, btpn = 4′,5′-bis(methyloxycarbonyl)dithiotetrathiafulvenyl[4,5-f][1,10]phenanthroline), have been prepared. These new compounds are characterized by UV–vis, IR, 1H NMR, ESI-MS spectroscopic methods and elemental analysis. Cyclic and differential-pulse voltammetry reveal that all the compounds show interesting stepwise redox processes in solution. [Copyright &y& Elsevier]

Abstract: Reactions of [RuHCl(CO)(PPh3)3] with NaBmR (BmR =bis(2-mercapto-1-arylimidazolyl)borates, R=4-chloro-phenyl; 4-methyl-phenyl; 4-nitro-phenyl) in refluxing THF afforded hydrido ruthenium complexes [RuH(CO)(PPh3)(κ 3-H,S,S′-BmR)] (1–3). Treatment of 1 in refluxing chloroform gave ruthenium chloride complex [RuCl(CO)(κ 3-H,S,S′-BmR)(PPh3)] (4). Interactions of 1 with Br2 or I2 in THF at room temperature led to isolation of ruthenium bromide complex [RuBr(CO)(κ 3-H,S,S′-BmR)(PPh3)] (5) and ruthenium iodide complex [RuI(CO)(κ 3-H,S,S′-BmR)(PPh3)] (6), respectively. Complexes 1–6 were characterized by microanalyses, IR, and (1H, 11B, 13C, 31P) NMR spectroscopies. The molecular structures of 1, 2, 5, and 6 have been determined by single-crystal X-ray diffraction. [Copyright &y& Elsevier]

Abstract: [Ru(CO)2Cl2(α/β-NaiR)] (1, 2) and [Ru(CO)2I2(α/β-NaiR)] (3, 4) are synthesized by the reaction of [Ru(CO)2Cl2] n or [Ru(CO)4I2] with α/β-NaiR (1-alkyl-2-(naphthyl-α/β-azo)imidazole (α-NaiR/β-NaiR, where, R = Me, CH2CH3 and CH2Ph)) and have been characterized by spectroscopic data. The geometry of the representative complexes [Ru(CO)2Cl2(β-NaiMe)] (2a) and [Ru(CO)2I2(β-NaiEt)] (4b) have been structurally confirmed by X-ray diffraction study. The redox property is examined by electrochemistry. Catalytic activity of these compounds is investigated to the oxidation of PhCH2OH to PhCHO, 2-butanol (C4H9OH) to 2-butanone, 1-phenylethanol (PhC2H4OH) to acetophenone, cyclopentanol (C5H9OH) to cyclopentanone and cyclohexanol to cyclohexanone by N-methylmorpholine-N-oxide (NMO), H2O2 or Bu t OOH in CH2Cl2 and NMO shows highest yield. The catalytic efficiency is again dependent on Ru–X (X = Cl or I) bond and higher yield is observed for [Ru(CO)2Cl2(α/β-NaiR)] (1, 2). Electronic structure, spectral and redox properties are explained based on DFT and TD-DFT calculations on the representative complexes. [Copyright &y& Elsevier]

Abstract: A series of heterobimetallic complexes have been prepared by π-coordination of the [CpRu]+ fragment to the aromatic ring of POCOP pincer complexes of nickel, palladium and platinum. Their molecular structures were unequivocally determined by single-crystal X-ray diffraction, exhibiting the ruthenium moiety and the POCOP aromatic ring forming sandwich like species. The analysis in the solid state and in solution clearly showed that the coordination occurs in an orthogonal fashion and, as a consequence, both faces of the pincer complexes become non equivalent, thus conferring diastereotopicity to the isopropyl substituents. The electrochemical behavior of the new bimetallic complexes was studied and compared with that of the monometallic POCOP pincer precursors. [Copyright &y& Elsevier]

Abstract: We have developed a series of hybrid P450 BM3 enzymes to perform the light-activated hydroxylation of lauric acid. These enzymes contain a Ru(II)-diimine photosensitizer covalently attached to single cysteine residues of mutant P450 BM3 heme domains. The library of hybrid enzymes includes four non-native single cysteine mutants (K97C, Q397C, Q109C and L407C). In addition, mutations around the heme active site, F87A and I401P, were inserted in the Q397C mutant. Two heteroleptic Ru(II) complexes, Ru(bpy)2phenA (1) and Ru(phen)2phenA (2) (bpy=bipyridine, phen=1,10-phenanthroline, and phenA=5-acetamido-1,10-phenanthroline), are used as photosensitizers. Upon visible light irradiation, the hybrid enzymes display various total turnover numbers in the hydroxylation of lauric acid, up to 140 for the L407C-1 mutant, a 16-fold increase compared to the F87A/Q397C-1 mutant. CO binding studies confirm the ability of the photogenerated Ru(I) compound to reduce the fraction of ferric high spin species present in the mutants upon substrate binding. [Copyright &y& Elsevier]

Abstract: A series of ruthenium(II) complexes bearing hydroxypicolinato ligands was synthesized and characterized. The reaction of [Ru(NNN)(pic-6OH)Cl] (1), where NNN is 2,6-bis(dimethylamino)methylpyridine and featuring the 6-hydroxypicolinate ligand (pic-6OH), with KOtBu in acetonitrile produced [Ru(NNN)(CH3CN)(2-pyridonato)] (4), in which pic-6OH was converted into its pyridonato tautomer form. The pyridonato-ligated complex 4 reacts with HCl to quantitatively regenerate 1, thus the interconversion between the pyridinol and pyridonato forms of hydroxypicolinate was successfully achieved using a Ru(II) complex supported by the NNN-pincer ligand. The complexes [Ru(NNN)(pic-3OH)Cl] (2) and [Ru(NNN)(pic)Cl] (3) were also prepared and characterized for comparison. [Copyright &y& Elsevier]

Abstract: The [RuCl3(PPh3)2(HPz)]·C6H6 and t,t,t-[RuCl2(PPh3)2(HPz)2]·2C6H6 complexes have been obtained in the reaction of [RuCl3(PPh3)3] with pyrazole, and characterized by IR, UV–Vis and NMR spectroscopies. The crystal and molecular structures of the complexes have been determined by X-ray crystallography. Based on the molecular geometries, electronic structures and UV–Vis spectra of the complexes have been calculated using the DFT and TD-DFT methods. A discussion on the stability of the two isomers of the [RuCl2(PPh3)2(HPz)2] complex, based on an analysis of overlap partial density-of-state diagrams, has been presented. The combined interactions between pyrazole, chloride and PPh3 ligands stabilize the cis, cis, trans form of the [RuCl2(HPz)2(PPh3)2] complex, as was unequivocally exhibited. [Copyright &y& Elsevier]

Abstract: The [{(η6-p-cymene)RuCl(μ-Cl)}2] reacts with N-{2-(phenylthio)ethyl}morpholine (L) and excess NH4PF6 in CH3OH at room temperature (24 h), resulting in [(η6-p-cymene)RuCl2(L)][PF6] (1) and [(η6-p-cymene)RuCl(NH3)2][PF6] (2) unexpectedly. The complex 1 is first example of a 17e− half-sandwich complex of η6-arene with Ru(III) formed due to unexpected oxidation of Ru(II) in the presence of excess NH4PF6. The 1 is authenticated by EPR and on the basis of DFT calculations. The single crystal structures authenticate both 1 and 2. The Ru—S bond length in 1 is 2.413(3) Å whereas in 2 Ru—N bond distances are 2.141(3) and 2.149(3) Å. Attempt to catalyze transfer hydrogenation of ketones with 2-propanol with 1 has given spherical and block shaped Ru–RuS2 (70:30 w/w%) nano-particles of average size 5–8 nm. [Copyright &y& Elsevier]

Abstract: The tetradentate N,N-bis(diphenylphosphanyl)amine ligand (Ph2P)2NCH2C6H4CH2N(PPh2)2 (1, xdppa) reacted with in situ prepared [Ru2(μ-H)(μ-PBu t 2)(PBu t 2H)2(CO)4] (2) in a molar ratio of 1:2 affording the novel twofold coordinatively unsaturated tetranuclear metal complex [Ru2(μ-H)(μ-PBu t 2)(CO)4(μ-xdppa)Ru2(μ-H)(μ-PBu t 2)(CO)4] (3). Compound 3 was protonated by tetrafluoroboric acid at each side of the unsaturated diruthenium frameworks affording the oxidative addition product [Ru2(μ-H)2(μ-PBu t 2)(CO)4(μ-xdppa)Ru2(μ-H)2(μ-PBu t 2)(CO)4](BF4)2 (4). All new compounds were characterized by spectroscopic means and the molecular structures of compounds 1 and 4 were determined by X-ray diffraction. [Copyright &y& Elsevier]

Abstract: A new thiocyanate-free cyclometallated 2-phenylpyridine Ru(II) complex, [Ru(dFppyCF3)(dcbpy)2]+PF6 − (dFppyCF3 = 2-(2,4-difluorophenyl)-5-trifluoromethyilpyridine; dcbpy = 2,2′-bipyridine-4,4′-dicarboxylic acid), containing an electronwithdrawing trifluoromethyl group on the pyridine ring of the cyclometallated ligand, was synthesized and used as photosensitizer in DSSC devices. Its optical and electrochemical properties and stability behaviour towards ligand exchange with the common solar cell additive 4-tert-butylpyridine was compared to that of benchmark DSSC dye N719 and of the reference complex [Ru(dFppy)(dcbpy)2]+PF6 −. Substitution of the pyridine ring by the CF3 group afforded enhanced optical properties and a larger overall power conversion efficiency of the corresponding DSSC (3.7%), with a significant improvement compared to the reference cyclometallated complex under the same fabrication conditions. [Copyright &y& Elsevier]

Abstract: The synthesis and the crystal structures of several wheel-and-axle metal–organic (waamo) complexes are studied. The design of such systems is basically constituted by the binding between two Ru(II)(p-cymene)Cl2 units (wheels) and an organic spacer (axle), bearing pyridinic and/or cyano functions. Particular attention is given to the solid-state organization of the waamo complexes and to their propensity to create acceptors sites for guest species The inverted piano-stool motif, a characteristic synthon of half-sandwich ruthenium units, is always observed here, generating well defined layers of host molecules. Both polycatenated and host–guest systems were generated in order to achieve a compact packing. [Copyright &y& Elsevier]

Abstract: Reaction of the water-soluble complex [CpRu(TPPMS)2Cl] (1) [TPPMS=sodium salt of m-monosulfonated triphenylphosphine, Ph2P(m-C6H4SO3Na)] with 1equiv of white phosphorus in the presence of TlPF6 or AgBF4 as chloride scavengers, yielded the stable hydrosoluble complexes [CpRu(TPPMS)2(η1-P4)]X (2) (X=PF6, BF4). Addition of water to DMF solutions of 2 causes hydrolysis ovf coordinated P4 giving as main products complexes [CpRu(TPPMS)2(PH3)]X (3) (X=PF6, BF4) together with hydrogen and phosphorous acid, H3PO3. The new complexes have been characterized by 1H and 31P NMR spectroscopy in solution. Kinetic data and activation parameters of the hydrolysis process are reported. [Copyright &y& Elsevier]

Abstract: The hydride carbonyl ruthenium(II) [RuH(CO)(bzimpy)(PPh3)2]Cl·CH3OH (1) and [RuH(CO)(bzimpy)(PPh3)2]·CH3OH (2) complexes were synthesized and characterized by IR, 1H, 31P NMR, UV–Vis spectroscopy and X-ray crystallography. In the complexes the 2,6-bis-(benzimidazol-2-yl)-pyridine functions as bidentate ligand exists as protonated in (1) and deprotonated form in (2). The experimental studies were complemented by quantum chemical calculations which were used to identify the nature of the interactions between the ligands and the central ion and the orbital compositions in the frontier electronic structures. Based on a molecular orbital scheme, the calculated results allowed the interpretation of the UV–Vis spectra obtained at an experimental level. [Copyright &y& Elsevier]

Abstract: The new tetraruthenium compound {[Ru(NH3)5]4(μ4-TCNQF4)}(PF6)8, TCNQF4 =2,3,5,6-tetrafluoro-7,7,8,8,-tetracyano-p-benzoquinodimethane, was studied by cyclic voltammetry, IR, UV–Vis–NIR and EPR spectroelectrochemistry. The better π acceptor qualities of TCNQF4 in comparison to TCNQ cause more accessible reduction to produce {[Ru(NH3)5]4(μ4-TCNQF4)}7+ with enhanced metal contribution to the singly occupied MO and low-energy shifted IR vibrational and NIR electronic absorptions. However, the two-electron oxidation to the (10+) ion is also facilitated. The reason is seen in a more metal-centered oxidation for the TCNQF4 complex while the previously studied TCNQ analogue is assumed to undergo a higher degree of oxidation at the bridging ligand. As a result, the title species has a redox potential range of only 0.52V, indicating a significantly diminished HOMO–LUMO gap. [Copyright &y& Elsevier]

Abstract: A series of mono-Ru II and di-nuclear complexes, [RuII–MI(COD)Cl and RuII–MI(CO)2Cl] (M=Ir, Rh), have been prepared by using a bridging ligand, 1,3-dibutyl-2,3-dihydro-1H-imidazo[4,5-f][1,10]phenanthroline-2-yl (IL). This bridging ligand consists of 1,10-phenanthroline and N-heterocyclic carbene (NHC) and has two coordinating sites which can bind two different metals. The complexes synthesized have been fully characterized by 1H NMR, 13C NMR, high resolution mass spectrometry (HRMS), elemental analysis, and X-ray crystallography in one case. These complexes exhibited typical π–π ∗ and metal-to-ligand charge transfer (MLCT) bands in the UV and visible regions, respectively. Compounds RuII–IrI(CO)2Cl and RuII–RhI(CO)2Cl have the stronger emission intensities and the longer luminescence lifetimes (τ) than those of RuII–IrI(COD)Cl and RuII–RhI(COD)Cl, respectively. Complex RuII–IrI(COD)Cl was applied to detect carbon monoxide. [Copyright &y& Elsevier]