Chloro Ruthenium Research Articles

Ruthenium complexes bearing amino-bis(phosphinite) or amino-bis(aminophosphine) ligands: Application in catalytic ester hydrogenation

Mononuclear hydrido and dinuclear chloro ruthenium(II) complexes derived from readily available amino-bis(phosphinite) and amino(bisaminophosphine) tridentate ligands were applied in the catalytic hydrogenation of ester derivatives. Notably, the cationic ruthenium dimer 2c proved to be an efficient pre-catalyst when used in combination with KOtBu in THF at 120°C and 50bar H2 with aromatic and aliphatic esters.

A re-examination of the reaction of dichloro-tris-(triphenylphosphino)ruthenium(II) with benzonitrile: Crystal structures of triphenylphosphine chloro ruthenium complexes

The reaction of RuCl2(PPh3)3 with benzonitrile has been investigated in toluene. When excess benzonitrile is employed cis-RuCl2(PPh3)2(NCPh)2 is obtained and has been characterized by X-ray diffraction. This contrasts to acetonitrile which yields trans-RuCl2(PPh3)2(NCMe)2. With excess RuCl2(PPh3)3 a triply chloro bridged diruthenium compound (PPh3)2(Cl)Ru(μ-Cl)3Ru(NCPh)(PPh3)2 is obtained. A dark red crystalline side product, formed during the preparation of RuCl2(PPh3)3, is identified as [Ph3PMe][RuCl4(PPh3)2] by low temperature crystal structure determination with better precision than previously reported. In each case, the Ru atom presents octahedral coordination geometry.

Amperometric Folic Acid Quantification Using a Supramolecular Tetraruthenated Nickel Porphyrin µ‐Peroxo‐Bridged Matrix Modified Electrode Associated to Batch Injection Analysis

AbstractA supramolecular Nickel (II) porphyrin complex containing four pyridyl‐bis(2,2′‐bipyridyl)chloro ruthenium meso substituents was submitted to successive voltammetric cycles in high alkaline media to produce a supramolecular matrix with Nickel centers linked by µ‐peroxo bridges, producing a highly stable thin film able to act as redox mediator for electrocatalytic oxidation of folic acid. The characterization of electrode surface material was performed by Scanning Electron Microscopy and Electrochemical Impedance Spectroscopy. The modified electrode was inserted into a batch injection electrochemical cell used for the rapid and precise quantification of folic acid in pharmaceutical products. The favorable hydrodynamic conditions provided by amperometry‐BIA association allowed a very high throughput with good linear range (1 to 200 µmol L−1) and low detection limit (7.37×10−7 mol L−1). The electrochemical method was applied to the quantification of folic acid in different tablet samples. The results were comparable with values indicated by the manufacturer and those found using high HPLC according to the Brazilian Pharmacopoeia; commercial samples were submitted to a procedure in order to remove lactose of tablets, since carbohydrates act as interfering species. This procedure together with the electrochemical method showed to be simple, rapid, efficient and an appropriate alternative for quantifying this compound in real samples.

Synthesis, X‐ray Diffraction Study, and Cytotoxicity of a ­Cationic p‐Cymene Ruthenium Chloro Complex Containing a Chelating Semicarbazone Ligand

AbstractAn organometallic salt composed of a new cationic p‐cymene ruthenium chloro complex containing a chelating benzaldehyde semicarbazone ligand and of the known anionic p‐cymene ruthenium trichloro complex, [(η6‐p‐cymene)Ru(bzsc)Cl]+[(η6‐p‐cymene)RuCl3]– (1) (bzsc = benzaldehyde semicarbazone) was synthesized and further characterized by IR, 1H NMR, and UV/Vis spectroscopy HR‐ESI mass spectrometry, and elemental analysis. The single‐crystal structure of 1 was also determined. The in vitro anticancer activities of the complex was evaluated against three human cancer cell lines (SGC‐7901, BEL‐7404 and CNE‐1), and the IC50 values were 20.7, 71.1 and 42.6 μM, respectively.

Different coordination modes of dipyridyl ketimine ligands in cationic arene ruthenium complexes

Abstract 2,2′-Dipyridyl- N -arylimines L (L 1 = 2,4,6-trimethyl(di-2-pyridylmethylene)aniline, L 2 = 2,6-diisopropyl(di-2-pyridylmethylene)aniline) react with arene ruthenium dichloride dimer in methanol to give cationic arene ruthenium complexes of the general type [(arene)Ru(η 2 - N , N -L)Cl] + (arene = C 6 H 6 , p -MeC 6 H 4 Pr i ). Two coordination modes of the chelating ligands N , N -L are observed. In the major isomer, the ketimine nitrogen atom and one of the two pyridine nitrogen atoms are coordinated to ruthenium, while in the minor isomer the two pyridine nitrogen atoms coordinate to the metal center. In the case of L 1 , the minor isomer of the p -cymene ruthenium chloro complex could be isolated as the tetrafluoroborate salt and characterized by single crystal X-ray analysis. The molecular structure of the major isomer was determined by X-ray crystallography in the case of the tetraphenylborate salt of the benzene ruthenium chloro derivative. In both structures, the ruthenium atom shows the expected pseudo-tetrahedral coordination geometry.

Ruthenium Hydride Complexes of the Hindered Phosphine Ligand Tris(3-diisopropylphosphinopropyl)phosphine

The synthesis and characterization of the novel hindered tripodal phosphine ligand P(CH(2)CH(2)CH(2)P(i)Pr(2))(3) (P(3)P(3)(iPr)) (1) are reported, along with the synthesis and characterization of ruthenium chloro and hydrido complexes of 1. Complexes [RuCl(P(3)P(3)(i)Pr)][BPh(4)] (2[BPh(4)]), RuH(2)(P(3)P(3)(i)Pr) (3), and [Ru(H(2))(H)(P(3)P(3)(iPr))][BPh(4)] (4[BPh(4)]) were characterized by crystallography. Complex 2 is fluxional in solution, and low-temperature NMR spectroscopy of the complex correlates well with two dynamic processes, an exchange between stereoisomers and a faster turnstile-type exchange within one of the stereoisomers.

Synthesis of Monomeric Fe(II) and Ru(II) Complexes of Tetradentate Phosphines

rac-Bis[{(diphenylphosphino)ethyl}-phenylphosphino]methane (DPPEPM) reacts with iron(II) and ruthenium(II) halides to generate complexes with folded DPPEPM coordination. The paramagnetic, five-coordinate Fe(DPPEPM)Cl(2) (1) in CD(2)Cl(2) features a tridentate binding mode as established by (31)P{(1)H} NMR spectroscopy. Crystal structure analysis of the analogous bromo complex, Fe(DPPEPM)Br(2) (2) revealed a pseudo-octahedral, cis-α geometry at iron with DPPEPM coordinated in a tetradentate fashion. However, in CD(2)Cl(2) solution, the coordination of DPPEPM in 2 is similar to that of 1 in that one of the external phosphorus atoms is dissociated resulting in a mixture of three tridentate complexes. The chloro ruthenium complex cis-Ru(κ(4)-DPPEPM)Cl(2) (3) is obtained from rac-DPPEPM and either [RuCl(2)(COD)](2) [COD = 1,5-cyclooctadiene] or RuCl(2)(PPh(3))(4). The structure of 3 in both the solid state and in CD(2)Cl(2) solution features a folded κ(4)-DPPEPM. This binding mode was also observed in cis-[Fe(κ(4)-DPPEPM)(CH(3)CN)(2)](CF(3)SO(3))(2) (4). Addition of an excess of CO to a methanolic solution of 1 results in the replacement of one of the chloride ions by CO to yield cis-[Fe(κ(4)-DPPEPM)Cl(CO)](Cl) (5). The same reaction in CH(2)Cl(2) produces a mixture of 5 and [Fe(κ(3)-DPPEPM)Cl(2)(CO)] (6) in which one of the internal phosphines has been substituted by CO. Complexes 2, 3, 4, and 5 appear to be the first structurally characterized monometallic complexes of κ(4)-DPPEPM.

Synthesis and characterisation of a series of mononuclear ruthenium(II) carbonyl complexes of heterocycle-based asymmetric bidentate ligands

In this contribution, the synthesis and characterisation of a series of complexes of the type [Ru(L–L′)(CO) 2Cl 2] are reported, where L–L′ are the chelating ligands L1–L8, 2-(4H-[1,2,4]triazol-3′-yl)-pyridine (L1); 2-(4H-[1,2,4]triazol-3′-yl)-pyrazine; (L2); 2-(1-methyl-4H-[1,2,4]-triazol-3-yl)pyridine (L3); 2-(5-pyridin-2-yl-4H-[1,2,4]-triazole-3-yl)phenol (L4); 3-(5-methylphenyl)-pyridin-2-yl-1,2,4-triazole (L5); 3-(4-methylphenyl)-pyridin-2-yl-1,2,4-triazole (L6); 3-(4-methoxyphenyl)-pyridin-2-yl-1,2,4-triazole (L7); 3,6-bis[(4-methoxyphenyl)iminomethyl]pyridazine (L8). L1–L7 are triazole-based ligands, which provide two distinct bidentate coordinate modes (via N2 or N4 of the triazole) whereas L8 is pyridazine-based and contains two identical bidentate binding pockets. The products obtained are analysed using infrared and NMR spectroscopy. The X-ray and molecular structures of the complexes with the ligands L2, L6, L7 and L8 are reported. These structures are the first to be reported for triazole based ruthenium chloro and ruthenium pyridazine imine complexes. The data show that the triazole ring in L2, L6 and L7 is coordinated via the N2 atom, and that the pyridazine-based ligand L8 uses only one binding pocket hence accommodating only one ruthenium(II) centre. For all compounds the cis(CO) transCl conformation is obtained. The results obtained are compared with those obtained for other similar compounds.

Ruthenium(II) Complexes of Pentamethylated [60]Fullerene. Alkyl, Alkynyl, Chloro, Isocyanide, and Phosphine Complexes

A ruthenium chloro dicarbonyl complex bearing a pentamethylated [60]fullerene ligand, Ru(η5-C60Me5)Cl(CO)2 (1), was prepared by the reaction of [RuCl2(CO)3]2 with C60Me5K in THF. A variety of ligand exchange reactions involving the carbonyl and chloro ligands took place on the ruthenium metal attached directly to the exterior of the fullerene framework. Treatment of 1 with a phosphine ligand afforded phosphine complexes, Ru(η5-C60Me5)Cl(PEt3)(CO) (2) and Ru(η5-C60Me5)Cl(PPh3)(CO) (3). Isocyanide complexes, Ru(η5-C60Me5)Cl(tBuNC)(CO) (4), Ru(η5-C60Me5)Cl(MeNC)(CO) (5), and Ru(η5-C60Me5)Cl(XylNC)(CO) (6; Xyl = 2,6-dimethylphenyl), were also prepared by reaction with an appropriate isocyanide ligand, while the use of a large excess of the same isocyanides gave bis(isocyanide)complexes, Ru(η5-C60Me5)Cl(tBuNC)2 (7) and Ru(η5-C60Me5)Cl(XylNC)2 (8). Metathetic replacement of the halogen atom on the transition-metal fullerene complexes was achieved: methyl and (trimethylsilyl)methyl Grignard reagents reacted with 1 to give a methyl complex, Ru(η5-C60Me5)Me(CO)2 (9), and a (trimethylsilyl)methyl complex, Ru(η5-C60Me5)(CH2SiMe3)(CO)2 (10), respectively. Alkynylation reactions gave various alkynyl complexes, Ru(η5-C60Me5)(C⋮CPh)(CO)2 (12), Ru(η5-C60Me5)(C⋮CnBu)(CO)2 (13), Ru(η5-C60Me5)(C⋮CSiMe3)(CO)2 (14), and Ru(η5-C60Me5)(C⋮CH)(CO)2 (15). X-ray single-crystal structure analyses and electrochemical studies of a series of new ruthenium fullerene complexes were performed.

Control of intramolecular electron transfer by protonation: oligomers of ruthenium porphyrins bridged by 4,4'-azopyridine

The association of pentaammineruthenium(II) with the reducible ligand 4,4[prime]-azopyridine leads to a pH-induced redox reaction in which ruthenium is oxidized to the III state, while 4,4[prime]-azopyridine is reduced to hydrazopyridine. In this process, the conjugated ligand is transformed in a nonconjugated one, with loss of its intramolecular electron-transfer properties. In order to exploit this control of an intramolecular electron transfer by a protonation process, the authors have prepared shish kebab oligomers by first inserting a ruthenium chloro carbonyl complex in tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)porphyrin. The resulting Ru(CO)(porphyrin) complex is photochemically decarbonylated in the presence of bridging ligands (4,4[prime]-azopyridine or pyrazine). Oligomers are thus obtained, which can be oxidized by iodine, giving rise to intervalence transitions between ruthenium(II) and -(III) in the near-infrared. This provides a convenient way to monitor electron transfer along the oligomer chain. In the case of 4,4[prime]-azopyridine, the pH-induced redox reaction is again observed. Starting from a homovalent ruthenium(II) chain, this gives the possibility to switch on or off the intervalence transition by a protonation/deprotonation reaction. 17 refs., 8 figs. 2 tabs.

Allyldifluorophosphite-metal chemistry: Ru complexes of F2POC3H5 and the crystal structure of (Ph3P)2(F2POC3H5)Ru(CO)(Cl)H

Abstract With several chloro ruthenium phosphine complexes, allyldifluorophosphite, F2POC3H5, displaces triphenylphosphine to form new compounds in which it acts as a phosphorus donor ligand. The new complexes [PPh3]2[F2POC3H5]Ru[CO][Cl][H], I, and [(PPh3)2(F2POC3H5)2RuCl2]n II, hav characterized by chemical, spectroscopic, and, in the case of I, crystallographic means. This behaviour of F2POC3H5 contrasts to its reactions with several platinum and palladium chloro complexes where it undergoes Arbuzov-type rearrangements.

Studies on the metabolism of some chemical species of radioruthenium in the rat. I. Early fate of ingested ruthenium.

The whole body retention of three chemical species of 106Ru was studied in rats. Three ruthenium species were ruthenium chloro complex (Ru-chloro), nitrosyl ruthenium nitrato complex (RuNO-nitrato) and nitrosyl ruthenium nitro complex (RuNO-nitro). When the compounds were administered orally, RuNO-nitro complex showed the highest retention, while RuNO-nitrato and Ru-chloro complexes demonstrated a comparablly low retention. The cumulative urinary excretion for three days of RuNO-nitro complex was the highest. The excretion of RuNO-nitrato was slightly but significantly higher than that of Ru-chloro complex. When the compounds were injected intravenously, the whole body retention of Ru-chloro complex was the highest, followed by RuNO-nitrato and RuNO-nitro in this order. These results suggest (1) that RuNO-nitro complex was absorbed more readily through gastrointestinal wall to the body than RuNO-nitrato and Ru-chloro and (2) that RuNO-nitro and -nitrato complexes in the body were metabolized and excreted faster than Ru-chloro complex.