The first ruthenium carbonyl derivative of fullerene: (η2-C60)Ru(CO)4

Buckminsterfullerene, C₆₀, reacts with Ru(CO)₅ to give a 1:1 adduct (η²-C₆₀)Ru(CO)₄. The synthesis and spectroscopic (IR and ¹³C NMR) characterization of this compound are described.     

Ru3(CO)9(PPh3)3: a convenient starting material for the synthesis of binuclear ruthenium(I) complexes. Crystal structure of Ru2(μ-L2)(CO)4(PPh3)2 (H2L2 = 1,8-diaminonaphthalene)

The thermal reaction of Ru₃(CO)₉(PPh₃)₃ with precursors (HL) of binucleating anionic ligands affords the ruthenium(I) dimers Ru₂(μ-L)₂(CO)₄(PPh₃)₂ (3), t-butylmercaptane (4); H₂L₂ = 1,8-diaminonaphthalenene (5)]. The crystal structure of complex 5 shows that each nitrogen of the 1,8-diiminonaphthalene ligand bridges the two ruthenium atoms, leading to a vary distorted, octahedral arrangement of the ligands and a very short RuRu distance, 2.5788(3) Å.     

Thermodynamics of Formation of Ru(III) and Ru(IV)-μ-Peroxo Complexes

Abstract

Reaction of one half and one equivalents of H₂O₂ with K[Ru^III(pdta-H)Cl].2H₂O gives rise to the μ-peroxo complexes [Ru^III (pdta-H)]₂H₂O₂ and [Ru^IV(pdta-H)]₂O₂, respectively. Equilibrium constants for the formation of the various peroxo species were determined between pH 3-11, in the temperature range 283-313 K and with μ = 0.10 M in KC1. The existence of the various peroxo species was substantiated by potentiometry, spectrophotometry and electrochemical studies. Thermodynamic quantities associated with the formation of the (pdta)Ru^III and (pdta)Ru^IV-μ-peroxo species and their hydrolysis products are reported.     

Interaction of tris(2,2′-bipyrazine)ruthenium(2+) ion with radiolytically-generated radicals in aqueous solution. Reactivity of Ru(bpz)+3 toward electron relays

The one-electron reduction of Ru(bpz)²⁺₃ by (CH₃)₂ḢOH is rapid (k = 3.5 × 10⁹ M^-1 s^-1) and quantitative. The product of the reaction, which possesses a ligand-radical coordinated to a Ru(II) center, can be written generically as Ru(bpz)⁺₃, and represented as Ru(bpz)₂(^.bpz^-)⁺ in alkaline solution and its conjugate acid [Ru(bpz)₂(^.bpzH)²⁺; pK_a = 7.1] in acidic solution. The reaction of Ru(bpz)²⁺₃ with ^.OH (k = 5.5 × 10⁹ M^-1 s^-1) yields the OH-adduct to the ring system of the ligands; Ru(bpz)₂(^.bpzOH)²⁺ is unstable toward bimolecular decay (k ∼4× 10⁸ M^-1 s^-1). Reaction with H^. (k = 3 × 10⁹ M^-1 s^-1) results in hydrogenation at a ring-carbon; this product is unstable in the time frame of seconds. No reaction is observed between Ru(bpz)²⁺₃ and Cl^-.₂. Ru(bpz)₂(^.bpz^-)⁺ reduces Co(sep)³⁺ (k = 3.3 × 10⁵ M^-1 s^-1) at pH 10, but there is no reaction at pH 4. However, Ru(bpz)₂(^.bpzH)²⁺ establishes an electron-transfer equilibrium (K_eq = 7) with Cr(bpy)³⁺₃ at pH 3.     

Electrochemistry of microparticles of tris (2,2′-bipyridine) ruthenium(II) hexafluorophosphate

The electrochemical behaviour of tris(2,2′-bipyridine)ruthenium(II) hexafluorophosphate (Ru(II)) microparticles, immobilised on a graphite electrode and adjacent to an aqueous electrolyte solution, has been studied by cyclic voltammetry and an in situ spectroelectrochemical technique. The solid Ru(II) complex exhibits one reversible redox couple with a formal potential (E_f) of 1.1 V versus Ag¦AgCl. The continuous cyclic voltammetric experiments showed that the Ru(II) microparticles are stable during the electrochemical conversions. The in situ spectroelectrochemical study showed that the absorbance at 463 nm decreased due to the oxidation of Ru(II) to Ru(III). Upon reduction, the growth of absorbance at 463 nm was observed due to the formation of Ru(II) complex and this process was reversible.     

Synthesis of 2-picolyl functionalized η-cyclopentadienyl derivatives of rhodium(I) and iridium(I) and preliminary study of their reaction with ruthenium(II) for assembling hetero-bimetallic complexes

The 2-picolylcyclopentadienyl derivatives of rhodium(I) and iridium(I) of formula [M{η⁵-C₅H₄(2-CH₂C₅H₄N)}(η⁴-C₈H₁₂)] (3) (M = Rh) and (4) (M = Ir) are obtained in good yields by reacting 2-picolylcyclopentadienyllithium (7) with [RhCl(η⁴-C₈H₁₂)]₂ and [IrCl(η⁴-C₈H₁₂)]₂, respectively. The corresponding dicarbonyl derivatives, [M{η⁵-C₅H₄(2-CH₂C₅H₄N)}(CO)₂] (5) (M = Rh) and 6 (M = Ir), are obtained in good yields by reacting 2-picolylcyclopentadienylthallium(I) (8) with [RhCl(CO)₂]₂ and [IrCl(C₅H₅N)(CO)₂], respectively. 5 has already been reported in the literature. The new complexes were characterized by elemental analysis, mass spectrometry, ¹H NMR, FT-IR, and UV-Vis (210-330 nm) spectroscopy. The UV-Vis spectra indicate the existence of some electronic interaction between the 2-picolinic chromophore and the cyclopentadienyl-metal moiety. The study of the electrochemical behaviour of 3-6 by cyclic voltammetry (CV) allows the interpretation of the electrode processes and gives information about the location of the redox sites. Moreover, various synthetic strategies were tested in order to try to coordinate the complexes 3-6 to a ruthenium(II) centre, but most of them failed. Instead, the hetero-bimetallic complex bis(2,2′-bipyridine)[(η⁵-2-picolylcyclopentadienyl)(η⁴-cycloocta-1,5-diene)rhodium(I)]chlororuthenium(II)-(hexafluorophosphate) (13), was obtained, although in poor yields (10%), by reacting the nitrosyl complex [RuCl(bipy)₂(NO)][PF₆]₂14 (bipy = 2,2′-bipyridine) first with potassium azide and then with the rhodium(I) complex 3. The analogous complex bis(2,2′-bipyridine)(2-picoline)chlororuthenium(II)-(hexafluorophosphate) (15), that carries a ruthenium-bonded 2-picoline molecule instead of 3, has prepared in the same way. 13 and 15 were characterized by elemental analysis, mass spectrometry, and ¹H NMR.     

A dinuclear triple bonded RuRu compound: preparation and crystal structure of μ,μ′-1,2-phenylenediimine-(N,N′)-dicarbonylbis(triphenylphosphine)diruthenium(RuRu) (I)

Reaction of [Ru{1,2-C₆H₄(NH)₂}(PPh₃)₃] (1) with CO in toluene at room temperature afforsa as one of the products the dinuclear complex syn-[Ru₂{μ-1,2-C₆H₄(NH)₂}(CO)₂(PPh₃)₂] (2). The crystal structure of 2 reveals it to be an unsaturated bimetallic species, with two Ru(CO)(PPh₃) moieties bridged by an 8e⁻ donor η²-diimine ligand in a tetrahedral-like fashion and involving a triple RuRu bond.     

The reactivity of a ruthenium(III) ammine complex, [Ru(NH3)5Cl]Cl2, towards α-N-heterocyclic mono- and di-carboxylic acids. The synthesis and characterisation of biologically active mixed ligand ruthenium(III) complexes

Ruthenium(III) complexes containing one, two or three -N-heterocyclic mono- and di-carboxylic acid groups were prepared from the ammine complex, [Ru(NH₃)₅Cl]Cl₂ by judicious interplay of controlling factors such as the metal:ligand ratio, reflux time etc. All the complexes were characterised by elemental analyses, spectroscopic (u.v.-vis., i.r., e.p.r.) techniques, magnetic measurements (at room temperature) and conductance measurements in solution. The electrochemical behaviour of the soluble complexes was studied by cyclic voltammetry. Their biological activity, in terms of the growth inhibition of Escherichia coli 10536, has been examined.     

Solvatochromism and piezochromism of pentacyanoferrates(II) and of mixed valence iron(II)—iron(III) and ruthenium(II)—ruthenium(III) species

Pressure effects on the MLCT bands of the pyrazine- and 4-cyanopyridine-pentacyanoferrate(II) anions have been established. The relation of these piezochromic effects to the solvatochromism of each complex is put into the correlation between these parameters developed for other d⁶ ternary complexes. The conformance of piezochromic and solvatochromic efrects on MMCT bands for diiron and diruthenium mixed valence complexes to this correlation is examined.     

Carbonylation. 9. Alkoxycarbonylation of pent-3-ene nitrile with homogeneous Co−Ru catalysts: The respective roles of cobalt and ruthenium

Addition of ruthenium compounds (Ru(acac)₃, Ru₃(CO)₁₂) to cobalt catalysts for pent-3-ene nitrile alkoxycarbonylation increases both activity and selectivity in the production of cyanoesters by (i) reducing the amount of Co(II) and facilitating the generation of the active carbonylation species, HCo(CO)_n, and (ii) improving the isomerisation of pentene nitriles, providing significant amounts of pent-4-ene nitrile for the formation of the ω-ester.     

(Tetragermacyclobutadiene)ruthenium tricarbonyl [η4-(But 2MeSi)4Ge4]Ru(CO)3

Tetrakis(di-tert-butylmethylsilyl)tetragermacyclobutadiene]ruthenium tricarbonyl [η⁴-(Bu^t ₂MeSi)₄Ge₄]Ru(CO)₃ is synthesized. This analogue of well-known cyclobutadiene transition metal complexes bears a tetragermacyclobutadiene derivative as ligand. The structure and spectroscopic parameters of the complex are compared with those of its iron-containing analogue [η⁴-(Bu^t ₂MeSi)₄Ge₄]Fe(CO)₃. Based on experimental data and results of quantum chemical calculations, it is shown that the π-donating ability of ligands increases upon replacement of carbon atoms in the cyclobutadiene moiety by silicon or germanium atoms, tetrasilacyclobutadiene and tetragermacyclobutadiene being comparable in π-donating activity.     

A cyclometallated analogue of tris(2,2′-bipyridine)ruthenium(II)

A cyclometallated analogue of the well-known tris(2,2′-bipyridine)ruthenium(II) cation has been prepared from 2-phenylpyridine. The bis(2,2′-bipyridine)(2-phenylpyridine-C,N)ruthenium(II) cation is readily prepared from [Ru(bipy)₂Cl₂] and 2-phenylpyridine in the presence of silver(I); the spectroscopic and electrochemical properties of this species are compared with those of [Ru(bipy)₃]²⁺.     

Spectroscopy studies on DNA binding of two ruthenium complexes [Ru(MeIm)4(L)]2+ (L = iip and tip)

Two ruthenium(II) complexes [Ru(MeIm)₄(L)]²⁺ (L?=?2-(imidazo-4-group)-1H-imidazo-[4,5-f][1,10]phenanthroline, 2-(thiophene-2-group)-1H-imidazo[4,5-f][1,10]phenanthroline, MeIm?=?1-methylimidazole) have been synthesized according to literature and structurally characterized. The interaction of the complexes with calf thymus DNA has been explored using electronic absorption titration, competitive binding experiment, circular dichroism, thermal denaturation, and viscosity measurements. The results show that both complexes could bind DNA in a intercalation mode and the DNA-binding affinity of [Ru(MeIm)₄(tip)]²⁺ (K _b?=?(7.2?±?0.3)?×?10⁵?(mol?L^?1)^?1) is greater than that of [Ru(MeIm)₄(iip)]²⁺ (K _b?=?(6.1?±?0.2)?×?10⁵?(mol?L^?1)^?1).     

Complexes of tetracyanobiimidazole—V. Self-association of Ir(I) complex anions

The self-association of the planar anion [Ir(CO)₂Tcbiim]⁻ where H₂Tcbiim is 4,4′,5,5′-tetracyano-2,2′-biimidazole has been studied in acetontrile solution by analysis of the charge-transfer spectra. At low concentrations (∼ 10⁻⁵ M) monomer units prevail. At intermediate concentrations (∼ 10⁻³ M) dimerization is evident and a very strong (ε = 18 500 M⁻¹ cm⁻¹) new absorption appears at 475 nm. A novel procedure was used to obtain this value and to estimate the equilibrium constant for dimerization, 13.2 M⁻¹ at 24.4°C. From the temperature dependence of the spectra, ΔH is calculated to be −28 to −30 kJ M⁻¹. At higher concentrations (∼ 10⁻² M) spectral changes consistent with further oligomerization are observed.     

Inhibiting the growth of tumor cells by ruthenium(II) complexes [Ru(phen)2L] (L = o-TFMPIP and p-CPIP) through DNA-binding

[Ru(phen)₂o-TFPIP]²⁺ (1) and [Ru(phen)₂p-CPIP]²⁺ (2) have been synthesized and demonstrated to inhibit the growth of tumor cells. The inhibitory activities (IC₅₀) of 1 against the growth of C6, MDA-MB-231 and HepG2 cells were about 24.5, 36.7, and 36.1 μM, respectively. Studies show that both complexes bind to CT-DNA, explained by using density functional theory calculations. The LogP calculated for 1 and 2 are ?0.4859 and ?1.279, respectively. These complexes, especially 1, can be used as promising inhibitors in chemotherapy, and their DNA-binding behaviors play a key role.     

Synthesis, DNA-binding and photocleavage studies of ruthenium(Ⅱ) complexes [Ru(btz)_3]~(2+) and [Ru(btz)(dppz)_2]~(2+)

Two new ruthenium(Ⅱ) complexes, [Ru(btz)3](ClO4)2 (1) and [Ru(btz)(dppz)2](ClO4)2 (2) (btz = 4,4′-bithi-azole, dppz = dipyrido[3,2-a:2′,3′-c]phenazine), have been synthesized and characterized by elemental analysis, 1H NMR, ES-MS and X-ray crystallography. The DNA binding behaviors of two complexes have been studied by spectroscopic and viscosity measurements. The results suggest that complex 1 binds to CT-DNA via an electrostatic mode, while complex 2 via an intercalative mode. Under irradiation at 365 nm,...     

Contrasting halogenating action of halogenoalkanes and halogens towards diphosphazane-bridged derivatives of iron and ruthenium nonacarbonyl. Crystal structure of [Ru2Cl2(CO)4{μ-(MeO)2PN(Et)P(OMe)2}2]

Dissolution of [Fe₂(μ-CO)(CO)₄{μ-(RO)₂PN(Et)P(OR)₂}₂] (R = Me, Prⁱ or Ph) and [Ru₂(μ-CO)(CO)₄{μ-(RO)₂PN(Et)P(OR)₂}₂](R = Me or Prⁱ) in CCl₄ leads to the rapid formation of [Fe₂(μ-Cl)(CO)₄ {μ-(RO)₂PN(Et)P(OR)₂}₂]Cl and [Ru₂Cl₂(CO)₄ {μ-(RO)₂ PN(Et)P(OR)₂}₂], respectively, with the latter isomerising in dichloromethane or chloroform solution to [Ru₂(μ-Cl)(Cl(CO)₄{μ-(RO)₂PN(Et)P(OR)₂}₂]Cl, which in turn decarbonylates to [Ru₂(μ-Cl)Cl(CO)₃{μ-(RO)₂PN(Et)P(OR)₂}₂]; the structure of [Ru₂Cl₂(CO)₄{μ-(MeO)₂PN(Et)P(OMe)₂}₂] has been established X-ray crystallographically.     

The preparation and structure of the tetranuclear ruthenium cluster [Ru4(CO)10(μ2-Cl)2(μ3-OEt)2]

The tetranuclear ruthenium cluster [Ru₄(CO)₁₀Cl₂(OEt)₂] has been prepared in low yield by the reaction of [Ru₃(CO)₁₂] with [N(PPh₃)₂]Cl in refluxing EtOH, followed by oxidation with either [NO][BF₄] or Ag[ClO₄]. A single-crystal X-ray analysis of the complex shows that the four metal atoms adopt a planar geometry with one ruthenium bonded by two μ₂-Cl ligands and two μ₃-OEt ligands to a trinuclear fragment. This complex crystallises in the monoclinic space group I2/c, with a 14.458(3), b 22.073(6), c 15.302(4) Å, β 99.54(2)°, Z = 8; 3113 observed data with F > 3σ(F) were refined by blocked full-matrix least squares to R = 0.031, R_w = 0.034.     

Synthesis and Properties of Three Tris(1,10-phenanthroline) ruthenium (Ⅱ) Derivatives

MThekeymaterials,5-amino-l,10-phenanthrolineandetS-Ru(phew,CI,,werepreparedbythemethodsofreferences"'.Synthesisofla,foandicEquimolaramountsofcorrespondingto-bromo-alkyIacyIohIondewasaddeddropwisetoasuspensionof5-amino-l,10-phenanthrolineandsodiumdicarbonateindryacetonitrilewithstirringatroomtemperatureundernitrogenfor4-6hours.Thentheresultingsolidwasfilteredandwashedbyacetonitrile,5%sodiumbicarbonateaqueoussolutionandwaterinturn.Afterbeingdriedicvacuo,yellowmicrocrystalsla-cwereobtained.Sy…