Reaction Of RuCl3 Research Articles

Insights into the effect of contact ion-pairs on C[sbnd]H bond activation for the synthesis of Ru(III)-NHC complexes: A combined experimental and computational study

The effect of contact ion pairs and comparison of the three halide ions on the electrophilic CH activation during the base-free synthesis of Ru(III)-NHC complexes [RuIII(PyNHCR)(Cl)3(H2O)] (1a; R = Me, and 1b; R = iPr) have been investigated. DFT modelling of two pathways for the formation of Ru(III)-NHC complexes, viz. halide coordination pathway and ion-pair pathway, reveals the effect of halide ions during electrophilic CH activation for the generation of carbene. The ion-pair path is preferred for azolium salts with Cl− and I−, whereas with Br−, the reaction follows the halide coordination route leading to the mixed halide complex. The synthetic route follows concerted-metalation-deprotonation (CMD) mechanism for ion pair pathway. The higher activation barrier for the reaction with Cl− ions can be explained in terms of greater stabilization of the intermediates, compared to the transition states, due to halide coordination or hydrogen bonding with Cl− ions. Furthermore, the successful synthesis of 1b from the reaction of RuCl3·3H2O and the corresponding imidazolium salt precursor with Cl− in dioxane at 100 °C validates the conclusions of the DFT studies.

Synthesis of Ruthenium Catalysts with a Chiral Arene Ligand Derived from Natural Camphor

AbstractA ruthenium complex with a chiral arene ligand [(camphor–arene)RuCl2]2 was synthesized by the reaction of RuCl3·nH2O with a chiral diene which was obtained from natural camphor in three steps. This complex catalyzed the asymmetric hydrogenation of acetophenone (64–85% ee), but decomposed in catalytic reactions involving C–H activation of 2-phenylpyridine or benzoic acid derivatives.

Ru(III)-pseudohalide complexes with alkynyl functionalized salicylaldimine ligand and heterocyclic coligand: Synthesis, characterization, electrochemical and luminescence properties

A new series of hexa-coordinated Ru(III) complexes of the type [Ru(L)(phen)X2] (1a-3a) and [Ru(L)(bipy)X2](1b-3b) [where, X = NCS, N3, CN] have been prepared by the reaction of RuCl3·H2O with 2-((E)-(4-(2-(4-methoxyphenyl)ethynyl)phenylimino)methyl)-4-(2-(4-methoxy phenyl)ethynyl)phenol (L) in presence of 1,10-phenanthroline (phen) or 2,2′-bipyridine (bipy) as a ligand. The molecular structure of ligand L was confirmed by single crystal X-ray diffraction. All complexes were characterized on the basis of elemental analysis, magnetic moment, TGA, IR, UV–Vis, EPR and mass spectral studies. The EPR spectral data and magnetic susceptibility measurement showed octahedral geometry around Ru(III). The electrochemical properties of all complexes indicate quasireversible redox behaviour corresponding to Ru(III)/Ru(IV) and Ru(III)/Ru(II) couple and are variable to π-acidic character of phen and bipy. All complexes exhibit strong emissions from lowest energy ILCT state with some LMCT character in DMF (10-4 M) at room temperature indicating that alkynyl functionality on salicylaldimine ligand enhances the emission property of the complexes and varies considerably with quenching ability of pseudohalides.

The formation of dinuclear trichloro-bridged and mononuclear ruthenium complexes from the reactions of dichlorotris(p-tolylphosphine)ruthenium(II) with diazabutadiene ligands

Ru(II) complexes with diazabutadiene (R-DAB) ligands have been prepared. The reaction of RuCl3·nH2O with P(p-tolyl)3 gave a [RuCl2{P(p-tolyl)3}] precursor, whose reactions with R-DAB in toluene gave dinuclear trichloro-bridged Ru(II) complexes [Ru2Cl3(P(p-tolyl)3)2(R-DAB)2](BF4) which have been characterized by spectroscopic methods. In addition, one of the complexes was characterized using X-ray crystallography. Meanwhile, two mononuclear Ru(II) complexes [RuCl2(P(p-tolyl)3)2(R-DAB)] were obtained from the reactions of the [RuCl2{P(p-tolyl)3}] precursor with R-DAB ligands in THF. The two trans-mononuclear complexes were characterized by X-ray crystallography and solid-state 31P NMR. A temperature-dependent 31P NMR study was carried out to monitor the formation of dinuclear and mononuclear complexes.

The reactions of RuCl3(NO)(PPh3)2 and RuCl3(NO)·H2O with Ph2P(CH2)nP(O)Ph2, n = 1, 2, or 3: Crystal structures of ruthenium nitrosyl complexes containing monodentate and chelating Ph2P(CH2)nP(O)Ph2 ligands

The reaction of RuCl3(NO)(PPh3)2 or RuCl3(NO)·H2O with Ph2P(CH2)nP(O)Ph2 (n = 1, 2, or 3) yields trans-RuCl3(NO)[Ph2P(CH2)nP(O)Ph2]2. Depending on conditions {RuCl2(NO)[Ph2PCH2P(O)Ph2]2}Cl, which contains one chelating and one monodentate ligand, can also be obtained. Reactions of RuCl3(NO)[Ph2PCH2P(O)Ph2]2 with AgBF4 form {RuCl2(NO)[Ph2PCH2P(O)Ph2]2}BF4, which contains the same cation as {RuCl2(NO)[Ph2PCH2P(O)Ph2]2}Cl, and RuCl(NO)[Ph2PCH2P(O)Ph2]2}(BF4)2, in which both ligands chelate. The reaction of RuCl3(NO)[Ph2P(CH2)2P(O)Ph2]2 with AgBF4 has led to {RuCl2(NO)[Ph2P(CH2)2P(O)Ph2]2}(BF4), where one ligand chelates and the second is monodentate, and to{RuCl2[Ph2P(CH2)2P(O)Ph2]2}(BF4)2, a Ru(III) complex that no longer contains an nitrosyl ligand. With the exception of trans-RuCl3(NO)[Ph2P(CH2)3P(O)Ph2]2 and {RuCl2(NO)[Ph2PCH2P(O)Ph2]2}(BF4) crystal structures of these compounds have be obtained.

Synthesis of Homoleptic and Heteroleptic Ruthenium Complexes Appended with Glucosyl Ligand by the Click-to-Chelate Approach

Homoleptic and heteroleptic complexes of Ru(TAGP-tapy)3Cl2 {TAGP-tapy is 2-[1-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)-1H-1,2,3-triazol-4-yl]-pyridine} bearing a clustered glucose-derived ligand and Ru(bpy)2(TAGP-tapy)Cl2 (bpy is 2,2'-bipyridine) have been synthesized by the chelating reaction of RuCl3·3H2O with TAGP-tapy and cis-Ru(bpy)2Cl2 with TAGP-tapy, respectively. The bidentate 1,2,3-triazolelinked glucose-derived ligand TAGP-tapy was prepared by copper-catalyzed coupling (click reaction) of 2-ethynylpyridine with acetyl protected glucosyl azide, 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl azide (TAGP-N3). TAGP-N3 was prepared by nucleophilic substitution reaction of 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide (TAGP-Br) with NaN3. These ruthenium complexes were purified by column chromatography or HPLC. Structures of the intermediates and ruthenium complexes were confirmed by HPLC, 1H and 13C NMR, FT-IR, and ESI-MS spectroscopies. UV-Vis and fluorescence spectroscopic methods were used to study optical properties of the ligand TAGP-tapy and ruthenium complexes. TAGP-tapy exhibited interesting solvent-polarity dependent fluorescence properties and a significant red-shift in emissions. Both complexes demonstrated distinctive fluorescence emission band in the visible region.

Synthesis and antiproliferatory activity of ruthenium complexes containing N-heterocyclic carboxylates

Solvates of the complexes Ru2Cl(pic)4(EtOH) (2), Ru(Im-CO2)3 (3), and Ru(Im-CO2)(Im-CO2H)Cl2 (4), were synthesized from reaction of RuCl3·3H2O or K3[RuCl6] with the N-heterocyclic carboxylic acids pyridine-2-carboxylic acid (picolinic acid, Hpic), and imidazole-4-carboxylic acid (Im-CO2H). Crystals of 2–4 could not be grown and hence characterization was done by elemental analysis, NMR, IR, and conductivity data; 2 and 4 were tested for antiproliferatory activity in vitro against a human breast cancer cell line, but were less active than, for example, Ru complexes containing bis-imidazole or 4,4′-biimidazole that we studied previously [see Can. J. Chem. 89 (2011) 948]. Preliminary work with a third potential ligand, 3-nitro-1,2,4-triazole-5-carboxylic acid (abbreviated HCANT), and other nitro heterocyclic compounds is also presented.

In vitro anticancer and antibacterial activities of octahedral ruthenium(III) complexes with hydroxamic acids. Synthesis and spectroscopic characterization

Five new ruthenium(III) complexes of the general formulas [RuCl(H2O)L2] (1–4) and [RuCl3(H2O)(HL)2] (5), where L = benzohydroximato (1), salicylhydroximato (2), acetohydroximato (3), hydroxyureato (4), LH = N-hydroxy-N-phenylbenzamide (5), were synthesized by reaction of RuCl3 · 3H2O with the corresponding hydroxamic acids at a molar ratio of 1: 2 molar. The complexes were characterized by elemental analyses and FT-IR, UV-Vis, 1H and 13C NMR, and mass spectra. The complexes showed higher antibacterial activity against ten pathogenic bacterial strains than the corresponding ligands. The anticancer activity of the complexes against IMR-32 (neuroblastoma) cancer and CHO (Chinese hamster ovary) normal cell lines was evaluated using MTT assay with respect to camptothecin as control. Complex 5 was found to exhibit an appreciable cytotoxicity against IMR-32 cell line with an IC50 value of 102.27 μM.

Synthesis, spectroscopic characterization, catalytic and antibacterial studies of ruthenium(III) Schiff base complexes

The bidentate Schiff base ligands (HLn) have been synthesized by condensation of 2-hydroxy-l-naphthaldehyde with aniline and its p-substituted derivatives in ethanol. Ruthenium(III) complexes of the type [Ru(Ln)2(H2O)2]Cl have been synthesized by the reaction of RuCl3·nH2O with the Schiff base ligands (in a molar ratio 1:2) in ethanol. The ligands and their Ru(III) complexes have been characterized by elemental analysis, magnetic susceptibility, spectroscopic (FTIR, UV–vis, 1H NMR and X-ray diffraction) and thermal analysis techniques. All the ruthenium(III) complexes are found to be stable, paramagnetic, low spin and octahedrally coordinated by the ligands through the nitrogen atom of the azomethine (–CN–) group and the oxygen atom of the deprotonated phenolic group. The molecular and electronic structures of the investigated ligands (HLn) were also studied using quantum chemical calculations. The complexes (1, 3 and 5) exhibited a catalytic activity for the oxidation of benzoin to benzil with moderate to high yield in the presence of sodium periodate as co-oxidant. The antibacterial activities of the ligands (HLn) and their Ru(III) complexes towards Gram positive and Gram negative bacteria have been investigated.

ChemInform Abstract: Cyclopentadienyl Ruthenium Complexes with Naphthalene and Other Polycyclic Aromatic Ligands

AbstractReview: synthesis, reactivity and applications; 137 refs.

Synthesis, Characterization, and Reactions of Ruthenium(II), -(III), and -(IV) Complexes with Sterically Demanding 1,2,4-Tri-tert-butylcyclopentadienyl Ligands

The reaction of RuCl3·3H2O with 1,3,5-C5(tBu)3H3 afforded a dimeric Ru(III) dichloride complex, [Cp‡RuCl(μ-Cl)]2 (1b; Cp‡ = η5-1,2,4-C5(tBu)3H2). The treatment of 1b with gaseous oxygen afforded the tetravalent ruthenium μ-oxo complex [Cp‡RuCl2]2(μ-O) (2b). The treatment of 2b with a primary or secondary alcohol regenerated 1b with concomitant dehydrogenative oxidation of the alcohol to afford the corresponding aldehyde or ketone, respectively. The treatment of 2b with refluxing 2-propanol or an excess of zinc powder in tetrahydrofuran efficiently afforded a novel dimeric Ru(II) monochloride with a butterfly structure, [Cp‡Ru(μ-Cl)]2 (4), with unsaturated ruthenium centers and high reactivity toward electron-donating reagents. The reaction of 1b with 4 afforded the mixed-valence Ru(III)/Ru(II) complex Cp‡Ru(μ-Cl)3RuCp‡ (7). The treatment of the appropriate precursor 1b or 2b with an excess of a hydride reagent such as LiEt3BH or LiAlH4 afforded the novel dinuclear ruthenium tetrahydride-bridged complex Cp‡Ru(μ-H)4RuCp‡ (9b). The treatment of a mixture of [Cp*Ru(μ3-Cl)]4 and 4 with LiEt3BH afforded the analogous dinuclear ruthenium tetrahydride-bridged complex bearing Cp* (Cp* = η5-C5Me5) and Cp‡ ligands, Cp*Ru(μ-H)4RuCp‡ (9c). The molecular structures of the newly synthesized complexes 1b, 2b, 4, 7, 8b, and 9b,c were determined by X-ray diffraction (XRD) studies. The reaction of 9b with ethylene exclusively afforded a μ-ethylidyne μ-ethylidene complex, Cp‡Ru(μ-CCH3)(μ-CHCH3)(μ-H)RuCp‡ (11), whereas the reaction of 9a with excess ethylene selectively afforded a dinuclear ruthenium diviny ethylene complex, Cp*Ru(μ-CHCH2)2(CH2CH2)RuCp* (10). The difference in the reactivities can be attributed to the difference in the spatial size of the reaction sites rather than their electronic properties such as electron density at the ruthenium centers. Irradiation of 11 with UV light (365 nm) effectively afforded a bis(μ-ethylidyne) complex, Cp‡Ru(μ-CCH3)2RuCp‡ (12). The structures of 11 and 12 were also determined by XRD studies.

Cis–trans Isomerism in mixed-ligand ruthenium(II) complexes containing bis(phosphine) and azoimine ligands

This study presents the syntheses and characterization of mixed-ligand azoimine-diphosphine ruthenium complexes of the general formula [RuCl2(Azo)(P–P)] (C1–C5) {Azo=C6H5NNC(COCH3)NC6H5; P–P=1,2-bis(dimethylphosphino)ethane (dmpe) (C1), cis-1,2-bis(diphenylphosphino)ethylene (depe) (C2), 1.1′-bis(diphenylphosphino)methane (dppm) (C3), 1,2-bis(diphenylphosphino)benzene (dbpe) (C4), 1,2-bis(di(pentaflurophenyl)phosphino)ethane (F-dppe) (C5)}. These complexes were synthesized via the reaction of RuCl3, azoimine and the diphosphine ligands in ethanol solutions. The X-ray structure of C2 reveals a cis-dichloro geometry, in spite of the bulky P–P ligand, and this is attributed to the presence of an intramolecular π–π interaction between benzene rings (on the Azo and P–P ligands) [centroid–centroid distances=3.596 and 3.654Å; dihedral angle between ring planes=13.2(3) and 15.4(4)° for the two independent molecules]. In contrast, the X-ray structure of C1, with a less bulky dmpe ligand in which no Ph rings are available for π–π bonding, revealed a trans-dichloro geometry. In addition to the X-ray structures of C1 and C2, this work presents and discusses the spectroscopic (IR, UV–Vis, 1H NMR and 31P NMR) and electrochemical (cyclic voltammetry) behavior of C1–C5.

Synthesis, characterization, crystal structure, and DNA-binding of ruthenium(II) complexes of heterocyclic nitrogen ligands resulting from a benzimidazole-based quinazoline derivative

The reaction of cis-[RuCl2(dmso)4] with [6-(2-pyridinyl)-5,6-dihydrobenzimidazo[1,2-c]quinazoline] (L) afforded in pure form a blue ruthenium(II) complex, [Ru(L1)2] (1), where the original L changed to [2-(1H-benzoimidazol-2-yl)-phenyl]-pyridin-2-ylmethylene-amine (HL1 ). Treatment of RuCl3 · 3H2O with L in dry tetrahydrofuran in inert atmosphere led to a green ruthenium(II) complex, trans-[RuCl2(L2)2] (2), where L was oxidized in situ to the neutral species 6-pyridin-yl-benzo[4,5]imidazo[1,2-c]quinazoline (L2 ). Complex 2 was also obtained from the reaction of RuCl3 · 3H2O with L2 in dry ethanol. Complexes 1 and 2 have been characterized by physico-chemical and spectroscopic tools, and 1 has been structurally characterized by single-crystal X-ray crystallography. The electrochemical behavior of the complexes shows the Ru(III)/Ru(II) couple at different potentials with quasi-reversible voltammograms. The interaction of these complexes with calf thymus DNA by using absorption and emission spectral studies allowed determination of the binding constant K b and the linear Stern–Volmer quenching constant K SV.

Ruthenium complexes of 4,4′-bi-1,2,3-thiadiazole and azoimine ligands: syntheses, crystallography, and electrochemical studies

Five ruthenium complexes of the general type trans-(Ru II (btd)(Azo)Cl2) ({Azo = PhN=NC(COMe) = NC6HY, where Y = H (a), Me (b), OMe (c), Cl (d) or Br (e)} and btd = 4,4 0 -bi-1,2,3-thiadiazole) have been pre- pared by the reaction of RuCl3 with the ligands in the presence of LiCl. These complexes have been character- ized by spectroscopic (IR, UV-Vis, and NMR) and electrochemical techniques. In addition, the complex trans- (Ru II (btd)(L5)Cl2) (complex 5) has been characterized by X-ray diffraction analysis. The electrochemical parameter for the p-excessive ligand (btd) is reported. The absorption spectrum of complex 5 in acetonitrile has been modeled by time-dependent density functional theory.

Aqueous-Phase Fischer-Tropsch Process with Nano-Ruthenium

Aqueous-phase Fischer-Tropsch synthesis was described with a PVP-supported ruthenium nanocluster catalyst. Thus, the reaction of RuCl3×nH2O (2.79 x 10-4 mol Ru) and PVP (1.12 x 10-2 mol) in water under 2.0 MPa H2 at 150 °C gave PVP-supported ruthenium nanoparticles with an average diameter of 2.0 0.2 nm. The Fischer-Tropsch hydrogenation of CO (1.0 MPa) with H2 (2.0 MPa) catalyzed by ruthenium nanoclusters (2.79 x 10-4 mol Ru) was performed in water at 150 °C, until the total pressure decreased to about 1.2 MPa, to give hydrocarbons where C5-C20 hydrocarbons made up the vast majority (80.9%).

Six-Coordinate Alkynyldiphenylphosphine Ruthenium(II) Complexes: Synthesis, Structure, and Catalytic Activity as ROMP Initiators

Six-coordinate [trans-RuCl2(PPh2C⋮CR)4] (R = Ph (1), (4-CH3)C6H4 (2), (4-OCH3)C6H4, (3), (4-CF3)C6H4 (4)) were obtained from the reaction of RuCl3·xH2O with the appropriate alkynylphosphine (PPh2C⋮CR) in ethanol. An X-ray crystal structure analysis of 1·4H2O reveals that the complex is obtained as the trans isomer, with the halides occupying apical positions and the phosphorus atoms lying in the equatorial plane. The alkynyl substituents of adjacent P ligands are alternatively pointing up and down and are maintained within the vertical plane by a set of weak hydrogen interactions [intra C−H···Cl and C−H···π(C⋮CPh)] connecting the ortho-H of the phenyl rings with the chloride and acetylenic moieties, respectively. Complexes 1 and 2 react cleanly with phenylacetylene via dissociative loss of one alkynyphosphine ligand to yield saturated 18 e- Ru(II) vinylidene complexes [mer,cis-RuCl2(CCHPh)(PPh2C⋮CR)3] (R = Ph (12), Tol (13)). The catalytic activity of 1−4 in ROMP reactions of norbornene and several functionalized norbornenes in the presence of trimethylsilyldiazomethane (TMSD) as the carbene source is also described.

Synthesis of Imidazolium-Tethered Ruthenium(II)-Arene Complexes and Their Application in Biphasic Catalysis

Reaction of RuCl3 with 1-[2-(1,4-cyclohexadiene-1-yl)alkyl]-3-methylimidazolium chloride (alkyl = Et, butyl) and 1-[2-(1,4-cyclohexadiene-1-yl)ethyl]-2,3-dimethylimidazolium chloride affords a series of dimeric ruthenium complexes of the type [RuCl2(η6-arene)]2Cl2. Treatment of these dimeric salts with phosphine ligands leads to the highly water-sol. monomeric complexes [RuCl2PR3(η6-arene)]Cl (PR3 = PPh3, PCy3). Reaction of [RuCl2(η6-1-(2-benzylethyl)-3-butylimidazolium)]Cl with Ag2O gives rise to a η6-arene-carbene chelate complex. The phosphine complexes have been tested as catalysts in the hydrogenation of styrene immobilized in water or an ionic liq. and in the aq. redn. of CO2/CO32-. A carbonate-hydride complex has been identified as intermediate by high-pressure NMR measurements. The solid-state structures of several of the new imidazolium-functionalized arene complexes including the arene-carbene chelate complex are reported.

A Convenient One-Pot Synthesis of a Functionalized-Arene Ruthenium Half-Sandwich Compound [RuCl2(η6-C6H5OCH2CH2OH)]2

Reaction of RuCl3·xH2O with 1-methoxy-1,4-cyclohexadiene in an alcohol solvent, ROH, gives [RuCl2(η6-C6H5OR)]2 (R = Me, Et, or HOCH2CH2) in up to 79% yield. The crystal structures of [Ru2(μ-Cl3)(η6-C6H5OEt)2]+[BPh4]- and [RuCl2(η6-C6H5OCH2CH2OH)]2 are also reported.

FOREWORD / AVANT-PROPOS

This issue of the Canadian Journal of Chemistry commemorates the 40th anniversary of a landmark Canadian discovery by A.D. Allen and C.V. Senoff at the University of Toronto in the mid-60s. In 1965, a paper appeared in Chemical Communications, entitled “Nitrogenopentaammineruthenium(II) Complexes” that detailed the serendipitous formation of the [Ru(NH3)5N2] 2+ complex cation, the first dinitrogen complex, from the reaction of RuCl3 with hydrazine hydrate. Instead of ending up as a curiosity and relegated to secondary literature reviews of esoteric inorganic complexes, this report sparked an intense effort in the coordination chemistry and reactivity of molecular nitrogen that continues to this day. Research into nitrogen fixation is a topic with great historical perspective and continues even today on three fronts. The first front stems from the early work by Haber on ammonia synthesis, and is concerned with efforts to further improve the efficiency of the heterogeneous reaction of N2 and H2 over activated metal surfaces to produce NH3. Another active front involves understanding the biological fixation of nitrogen by certain enzymes. The third front involves homogeneous activation and functionalization of molecular nitrogen by metal complexes, an area that overlaps with the previous two fronts from a modeling point of view, but also is concerned with expanding the known reactivity patterns of the simple N2 molecule. In this issue, an international slate of authors who are active in the area of dinitrogen chemical research were contacted to submit an article, either original or a minireview of their work. Authors from Japan, Germany, the United States, and Canada have submitted 13 articles that provide retrospective and updates of current research in this important area. It is interesting that four of the principal authors were not even born in 1965, a testament to the importance of this long-standing problem in chemistry. A number of the other authors clearly indicate how important this complex was to this area of research. In the following pages, the original article from 1965 is reproduced (by permission of The Royal Society of Chemistry). In addition, a brief historical perspective is given by G.J. Leigh on A.D. (Bert) Allen and this discovery. The goal of this commemorative issue is to provide a forum for recent work in dinitrogen coordination chemistry and celebrate an important Canadian milestone. I want to personally thank all of the contributors for their enthusiasm and support of this project.

Synthesis, Structure and Reactivity of Ruthenium(II) Carbonyl Complexes Containing Bis(pyrazol‐1‐yl)methane and Bis(N‐methylimidazol‐2‐yl)methane

AbstractA series of ruthenium(II) complexes with the pyrazolylalkane ligands bis(pyrazol‐1‐yl)methane (BPM) (I) and bis(3,5‐dimethylpyrazol‐1‐yl)methane (dmBPM) (II), and the imidazolylalkane ligand bis(N‐methylimidazol‐2‐yl)methane (BIM) (III) have been synthesised and characterised. The complexes [Ru(N‐N)(CO)2X2] [N‐N = BPM, X = Cl (1a), Br (1b); N‐N = dmBPM, X = Cl (2); N‐N = BIM, X = Cl (3)] were prepared from the stoichiometric reaction of [Ru(CO)2X2]n and the bidentate N‐donor ligand in refluxing methanol. The crystal structure of 2 showed the complex to have octahedral geometry about the ruthenium centre, with the carbonyl and chloride ligands being coordinated cis and trans, respectively. The complex [Ru(BPM)2(CO)(Cl)][BPh4] (4) was prepared from the reaction of RuCl3 and BPM in refluxing DMF, or from the decarbonylation of [Ru(BPM)(CO)2Cl2] (1a) in the presence of BPM and NaBPh4. The NMR spectra of 4 were fully assigned from 2D NMR experiments. The NOESY showed a cis coordination of the chloride and carbonyl ligands, and this was confirmed by single crystal X‐ray diffraction studies. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)