Synthesis of chiral-at-metal half-sandwich ruthenium(II) complexes with the CpH(PNMent) tripod ligand

Treatment of the chiral tripod ligand (L_Ment,S_C)-CpH(PN_Ment) with (Ph₃P)₃RuCl₂ in ethanol afforded the two chiral-at-metal diastereomers (L_Ment,S_C,R_Ru)- and (L_Ment,S_C,S_Ru)-[Cp(PN_Ment)Ru(PPh₃)Cl] (70% de) in which the cyclopentadienyl group and the P atom of the ligand coordinated at the metal center. The (L_Ment,S_C,R_Ru)-diastereomer was isolated by crystallization from ethanol-pentane and its structure was established by X-ray crystallography. The (L_Ment,S_C,R_Ru)-diastereomer epimerized in CDCl₃ solution at 60 °C in a first-order reaction with a half-life of 5.66 h. In alcoholic solution epimerization occurred at room temperature. Substitution of the chloride ligand in (L_Ment,S_C,R_Ru)- and (L_Ment,S_C,S_Ru)-[Cp(PN_Ment)Ru(PPh₃)Cl] by nitriles NCR (R = Me, Ph, CH₂Ph) in the presence of NH₄PF₆ gave mixtures of the diastereomers (L_Ment,S_C,R_Ru)- and (L_Ment,S_C,S_Ru)-[Cp(PN_Ment)Ru(PPh₃)NCR]PF₆. Treatment of (L_Ment,S_C,R_Ru)- and (L_Ment,S_C,S_Ru)-[Cp(PN_Ment)Ru(PPh₃)Cl] with piperidine or morpholine in the presence of NH₄PF₆ led to the chiral-at-metal diastereomers (L_Ment,S_C,R_Ru)- and (L_Ment,S_C,S_Ru)-[Cp(PN_Ment)Ru(PPh₃)NH₃]PF₆ (6% de).     

Asymmetric transfer hydrogenation of ketones catalyzed by ruthenium(II) complexes bearing a chiral phosphinoferrocenyloxazoline ligand

The catalytic activity in asymmetric transfer hydrogenation of ketones using octahedral and half-sandwich (η⁵-indenyl and η⁶-arene) ruthenium(II) complexes containing the chiral ligand (4S)-2-[(S_p)-2-(diphenylphosphino)ferrocenyl]-4-(isopropyl)oxazoline (FcPN) has been explored. Catalytic studies with complex fac-[RuCl₂{η²(P,N)-FcPN}(PMe₃)₂] (1) show excellent TOF values (9600 h⁻¹). Experiments in the presence of free FcPN, which lead to an increase in conversion rates and ee values when the catalyst is complex [Ru(η⁵-C₉H₇){κ²(P,N)-FcPN}(PPh₃)][PF₆] (4) have been carried out. The characterization of the new complexes mer-trans-[RuCl₂{P(OMe)₃}₂{κ²(P,N)-FcPN}] and of the water-soluble complexes fac- and mer-trans-[RuCl₂(PTA)₂{κ²(P,N)-FcPN}] is also reported.     

Half-sandwich Ru(II), Ir(III) and Rh(III) complexes with bridging or chelating N-heterocyclic bis-carbene ligand: Synthesis and characterization

N-heterocyclic bis-carbene ligand (bis-NHC) which was derived from 1,1′-diisopropyl-3,3′-ethylenediimidazolium dibromide (L·2HBr) via silver carbene transfer method, reacted with [(η⁶-p-cymene)RuCl₂]₂ and [Cp^∗MCl₂]₂ (Cp^∗ = η⁵-C₅Me_5, M = Ir, Rh) respectively, afforded complexes [(η⁶-p-cymene)RuCl₂]₂(L) (1), [Cp^∗IrCl₂]₂(L) (2) and [Cp^∗RhCl(L)][Cp^∗RhCl₃] (3). When [Cp^∗IrCl₂]₂ was treated with 2 equiv AgOTf at first, and then reacted with bis-NHC ligand, [Cp^∗IrCl(L)]OTf (4) was obtained. The molecular structures of complexes 1-4 were determined by X-ray single crystal analysis, showing that 1 and 2 adopted bridging coordination mode, 3 and 4 adopted chelating coordination mode. All of these complexes were characterized by ¹H, ¹³C NMR spectroscopy and element analysis.     

Studies on the reactivity of cis-RuCl2 fragment in Ru(PPh3)2(TaiMe)Cl2 with N,N-chelators (TaiMe = 1-methyl-2-(p-tolylazo)imidazole). Spectral and electrochemical characterisation of the products

Dechlorination of Ru(PPh₃)₂(TaiMe)Cl₂ (TaiMe = p-Me-C₆H₄-N=N-C₃H₂NN(1)-Me (1), 1-methyl-2-(p-tolylazo)imidazole) has been carried out in acetone solution by Ag⁺ and reacted with N,N’-chelators to synthesise [Ru(PPh₃)₂ (TaiMe)(N,N’)]²⁺. The complexes have been isolated as their perchlorate salts. The N,N’ chelators are 1-alkyl-2-(phenylazo)imidazoles (PaiX, X = Me, Et, CH₂Ph); 2-(arylazo)pyridines, (Raap,p-R-C₆H₄-N=N-C₅H₄N; R = H, Me, Cl); 2-(arylazo)pyrimidines (Raapm,p-R-C₆H₄-N=N-C₃N₂H₂; R = H, Me, Cl); 2,2’-bipyridine (bpy) and 1,10-phenanthroline (o-phen). Unsymmetrical N,N’ chelators may give two isomers and this is indeed observed. The¹H NMR spectral data refer to the presence of two isomers in the mixture in different proportions. With consideration of coordination pairs in the order of PPh₃, PPh₃; N,N (N refers to N(immidazole)) and N’,N (N’ refers to N(azo)), the complexes have been characterised astrans-cis-cis andtrans-trans-trans configuration; the former predominates in the mixture. Electrochemical studies exhibit high potential Ru(III)/Ru(II) couple and quasireversible N=N reduction. Electronic spectra show high intensity (ε ∼ 10⁴) MLCT transition in the visible region (520 ±10) nm along with a shoulder (ε ∼ 10³) in the longer wavelength region.     

Synthesis and derivative chemistry of [Ru2(μ-PPh2) (μ-OH) 2(μ-p-cymene) 2]

The cationic diphenylphosphido-bridged compound [Ru₂(μ-PPh₂)(μ-OH)₂(η⁶-p-cymene)₂][PF₆) (2) has been prepared by reaction of the tri-μ-hydroxo complex [Ru₂(μ-OH)₃(η-p-cymene)₂][PF₆] (1) with diphenylphosphine. Complex 2 eliminates water on reaction with protic acids, incorporating the conjugate base of the added acid as a bridging ligand. Formic acid, acetic acid, phenol, and aniline react with 2 to give the monosubstituted compounds [Ru₂(μ-PPh₂)(μ-OH)(μ-L)(η⁶-p-cymene)₂]PF₆] (L = HCO₂, MeCO₂, OPh, or NHPH), whereas methanol, thiophenol, 1,2-benzenedithiol, hydrochloric acid and isopropanol afford the disubstituted derivatives [Ru₂(μ-PPh₂)(μ-L)₂(η⁶-p-cymene)₂]PF₆] (L = OMe, SPh, S₂C₆H₄, Cl, or H).     

Reactions of tetrakis(trifluoromethyl) diphosphine and bis(trifluoromethyl) phosphine with ruthenium carbonyl clusters; X-ray structure of tetraruthenium carbonyl cluster derivatives

Reaction of [Ru₃(CO)₁₂ with (CF₃)₂P---P(CF₃)₂ in p-xylene at 140°C yielded the compounds [Ru₄(CO)₁₃{μ-P(CF₃)₂}₂] (1), [Ru₄(CO)₁₄{μ-P(CF₃)₂}₂] (2) and [Ru₄(CO)₁₁{μ-P(CF₃)₂}₄] (3). Reaction with [(μ-H)₄Ru₄(CO)₁₂] under similar conditions yielded [(μ-H)₃Ru₄(CO)₁₂{μ-P(CF₃)₂}] (4). All four compounds have been characterised by X-ray crystallography. The fluxional behaviour of the hydrides in 4 has also been studied by variable-temperature NMR spectroscopy. Compounds 1, 2 and 4 were also obtained from the reactions of Ru₃(CO)₁₂ with (CF₃)₂PH in dichloromethane at 80°C.     

Transition metal chemistry of phosphorus based ligands. Ruthenium(II) chemistry of bis(phosphino)amines, X2PN(R)PX2 (R=H or Ph, X=Ph; R=Ph, X2=O2C6H4)

Reactions of CpRuCl(PPh₃)₂ with bis(phosphino)amines, X₂PN(R)PX₂ (1 R=H, X=Ph; 2 R=X=Ph; 3 R=Ph, X₂=O₂C₆H₄) give neutral or cationic mononuclear complexes depending on the reaction conditions. Reaction of 1 with CpRuCl(PPh₃)₂ gives one neutral complex, [CpRu(Cl)(η²-Ph₂PN(H)PPh₂)] (4) and two cationic complexes, [CpRu(η²-Ph₂PN(H)PPh₂)(η¹-Ph₂PN(H)PPh₂)]Cl (5) and [CpRu(PPh₃)(η²-Ph₂PN(H)PPh₂)]Cl (6), whereas the reaction of 2 with CpRuCl(PPh₃)₂ leads only to the isolation of cationic complex, [CpRu(PPh₃)(η²-Ph₂PN(Ph)PPh₂)]Cl (7). The catechol derivative 3, in a similar reaction, affords an interesting mononuclear complex [CpRu(PPh₃){η¹-(C₆H₄O₂)PN(Ph)P(O₂H₄C₆)}₂]Cl (8) containing two monodentate bis(phosphino)amine ligands. The structural elucidation of the complexes was carried out by elemental analyses, IR and NMR spectroscopic data.     

Ruthenium-catalyzed transfer hydrogenation of aromatic ketones with aminophosphine or bis(phosphino)amine ligands derived from isopropyl substituted anilines

A series of new highly active Ru(II) complexes with two new (N-diphenylphosphino)isopropylanilines, having an isopropyl substituent at carbon 2- (1) or 2,6- (2) and two new bis(diphenylphosphino)isopropylanilines, having an isopropyl substituent at carbon atom 2- (3) or 4- (4), were prepared starting from the dimeric complex [Ru(η⁶-p-cymene)(μ-Cl)Cl]₂. All the compounds have been fully characterized by microanalysis, IR, ³¹P{1H} NMR, ¹H NMR and ¹³C NMR spectroscopies. Following activation by NaOH, complexes 5–8 were tested in the transfer hydrogenation of acetophenone derivatives with iso-PrOH as the hydrogen source. Catalytic studies showed that the complexes are excellent catalytic precursors for the transfer hydrogenation of acetophenone derivatives.     

Mono and dinuclear arene ruthenium complexes containing 6,7-dimethyl-2,3-di(pyridine-2-yl)quinoxaline as chelating ligand: Synthesis and molecular structure

The mononuclear cations of the general formula [(η⁶-arene)RuCl(dpqMe₂)]⁺ (dpqMe₂ = 6,7-dimethyl-2,3-di(pyridine-2-yl)quinoxaline; arene = C₆H₆, 1; C₆H₅Me, 2; p-PrⁱC₆H₄Me, 3; C₆Me₆, 4) as well as the dinuclear dications [(η⁶-arene)₂Ru₂Cl₂(μ-dpqMe₂)]²⁺ (arene = C₆H₆, 5; C₆H₅Me, 6; p-PrⁱC₆H₄Me, 7; C₆Me₆, 8) have been synthesised from 6,7-dimethyl-2,3-di(pyridine-2-yl)quinoxaline (dpqMe₂) and the corresponding chloro complexes [(η⁶-C₆H₆)Ru(μ-Cl)Cl]₂, [(η⁶-C₆H₅Me)Ru(μ-Cl)Cl]₂, [(η⁶-p-PrⁱC₆H₄Me)Ru(μ-Cl)Cl]₂ and [(η⁶-C₆Me₆)Ru(μ-Cl)Cl]₂, respectively. The X-ray crystal structure analyses of [1][PF₆], [3][PF₆] and [6][PF₆]₂ reveal a typical piano-stool geometry around the metal centre; in the dinuclear complexes the two chloro ligands, with respect to each other, are found to be trans oriented.     

Molecular structure of (3,5-diallylisocyanuratomethyl)bis(chloromethyl)phosphine oxide. Synthesis of (3,5-diallylisocyanuratomethyl)phosphine sulfides

X-Ray study of the (3,5-diallylisocyanuratomethyl)bis(chloromethyl)phosphine oxide showed that the phosphorylmethyl group is bonded to the nitrogen atom of the cycle. Reaction of the tris(chloromethyl)phosphine sulfide with sodium diallylisocyanurate gave (3,5-diallylisocyanuratomethyl)bis(chloromethyl)phosphine sulfide, and treatment of the tris(3,5-diallylisocyanuratomethyl)phosphine oxide with phosphorus pentasulfide gave a tris(3,5-diallylisocyanuratomethyl)bis(chloromethyl)phosphine sulfide.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1446–1448, August, 1993.     

Anticancer activity of new organo-ruthenium, rhodium and iridium complexes containing the 2-(pyridine-2-yl)thiazole N,N-chelating ligand

The dinuclear dichloro complexes [(η⁶-arene)₂Ru₂(μ-Cl)₂Cl₂] and [(η⁵-C₅Me₅)₂M₂(μ-Cl)₂Cl₂] react with 2-(pyridine-2-yl)thiazole (pyTz) to afford the cationic complexes [(η⁶-arene)Ru(pyTz)Cl]⁺ (arene = C₆H₆1, p-ⁱPrC₆H₄Me 2 or C₆Me₆3) and [(η⁵-C₅Me₅)M(pyTz)Cl]⁺ (M = Rh 4 or Ir 5), isolated as the chloride salts. The reaction of 2 and 3 with SnCl₂ leads to the dinuclear heterometallic trichlorostannyl derivatives [(η⁶-p-ⁱPrC₆H₄Me)Ru(pyTz)(SnCl₃)]⁺ (6) and [(η⁶-C₆Me₆)Ru(pyTz)(SnCl₃)]⁺ (7), respectively, also isolated as the chloride salts. The molecular structures of 4, 5 and 7 have been established by single-crystal X-ray structure analyses of the corresponding hexafluorophosphate salts. The in vitro anticancer activities of the metal complexes on human ovarian cancer cell lines A2780 and A2780cisR (cisplatin-resistant), as well as their interactions with plasmid DNA and the model protein ubiquitin, have been investigated.     

Synthesis and reactivity of ruthenium tetrazolate complexes containing a tris(pyrazolyl)borato (Tp) ligand

Facile ligand substitutions are observed when the neutral ruthenium cyclopropenyl complex (PPh₃)[Ru]-CC(Ph)CHCN (1, [Ru] = Tp(PPh₃)Ru) is treated with MeCN and pyrazole yielding the nitrile substituted ruthenium cyclopropenyl complex (MeCN)[Ru]-CC(Ph)CHCN (4a) and the ruthenium metallacyclic pyrazole complex (C₃H₃NN)[Ru]-CC(Ph)CH₂CN (7a), respectively. The reactions of Me₃SiN₃ with 1, 4a and 7a are investigated. Treatment of 1 with Me₃SiN₃ affords in high yield the cationic N-coordinated nitrile complex {(PPh₃)[Ru]NCCH(Ph)CH₂CN}N₃ (3). Interestingly, the reaction of 4a with Me₃SiN₃ in CH₂Cl₂ in the presence of NH₄PF₆ results in an insertion of four nitrogen atoms into the Ru-C_α bond to form a diastereomeric mixture of the bright yellow zwitterionic tetrazolate complex (MeCN)[Ru]-N₄CCH(Ph)CH₂CN (6a) in a 3:2 ratio. The reaction of 7a with Me₃SiN₃ gives the zwitterionic tetrazolate complex (C₃H₃NNH)[Ru]-N₄CCH(Ph)CH₂CN (9a). The two cationic tetrazolate complexes {(C₃H₃NNH)[Ru]-N₄(R)CCH(Ph)CH₂CN}⁺ (12a, R = CH₃, 12b, R = C₆H₅CH₂) are prepared by electrophilic addition of organic halides to 9a. All of the complexes are identified by spectroscopic methods as well as elemental analysis. Pathways for the synthesis of these compounds are proposed.     

DNA interaction and cytotoxicity studies of ruthenium(III) complexes containing 3-(benzothiazol-2-yliminomethyl)-naphthalen-2-ol ligand

A new Schiff base, 3-(benzothiazol-2-yliminomethyl)-naphthalen-2-ol, has been synthesized and characterized by elemental analysis, Fourier transform infrared spectroscopy (FT-IR), UV–vis, nuclear magnetic resonance, and single-crystal X-ray diffraction. Ruthenium(III) complexes of the Schiff base were synthesized and characterized by analytical and spectroscopic (FT-IR, UV–vis, and electron paramagnetic resonance) data as well as magnetic susceptibility measurements. DNA-binding properties of the ligand and its ruthenium(III) complexes have been investigated by electronic absorption spectroscopy. The three ruthenium(III) complexes were tested for DNA cleavage. Further in vitro study of the cytotoxity of the ligand and the complexes on human cervical cancer cell line and human laryngeal epithelial carcinoma cell line were carried out.     

Reactions of Bis(Trifluoromethyl)Phosphine and Tetrakis(Trifluoromethyl)Phosphine with Ruthenium Carbonyl Clusters

Abstract

The reaction of (CF₃)₂P-P(CF₃)₂ with [Ru₃(CO)₁₂] yielded compounds : [Ru₁₄(CO)₁₃{μ-P(CF₃)₂)₂] (1), [Ru₄(CO)₁₄{μ-P(CF₃)₂}₂] (2), and [Ru₄(CO)₁₁{μ-P(CF₃)₂}₄] (3); reaction with [μ-H)₄Ru₄(CO)₁₂] yielded (1) and [(μ-H)₃Ru₄(CO)₁₂{μ-P(CF₃)₂}] (4). The reaction of (CF₃)₂PH with [Ru₃(CO)₁₂] yielded compounds (1) and (4) and compounds (1) and (2) using cluster : ligand ratios of 1:1 and 1:2 respectively. All the compounds have been characterised by X-ray crystallography; a schematic diagram of their structures is shown in Figure 1. The fluxional behaviour of the hydrides in (4) was studied using variable temperature ¹H NMR spectroscopy (see Figure 2). The result of this study was used in the assignment of hydride positions of (4) in the solid state.     

The substitution chemistry of RuCp* (temeda)Cl

Summary Halide abstraction from RuCp*(tmeda)Cl (1,tmeda=Me₂NCH₂CH₂NMe₂) with NaBPh₄ in CH₂Cl₂ leads to the formation of the sandwich complex RuCp*(⁶-C₆H₅BPh₃) (2). In the presence of CH₃CN (1 equiv.) and CO, however, the cationic complexes [RuCp*(tmeda)(CH₃CN)]⁺ (3) and [RuCp*(temeda)(CO)]⁺ (5) are obtained. In CH₃CN,tmeda is also replaced giving [RuCp*(CH₃CN)₃]⁺ (4). Complex1 reacts readily with terminal acetylenes HCCR, the products depending on the nature ofR (Ph, SiMe₃,n-Bu, COOEt). Thus, withR=Ph the ruthenacyclopentatriene complex RuCp*(,-C₄Ph₂H₂)Cl (6), withR=SiMe₃ the cyclobutadiene complex Ru(Cp*)(⁴-C₄H₂(1,2-SiMe₃)₂)Cl (7), and withR=n-Bu and COOEt the binuclear complexes (Cp*)RuCl₂(²:⁴-₂-C₄H₂(1,3-R)₂)Ru(Cp*) (8,9) are obtained. Furthermore, with diethyl maleate in the presence of 1 equiv. of LiCl,1 transforms into the new anionic complex Li[Ru(Cp*) (²-C₂H₂(COOEt)₂)Cl₂] (10). X-ray structures of2,3,4,7, and10 are included.

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Substitutionsreaktionen von RuCp*(tmeda)Cl

Zusammenfassung Chloridabspaltung von RuCp*(tmeda)Cl (1,tmeda=Me₂NCH₂CH₂NMe₂) mittels NaBPh₄ in CH₂Cl₂ führt zur Bildung des Halbsandwich-Komplexes RuCp*(⁶-C₆H₅BPh₃) (2), während in Gegenwart von CH₃CN oder CO die beiden kationischen Verbindungen [RuCp*(tmeda)(CH₃CN)]⁺ (3) und [RuCp*(tmeda)(CO)]⁺ (5) entstehen. In CH₃CN als Lösungsmittel wird sogartmeda unter Bildung von [RuCp*(CH₃CN)₃]⁺ (4) verdrängt. Komplex1 reagiert sehr leicht mit terminalen Alkinen HCCR, wobei die Produkte stark von der Natur des SubstituentenR (Ph, SiMe₃,n-Bu, COOEt) abhängen. Im Fall vonR=Ph entsteht der Ruthenacyclopentatrien-Komplex RuCp*(-C₄Ph₂H₂)Cl (6), mitR=SiMe₃ der Cyclobutadien-Komplex Ru(Cp*)(⁴-C₄H₂(1,2-SiMe₃)₂)Cl (7), und im Fall vonR=n-Bu und COOEt bilden sich die binuklearen Komplexe (Cp*)RuCl₂(²:⁴-₂-C₄H₂(1,3-R)₂)Ru(Cp*) (8,9). Überdies reagiert1 mit Maleinsäurediethylester in Gegenwart von LiCl zum neuen anionischen Komplex Li[Ru(Cp*) (²-C₂H₂(COOEt)₂)Cl₂] (10). Von2,3,4,7 und10 wurden die Kristallstrukturen bestimmt.

     

Synthesis and transition metal chemistry of a bridging diphosphinite, 1,4 bis(diphenylphosphinoxy)benzene

Diphosphinite ligand, [Ph₂POC₆H₄OPPh₂] (1), is obtained by reacting chloro diphenylphosphine, with 1,4-dihydroxy benzene in presence of triethylamine. Treatment of 1 with elemental sulfur or selenium resulted in the formation of bis(chalcogenide) derivatives, [Ph₂(E)POC₆H₄OP(E)Ph₂] (2, E = S; 3, E = Se) in almost quantitative yield. The binuclear complex [{(η⁶-p-cymene)RuCl₂}₂(Ph₂POC₆H₄OPPh₂)] (4) is produced in the reaction between [Ru(η⁶-p-cymene)Cl₂]₂ and diphosphinite 1. Similarly the reaction of 1 with [Rh(COD)Cl]₂ afforded a binuclear complex [{(COD)RhCl}₂(Ph₂POC₆H₄OPPh₂)] (5), whereas the macrocyclic complex [{(CO)RhCl}(Ph₂POC₆H₄OPPh₂)]₂ (6) is isolated in the reaction of 1 with 0.5 equiv of [RhCl(CO)₂]₂. Compound 1 on treatment with [Pd(COD)Cl₂] or [PdCl₂(SMe₂)₂] in 1:1 molar ratio produced the chloro-bridged binuclear complex [{(PPh₂O)Pd(μ-Cl)(PPh₂OH)}₂] (7) through P-O bond cleavage. Treatment of 1 with two equivalents of CuI in dichlormethane/acetonitrile (1:1) afforded a coordination polymer, [{Cu₂(μ-I)₂(Ph₂POC₆H₄OPPh₂)}_∞] (8) in moderate yield. The binuclear complex, [{AuCl}₂(μ-Ph₂POC₆H₄OPPh₂)] (9) is obtained in the reaction of compound 1 with two equiv of AuCl(SMe₂), where the ligand exhibits bridged bidentate mode of coordination. The molecular structures of 1-4, and 6 are determined by X-ray diffraction studies.     

A novel arene bonding mode in the mixed-metal cluster Os4Ru(μ-H) 3(CO) 12(μ3-η-C6H5) P(OMe)3

The ionic coupling of [Os₄H₂(CO)₁₂]²⁻ with [Ru(η⁶-C₆H₆)(MeCN)₃]²⁺ affords the neutral mixed metal cluster Os₄Ru(μH)₂(CO)₁₂(η⁶-C₆H₆) 1. The reaction of 1 with trimethylphosphite leads to the initial formation of the addition product Os₄Ru(μH)₂(CO)₁₂(η⁶-C₆H₆)P(OMe)₃ 2, but this complex rearranges in solution to give Os₄Ru(μ-H)₃(CO)₁₂(μ₃-η⁶-C₆H₅)P(OMe)₃ 3. An X-ray structure of 3 shows that the metal core of the cluster is a ruthenium-spiked Os₄ tetrahedron, with one hydrogen atom from the arene having transferred to the Os₄ core, and one arene carbon bridging an Os-Os edge, while the ring as a whole remains η⁶-bound to the Ru atom.     

The Synthesis and Structure of Hexakis(dimethylphenylphosphonite)ruthenium(II) bis[tetraphenylborate(–1)]

Abstract . Treatment of the hydrazine salt [Ru(COD)(H₂NNH₂)₄][BPh₄]₂ with excess of P(OMe)₂Ph in acetone gave a homoleptic complex trans‐[Ru{P(OMe)₂Ph}₆][BPh₄]₂, which was characterized by IR, ³¹P{¹H}, ¹³C{¹H}, and ¹H NMR spectroscopy, elemental analysis, and X‐ray crystallography. The ruthenium in the complex has distorted octahedral coordination arrangement and bonded to all the six P(OMe)₂Ph molecules through the phosphorus atoms.