Sulphoxide complexes of ruthenium

Summary Compounds of the type RuL_4–nX_2+n where L = dimethyl sulphoxide (DMSO), tetramethylene sulphoxide (TMSO) and X = Cl, Br or I for n = 0 and L = di-n-propyl sulphoxide (n-Pr₂SO) and di-n-butyl sulphoxide (n-Bu₂SO) X = Cl or Br for n = 1 and also Ru(DMSO)₆Br₃ have been prepared and studied. The important i.r. bands of all compounds together with their electronic spectra and the thermograms of some of them are discussed. In order to interpret the i.r. data, the corresponding deuteriated (DMSO-d₆) analogues have also been prepared. In the majority of the compounds of the type RuL₄X₂ the sulphoxide ligands are bonded through the sulphur atom; in a few cases, bonding through both S- and O-donor sites has been found. A mixed type of bonding is also observed in Ru(DMSO)₆Br₃ and in RuL₃X₃.     

Synthesis,characterization, electrochemical and theoretical study of substituted phenyl-terpyridine and pyridine-quinoline based mixed chelate ruthenium complexes

In the present work, we report two methoxy-substituted phenyl-terpyridine ruthenium complexes with pyridine carboxyquinoline and NCS as ancillary ligands, [Ru(OMePhtpy)(pcqH)(NCS)](PF₆) (1) and [Ru(triOMePhtpy)(pcqH)(NCS)](PF₆) (2) (where OMePhtpy = (4′-(4-methoxy)phenyl-2,2′:6′,2″-terpyridine, triOMePhtpy = (4′-(3,4,5-trimethoxy)phenyl-2,2′:6′,2″-terpyridine and pcqH = pyridine-carboxyquinoline). Both complexes have been characterized by spectroscopic techniques e.g., mass, ¹H-NMR and FTIR. UV–vis spectrophotometric and electrochemical studies for both complexes have been performed. The substitution pattern of the –OMe groups have been successfully utilized to tune the redox potential of the metal complexes. On the anodic side of cyclic voltammogram, 1 and 2 show an irreversible wave corresponding to Ru^II/III couple at 0.95 and 0.85 V, respectively. The lower Ru^II/III oxidation potential for 2 may be attributed to increased electron density on ruthenium due to three (+R) methoxy–groups appended to the phenyl moiety of triOMePhtpy. DFT optimization of structure and energy calculation reveals that in both complexes, HOMO is metal- and thiocyanate-based, whereas the LUMO is based on pcqH. Correlation of TDDFT results with experimental electronic spectrum indicates that bands at 502 nm (1) and 528 nm (2) are of MLLCT character from ruthenium-thiocyanate to pcqH.     

Tribochemically active chelate complexes of salicylideneimines

N-Alkylsalicylideneimines and their complexes with 3d metals were obtained by chemical (from metal salts) and electrochemical methods (from metals in the zero oxidation state). The compounds obtained were characterized by IR and ¹H NMR spectroscopy and X-ray diffraction analysis. According to crystallographic data, nickel bis(chelate) exists in the trans-planar configuration. A friction test revealed that the tribotechnical characteristics of lubricating formulations are substantially enhanced in the presence of N-alkylsalicylideneiminates.     

Cyclopentadienyl ruthenium alkynyldithiocarboxylate complexes

Treatment of the ruthenium chloride, CpRu(PPh₃)₂Cl, with the alkynyldithiocarboxylate anions, , in refluxing THF affords the chelate complexes CpRu(PPh₃)(κ²S,S-S₂CCCR) (1) (R = Bu^t (a), Buⁿ (b), Ph (c), SiMe₃ (d)) in high yield. The room temperature reaction of the solvated species, [CpRu(PPh₃)₂(NCPh)]⁺, with the alkynyldithiocarboxylate anions, , produces the chelate complexes 1 and the mono-coordinated complexes CpRu(PPh₃)₂(κS-S₂CCCR) (2). Complexes 2 are converted to 1 in solution so that they were characterized spectroscopically.     

Half-sandwich trihydrido ruthenium complexes

This paper reports facile preparation of half-sandwich trihydrido complexes of ruthenium based on the reactions of the readily available precursors [Cp(R₃P)Ru(NCCH₃)₂][PF₆] with LiAlH₄. The target complexes were characterized by spectroscopic methods and X-ray structure analysis of .     

Tautomerization of methyldiazene to formaldehyde-hydrazone in ruthenium and osmium complexes

Mixed-ligand hydrazine complexes [M(CO)(RNHNH2)P4](BPh4)2 (1, 2) [M = Ru, Os; R = H, CH3, C6H5; P = P(OEt)3] with carbonyl and triethyl phosphite were prepared by allowing hydride [MH(CO)P4]BPh4 species to react first with HBF4.Et2O and then with hydrazines. Depending on the nature of the hydrazine ligand, the oxidation of [M(CO)(RNHNH2)P4](BPh4)2 derivatives with Pb(OAc)4 at -30 C gives acetate [M(kappa1-OCOCH3)(CO)P4]BPh4 (3a), phenyldiazene [M(CO)(C6H5N=NH)P4](BPh4)2 (3c, 4c), and methyldiazene [M(CO)(CH3N=NH)P4](BPh4)2 (3b, 4b) derivatives. Methyldiazene complexes 3b and 4b undergo base-catalyzed tautomerization of the CH3N=NH ligand to formaldehyde-hydrazone NH2N=CH2, giving the [M(CO)(NH2N=CH2)P4](BPh4)2 (5, 6) derivatives. Complexes 5 and 6 were characterized spectroscopically and by the X-ray crystal structure determination of the [Ru(CO)(NH2N=CH2)[P(OEt)3]4](BPh4)2 (5) derivative. Acetone-hydrazone [M(CO)[NH2N=C(CH3)2]P4](BPh4)2 (7, 8) complexes were also prepared by allowing hydrazine [M(CO)(NH2NH2)P4](BPh4)2 derivatives to react with acetone.     

A facile route to bimetallic ruthenium dipyridophenazine complexes

Using achiral coordinatively unsaturated metal complex building-blocks, the two step synthesis of a bimetallic complex containing independent [Ru(II)dppz] units tethered together by a linking 4,4'dipyridyl-1,5-pentane ligand is reported. Photophysical studies on this prototype system indicate that the characteristic luminescence of the [Ru(II)dppz] moieties is perturbed by self-quenching processes. Preliminary binding studies on the complex with natural and synthetic duplex DNA is reported. Luminescence and calorimetric titrations reveal that the complex does not show enhanced binding affinity with respect to analogous monometallic complexes. This result is interpreted by a consideration of the length and rigidity of the linker employed in the complex.     

Trimethyltantalum(V) chelate complexes

Interaction of trimethyldichlorotantalum with potassium bis(pyrazolyl)borate, K⁺[pz₂BH₂]^—, gives the chloride-free complex Me₃Ta(pz₂BH₂)₂; other examples of similar reactions are reported.     

Binding of rigid dendritic ruthenium complexes to carbon nanotubes

Single-walled carbon nanotubes (SWNTs) bind strongly to rigid ruthenium metallodendrimers. High valence ions effectively coagulate these nanotubes from stable dispersions in N,N-dimethylforamide. While ruthenium salts and small [Ru(diimine)(3)](2+) complexes also coagulate the nanotubes, they require much higher concentrations and are easily extracted from the nanotubes with acetonitrile. Enantiomerically pure ruthenium metallodendrimer [Lambda(6)Delta(3)Lambda-Ru(10)](20+)[PF(6)(-)](20) is shown to bind strongly and specifically to the SWNTs. Most of the nanotube's ends are functionalized with this large (5.8 nm), optically active, rigid supramolecular complex. We study the binding capacity with UV-vis and atomic absorption spectroscopy. Imaging the functionalized nanotubes with scanning electron microscopy and atomic force microscopy (AFM) yields direct confirmation of end functionalization. Statistical analysis of the AFM images shows the morphology of the functionalized ends is consistent with the nanotubes binding to one of the endo- or exoreceptors around the dendrimer. Implications of these results toward efficient nanomanufacturing of carbon nanotube devices are discussed.     

钌卟啉配合物化学研究进展

本文从三方面介绍了钌卟啉配合物化学的研究进展。较详细地讨论了各种类型钌卟啉配合物的制备方法; 总结了钌卟啉配合物的结构特征及常见的结构表征方法; 并从几方面展示了钌卟啉配合物的应用及发展前景。     

Quantum chemical aspects of the chelate effect in complexes

A typical “chelate” effect is demonstrated by means of all-electron ab initio LCGO SCF calculations on the [Li(HCONH₂)₂]⁺ complex in different geometrical arrangements. Energetic factors and the electronic structure of the complexes are discussed, showing the chelate effect to be connected with striking changes in bonding, density distribution and electronic energy.     

Self-assembled chiral terpyridine ruthenium complexes

A rigid terpyridine ligand containing chiral alkyl chains has been synthesized, characterized and subsequently complexed with ruthenium(II) ions. The product was characterized by MALDI-TOF-MS, UV-vis and NMR. Circular dichroism showed the appearance of extended helical columnar aggregates.     

Rhenium chelate complexes with maltolate or kojate

Novel rhenium complexes containing the maltolate (mal) or kojate (koj) anions as chelating ligands have been synthesized: [ReOCl(mal)₂] (1), [ReOCl₂(mal)(PPh₃)] (2), [ReOBr₂(mal)(PPh₃)] (3), [ReOCl₂(koj)(PPh₃)] (4) and [ReOBr₂(koj)(PPh₃)] (5). The products have been characterized by FTIR, ¹H, ¹³C, and ³¹P NMR spectroscopies and elemental analysis. The crystal and molecular structures of all complexes were determined. Complex 1 crystallizes monoclinic, space group C2/c, Z = 8. It contains two O,O′-bidentate maltolate ligands and one chloro ligand at the (ReO)³⁺ unit, so that a distorted octahedral geometry is adopted by the six-coordinated rhenium(V) center. The chloro ligand occupies a cis position to the oxo ligand. Complexes 2 and 3 are isostructural and crystallize orthorhombic, space group Pbca and Z = 8. The isostructural complexes 4 and 5 crystallize monoclinic, space group P2₁/n and Z = 4. In complexes 2–5, the (ReO)³⁺ unit is coordinated by a monoanionic O,O-bidentate unit of the maltolate (2 and 3) or kojate (4 and 5) ligand, one triphenylphosphine and two halogeno ligands (Cl in 2 and 4; Br in 3 and 5), with the rhenium(V) center in a distorted octahedral environment. The halide ligands are in cis positions to each other.     

Further chemistry of ruthenium butatrienylidene complexes

Several complexes have been obtained from reactions carried out in early attempts to prepare the diynyl complexes Ru(CCCCR)(dppe)Cp* (R = H, SiMe₃). These have been identified crystallographically as the acyl complex Ru{CCC(O)Me}(dppe)Cp* (3), the cationic imido complex [Ru{CCC(NH₂)Me}(dppe)Cp*]PF₆ (4), the binuclear butenynylallenylidene [{Ru(dppe)Cp*}₂{μ-CCC(OMe)CHCMeCC}]PF₆ (5), and the bis(ethynyl)cyclobutenylidene [{Ru(dppe)Cp*}₂{μ-CCC₄H₂(SiMe₃)CC}]PF₆ (6). NMR studies of 5 have revealed the existence of two isomers. Plausible routes for their formation from the putative butatrienylidene intermediate [Ru(CCCCH₂)(dppe)Cp*]⁺ (A) are discussed.     

From alkenylphosphane aminoallenylidene ruthenium(II) complexes to highly unsaturated ruthenaphosphabicycloheptene complexes

The alkenylaminoallenylidene complex [Ru(η⁵-C₉H₇){CCC(NEt₂)[C(Me)CPh₂]}{κ(P)-Ph₂PCH₂CHCH₂}(PPh₃)][PF₆] (2) has been prepared by the reaction of the allenylidene [Ru(η⁵-C₉H₇)(CCCPh₂){κ(P)-Ph₂PCH₂CHCH₂}(PPh₃)][PF₆] (1) with the ynamine MeCCNEt₂. The reaction proceeds regio- and stereoselectively, and the insertion of the ynamine takes place exclusively at the C_βC_γ bond of the unsaturated chain. The secondary allenylidene [Ru(η⁵-C₉H₇){CCC(H)[C(Me)CPh₂]}{κ(P)-Ph₂PCH₂CHCH₂}(PPh₃)][PF₆] (3) is obtained, in a one-pot synthesis, from the reaction of aminoallenylidene 2 with LiBHEt₃ and subsequent treatment with silica. Moreover, the addition of an excess of NaBH₄ to a solution of the complex 2 in THF at room temperature gives exclusively the alkynyl complex [Ru(η⁵-C₉H₇){CCCH₂[C(Me)CPh₂]}{κ(P)-Ph₂PCH₂CHCH₂}(PPh₃)] (5). The heating of a solution of allenylidene derivative 3 in THF at reflux gives regio- and diastereoselectively the cyclobutylidene complex [Ru(η⁵-C₉H₇) (PPh₃)][PF₆](4) through an intramolecular cycloaddition of the CC allyl and the C_αC_β bonds in the allenylidene complex 3. The structure of complex 4 has been determined by single crystal X-ray diffraction analysis.     

Pyrrolyl substituted allenylidene complexes of ruthenium

Pyrrolyl and indolyl substituted allenylidene complexes of ruthenium have been prepared from the trapping of cationic trans-[Cl(dppm)(2)Ru=C=C=C=CH(2)](+) with various pyrroles or N-methylindole. The reaction is rationalized as involving regioselective attack of the organometallic electrophile on the electron-rich heterocycle followed by proton migration to the terminal =CH(2) entity of the intermediate butenynyl substituted sigma-complex. Pyrrolyl substituted allenylidene complexes have spectroscopic and electrochemical properties intermediate between those of amino and aryl substituted congeners and can thus be regarded as vinylogous aminoallenylidene complexes. We present spectroscopic evidence that the pyrrole pi-system is efficiently incorporated into the metallabutatriene chromophore including resonance Raman spectroscopy. According to our results, the respective frontier orbitals are delocalized across the entire ClRuC(3)(pyrrolyl) entity which defies any classification of the individual redox events as metal or ligand centered redox processes. This issue has been specifically addressed by spectroelectrochemistry. The structure of the 1-methylindole-3-yl complex has been determined by X-ray crystallography. Bond parameters along the ruthenium-allenylidene chain are intermediate between those of amino and aryl substituted congeners and support our conclusions drawn from the spectroscopic results. While still electron rich, pyrrolyl substituted allenylidene complexes are easily deprotonated to their conjugate bases, which are substituted butenynyl complexes. This has been exemplified with the tetrahydroindole derived complex 3f.     

Some ruthenium complexes of fluorinated alkynylcyclopentenes

Reactions between 1,2-dichlorohexafluorocyclopentene and Ru(CCH)(dppe)Cp∗ or Ru(CCCCLi)(dppe)Cp∗ have given Ru(CC-c-C₅F₆Cl-2)(dppe)Cp∗ 4 and Ru(CCCC-c-C₅F₆Cl-2)(dppe)Cp∗ 7, respectively. Ready hydrolysis of 4 to the ketone Ru{CC[c-C₅F₄Cl(O)]}(dppe)Cp∗ 5 occurs, which can be converted to Ru{CC(c-C₅F₄Cl[C(CN)₂])}(dppe)Cp∗ 6 by treatment with CH₂(CN)₂/basic alumina. Spectroscopic, electrochemical and XRD structural studies for 4-7 are reported: for 6, these suggest that the cyanated fluorocarbon ligand is a very powerful electron-withdrawing group.