- Synthesis and characterization of rigid +2 and +3 heteroleptic dinuclear ruthenium(II) complexes
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Synthesis and characterization of the dinuclear ruthenium coordination complexes with heteroleptic ligand sets, [Cl(terpy)Ru(tpphz)Ru(terpy)Cl](PF 6)2 (7) and [(phen)2Ru(tpphz)Ru(terpy)Cl] (PF6)3 (8), are reported. Both structures contain a tetrapyrido[3,2-α:2′,3′-c:3″,2″-h:2″, 3″-j]phenazine (tpphz) (6) ligand bridging the two metal centers. Complex 7 was obtained via ligand exchange between, RuCl2(terpy)DMSO (5) and a tpphz bridge. Complex 8 was obtained via ligand exchange between, [Ru(phen)2tpphz](PF6)2 (4) and RuCl 2(terpy)DMSO (5). Metal-to-ligand-charge-transfer (MLCT) absorptions are sensitive to ligand set composition and are significantly red-shifted due to more electron donating ligands. Complexes 7-9 have been characterized by analytical, spectroscopic (IR, NMR, and UV-Vis), and mass spectrometric techniques. The electronic spectral properties of 7, 8, and [(phen) 2Ru(tpphz)Ru(phen)2](PF6)4 (9), a previously reported +4 analog, are presented together. The different terminal ligands of 7, 8, and 9 shift the energy of the MLCT and the π-π* transition of the bridging ligand. These shifts in the spectra are discussed in the context of density functional theory (DFT). A model is proposed suggesting that low-lying orbitals of the bridging ligand accept electron density from the metal center which can facilitate electron transfer to nanoparticles like single walled carbon nanotubes and colloidal gold.
- Alston,Kobayashi,Younts,Poler
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- α-RuCl3/polymer nanocomposites: The first group of intercalative nanocomposites with transition metal halides
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Different types of polymers can be intercalated into α-RuCl3 with different synthetic methodologies. Polyaniline/α-RuCl3 nanocomposite was prepared by the in situ redox intercalative polymerization method, in which α-RuCl3 was exposed to an aniline/acetonitrile solution in open air. Water-soluble polymers such as poly(ethylene oxide), poly(vinyl pyrrolidone), and polyethylenimine were intercalated by an encapsulative precipitation method using monolayer suspensions of α-RuCl3. A modification of this method led to insertion of polypyrrole. Monolayer suspensions of α-RuCl3 can be prepared from LixRuCl3 (x ～ 0.2). The latter is produced by the reaction of α-RuCl3 with 0.2 equiv of LiBH4. The polymer insertion is topotactic and does not cause structural changes to the host. The metal chloride layers in these materials possess mixed valency. The reduction and polymer intercalation of α-RuCl3 alters the intralayer and interlayer Ru3+ (low spin d5) magnetic coupling, so that interesting magnetic properties appear in the nanocomposites. In addition, the reduction brings in free hopping electrons to the RuCl3 layers and the polymer intercalation builds up new electronic or ionic conducting channels in the galleries, so that the charge transport properties are changed dramatically. For example, LixRuCl3 shows an electrical conductivity 3 orders of magnitude higher than pristine α-RuCl3 at room temperature and Lix(PEO)yRuCl3 has an ion conductivity comparable with the best (lithium salt)-polymer electrolytes. For a comprehensive understanding of the structure of the representative nanocomposite Lix(PEO)yRuCl3, the arrangement of polymer chains inside the galleries was explored with analysis of its one-dimensional (00l) X-ray diffraction pattern. Calculated electron density maps along the stacking c-axis lead to a structural model that fills each gallery with two layers of polymer chains exhibiting a conformation found in type-II PEO-HgCl2. The most consistent PEO arrangement in the gallery generates oxygen-rich channels in the middle of the gallery in which the Li ions can reside. The new nanocomposites were characterized with thermogravimetric analysis, infrared spectroscopy, powder X-ray diffraction, magnetic measurements, as well as electrical and ionic conductivity and thermopower measurements.
- Wang, Lei,Rocci-Lane, Melissa,Brazis, Paul,Kannewurf, Carl R.,Kim, Young-Il,Lee, Woo,Choy, Jin-Ho,Kanatzidis, Mercouri G.
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- About trihalides with TiI3 chain structure: Proof of pair forming of cations in β-RuCl3 and RuBr3 by temperature dependent single crystal X-ray analyses
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Single-crystal X-ray studies on β-RuCl3 and RuBr 3 at different temperatures verified, that both compounds are dimorphic and show reversible phase transitions at 206 K resp. 384 K. In the HT-forms the Aristo-type of the hexagonal TiI3-structure with space group P63/m c m (Z = 2, β-RuCl3 at 293(2) K: a = 6.121(2) A, c =5.655(2) A, RuBr3 at 423(3) K: 6.5215(12) A, c = 5.8851(13) A) has been found, in the LT-forms the RuBr 3-type structure, an orthorhombic distorted variant with space group Pmmn (Z = 4, β-RuCl3 at 170(3) K: a = 10.576(2) A, b = 5.634(1) A, c = 6.106(1) A, RuBr3 at 293(2) K: a =11.2561(16) A, b = 5.8725(12) A, c = 6.4987(9) A). A hexagonal closest packing of X- anions forms the basis of an arrangement of infinite chains with face-connected [RuX6/2] octahedra. While in the chains of the hexagonal HT-forms the Ru-Ru-distances are identical (d(Ru-Ru) = 2.8275(10) A for β-RuCl3, d(Ru-Ru) = 2.9425(6) A for RuBr 3), in the orthorhombic structures the chains are distorted through pairing of the ruthenium(III) atoms (d(Ru-Ru) = 2.6328(14) A / 3.0010(15) A for β-RuCl3 at 170(3) K, d(Ru-Ru) = 2.765(1) A / 3.108(1) A for RuBr3 at 293(2) K). The hexagonal metric with a/c= √3 holds also for the orthorhombic LT-forms. Large crystals and the final products of the phase transition from HT- to LT-forms are pseudomerohedral twins of three twin domains with nearly equal amounts complicating proof and analysis of the LT-forms.
- Hillebrecht,Ludwig,Thiele
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- Electronic properties of the narrow-band material α-RuCl3
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X-ray angle-integrated and ultraviolet angle-resolved photoemission spectra of the low-spin compound t2g5 α-RuCl3 show that Ru 4d and Cl 3p states contribute to the valence-band structure of this magnetic material. The energy distribution curves measured along the azimuthal directions Γ-M′-π and Γ-K-M using He I radiation indicate an uppermost nearly dispersionless structure of Ru 4d origin, and two dispersive features obtained from Cl 3p-derived bands. The photoemission results, together with the optical and magnetic properties described by ligand-field theory, support the view of localized 4d states forming a very narrow Ru 4d band in the vicinity of the Fermi energy. The main 4d emission structure has been thus assigned to 4d4 unscreened hole states, where the band gap corresponds to intersite d-d transitions, and α-RuCl3 can be classified as a Mott-Hubbard compound in consideration of its electronic and magnetic characteristics. The inconsistency between the photoemission results and the transport properties, describing this material as a conventional band-gap semiconductor, is finally discussed.
- Pollini
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- Process for production of bis (alkyl cyclopentadienyl) ruthenium and bis (alkyl cyclopentadienyl) ruthenium produced by the process
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The present invention provides a process for producing bis(alkyl cyclopentadienyl ruthenium comprising reacting alkyl cyclopentadiene with ruthenium chloride and zinc powder in an alcohol solvent, the reaction being effected at a temperature within from ?
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- Influence of solvent on aromatic interactions in metal tris-bipyridine complexes
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The conformational properties of a series of iron(II) and ruthenium(II) tris-bipyridine complexes have been investigated in a range of solvents. The complexes are equipped with pendant aromatic esters attached by flexible aliphatic linkers, and aromatic i
- Breault, Gloria A.,Hunter, Christopher A.,Mayers, Paul C.
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p. 3402 - 3410
(2007/10/03)
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- Thermodynamic Properties of Ruthenium and Rhodium Chlorides
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Thermodynamic properties of ruthenium and rhodium trichlorides were studied by high-temperature mass spectrometry from 591 to 724 and 500 to 683 K, respectively. RuCl3 and RhCl3 dissociate to metal at these temperatures. The dissociation pressures of RuCl3 and RhCl3 were measured. No ruthenium or rhodium chlorides were found in the gas phase.
- Tagirov,Makarov,Bryukvin
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p. 919 - 921
(2008/10/08)
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- High Oxidation State Binary Transition Metal Fluorides as Selective Fluorinating Agents
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High oxidation state transition metal fluorides are selective fluorinating agents for dichloromethane, those with d0 electronic configurations undergo hydrogen-fluorine exchange and metal reduction, while dn species undergo chlorine-
- Dukat, Wolfgang W.,Holloway, John H.,Hope, Eric G.,Rieland, Matthias R.,Townson, Paul J.,Powell, Richard L.
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p. 1429 - 1430
(2007/10/02)
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- M?ssbauer spectroscopy and magnetization studies of α- and β-RuCl3
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99Ru M?ssbauer spectroscopy and magnetization studies were performed on anhydrous ruthenium trichlorides, black α-RuCl3 and brown β-RuCl3. Measurements on the β-form were made on samples prepared by a new method. The isomers were found to have quite distinct magnetic properties. The 99Ru M?ssbauer spectrum of α-RuCl3 exhibits large hyperfine magnetic splitting at 5 K with the magnitude of the hyperfine magnetic field being 209 kOe. This result is consistent with the magnetic susceptibility measurements, which show a sharp cusp, indicating an antiferromagnetic order at TN = 15.6 ± 0.5 K. The 99Ru M?ssbauer spectrum of β-RuCl3 exhibits an electric quadrupole interaction with no hyperfine magnetic interaction. The β-form is thus concluded to be paramagnetic down to 5 K on the basis of the results of the magnetic susceptibility measurements from room temperature to 7 K. The conspicuous difference in the magnetic properties between the two forms is attributable to their crystal structures; i.e., Ru atoms in α-RuCl3 form two-dimensional honeycomb lattices, while those in β-RuCl3 form one-dimensional chains along the c direction.
- Kobayashi,Okada,Asai,Katada,Sano,Ambe
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p. 4570 - 4574
(2008/10/08)
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- Chloro Nitrosyl Complexes of Ruthenium(II). The Crystal Structure of (PPh3Me)22*2CH2Cl2
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Ruthenium trichloride, obtained from its hydrate with thionyl chloride, reacts with excess trichloronitromethane yielding polymer ; by addition of triphenylmethylphosphonium chloride in dichloromethane (PPh3Me)22*2CH2Cl2 is obtained, the IR spectrum of which is reported and assigned.Its crystal structure was determined with X-ray diffraction data (6404 independent observed reflexions, R = 0.068).Crystal data at -90 deg C: a = 1145, b = 1591, c = 1406 pm, β = 96.0 deg, Z = 2, space group P21/c.The structure consists of PPh3Me(+) cations, centrosymmetric anions 2(2-) nearly fulfilling C2h symmetry, and CH2Cl2 molecules.In the anions the Ru atoms are linked via chloro bridges; the nitrosyl groups occupy axial positions with bond distances RuN of 175 and NO of 113 pm, bond angle RuNO 172.7 deg. - Key words: Chloro Nitrosyl Complexes of Ruthenium(II), Syntheses, IR Spectra, Crystal Structure
- Fenske, Dieter,Demant, Udo,Dehnicke, Kurt
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p. 1672 - 1676
(2007/10/02)
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