Search results for "Metallic"

Ti2Sn3:  A Novel Binary Intermetallic Phase, Prepared by Chemical Transport at Intermediate Temperature

2000

Ti2Sn3 was obtained by chemical transport using iodine as the transport agent in a sealed quartz ampule at 500 °C. Its crystal structurea new type structurewas determined via single-crystal structure analysis to be orthorhombic, space group Cmca, a = 595.56(4), b = 1996.4(2), c = 702.81(5) pm, V = 835.6(1) × 106 pm3, and Z = 8. The structure can be derived from a three-dimensional condensation of a single polyhedron, which comprises a Ti atom in the center, surrounded by seven Sn and four Ti atoms forming a tri-capped square antiprism. Supporting the results of the self-consistent band structure calculations, Ti2Sn3 is a metallic p-type conductor, exhibiting Pauli paramagnetism and a specif…

Crystal Fields in PrX3 (X=In, Tl, Pb, Sn) Intermetallic Compounds with Cu3Au Structure

1977

We have determined the crystal field splittings of Pr3+ in PrIn3, PrTl3, PrPb3, and PrSn3 by inelastic neutron scattering. The values of the deduced crystal field parameters are found to depend strongly on the constituent X, though all systems have nonmagnetic ground-states. The line widths in the different systems are compared.

Crystal field splitting of some rare earth intermetallic compounds with Cu3Au structure

1980

Inelastic neutron scattering studies were performed in the paramagnetic phases of several rare earth compounds that crystallize in the cubic Cu3Au structure: ErPb3, ErTl3, ErIn3, HoPb3, HoTl3, HoIn3, PrSn3, PrPb3, PrTl3, PrIn3, CeIn3, La1−c Pr c Tl3, and Pr(In0.5Tl0.5)3. The energies, widths and intensities of the crystal field excitations are determined and discussed in terms of interactions between the rare earth ions. Variations of the crystal field parameters are observed across the series.

Structural diversity of cyanide-bridged bimetallic clusters based on hexacyanometallate building blocks

2002

Abstract Four new cyanide-bridged bimetallic complexes, with different geometries and nuclearities, have been synthesized and characterized by single crystal X-ray crystallography. The trinuclear compound {〚Zn(bpy)2(OH2)〛2〚Fe(CN)6〛}Cl (1)·2 MeOH·12 H2O crystallizes in the triclinic space group P 1 , with a = 12.010(2) A, b = 16.316(3) A, c = 16.325(3) A, α = 97.47(3)°, β = 92.14(3)°, γ = 92.43(3)°, V = 3166(1) A3 and Z = 4. The tetranuclear compound {〚Zn(phen)2〛2〚Fe(CN)6〛2}2– (2) cocrystallizes with 〚Zn(bpy)3〛2+ and 32 H2O molecules in the monoclinic space group C2/c with a = 42.047(8) A, b = 13.541(2) A, c = 28.781(5) A, β = 120.23(3)°, V = 14158(4) A3 and Z = 2. The pentanuclear compound …

Synthesis, Chirality, and Magnetic Properties of Bimetallic Cyanide-Bridged Two-Dimensional Ferromagnets

2006

The assembly of hexacyanoferrate(III) anions and nickel(II) bis-diamino complexes of the chiral ligand trans-cyclohexane-1,2-diamine (trans-chxn) yields cyanide-bridged two-dimensional ferromagnets of the general formula [Ni(trans-chxn)2]3[Fe(CN)6]2‚2H2O. Their crystal structure is built from cyanide-bridged bimetallic planes separated by the bulky chxn ligands, giving rise to a large interlayer distance ( d ) 11.7 A). These materials order ferromagnetically at the Curie temperature TC ) 14 K. AC susceptibility measurements evidence an unusual magnetic behavior below TC, with a marked frequency dependence. A thorough magnetic analysis demonstrates that this complex behavior is due to the pi…

Cobalt(II)-Copper(II) Bimetallic Chains as a New Class of Single-Chain Magnets

2004

Synthesis, characterization and crystal structure of the bimetallic cyano-bridged [(η5-C5H5)(PPh3)2Ru(μ-CN)Ru(PPh3)2(η5-C5H5)][PF6]

2005

Abstract The bimetallic cyano-bridged [(η 5 -C 5 H 5 )(PPh 3 ) 2 Ru(μ-CN)Ru(PPh 3 ) 2 (η 5 -C 5 H 5 )][PF 6 ] ( 1 ) was prepared by reaction of [(η 5 -C 5 H 5 )(PPh 3 ) 2 RuCl] with N , N ′-bis(cyanomethyl)ethylenediamine. The single crystal structure determined by X-ray diffraction showed crystallization on the triclinic P1 space group with a perfect alignment of the cyanide bridges. This accentric crystallization was explored having in view the NLO properties at the macroscopic level, determined by the Kurtz Powder technique. Besides the very low efficiency values for the second harmonic generation, the value obtained for the bimetallic complex 1 showed to be higher than one of the parent…

Spin-Crossover and Liquid Crystal Properties in 2D Cyanide-Bridged FeII−MI/II Metalorganic Frameworks

2010

Novel two-dimensional heterometallic Fe(II)-M(Ni(II), Pd(II), Pt(II), Ag(I), and Au(I)) cyanide-bridged metalorganic frameworks exhibiting spin-crossover and liquid crystal properties, formulated as {FeL(2)[M(I/II)(CN)(x)](y)}·sH(2)O, where L are the ligands 4-(4-alkoxyphenyl)pyridine, 4-(3,4-dialkoxyphenyl)pyridine, and 4-(3,4,5-trisalkoxyphenyl)pyridine, have been synthesized and characterized. The physical characterization has been carried out by means of EXAFS, X-ray powder diffraction, magnetic susceptibility, differential scanning measurements, and Mössbauer spectroscopy. The 2D Fe(II) metallomesogens undergo incomplete and continuous thermally induced spin transition at T(1/2) ≈ 170 …

Thermal-,Pressure-, and Light-Induced Spin Transition in Novel Cyanide-Bridged FeII-AgI Bimetallic Compounds with Three-Dimensional Interpenetrating …

2002

[EN] Low-spin, high-spin and spin-transition behaviours have been observed for the doubly interpenetrating three-dimensional bimetallic compounds {Fe-II(pz)[Ag(CN)(2)](2)}.pz (pz= pyrazine), {Fe-II(4,4'-bipy)(2)[Ag(CN)(2)](2)} (4,4'-bipy-4,4'-bipyridine), and {Fe-II-(bpe)(2)[Ag(CN)(2)](2)} (bpe = bispyridylethylene), respectively. The single crystals of the bpe derivative undergo a spin transition with a large hysteresis loop at about 95 K. After several warming and cooling cycles, the single crystals become a microcrystalline powder with 50% spin transition. Influence of pressure- as well as light-induced excited spin-state trapping (LIESST) on the thermal 50% spin transition of the microc…

Ruthenium titanocene and ruthenium titanium half-sandwich bimetallic complexes in catalytic cyclopropanation

2005

Abstract The reaction of the phosphine functionalised titanium half-sandwich complexes 7, 9 and 10 with the binuclear complex [(p-cymene)RuCl2]2 allowed the access to three new early-late bimetallic complexes (p-cymene)[(μ-η5:η1-C5H4(CH2)nPR2)TiX3]RuCl2 (11–13). The structure of 11 (n = 0, X = Cl) has been confirmed by X-ray diffraction. The ruthenium titanium half-sandwich bimetallic complexes so formed and the ruthenium titanocene analogues 4–6 catalyse the addition of ethyl diazoacetate to styrene with high selectivity toward cyclopropanation versus metathesis contrary to the monometallic complexes (p-cymene)RuCl2PR3.