8,049 research outputs found
Tricarbonylchlorido(6'7'-dihydro-5’H-spiro[cyclopentane-1,6'-dipyrido-[3,2-d:2',3'-f][1,3]diazepine]-κ2N1,N11)-rhenium(I)
In the title compound, [ReCl(C15H16N4)(CO)3], the ReI ion is coordinated in a distorted octahedral geometry by one Cl atom, two N atoms of the bidentate ligand and three carbonyl groups. The cyclopentane group is orientated in a transoid fashion with respect to the chloride ligand. The dihedral angle between the pryridine rings is 10.91 (12)°. In the crystal, N-H...Cl hydrogen bonds link complex molecules, forming a two-dimensional network parallel to (001)
NaV2O4: a Quasi-1D Metallic Antiferromagnet with Half-Metallic Chains
NaV2O4 crystals were grown under high pressure using a NaCl flux, and the
crystals were characterized with X-ray diffraction, electrical resistivity,
heat capacity, and magnetization. The structure of NaV2O4 consists of double
chains of edge-sharing VO6 octahedra. The resistivity is highly anisotropic,
with the resistivity perpendicular to the chains more than 20 times greater
than that parallel to the chains. Magnetically, the intrachain interactions are
ferromagnetic and the interchain interactions are antiferromagnetic; 3D
antiferromagnetic order is established at 140 K. First principles electronic
structure calculations indicate that the chains are half metallic.
Interestingly, the case of NaV2O4 seems to be a quasi-1D analogue of what was
found for half-metallic materials.Comment: 14 pages, including 4 figures and 1 table, accepted for publication
in PR
Substitutional disorder in the ionic diorganoantimony halide adduct [bromido/chlorido(0.33/0.67)][2-(dimethylaminomethyl)phenyl][2-(dimethylammoniomethyl)phenyl]antimony(III) 0.75-bromide 0.25-chloride
The title complex, [SbBr0.33Cl0.67(C9H13N)(C9H12N)]Br0.75Cl0.25, exhibits substitutional disorder of both halogen atoms in the asymmetric unit, however, with different occupancies. Thus, the halogen atom bonded to Sb has 0.67 (4) occupancy for Cl and 0.33 (4) for Br, while the anionic halogen atom shows 0.75 (4) occupancy for Br and 0.25 (4) for Cl. An N—H⋯Cl/Br hydrogen bond is established between the cation and the halide anion. The coordination geometry of the Sb center in the cation is distorted pseudo-trigonal-bipyramidal as a result of the strong intramolecular N→Sb coordination trans to the Sb—Cl/Br bond. The pendant arm on the second ligand is twisted away from the metal center. The compound crystallizes as a racemate, i.e. a mixture of (R
N2,C
Sb1) and (S
N2,A
Sb1) isomers with respect to planar chirality induced by the coordinating N atom and chelate-induced Sb chirality. These isomers are associated through Cphenyl—H⋯Cl/Br hydrogen bonds, forming a three-dimensional architecture
CRYSTAL AND MOLECULAR-STRUCTURE OF 2',3',5'-TRI-O-ACETYL-6-O-(MESITYLENESULPHONYL)GUANOSINE
The structure of a 6-O-mesitylenesulphonyl derivative of 2',3',5'-tri-O-acetylguanosine, C 24 H 29 N50 10 S, has
been determined by X-ray diffraction. Crystals are monoclinic, a = 26.370 (4), b = 8.200 (2), c =
17.991 (3) A, fl = 132.77 (4) o. The solution of the structure in space group C2 was not straightforward and is
described in detail. Refinement converged at R = 0.110 for 1102 observed reflections. The guanine base
displays some deviations from its usual geometry due to the loss of C(6)-O(6) double-bond character. The
ribose sugar is C(2')-endo puckered
4-Hydroxy-4,4-diphenylbutan-2-one
The molecules of the title compound, C16H16O2, display an intramolecular O—H⋯O hydrogen bond between the hydroxyl donor and the ketone acceptor. Intermolecular C—H⋯π interactions connect adjacent molecules into chains that propagate parallel to the ac diagonal. The chains are arranged in sheets, and molecules in adjacent sheets interact via intermolecular O—H⋯O hydrogen bonds
{Tris[2-(imidazol-2-ylmethylimino)ethyl]methylammonium}iron(II) tris(perchlorate) dihydrate
The title complex, [Fe(C19H27N10)](ClO4)3·2H2O, is a new polymorph of an iron(II) Schiff base complex of tris(2-aminoethyl)methylammonium with imidazole-2-carboxaldehyde. The octahedral FeII atom is bound to three facial imidazole N atoms with average Fe—Nimidazole and Fe—Nimine bond distances of 1.963 (5) and 1.951 (5) Å, respectively. The central N atom of the tripodal ligand is outside the bonding distance at 3.92 Å. The crystal packing is stabilized by the hydrogen-bonding interactions between the two water molecules (acceptor) and two of the three imidazole NH groups (donor). The third imidazole NH group (donor) forms a hydrogen bond to one of the three perchlorate counter-ions (acceptor)
Non-Fermi liquid behavior in a fluctuating valence system, the filled skutterudite compound CeRu_{4}As_{12}
Electrical resistivity , specific heat C, and magnetic susceptibility
measurements made on the filled skutterudite CeRu_4As_{12} reveal
non-Fermi liquid (NFL) T - dependences at low T, i.e., (T) T^{1.4}
and weak power law or logarithmic divergences in C(T)/T and (T).
Measurements also show that the T - dependence of the thermoelectric power S(T)
deviates from that seen in other Ce systems. The NFL behavior appears to be
associated with fluctuations of the Ce valence between 3^+ and 4^+ rather than
a typical Kondo lattice scenario that would be appropriate for an integral Ce
valence of 3^+.Comment: 18 pages, 5 figure
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