Search results for " susceptibility"

Spin Crossover in Double Salts Containing Six- and Four-Coordinate Cobalt(II) Ions

2017

The preparation and spectroscopic and structural characterization of three cobalt(II) complexes of formulas [Co(tppz)2](dca)2 (1), [Co(tppz)2][Co(NCS)4]·MeOH (2), and [Co(tppz)2][Co(NCO)4]·2H2O (3) [tppz = 2,3,5,6-tetrakis(2-pyridyl)pyrazine and dca = dicyanamide] are reported here. Compounds 1–3 have in common the presence of the cationic [Co(tppz)2]2+ entity where each mer-tridentate tppz ligand coordinates to the cobalt(II) ion equatorially through two pyridyl donors and axially via the pyrazine, completing the six-coordination. The electroneutrality is achieved by the organic dca group (1) and the anionic tetrakis(thiocyanato-κN)cobaltate(II) (2) and tetrakis(cyanato-κN)cobaltate(II) (3…

Chains and channels in polynuclear copper(II) complexes with 2,3-bis(2-pyridyl)pyrazine (dpp) as bridging ligand; syntheses, crystal structures and m…

2000

Abstract The preparation and crystal structures for three Cu(II) polynuclear, chain complexes with 2,3-bis(2-pyridyl)pyrazine (dpp) as bridging ligand are reported, [Cu(dpp)(H2O)2]n(NO3)2n·2n/3H2O (1), [Cu(dpp)(H2O)2]n(CF3SO3)2n (2), and [Cu(dpp)(H2O)2]n(BF4)2n·2nH2O (3). For the latter compound the crystal structure at four different temperatures have been studied. Variable-temperature magnetic susceptibility data and ESR measurements of 1–3 and of the related copper(II) chain [Cu(dpp)(H2O)2]n(ClO4)2n·2nH2O (4) (whose structure was previously reported) have been performed. Compounds 1 and 2 crystallize in the same trigonal space group, R 3 c; 3 is orthorhombic, space group Pbca. Complexes …

Crystal engineering of 3-D coordination polymers by pillaring ferromagnetic copper(ii)-methylmalonate layers

2007

Three new copper(II) complexes of formula [Cu(Memal)(H2O)]n (1), [Cu2(pyz)(Memal)2] (2) and [Cu2(4,4′-bpy)(Memal)2(H2O)2] (3) (Memal = methylmalonate, pyz = pyrazine and 4,4′-bpy = 4,4′-bipyridine) were obtained and structurally characterized by X-ray diffraction. Complex 1 is a square grid of aquacopper(II) units which are linked by carboxylate-methylmalonate groups in the anti–syn (equatorial–equatorial) coordination mode. The crystal structures of 2 and 3 consist of corrugated layers of copper(II) (2) and aquacopper(II) (3) units with intralayer carboxylate-methylmalonate bridges in the anti–syn (equatorial–apical) coordination mode which are linked through pyrazine (2) and 4,4′-bipyridi…

Influence of the coligand in the magnetic properties of a series of copper(ii)–phenylmalonate complexes

2014

This work presents a series of layered systems based on phenylmalonate-containing copper(II) complexes and different coligands. Eight compounds [Cu(L)(Phmal)]n where L = pyrimidine (pym, 1) pyrazine (pyz, 2), 3-cyanopyridine (3-CNpy, 3), 4-cyanopyridine (4-CNpy, 4), 3-fluoropyridine (3-Fpy, 5), 3-chloropyridine (3-Clpy, 6), 3-bromopyridine (3-Brpy, 7) and 3-iodopyridine (3-Ipy, 8), have been synthesized and magneto-structurally characterized. The coligands selected not only modify the coordination environment of the metal ion, blocking or extending the polymerization, but also interact with the phenyl ring of the phenylmalonate ligand and dramatically affect the crystal packing through weak…

Solid state polymerization causing transition to a ferromagnetic state. Crystal structures and magnetic properties of [Cu2(dpp)(H2O)(dmso)Cl4]·dmso a…

2001

The preparation, crystal structures and variable-temperature magnetic susceptibility data for [Cu2(dpp)(H2O)(dmso)Cl4]·dmso (1a) and [Cu2(dpp)Cl4]n (2) (dpp = 2,3-bis(2-pyridyl)pyrazine, dmso = dimethyl sulfoxide) are reported. 1a consists of dinuclear dpp-bridged molecules with chlorine, water and dmso serving as terminal ligands. The two copper atoms are crystallographically independent, with distorted square pyramidal and trigonal bipyramidal coordination geometries, respectively. In a first approximation 2 may be described as a chain compound with out-of-plane mono-μ-chloro bridges (Cu–Cl–Cu–Cl). Only one of the crystallographically independent copper atoms participates in this chain fo…

High-dimensional malonate-based materials: Synthesis, crystal structures and magnetic properties of [M2(mal)2(L)(H2O)2]n·n(H2O) M = Zn(ii), Co(ii); H…

2003

Four novel coordination polymers [M2(mal)2(pym)(H2O)]n·nH2O, M = Zn (1), Co (2) and [M2(mal)2(pyz)(H2O)]n·nH2O, M = Zn (3), Co (4) (H2mal = malonic acid, pym = pyrimidine, pyz = pyrazine), have been synthesized. Compounds 1 and 2 are isomorphous, as are compounds 3 and 4. X-ray diffraction experiments reveal that 1–4 exhibit an interesting 3D-network, containing malonate and either pyrimidine (1 and 2) and pyrazine (3 and 4) as organic ligands. Variable-temperature magnetic susceptibility measurements indicate the occurrence of weak antiferromagnetic interactions between Co(II) ions in 2 and 4.

Human Amnion-Derived Mesenchymal Stromal Cells: A New Potential Treatment for Carbapenem-Resistant Enterobacterales in Decompensated Cirrhosis

2022

Background: Spontaneous bacterial peritonitis (SBP) is a severe and often fatal infection in patients with decompensated cirrhosis and ascites. The only cure for SBP is antibiotic therapy, but the emerging problem of bacterial resistance requires novel therapeutic strategies. Human amniotic mesenchymal stromal cells (hA-MSCs) possess immunomodulatory and anti-inflammatory properties that can be harnessed as a therapy in such a context. Methods: An in vitro applications of hA-MSCs in ascitic fluid (AF) of cirrhotic patients, subsequently infected with carbapenem-resistant Enterobacterales, was performed. We evaluated the effects of hA-MSCs on bacterial load, innate immunity factors, and macr…

Magnetic-field-induced reentrance of Fermi-liquid behavior and spin-lattice relaxation rates in

2009

Abstract A strong departure from Landau–Fermi liquid (LFL) behavior have been recently revealed in observed anomalies in both the magnetic susceptibility χ and the muon and 63Cu nuclear spin-lattice relaxation rates 1 / T 1 of YbCu 5 − x Au x ( x = 0.6 ). We show that the above anomalies along with magnetic-field-induced reentrance of LFL properties are indeed determined by the dependence of the quasiparticle effective mass M ∗ on magnetic field B and temperature T and demonstrate that violations of the Korringa law also come from M ∗ ( B , T ) dependence. We obtain this dependence theoretically utilizing our approach based on fermion condensation quantum phase transition (FCQPT) notion. Ou…

Antimicrobial susceptibility and quinolone resistance mechanism of Arcobacter butzleri isolates from sewage samples in Spain

2012

Suicide and Ambient Temperature: A Multi-Country Multi-City Study

2019

Background: Previous literature suggests that higher ambient temperature may play a role in increasing the risk of suicide. However, no multi-country study has explored the shape of the association and the role of moderate and extreme heat across different locations. Objectives: We examined the short-term temperature–suicide relationship using daily time-series data collected for 341 locations in 12 countries for periods ranging from 4 to 40 y. Methods: We conducted a two-stage meta-analysis. First, we performed location-specific time-stratified case-crossover analyses to examine the temperature–suicide association for each location. Then, we used a multivariate meta-regression to combine t…