Search results for "Ferro"
showing 10 items of 2451 documents
[Criii(L)(CN)4]−: a new building block in designing cyanide-bridged 4,2-ribbon-like chains {[Criii(L)(CN)4]2Mn(H2O)2}·nH2O [L = 2-aminomethylpyridine…
2005
The preparation, X-ray crystallography and magnetic study of compounds PPh4[Cr(ampy)(CN)4]·H2O (1), PPh4[Cr(phen)(CN)4]·H2O·CH3OH (2), {[Cr(ampy)(CN)4]2Mn(H2O)2}·6H2O (3) and {[Cr(phen)(CN)4]2Mn(H2O)2}·4H2O (4), with PPh4+ = tetraphenylphosphonium cation, ampy = 2-aminomethylpyridine and phen = 1,10-phenanthroline, are reported here. 1 and 2 are mononuclear complexes whereas 3 and 4 are 4,2-ribbon-like bimetallic chains. The magnetic properties of 1–4 were investigated in the temperature range 1.9–300 K. A quasi Curie law behaviour for a magnetically isolated spin quartet is observed for 1 and 2. Compounds 3 and 4 are ferrimagnetic CrIII2MnII chains, which exhibit a metamagnetic behaviour, …
Structural and magnetic characterization of the tridimensional network [Fe(HCO2)3]n·nHCO2H
2013
In this work we report the structural and magnetic characterization of a new three-dimensional porous metal–organic framework (MOF) based on iron(III) and the formate anion, [Fe(HCO2)3]n·nHCO2H (1), which was obtained by solvothermal synthesis. The tridimensional structure crystallizes in the trigonal space group Rc and is formed by highly regular octahedral Fe(OHCO)6 units. These units contain six equal Fe–O distances, with angles slightly different from 90° or 180°. The packing of 1 corresponds to a 3D covalent network defined by face sharing between the parallelepipeds, which are formed by the interactions of Fe(OHCO)6 units through formate ligands, thus generating a 41263 topology. This…
Self-Assembled One- and Two-Dimensional Networks Based on NH2Me2[ReX5(DMF)] (X = Cl and Br) Species: Polymorphism and Supramolecular Isomerism in Re(…
2011
Three mononuclear rhenium(IV) compounds of general formula NH 2 Me 2 [ReX 5 (DMF)] [NH 2 Me 2 + = dimethylammonium cation, DMF = N,N-dimethylformamide, and X = Cl (1 and 2) and Br (3)] have been prepared and characterized. In all three cases, the rhenium atom is six-coordinated by five chloro (1 and 2) or bromo (3) atoms and one oxygen atom from a DMF molecule (1―3) building a somewhat distorted octahedral surrounding. Short Re IV ―X · · · X―Re IV contacts and H-bonds occur in the crystal lattice generating novel supramolecular Re(IV) architectures. 1 and 2 are polymorphs and supramolecular isomers that exhibit supramolecular ladder-like ( 1 ) and rectangular two-dimensional grids (2), the …
Dimetallic complexes derived from a novel dinucleating chelating symmetric triazole ligand; crystal structure, magnetic properties and ESR study of b…
1999
Reaction of 3,5-diacetylamino-1,2,4-triazole (Hdaat) with copper(II), nickel(II) and cobalt(II) salts yields dinuclear co-ordination compounds, which were spectroscopically characterized. The crystal and molecular structure of one of the compounds, bis[µ-3,5-diacetylamino-1,2,4-triazolato-O′,N 1,N 2,O″]bis[(nitrato)(aqua)copper(II)] 1, was determined by single-crystal X-ray diffraction. Complex 1 consists of dinuclear units with an inversion center at the midpoint of the Cu–Cu vector. The most remarkable feature of this structure is that the daat ligand forms a six-membered chelate ring [Cu–N3–C3–N1–C2–O1; Cua–N4–C4–N5–C5–O2], in contrast with the five-membered chelate rings always found in…
Azide bridged dicopper(II), dicobalt(II) complexes and a rare double μ-chloride bridged ferromagnetic dicobalt(II) complex of a pyrazolyl-pyrimidine …
2012
Abstract Two new dinuclear copper(II) complexes [Cu2(PymPz)2(N3)2Cl2] (1), [Cu2(PymPz)2(N3)4] (2) and two new dinuclear cobalt(II) complexes [Co2(PymPz)2Cl4] (3), [Co2(PymPz)2(N3)4] (4) [PymPz = 2-(3,5-dimethyl-1H-pyrazol-1-yl)-4,6-dimethylpyrimidine] have been synthesized and characterized crystallographically and spectroscopically. In each of the complexes 1, 2 and 4 the two adjacent metal centers are bridged by a pair of μ-1,1 azide groups whereas in 3 the metal centers are bridged by a pair of chloride ions. In the complexes, all the metal centers are pentacoordinated. In 1 and 2 the copper(II) centers have distorted square pyramidal geometry (τ = 0.18 for 1 and 0.091 for 2) but in 3 an…
Defective dicubane-like tetranuclear nickel(II) cyanate and azide nanoscale magnets.
2010
Four tetrameric nickel(II) pseudohalide complexes have been synthesized and structurally, spectroscopically, and magnetically characterized. Compounds 1-3 are isostructural and exhibit the general formula [Ni(2)(dpk·OH)(dpk·CH(3)O)(L)(H(2)O)](2)A(2)·2H(2)O, where dpk = di-2-pyridylketone; L = N(3)(-), and A = ClO(4)(-) for 1, L = NCO(-) and A = ClO(4)(-) for 2, and L = NCO(-) and A = NO(3)(-) for 3. The formula for 4 is [Ni(4)(dpk·OH)(3) (dpk·CH(3)O)(2)(NCO)](BF(4))(2)·3H(2)O. The ligands dpk·OH(-) and dpk·CH(3)O(-) result from solvolysis and ulterior deprotonation of dpk in water and methanol, respectively. The four tetramers exhibit a dicubane-like core with two missing vertexes where the…
"Through-space" 31P spin-spin couplings in ferrocenyl tetraphosphine coordination complexes: improvement in the determination of the distance depende…
2008
Abstract From the analysis of several nickel and palladium halide complexes of a constrained ferrocenyl tetraphosphine, the existence in solution phase of unique 31P–31P “through-space” nuclear spin–spin coupling constants (JPP) had been previously evidenced. Due to the blocked conformation of the species in solution, and based on the NMR spectra obtained for the complexes and their corresponding solid state X-ray structures, these JPP constants had been shown to clearly depend on the mutual spatial position of the corresponding phosphorus atoms. Herein, the quantitative correlation disclosed at that time (P⋯P distance dependence of coupling constants) is remarkably confirmed, and mathemati…
(2,2‐Dibromovinyl)ferrocene as a Building Block for the Assembly of Heterodinuclear Complexes – Preparation of an σ‐Alkenylpalladium Complex and Dime…
2007
The oxidative addition of (2,2-dibromovinyl)ferrocene [Br2C=C(H)–Fc] (1) to [Pd(PPh3)4] yields the heterodinuclear σ-alkenyl complex trans-[{Pd(Br)(PPh3)2}–C(Br)=C(H)–Fc] (2). Nucleophilic attack of sodium thiolates on 1 unexpectedly affords the vinyl thioether derivatives (Z)-[(RS)(H)C=C(H)–Fc] (4a: R = Ph; 4b: R = tBu; 4c: R = Et). Complexes 4a and 4c can also be prepared by addition of NaSR across the triple bond of Fc–C≡C–H (3). Addition of an excess of NaSR to 1 affords the dithioether derivatives (Z)-[(RS)(H)C=C(SR)–Fc] (5a: R = Ph; 5b: R = p-tolyl; 5c: R = Et). An addition/elimination sequence is suggested to account for this surprising result. The yield of 5c is very low due to a co…
Cobalt(II) Sheet-Like Systems Based on Diacetic Ligands: from Subtle Structural Variances to Different Magnetic Behaviors
2009
The preparation, X-ray crystallography, and magnetic investigation of the compounds [Co(H(2)O)(2)(phda)](n) (1), [Co(phda)](n) (2), and [Co(chda)](n) (3) [H(2)phda = 1,4-phenylenediacetic acid and H(2)chda = 1,1-cyclohexanediacetic acid] are described herein. The cobalt atoms in this series are six- (1) and four-coordinated (2 and 3) in distorted octahedral (CoO(6)) and tetrahedral (CoO(4)) environments. The structures of 1-3 consists of rectangular-grids which are built up by sheets of cobalt atoms linked through anti-syn carboxylate bridges, giving rise to either a three-dimensional structure across the phenyl ring (1 and 2) or to regularly stacked layers with the cyclohexyl groups acting…
Road restraint systems monitoring with stereoscopic dip-technique
2015
Road restraint systems (RRS) are used to protect vehicle occupants from dangerous roadside elements such as rigid obstacles, slopes, utility poles, etc. The crashes on a road restraint system damage its structure and, therefore, the functional behavioral; for this reason is required monitoring the RRS into their operational conditions. The research addresses the problem of the measurement of safety barrier (SB) deformations by means digital image processing technique (DIP). This technique is founded on the analysis of high resolution photos/videos, obtained by means of 3D camera installed into a data vehicle. The DIP technique has been used for evaluating the longitudinal safety barriers de…