Search results for "Cyana"
showing 10 items of 585 documents
Structural and Magnetic Characterization of a μ-1,5-Dicyanamide-Bridged Iron Basic Carboxylate [Fe3O(O2C(CH3)3)6] 1D Chain
2008
We are reporting an unprecedented example of a mu-1,5-dicyanamide (dca)-bridged iron basic carboxylate, [Fe3O(O2C(CH3)3)6], 1D chain. As revealed from X-ray determination, the Fe3O cores are arranged in a zigzag configuration along the chain and strictly aligned in the same plane. The chains are well-isolated by the bulky tert-butyl groups. Magnetic measurements showed that the Fe3O units are weakly antiferromagnetically coupled (J = -0.6 cm(-1)) through the dca ligand while possessing a well-isolated S = 1/2 spin ground state arising from competing antiferromagnetic interactions.
Structural analysis and magnetic properties of the copper(II) dicyanamide complexes [Cu2(dmphen)2(dca)4], [Cu(dmphen)(dca)(NO3)] and [Cu(4,4′-dmbpy)(…
2004
Abstract The preparation, crystal structures and magnetic properties of three copper(II) compounds of formulae [Cu2(dmphen)2(dca)4] (1), [Cu(dmphen)(dca)(NO3)]n (2) and [Cu(4,4′-dmbpy)(H2O)(dca)2] (3) (dmphen=2,9-dimethyl-1,10-phenanthroline, dca=dicyanamide and 4,4′-dmbpy=4,4′-dimethyl-2,2′-bipyridine) are reported. The structure of 1 consists of discrete copper(II) dinuclear units with double end-to-end dca bridges whereas that of 2 is made up of neutral uniform copper(II) chains with a single symmetrical end-to-end dca bridge. Each copper atom in 1 and 2 is in a distorted square pyramidal environment: two (1) or one (2) nitrile-nitrogen atoms from bridging dca groups, one of the nitrogen…
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…
Remarkable Steric Effects and Influence of Monodentate Axial Ligands L on the Spin-Crossover Properties of trans-[FeII(N4 ligand)L] Complexes
2007
Iron(II) complexes obtained from tetradentate, rigid, linear N4 ligands have been investigated to appraise the influence of steric effects and the impact of trans-coordinated anions on the spin-transition behavior. As expected, the well-designed ligands embrace the metal center, resulting in octahedral iron(II) complexes where the basal plane is fully occupied by the pyridine/pyrazole N4 ligand, while anions or solvent molecules are exclusively axially coordinated. Precursor complexes, namely, [Fe(bpzbpy)(MeOH)2](BF4)2 (where bpzbpy symbolizes the ligand 6,6'-bis(N-pyrazolylmethyl)-2,2'-bipyridine) and [Fe(mbpzbpy)(MeOH)2](BF4)2 (where mbpzbpy symbolizes the ligand 6,6'-bis(3,5-dimethyl-N-p…
Isobaric vapor-liquid equilibria for the extractive distillation of 2-propanol + water mixtures using 1-ethyl-3-methylimidazolium dicyanamide ionic l…
2017
Abstract Isobaric vapor–liquid equilibria for the binary systems 2-propanol + water, 2-propanol + 1-ethyl-3-methylimidazolium dicyanamide ([emim][DCA]), and water + [emim][DCA] as well as the vapor–liquid equilibria for the 2-propanol + water + [emim][DCA] ternary system have been obtained at 100 kPa using a recirculating still. The electrolyte nonrandom two-liquid (e-NRTL) model was used for fitting successfully the experimental data. The effect of [emim][DCA] on the 2-propanol + water system has been compared with that produced by other ionic liquids reported in the literature. From the results, [emim][DCA] appears as a good entrainer for the extractive distillation of this solvent mixtur…
Isobaric vapor-liquid equilibria for the 1-propanol + water + 1-ethyl-3-methylimidazolium dicyanamide system at 100 kPa
2017
Abstract Isobaric vapor–liquid equilibria for the 1-propanol + 1-ethyl-3-methylimidazolium dicyanamide ([emim [DCA] binary system and for the 1-propanol + water + [emim] [DCA] ternary system have been obtained at 100 kPa using a recirculating still. The electrolyte nonrandom two-liquid (e-NRTL) model was used for fitting successfully the experimental data. The effect of [emim][DCA] on the 1-propanol + water system has been compared with that produced by other ionic liquids reported in the literature. From the results, [emim][DCA] appears as a potential entrainer for the extractive distillation of this solvent mixture, causing the azeotrope to disappear at 100 kPa when the ionic liquid mole …
CCDC 293967: Experimental Crystal Structure Determination
2006
Related Article: R.Artali, G.Bombieri, N.Bertazzi|2005|Acta Crystallogr.,Sect.E:Struct.Rep.Online|61|m2733|doi:10.1107/S1600536805038870
Properties and structure of cyanate ester/polysulfone/organoclay nanocomposites
2006
In this paper, a cyanate ester (CE) matrix has been modified with polysulfone and an organic montmorillonite (Nanofil 919). The blend was thermally cured in presence of copper acetylcetonate and nonylphenol. The morphology of the cured materials was investigated by wide angle X-ray, scanning and transmission electron microscopy techniques. An intercalate structure of silicate platelets in the cyanate matrix has been obtained. Furthermore, results of thermogravimetric analysis (TGA) suggest that CE/PSF/Nanofil 919 nanocomposites have higher thermal stability than the neat resin, increasing the onset decomposition temperature. Flexural strength distributions of modified and neat cyanate matri…
Use of new hydroxytelechelic cis-1,4-polyisoprene (HTPI) in the synthesis of polyurethanes (PUs): Influence of isocyanate and chain extender naturean…
2006
AbstractNew segmented polyurethanes (thermoplastic-elastomers) based on previously described hydroxytelechelic cis-1,4-polyisoprene (HTPI), miscellaneous isocyanates and chain extenders at various equivalent ratios were prepared by the classical one-shot method. The influence of the nature of isocyanate and chain extender, as well as their equivalent ratios, on the mechanical and thermal materials behavior was investigated. Thus, a comparative assessment of material properties was performed. Microphase separation of hard and soft segments was observed by DMTA, DSC and AFM. Moreover, according to Thermogravimetric Analysis (TGA), linear relationships depending on the isocyanate and chain ext…
Influence of sample pan on the thermal behaviour of KSCN measured with TG
2003
Abstract In this study, the influence of the sample pan on the thermal behaviour of potassium thiocyanate (KSCN) was investigated. The measurements were performed with thermogravimetry (TG) and the two sample pans used were a platinum pan and a ceramic crucible. The samples were heated to 400–950 °C and the thermal products were identified by powder diffraction. The thermal behaviour of KSCN was found to be dependent on the sample pan used. With the platinum sample pan KSCN reacted in the first step into a mixture of K 2 SO 4 and potassium tetracyanoplatinate (K 2 Pt(CN) 4 ). In the second step, the mixture reacted further to pure K 2 SO 4 . In the ceramic sample crucible, however, the reac…