Octakis)di-p-methylphenyl sulfoxide)lanthanide(III) perchlorates and their decomposition

Lanthanide(III) complexes of general composition Ln(p-TSO)₈(ClO₄)₃ (where Ln = Tb-Lu or Y and p-TSO = di-p-methylphenyl sulfoxide) were synthesized and characterized by chemical and thermal analysis, magnetic moments and IR spectra in the solid phase, and by molar conductance and molecular weights in solution studies. The thermal decomposition, in an air stream, of these complexes leads to the formation of pure lanthanide oxysulfates at 900°C. The formation of these species requires the transformation of part of the ligand sulfoxide and this process is discussed in terms of the identification of the solid and gaseous products obtained after heating to different temperatures by X-ray diffraction, IR spectroscopy and mass spectrometry.     

Radiation Effects on Concentrated Potassium Hexacyanoferrate(III) Solutions

The neutron irradiated potassium hexacyanoferrate(III) solutions were analyzed for Fe(CN)₆^4?, Fe(CN)₆^3?, and Prussian blue. The retention values (1.1%) were constant throughout the pH and concentration ranges studied, and did not change with the length of irradiation. The complex behavior of the radiochemical yield of the Fe(CN)₆^4? and Prussian blue was attributed to the competition of the various reactions involved in the irradiation.     

The Solid State Electrochemistry of Dysprosium(III) Hexacyanoferrate(II)

A new electroactive polynuclear inorganic compound of rare earth metal hexacyanoferrate, dysprosium hexacyanoferrate (DyHCF), was prepared chemically and characterized using techniques of FTIR spectroscopy, thermogravimetric analysis (TGA), UV‐vis spectrometry and X‐ray photoelectron spectroscopy (XPS) etc. The cyclic voltammetric behavior of DyHCF mechanically attached to the surface of graphite electrode was well defined and exhibited a pair of redox peaks with the formal potential of 217 mV (vs. SCE) at a scan rate of 100 mV/s in 0.2 M NaCl solution and the redox peak currents increased linearly with the square root of the scan rates.     

Octakis(ferrocene)-substituted porphyrazines

Metal-free porphyrazine and metal porphyrazinates (M = Mg, Cu, Co or Zn) substituted with eight ferrocene moieties on the periphery through flexible alkylthio-bridges have been synthesised in a multi-step reaction sequence. The new compounds have been characterised by elemental analyses, i.r., ¹H- and ¹³C-n.m.r., u.v.–vis. and mass spectra. The electrochemical investigation of porphyrazines indicates that all the ferrocene moieties are oxidised at the same potential, confirming the lack of any interaction among ferrocene groups or between ferrocenes and the porphyrazine core.     

A pyrophosphate-responsive gadolinium(III) MRI contrast agent

This study shows that the relaxivity and optical properties of functionalised lanthanide‐DTPA‐bis‐amide complexes (lanthanide=Gd³⁺ and Eu³⁺, DTPA=diethylene triamine pentaacetic acid) can be successfully modulated by addition of specific anions, without direct Ln³⁺/anion coordination. Zinc(II)‐dipicolylamine moieties, which are known to bind strongly to phosphates, were introduced in the amide “arms” of these ligands, and the interaction of the resulting Gd–Zn₂ complexes with a range of anions was screened by using indicator displacement assays (IDAs). Considerable selectivity for polyphosphorylated species (such as pyrophosphate and adenosine‐5′‐triphosphate (ATP)) over a range of other anions (including monophosphorylated anions) was apparent. In addition, we show that pyrophosphate modulates the relaxivity of the gadolinium(III) complex, this modulation being sufficiently large to be observed in imaging experiments. To establish the binding mode of the pyrophosphate and gain insight into the origin of the relaxometric modulation, a series of studies including UV/Vis and emission spectroscopy, luminescence lifetime measurements in H₂O and D₂O, ¹⁷O and ³¹P NMR spectroscopy and nuclear magnetic resonance dispersion (NMRD) studies were carried out.     

Sorption of Hexacyanoferrate(II,III) Anions on Nickel(II) Hydroxide

Fe(CN)₆ ^{3 -} and Fe(CN)₆ ^{4 -} anions are sorbed from aqueous solutions of their potassium and cesium salts on -Ni(OH)2 by the mechanism of anion exchange with hydroxy groups. Alkali metal cations (K⁺, Cs⁺) are also partly sorbed on nickel(II) hydroxide in the form of anionic complexes (K,Cs) _z Fe(CN)₆ ^{(n - z)-}, where n = 3 or 4 (0 < z < n). The chemical composition of the new phase appearing in contact of nickel(II) hydroxide with aqueous potassium and cesium hexacyanoferrates(II, III) was determined by X-ray phase analysis and IR spectroscopy.     

Separation of gadolinium(III) and lanthanum(III) by nanofiltration-complexation in aqueous medium

A new method is proposed for the separation of gadolinium(III) and lanthanum(III) in aqueous medium by nanofiltration combined with a complexation step. First DTPA was chosen as ligand for a selective Gd(III)/La(III) complexation. Having investigated the influence of three factors (pH, temperature and amount of ligand) for the selective complexation of DTPA towards Gd(III) and La(III), the system is then combined with a nanofiltration separation process to remove 92% of initial Gd(III) and only 12% of initial La.     

Mathematical Modeling of Ru(VI)-catalyzed Oxidation of Alcohols by Hexacyanoferrate(III)

The title kinetics reaction has been modeled with a system of ordinary differential equations, for the concentrations of the compounds. In these equations, the velocity constants are unknown. In this work, the four constants had been evaluated by minimizing a mean squares expression comparing the experimental measures of the concentration of hexacyanoferrate(III) with the solution of the system of ordinary differential equations. This problem has not a unique solution and there is an infinite set of constants which minimize the expression. Several sets of possible constants have been analyzed. One of them has been obtained estimating two of the constants with the stationary state approach. For the model to be well posed the constants must fulfill a condition. Information about the order of magnitude of the constants has been reached.     

Thin-Layer Chromatography of Anions — Separation of Coexisting Hexacyanoferrate(II), Hexacyanoferrate(III) and Thiocyanate with a New Mobile Phase

JPC – Journal of Planar Chromatography – Modern TLC - The thin-layer chromatography of eighteen anions has been performed on silica layers with mixed aqueous–organic mobile...