Synthesis,physicochemical properties and voltammetric characterization of some new Fe(III) complexes with semicarbazone-based ligands

Several bis(ligand) octahedral complexes of iron(III) with salicylaldehyde semi-, thiosemi-, and S-methylthiosemi- carbazones have been synthesized and characterized by elemental analysis, conductivity and magnetic measurements, electronic and IR spectra, as well as by linear sweep and cyclic voltammetry. General procedures for the syntheses of all types of complexes have been established, giving better defined reaction conditions. Physicochemical properties of the novel complexes have been related to those of the already known compounds of the same type.     

Field-induced splitting of the OH-Stretch absorption line in KTaO3 and KTaO3 :Li

Abstract

We have studied the electric field-induced splitting of a single OH stretch mode in KTaO₃ and KTaO₃ :Li. For the three prominent directions [100], [110] and [111] we observed polarized splitting patterns with up to six components. The line positions exhibit no mirror symmetry with respect to the zero-field frequency. This behaviour can be interpreted by taking into account a field-dependent shift of the Ta⁵⁺ ion and a change of the covalent character of the bond. Li-doped KTaO₃ samples show for [Li] < 2mol% a line broadening, while for [Li] < 3.5 mol% a field dependent phase transition has been observed with evidence for a 90 degree domain structure.     

Crystal structure of K[PtCl3(caffeine)] and its interactions with important nitrogen-donor ligands

The crystal structure of K[PtCl₃(caffeine)] was determined. The coordination geometry around platinum is square-planar formed by N9 of the caffeine ligand and three Cl^? ions. The bond lengths and angles of K[PtCl₃(caffeine)] were compared with those reported for [PtCl₃(caffeine)]^? and K[PtCl₃(theobromine)]. At the level of the statistical significance of the data we have compared, no differences in the bond distances and angles for any of these compounds were noticed. Weak interactions between K⁺ and Cl^? are responsible for the formation of 1-D polymeric chains in the crystal structure of the complex. The interactions of K[PtCl₃(caffeine)] with inosine (Ino) and guanosine-5′-monophosphate (5′-GMP) were studied by ¹H NMR spectroscopy at 295 K in D₂O in a molar ratio of 1 : 1. The results indicate formation of the reaction product [PtCl₃(Nu)] (Nu=Ino or 5′-GMP) with the release of caffeine from the coordination sphere of the starting complex. The higher stability of the bond between the Pt(II) ion and Ino or 5′-GMP compared to the stability of the platinum–caffeine bond is confirmed by density functional theory calculations (B3LYP/LANL2DZp) using as models 9-methylhypoxanthine and 9-methylguanine.     

Dependence of the probability of biological effects per hit,induced by radiation emitted by <Superscript>222</Superscript>Rn,from alpha particle energies and the geometry of tracheobronchial tree

Biological effects of radiation in terms of their effect on living cells are considered in this work. In dosimetry of the human lung exist the need to include the influence of the biological effects. The aim of this work is to calculate the probability of biological effects (transformation cell and production of lesion) per hit induced by alpha particle radiation on sensitive cells of human lung. Probability was calculated by applying the analytical model cylinder bifurcation (Nikezić et al., Int J Radiat Biol 79(3):175–180, 2003; Nikezić and Yu, Radiat Environ Biophys 42:49–53, 2003) which was created to simulate the geometry of human lung with the geometric distribution of cell nuclei in the airway wall of the tracheobronchial tree. This analytical model of the human traheobronchial tree represent the exstension of the ICRP66 model, and follows it as much as possible. Reported probabilities are calculated for various targets and alpha particle energies in order to show dependence of the probability of biological effects (transformation cell and production of lesion) per hit from alpha particle energies and the geometry of tracheobronchial tree for the human lung.     

Optical and dielectric properties of fluorinated ethylene propylene and tetrafluoroethylene–perfluoro(alkoxy vinyl ether) copolymer films modified by low energy N and C ion beams

Fluorinated ethylene propylene (FEP) and tetrafluoroethylene–perfluoro(alkoxy vinyl ether) (PFA) copolymer films were irradiated in vacuum with 60 keV C⁴⁺ and N⁴⁺ ions to fluences ranging from 1.0×10¹² to 5.0×10¹⁵ cm⁻². Changes in optical and dielectric properties were analyzed by spectroscopic ellipsometry and ultraviolet–visible (UV–vis), Raman and dielectric relaxation spectroscopies. Direct and indirect energy band gap values were determined from the absorption edge in the 200–800 nm region using Tauc's relation. The values of the direct energy gap have been found to be greater than the corresponding values of the indirect energy gap. Significant changes in the index of refraction, and β and γ dielectric relaxations were observed in the case of N⁴⁺ irradiated FEP and PFA samples.     

ANGLE: A PC-code for semiconductor detector efficiency calculations

A broadly applicable, flexible and user-friendly PC-code (ANGLE) for calculations of semiconductor detector full energy peak efficiencies ( _p ) is presented. The physical model behind is the concept of the effective solid angle . Written in Pascal, and operating in windows and menus data manipulation mode, ANGLE yields the efficiencies for: (1) HPGe true- and closed-end coaxial (bothn- andp-types), (2) Ge(Li) open- and closed-end, (3) planar LEPD and (4) well-type detectors. Supposing coaxial positioning, cylindrical or Marinelli sources can be treated, regardless of their dimensions (this includes point, disk and ring sources, bulky samples and infinite geometrics). Possible displacement between source and detector axes is treated in our another work, relative to this one. ANGLE input parameters are: (1) reference efficiency curve for the detector used (i.e., efficiency vs. -energy for calibrated point sources at a reference distance), (2) detector type and configuration (active body and inactive layers, end cap, windows, housing, shielding, (3) source data (dimension and composition of both container and active material), (4) source-detector geometry (distance, intercepting layers and their composition) and (5) some computational data (Gauss integration coefficients). Gamma-attenuation is calculated upon an extensive (per element and per energy) data file. In the output, efficiency vs. -energy is found, both in forms of tables and graphs. In routine applications accuracies of 3–4% are achieved (not worse than 7% for the most unfavourable geometries). Computation times when using recent PC models are of the order of minutes. ANGLE frame is also easily adjustable to other semiempirical or Monte Carlo models for efficiency calculations.