Immobilization of complexes of some heavy metals with a 2-(4-pyridylazo)-resorcinol “PAR” on Algerian hydrothermal clay

International audienc

Effect of the chelating agents on bio-sorption of hexavalent chromium using Agave sisalana fibers

International audienc

Electron paramagnetic resonance and LIESST effect in spin-crossover cis-bis(thiocyanato)bis[N-(2-pyridyl-methylene)aminobiphenyl]iron(II) compound

Two different phases of spin-crossover cis-bis(thiocyanato)-bis(N-2′-pyridylmethylene)-4-(aminobiphenyl) iron(II), Fe(PM-BiA)2(NCS)2 have been investigated by EPR in X- and Q-bands. The EPR parameters for Mn2± show that the phase II has similar behavior to intentionally doped compound. EPR spectra as function of the temperature reveal that the spin transition of the iron(II) centers induced some modifications on the whole structure and then on the environment of the manganese ions. The LIESST effect is reported for the two phases and for Fe0.216Mn0.784(PM-BiA)2(NCS)2. The magnetic properties under irradiation of the phase II and of Fe0.216Mn0.784(PM-BiA)2(NCS)2 are very similar and the limit temperature of the HS metastable state is around Tliesst = 50 K, as compared to 80 K for the phase I. The new kind of bistability called LITH (Light Induced Thermal Hysteresis) has been observed for the three derivatives. The HS → LS relaxation is higher for the phase II and Fe0.216Mn0.784(PM-BiA)2(NCS)2 than for the Phase I

Electron Paramagnetic Resonance and LIESST Effect in Spin-Crossover Cis-Bis(Thiocyanato)Bis N-(2-Pyridyl-Methylene)Aminobiphenyl Iron(II) Compound

no abstrac

Electron Paramagnetic Resonance and LIESST Effect in Spin-Crossover Cis-Bis(Thiocyanato)Bis N-(2-Pyridyl-Methylene)Aminobiphenyl Iron(II) Compound

no abstrac

SILAR deposition of Ni(bpy)3X: {X = (NCS)2, (Fe(CN)5NO), and (Ag(CN)2)2} thin films on glass substrates

The authors focused on the preparation of thin layers based on hybrid materials (organometallic complexes) deposited onto glass substrates. The deposition experiments of [Ni(bpy)3](NCS)2, [Ni(bpy)3](Ag(CN)2)2, and [Ni(bpy)3](Fe(CN)5NO) were performed on glass slides (18 mm × 18 mm) by successive ionic layer adsorption and reaction (SILAR) method. The influence of some parameters, such as dipping cycle numbers (30, 60, and 120 dipping cycles), temperature (20°C, 30°C, 40°C, and 50°C), precursors concentration (10−3, 10−2, and 10−1 M), and the nature of the counteranions (NCS−, [Fe(CN)5NO]−2, [Ag(CN)2]−) were studied. Different methods (UV-Vis, SEM, FTIR, and XRD) were used to characterize the deposited layers to determine the absorption coefficient (α) and gap energy (Eg) of the materials

Classification and Identification of Enterococci: a Comparative Phenotypic, Genotypic, and Vibrational Spectroscopic Study

Rapid and accurate identification of enterococci at the species level is an essential task in clinical microbiology since these organisms have emerged as one of the leading causes of nosocomial infections worldwide. Vibrational spectroscopic techniques (infrared [IR] and Raman) could provide potential alternatives to conventional typing methods, because they are fast, easy to perform, and economical. We present a comparative study using phenotypic, genotypic, and vibrational spectroscopic techniques for typing a collection of 18 Enterococcus strains comprising six different species. Classification of the bacteria by Fourier transform (FT)-IR spectroscopy in combination with hierarchical cluster analysis revealed discrepancies for certain strains when compared with results obtained from automated phenotypic systems, such as API and MicroScan. Further diagnostic evaluation using genotypic methods—i.e., PCR of the species-specific ligase and glycopeptide resistance genes, which is limited to the identification of only four Enterococcus species and 16S RNA sequencing, the “gold standard” for identification of enterococci—confirmed the results obtained by the FT-IR classification. These results were later reproduced by three different laboratories, using confocal Raman microspectroscopy, FT-IR attenuated total reflectance spectroscopy, and FT-IR microspectroscopy, demonstrating the discriminative capacity and the reproducibility of the technique. It is concluded that vibrational spectroscopic techniques have great potential as routine methods in clinical microbiology