ISSN:
1434-4475
Schlagwort(e):
Chromium(III)complexes
;
Iron(II)complexes
;
Magnetic susceptibility measurements
;
Mössbauer spectra
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Chemie und Pharmazie
Beschreibung / Inhaltsverzeichnis:
Zusammenfassung Es wurden Komplexe von Pyridin-2-aldoxim (Hpox) mit Fe(II) und Cr(III) vom Typ [Fe(Hpox)2 X 2] (X=Cl, Br, I, NCS), [Cr(Hpox)3]Cl3·3 H2O, [Cr(Hpox)2 X 2]ClO4 (X=F, Cl, Br) und [Cr(Hpox)2(H2O)2]Br3·H2O hergestellt. Charakterisierung und Diskussion von Geometrie und Bindungsverhalten in den Komplexen erfolgte auf Grund von analytischen Daten, Röntgen-Pulveraufnahmen, Elektronenanregungsspektroskopie, Infrarotspektroskopie, magnetischen Messungen undMössbauer-Spektroskopie.
Notizen:
Abstract Complexes of pyridine-2-aldoxime (Hpox) with iron(II) and chromium(III) of type, [Fe(Hpox)2 X 2] (X=Cl, Br, I or NCS); [Cr(Hpox)3]Cl3·3 H2O; [Cr(Hpox)2 X 2]ClO4 (X=F, Cl or Br) and [Cr(Hpox)2(H2O)2]Br3·H2O were prepared and characterized by analytical X-ray powder diffraction, magnetism, vibrational (conventional and far-infrared) and electronic spectroscopy techniques. X-ray and electronic spectral data indicate that all the complexes except [Cr(Hpox)3]Cl3·3 H2O havetrans-pseudo-octahedral microsymmetry around the metal ion. Infrared spectral data indicate that the ligand, Hpox, behaves like a neutral ligand and coordinates to the metal ion through pyridine nitrogen atom and oxime nitrogen atom in all these complexes. The magnetic susceptibilities of chromium(III) complexes, measured over a temperature range 300–78 K, are independent of temperature whereas the magnetic moments of iron(II) complexes over a temperature range 300–20 K are dependent of temperature. The observed temperature dependence of magnetic moments of iron(II) complexes was used to evaluate the magnitude of orbital reduction factor,k, the low-symmetry distortion parameter, Δ, and the extent of reduction in spin-orbital coupling, λ. In all these iron(II) complexes the magnetic results indicate the presence of an orbitally non-degenerate,5B2g, ground state. Magnetically unperturbed and perturbedMössbauer spectra of iron(II) complexes at various temperatures have also been reported. Magnetically perturbedMössbauer spectra of iron(II) complexes at 4.2 K in an axial field of 60kGauss indicate that the principal component of electric field gradient tensor is positive and consistent with5B2g ground electronic state in a tetragonal (D 4h) local site symmetry.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00938718
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