Mössbauer effect studies of spin-spin relaxation in single crystals of Fe(NO3)3·9H2O at 4.2 K

Synthesis and characterization of dinuclear complexes containing the FeIII–F · · · (H2O)MII motif

“…A similar effect has been observed for Fe(NO 3 ) 3 ؒ9H 2 O and explained on the basis of the crystal symmetry. 19 The space group of with Fe ؒ ؒ ؒ Fe distance as small as 3.193(2) Å has been reported 20 (with an exogenous methoxide as bridging group) there do not appear to be geometrical contraints preventing the formation of a more usual µ-fluoride bridge rather than the aqua-fluoride-bridged compounds we have structurally characterized. This result has implications for the mode of inhibition by fluoride ions in PAPs.…”

“…Dry acetonitrile and dry MeOH were obtained from Sigma-Aldrich Chemical Company, Inc. (>99.8%) and used as received. The UV/VIS spectra were recorded on a Shimadzu UV-3100 spectrophotometer, IR spectra of the complexes in KBr discs using an Hitachi 270-30 IR spectrometer, fast atom bombardment mass spectra on a Kratos MS50RF spectrometer and 19 F NMR spectra were recorded on a Varian Gemini 2000 using α,α,α-trifluorotoluene as an internal reference. Elemental analyses were performed at the Chemistry Department II at Copenhagen University and Atlantic Microlab, Inc., Norcross, Georgia, USA.…”

Mössbauer Effect Studies of Iron in Kaolin. I. Structural Iron

“…The total area of the asymmetric contribution is greater than that which would be due only to the impurity mineral, indicating that not all of the Fe is in the -5/2 state. Morup et al (1978) obtained similar spectra for frozen ferric nitrate solutions in externally applied fields, although in that study fields of 50 kG resulted in symmetric lineshapes. Figure 6.…”

Revealing the nuclearity of iron citrate complexes at biologically relevant conditions

“…Application of the external magnetic field causes the energy splitting of ionic spin levels to depend on the angle between the applied field and the ligand field axis. Since the investigated samples were frozen solutions, ensuring the random orientation of the Fe entities, an application of external magnetic field may result in an increase of the spin–spin relaxation time, making the spectrum lines sharper, as was observed (Mørup et al 1978 ). The cross-relaxation theory described in (Vértes and Nagy 1990 ; Mørup et al 1978 ) suggests that increasing the applied magnetic field leads to the decrease of relaxation frequency.…”

“…Since the investigated samples were frozen solutions, ensuring the random orientation of the Fe entities, an application of external magnetic field may result in an increase of the spin–spin relaxation time, making the spectrum lines sharper, as was observed (Mørup et al 1978 ). The cross-relaxation theory described in (Vértes and Nagy 1990 ; Mørup et al 1978 ) suggests that increasing the applied magnetic field leads to the decrease of relaxation frequency. Indeed, in our case we have observed that while application of 0.5 T just causes the satellite peaks of the broad magnetic component to be more defined, the increase of magnetic field value up to 5 T allows to identify different lines of the sextet separately, suggesting that the relaxation time is high enough (Fig.…”