Magnetic interactions in frozen solutions of ironporphyrins

The powder samples of meso-tetraphenyloporphyrin iron(III) chloride and ferriprotoporphyrin IX chloride and their frozen in solutions N,N-dimethylformamide were studied by Mossbauer spectroscopy. The variation of the outer ligands of the porphyrin rings modifies their magnetic properties but the major influence on the magnetic relaxation process exerts the intermolecular magnetic interactions, which are eliminated in dilute solutions

Mobility of interacting inorganic nanoparticles

The mobility of the 110 nm-Fe_{2}O_{3} particles in a viscous sucrose solution depends on the concentration of the nanoparticles. When the average particle particle nearest neighbor distance is less than 250 rim, the particle interaction slows down their mobility. When is more than 170 rim, the small mobility of nanoparticles does not depend on their concentration. The critical distance is approximately equal to 2R_{h} = 260 nm, where R_{h} is the hydrodynamic radius, determined by the dynamic light scattering (DLS) method

Mössbauer study of a tetrakis (pentafluorophenyl) porphyrin iron (III) chloride in comparison with the fluorine unsubstituted analogue

Mossbauer investigations, in association with density functional theory (DFT) calculations, have been conducted for the molecular and electronic structures of iron (III) [tetrakis (pentafluorophenyl)] porphyrin chloride [(F_{20}TPP)Fe:Cl], as a Fe(III)-tetraphenylporphyrin complex containing chloride axial ligand and substituted hydrogen atoms by fluorine ones in the four phenyl rings, in comparison with its fluorine unsubstituted analogue [(TPP)Fe:Cl]. It was found that the parameters of Mossbauer spectra of both complexes are close to one another, and correspond to the high-spin state of Fe(III) ions, but they show the different temperature dependence and the quadrupole doublets in Mossbauer spectra show different asymmetry at low temperatures. Results of DFT calculations are analyzed in the light of catalytic activity of the halogenated complex

X-ray absorption near edge structure and Mössbauer spectroscopy in study of iron valence states in tissues

X-ray absorption near edge structure Fe K-edge spectra and $\text{}^{57}$Fe Mössbauer spectra of selected standard compounds were recorded at room temperature. Valence and spin states of Fe in these samples known from Mössbauer spectroscopy were correlated with the shapes of X-ray absorption near edge structure spectra in search of possible application of X-ray absorption near edge structure spectroscopy as analytical tool determining local electronic states of iron in tissues. As an example, the X-ray absorption near edge structure spectra of healthy and cancerous tissues of prostate are shown, suggesting Fe$\text{}^{3+}$ in cancerous tissues