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Magnetic, Electrochemical and Antimicrobial Properties of Some Cu(II) Complexes with TPMC

Vuckovic G., Antonijevic-Nikolic M., Korabik M., Mroziński J., Manojlovic D., Gojgic-Cvijovic G., Matsumoto N.

Polish Journal of Chemistry

2005

Vol. 79 / nr 4

679-687

Three complexes: [Cu2(C6H5COO)tpmc](ClO4)3.CH3OH, (A), (tpmc = N,N',N'',N'''- tetrakis(2-pyridilmethyl)-1,4,8,11-tetraazacyclotetradecane), [Cu2(Hpht)tpmc](ClO4)3.3H2O (H2pht = phtalic acid) (B) and [Cu4(ipht)(tpmc)2](ClO4)6_NaClO4_2CH3CN (H2ipht = isophtalic acid) (C) previously described were investigated by magnetic measurements, cyclic voltammetry (CV) and were tested towards some strains of microorganisms. It is found that all three complexes were electrochemically stable in the investigated ranges. The least stable was mi-iphtcomplex (C) due to the reaction of central ion, which is seen from weak peaks in its cyclic voltammogram. Complexes were characterized by variable temperature magnetic measurements (4.2-300 K) and the observed data were successfully simulated by the equation based on the spin Hamiltonian operator, H= - 2JSS1 2, giving the ferromagnetic exchange parameters J = 0.92 cm-1 forA, J = 0.55 cm-1 forB and J= 0.65 cm-1for C. For the complex C model of molecular magnet with two magnetically isolated dimeric subunits was used. These results indicate the presence of weak ferromagnetic spin exchange interaction between the CuII magnetic centers within each molecule.

Spin crossover in a supramolecular feii-feiii system

Ohta H., Sunatsuki Y., Ikuta Y., Matsumoto N., Lijima S., Akashi H., Kambe T., Kojima M.

Materials Science

2003

Vol. 21, No. 2

191-198

The structure of [FeII(H3L)](ClO4)2ˇ3H2O, where H3L is a tripodal hexadentate ligand derived from the 1:3 condensation of tris(2-aminoethyl)amine and 4-formylimidazole, has been determined by X-ray crystallography at 113 and 293°K. A spin transition was indicated from the Fe-N bond distances. The temperature dependence of the magnetic susceptibility revealed that the complex undergoes a gradual spin transition in the temperature range 150-270°K. A mixed-valence complex, [FeII(H3L)][FeIII(L)](BF4)2 1.5H2O, was prepared by the controlled deprotonation of the protonated species, [FeII(H3L)](BF4)2ˇ1.5H2O, under aerobic conditions, and the X-ray structure was determined at 293°K. Two species, [FeII(H3L)]2+ and [FeIII(L)], are linked by imidazole-imidazolate (NH-N) hydrogen bonds to form a puckered sheet structure. Magnetic susceptibility measurements and Mössbauer spectra provided evidence of spin-crossover at both the FeII and FeIII sites. There are three accessible electronic states: (LS FeII-LS FeIII), (HS FeII-LS FeIII), and (HS FeII-HS FeIII) that occur in passing from lower to higher temperatures.