Authors:R. Olar, M. Badea, N. Stanica, E. Cristurean and D. Marinescu
The investigations concerning the thermal behaviour of a series of Ni(II) and Cu(II) complexes of type [MLCln]·mH2O ((1) M:Ni, L:L(1), n=1, m=2; (2) M:Cu, L:L(2), n=1, m=2; (3) M:Ni, L:L(3), n=2, m=0; (4) M:Cu, L:L(3), n=1, m=2) are presented in this paper. The ligands L(1)-L(3) have been synthesised by template condensation of 1,2-diaminoethane with formaldehyde and 2-amino-1,3,4-thiadiazole-5-thiole or 2-acetamino-1,3,4-thiadiazole-5-sulfonamide. The bonding and stereochemistry of the complexes have been characterised by IR, electronic and magnetic studies at room temperature. The thermal behaviour provided confirmation of the complex composition as well as the number and the nature of water molecules and the intervals of thermal stability. The different nature of the ligands and/or the metallic ions generates a different thermal behaviour for complexes. The complexes do not show biological activity against HIV virus.
Authors:Oana Carp, E. Segal, Maria Brezeanu, Ruxandra Barjega and N. Stanica
Small particles of PbFe12O19 have been synthesized. X-ray diffraction, thermal analysis and magnetic investigations have been conducted in order to obtain
information on the mechanism of lead hexaferrite formation.
Authors:Oana Carp, Luminita Patron, G. Pascu, Ioana Mindru and N. Stanica
have been synthesized via thermal decomposition of polynuclear coordination
compounds containing as ligand the anion of malic acid, namely (NH4)[Fe2NixZn1–x(C4H4O5)(OH)3]nH2O (x
=0.25, 0.5 and 0.75, n=3 and 5). A comparison
between the thermal behaviour of the studied polynuclear coordination compounds
is inferred. Fe2NixZn1–xO4
(n=0.25, 0.5 and 0.75) ferrites with mean
particle sizes of 65–85 and free from other phases are formed
after a heating treatment of only one hour at 500C.
Authors:Oana Carp, E. Segal, Maria Brezeanu, Luminita Patron, R. Barjega and N. Stanica
The authors analyse the possibility of obtaining manganese-zinc ferrite through the transformations of polynuclear coordination compounds (pcc), either in the solid state or in a reaction medium. Polynuclear coordination compound precursors with the general molecular formula: [Fe(II)xFe(III)y(Mn0.5Zn0.5)(C2O4)2(OH)y+2(H2O)2] with 0.2<x<1.0, 1.0<y<1.8 and x+y=2, obtained through a forced hydrolysis were characterized by chemical and physicochemical procedures. A non-isothermal kinetic analysis of the thermal decomposition steps showed that all of them are described by contracting geometry rate equation. The influence of the thermal treatment on the properties of the final products of transformation was evidenced.