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Showing papers by "Mariana Mitewa published in 1999"


Journal ArticleDOI
TL;DR: A series of new Cu(II) complexes with important physiologically active cycloalkane-5-spirohydantoines are synthesized reacting as a result of CuCl2 · 2H2O interaction with the ligands in alkaline water medium as discussed by the authors.
Abstract: A series of new Cu(II) complexes with important physiologically active cycloalkane-5-spirohydantoines are synthesized reacting as a result of CuCl2 · 2H2O interaction with the ligands in alkaline water medium. Their structures were studied using spectroscopic (IR and EPR) methods. For comparison, ab initio calculations of the structure and IR spectra of the corresponding Cu(II) complexes were also performed. It was proven that with cyclopentane-5-spirohydantoins, distorted (flattened) tetrahedral structure is realized Cu(L−H)2(H2O)2, while with the higher cycloalkane-5-spirohydantoins linear Cu(II) complexes of the type CuL−H(OH) are formed.

9 citations


Journal ArticleDOI
TL;DR: In this article, a stable monomeric Pt(III) complex is obtained resulting from PtCl 4 2 - bilirubin interaction in basic-aqueous medium, by means of EPR method it is proven that in the course of the interaction a redox process proceeds, giving rise to a stable Pt( III) complex species and a free radical.
Abstract: A stable monomeric Pt(III) complex is obtained resulting from PtCl 4 2- - bilirubin interaction in basic-aqueous medium. By means of EPR method it is proven that in the course of the interaction a redox process proceeds, giving rise to a stable Pt(III) complex species and a free radical. On the basis of all spectroscopic (EPR, 195 Pt-NMR, IR, UV-Vis) and magnetochemical data obtained a square-pyramidal (e.g. distorted octahedral) structure is suggested. Most likely a biliverdin molecule (oxidation product of bilirubin) is placed in the xy plane, coordinated via the four pyrrole nitrogens of the ligand and the 5th site being occupied by a water molecule.

5 citations