Showing papers by "Mariana Mitewa published in 1996"
TL;DR: An approach for quantitative spectrophotometric analysis of binary mixtures based on first derivative spectra is developed and used for investigation of the complex formation of some aza-15-crown-5-containing ligands with Sr(2+), where the stability constant is low and the absorption spectrum of thecomplex cannot be obtained directly.
9 citations
TL;DR: In this article, the spectral properties of a series of styryl dyes containing the aza-15-crown-5 macrocycle were investigated using absorption UV-Vis spectroscopy.
8 citations
TL;DR: In this paper, the cobalt, nickel, and zinc complexes of diethyl (2-oxo-1-phenyl)ethylphosphonate were synthesized using the corresponding metal halides.
Abstract: The cobalt(II), nickel(II) and zinc(II) complexes of diethyl (2-oxo-1-phenyl)ethylphosphonate 1 (compounds 2, 3 and 4, respectively) were synthesized using the corresponding metal halides. Their structure was studied by spectroscopic (IR, electronic and EPR) and magnetochemical methods. The experimental data indicate that the cobalt and nickel complexes (2 and 3, resp.) are octahedrally coordinated by the bidentate phosphonyl ligand, two of the coordination sites being occupied by H2O molecules. The 1H, 13C and 31P NMR data for the zinc complex 4 prove that the product is a mixture of (Z)-and (E)-isomers, with the (Z)-isomer being predominant.
3 citations
TL;DR: In this paper, the structures and coordination mode of 3-dione complexes were studied using spectroscopic (EPR and IR) and magneto-chemical (MAG) methods.
Abstract: Co(II), Ni(II) and Cu(II) complexes of 2-nitroso-2, 3-dihydrophenalene-1, 3-dione were synthesized and their structures and the coordination mode of the ligand were studied using spectroscopic (EPR and IR) and magneto-chemical methods.
3 citations
TL;DR: The tetrakis (2-amino-1,5-dihydro-1-methyl-4H-imidazol-4-one-N 3 ) compound as discussed by the authors is a planar compound consisting of four creatinine ligands bonded through their endocyclic N atoms.
Abstract: The structure of the title compound, tetrakis(2-amino-1,5-dihydro-1-methyl-4H-imidazol-4-one-N 3 )platinum(II) dithiocyanate, [Pt(C 4 H 7 N 3 O) 4 ](SCN) 2 , consists of [Pt(creat) 4 ] 2+ (creat is 2-imino-1-methyl-4-imidazolidinone) complex cations possessing approximate D 2 symmetry and thiocyanate anions. The Pt atom is coordinated in a square-planar manner by four creatinine ligands bonded through their endocyclic N atoms. The Pt-N bond distances range from 1.980(6) to 2.034(7)A. The creatinine molecules are planar and participate in inter- and intramolecular hydrogen bonds. The ligands are almost perpendicular to the equatorial PtN 4 plane.
2 citations