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The Synthesis and Spectroscopic Study of Novel Binuclear Chromium(III) Complex with Pipemidic Acid

Skrzypek D., Kovala-Demertzi D., Szymanska-Niewiadomska B., Kourkoumelis N., Staninska M.

Polish Journal of Chemistry

2009

Vol. 83, nr 3

363-371

The interaction of Cr(III) with pipemidic acid, Hpipem, afforded the complex [Cr(pipem)(HO)2(H2O)]2 Cr2O3. The new complex has been characterized by elemental analysis, infrared, XRD and EPR spectroscopy. The EPR spectra of the complex have been recorded down to T = 3 K. The temperature dependence of EPR spectrum demonstrates that spectrum originates from septet transitions at a room temperature and from quintet state for lower temperatures for exchange coupled chromium pairs. The dimer characterizes antiferromagnetic interaction with J = -32 cm-1. The monoanion, pipem, exhibits obligation through the carbonyl and carboxylatooxygen atoms. Six-coordinate dimer distorted octahedral configuration has been proposed for [Cr(pipem)(HO)2(H2O)]2.

Synthesis and Characterization of Complexes of Transition Metal Ions with New Pentaazamacrocyclic Ligands

Nishat N., Rahis-ud-din, Haq M. M.

Polish Journal of Chemistry

2003

Vol. 77 / nr 12

1731-1740

New multidentate ligands 1,4,7,9,12-pentaaza-10,11-dioxo-8,9,12,13-bis-(1_,3_-dioxo- 6,6-diethyl-2_-hydropyrimidine)-trideca-7,13-diene, (L1) and 1,4,7,9,13-pentaaza-10,12- dioxo-8,9,13,14-bis-(1_,3_-dioxo-6,6-diethyl-2_-hydropyrimidine)-tetradeca-7,14-diene (L2) have been prepared by the reaction of 5,5-diethylbarbituric acid, diethylenetriamine, diethyl oxalate and 5,5-diethylbarbituric acid, diethylenetriamine, diethyl malonate. Their coordination properties with the first row of transition metal ions have been explored. The macrocyclic complexes were characterized by elemental analysis, IR, 1H NMR, UV-visible spectroscopy, magnetic moment measurements and molar conductance measurements. The electronic spectra and magnetic moment measurements are discussed with respect to assignment of square planar and tetrahedral structure except chromium(III), iron(III) ions. The chromium(III) and iron(III) complexes are considered to be octahedral. Molar conductance measurements suggest that the complexes of divalent metal ions are 1:1 electrolytes, while the trivalent metal ions are nonelectrolytes. The compounds have been tested against gram-positive bacteria Staphylococcus aureus and gram-negative bacteria Escherichia coli. The results show that all the compounds inhibit the growth of bacteria.