Eva A Enyedy

Publications (39) View all

• Article: Solution equilibrium studies on anticancer ruthenium(II)–η6-p-cymene complexes of 3-hydroxy-2(1H)-pyridones

  Éva A. Enyedy, Gabriella M. Bognár, Tamás Kiss, Muhammad Hanif, Christian G. Hartinger
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  ABSTRACT: RuII(η6-p-cymene) complexes of bidentate (O,O) alkoxycarbonylmethyl-3-hydroxy-2(1H)-pyridone ligands exhibit in vitro antitumor activity. We determined the stoichiometry and stability in aqueous solution of two examples by pH-potentiometry, 1H NMR spectroscopy and UV–vis spectrophotometry and also characterized the proton dissociation processes of the ligands. Formation of mono-ligand complexes with moderate stability was found to predominate in the physiological pH range. Moreover, the chlorido/aqua co-ligand exchange processes of the [RuII(η6-p-cymene)(L)(H2O)]+ species were also monitored and 55–65% of the aqua ligand was found to be replaced by chloride in 0.2 M KCl-containing aqueous solutions. Under basic conditions, the complexes decompose to dinuclear tri-hydroxido-bridged [Ru2(η6-p-cymene)2(OH)3]+ and metal-free ligand and also a hydroxido species [RuII(η6-p-cymene)(L)(OH)] was found. Furthermore, the ligands contain an ester functional group, which may hydrolyze at basic pH, which is however negligible at acidic or neutral pH.
  11/2012;
• Article: Comparative Solution Equilibrium Study of the Interactions of Copper(II), Iron(II) and Zinc(II) with Triapine (3‐Aminopyridine‐2‐carbaldehyde Thiosemicarbazone) and Related Ligands

  Éva A. Enyedy, Nóra V. Nagy, Éva Zsigó, Christian R. Kowol, Vladimir B. Arion, Bernhard K. Keppler, Tamás Kiss
  Berichte der deutschen chemischen Gesellschaft 03/2010; 2010(11):1717 - 1728. · 2.94 Impact Factor
• Article: Interaction between iron(II) and hydroxamic acids: oxidation of iron(II) to iron(III) by desferrioxamine B under anaerobic conditions.

  E Farkas, E A Enyedy, L Zékány, G Deák
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  ABSTRACT: Interaction between iron(II) and acetohydroxamic acid (Aha), alpha-alaninehydroxamic acid (alpha-Alaha), beta-alaninehydroxamic acid (beta-Alaha), hexanedioic acid bis(3-hydroxycarbamoyl-methyl)amide (Dha) or desferrioxamine B (DFB) under anaerobic conditions was studied by pH-metric and UV-Visible spectrophotometric methods. The stability constants of complexes formed with Aha, alpha-Alaha, beta-Alaha and Dha were calculated and turned out to be much lower than those of the corresponding iron(II) complexes. Stability constants of the iron(II)-hydroxamate complexes are compared with those of other divalent 3d-block metal ions and the Irving-Williams series of stabilities was found to be observed. Above pH 4, in the reactions between iron(II) and desferrioxamine B, the oxidation of the metal ion to iron(III) by the ligand was found. The overall reaction that resulted in the formation of the tris-hydroxamato complex [Fe(HDFB)]+ and monoamide derivative of DFB at pH 6 is: 2Fe2+ + 3H4DFB+ = 2[Fe(HDFB)]+ + H3DFB-monoamide+ + H2O + 4H+. Based on these results, the conclusion is that desferrioxamine B can uptake iron in iron(III) form under anaerobic conditions.
  Journal of Inorganic Biochemistry 02/2001; 83(2-3):107-14. · 3.35 Impact Factor
• Article: Some factors affecting metal ion-monohydroxamate interactions in aqueous solution.

  E Farkas, E A Enyedy, H Csóka
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  ABSTRACT: The chelating properties exhibited by a series of monohydroxamic acids (propanohydroxamic acid (Pha), hexanohydroxamic acid (Hha), benzohydroxamic acid (Bha), N-methyl-acetohydroxamic acid (MAha), N-phenyl-acetohydroxamic acid (PhAha) and 2-hydroxypyridine-N-oxide (PYRha)) towards copper(II), nickel(II), zinc(II), calcium(II), magnesium(II) and aluminium(III) ions were studied by pH-metric, spectrophotometric and, in one case, by 27Al NMR methods. The results were compared with the corresponding data for metal ion-acetohydroxamate (Aha) and metal ion-desferrioxamine B (DFB) complexes. Changes of the substituents either on the carbon or on the nitrogen of the hydroxamate moiety caused a measurable effect on the chelate stability only in the case of aluminium(III) complexes. The aromatic derivative, PYRha, formed significantly more stable complexes than expected on the basis of the ligand basicity. The higher complex-forming ability of DFB compared to monohydroxamic acids diminishes in the case of the largest calcium(II) ion.
  Journal of Inorganic Biochemistry 05/2000; 79(1-4):205-11. · 3.35 Impact Factor
• Article: Maleimide-functionalised platinum(iv) complexes as a synthetic platform for targeted drug delivery.

  Verena Pichler, Josef Mayr, Petra Heffeter, Orsolya Dömötör, Eva A Enyedy, Gerrit Hermann, Diana Groza, Gunda Köllensperger, Markus Galanksi, Walter Berger, Bernhard K Keppler, Christian R Kowol
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  ABSTRACT: Maleimide-functionalised Pt(iv) complexes with highly selective binding properties to thiol groups were synthesised as precursors for binding of thiol-containing tumour-targeting molecules like human serum albumin.
  Chemical Communications 02/2013; · 6.17 Impact Factor