Book of Abstracts - Ruhr-Universität Bochum

P-18
ISBOMC `10 5.7 – 9.7. 2010 Ruhr-Universität Bochum
Interaction between [Ru(� 6 -p-cym)(H2O)3] 2+ and (O,O) Donor Ligands of
Biological Importance in Aqueous Solution
Péter Buglyó, *a Linda Bíró, a and Etelka Farkas a
a University of Debrecen, Faculty of Science and Technology, Department of Inorganic and Analytical
Chemistry, P. O. Box 21, H- 4032 Debrecen, Hungary. E-mail: buglyo@delfin.unideb.hu
Numerous Ru(III) and Ru(II) complexes have been synthesized, characterized in the solid state and
tested for antitumor activity. The most promising candidates are shown to act differently both in vitro
and in vivo from the antitumor platinum complexes currently used in the therapy. Beside Ru(III)
complexes with octahedral geometry half-sandwich organometallic Ru(II) complexes with typical
“piano stool” geometry are also investigated intensively. 1
Recently we have shown that one class of important biomolecules, monohydroxamates (being also
(O,O) chelators), are capable to form stable complexes with the [Ru(� 6 -p-cym)(H2O)3] 2+ core both in
the solid state and in aqueous solution. 2 We have also explored in detail the hydrolysis of the metal ion
using different (pH-potentiometry, NMR, UV-VIS and ESI-MS) techniques and estimated the stability
constants of the hydroxo complexes formed in the H + –[Ru(� 6 -p-cym)(H2O)3] 2+ system. Taking into
consideration the hydrolysis we were able to obtain the pH dependent speciation of the H + –[Ru(� 6 -pcym)(H2O)3]
2+ –meaha system (meaha = N-methyl-acetohydroxamate) and to determine the
composition and stability constants of the complexes formed with the monohydroxamate.
In order to compare the [Ru(� 6 -p-cym)(H2O)3] 2+ binding strength of meaha with that of other (O,O)
donors partly used as building blocks in ruthenium complexes with potential anticancer activity or
present in biofluids a systematic study has been carried out. Ligands capable to form five membered
(oxalic acid, lactic acid, kojic acid, maltol, 3-hydroxy-1,2-dimethylpyridin-4(1H)-one, 1,2dihydroxybenzene-3,5-disulfonate)
and six-membered (cyclobutane-1,1-dicarboxylic acid,
acetylacetone, salicylic acid) chelates in which the donor atoms exhibit different basicity were choosen
and the interaction of these chelators with [Ru(� 6 -p-cym)(H2O)3] 2+ was investigated. This contribution
summarises the results of a detailed solution equilibrium work. During this study our goal was to
estimate the speciation and to compare the composition and stabiliy constants of Ru-(O,O) type
complexes formed applying different (pH-potentiometry, 1 H-NMR, ESI-MS) experimental techniques.
References
1. (a) P. C. A. Bruijnincx, P. J. Sadler, Adv. Inorg. Chem., 2009, 61, 1-62. (b) W. Kandioller, C. G.
Hartinger, A. A. Nazarov, M. L. Kuznetsov, R. O. John, C. Bartel, M. A. Jakupec, V. B. Arion, B. K.
Keppler, Organometallics, 2009, 28, 4249-4251.
2. P. Buglyó, E. Farkas, Dalton Trans., 2009, 8063-8070.
Acknowledgement: We thank the members of the EU COST Action D39 for motivating discussions.
This work was supported by the Hungarian Scientific Research Fund (OTKA K76142).
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