Wykład doktora Biljany D. Glišić

Szanowni Państwo;

Zapraszamy serdecznie na wykład dr Biljany D. Glišić.

Prelegent: dr Biljana D. Glišić - Department of Chemistry, Faculty of Science, University of Kragujevac, Serbia

Wykład odbędzie się w dniu: 19 maja 2015 roku (wtorek) o godz. 12:00 w sali F7, Budynek Wydziału Chemii, Gdańsk-Oliwa, ul. Wita Stwosza 63

Temat wystąpienia:

"Gold(III) complexes with some peptides and nitrogen-containing heterocycles"

Organizowane przez: Wydział Chemii Uniwersytetu Gdańskiego, Gdański Oddział Polskiego Towarzystwa Chemicznego oraz Wydział III Gdańskiego Towarzystwa Naukowego (Komisja Chemii).

Abstract: After the great success of cisplatin in cancer treatment, special attention was devoted to evaluation of gold(III) complexes as potential antitumor agents due to the fact that both Pt(II) and Au(III) ions possess the same d⁸ electronic configuration and preferentially form square-planar complexes. The possible involvement of gold(III) complexes in cancer treatment initiated an interest in the area of gold(III) interactions with different biologically important ligands such as peptides and aromatic nitrogen-containing heterocycles.

An overview of the results achieved in the field of synthesis and structural characterization of gold(III) complexes with histidine- and methionine-containing peptides, as well as with peptides containing no heteroatom in the side chain will be presented. Peptides containing no heteroatom in the side chain, as well as L-histidine containing peptides with N3 anchoring site of the imidazole ring have been shown as good coordinating ligands for Au(III) ion. The chelate gold(III) complexes with L-histidine-containing peptides have shown appreciable stability under physiological conditions and promising cytotoxic activity toward different tumor cell lines. On the other hand, the reactions of gold(III) with methionine-containing peptides primarily proceed through reduction of Au(III) ion and oxidation of the sulfur side chain.

The second part of the presentation will be focused on the results achieved in the synthesis and structural characterization of gold(III) complexes with some aromatic nitrogen-containing heterocycles, such as diazines (pyridazine, pyrimidine and pyrazine), diazanaphthalenes (quinazoline, phthalazine, quinoxaline, 1,5-naphthyridine, 1,6-naphthyridine and 1,8-naphthyridine), camphorquinoxaline derivatives and phenazine. It was shown that regardless of different stoichiometric ratio of the substrates, reactions of [AuCl₄]- with all these ligands lead to the formation of mononuclear complexes of the general formula [AuCl₃(N-heterocycle)], in which the corresponding nitrogen heterocycle acts as a monodentate ligand. This was attributed to the strong electron-withdrawing effect of Au(III) ion, i.e. the presence of an electron-pulling AuCl₃ group bound to the N-heterocycle ring made it electron-deficient and reduced nucleophilicity of the second nitrogen atom, preventing the formation of dinuclear species. However, this effect has not been manifested in the reactions of [AuCl₄]^- with 4,4’-bipyridine (4,4’-bipy) and 1,2-bis(4-pyridyl)ethane (bpe) performed in 2 : 1 molar ratio, respectively, which result in formation of the corresponding dinuclear {[AuCl₃]₂(μ-4,4-bipy)} and {[AuCl₃]₂(μ-bpe)} complexes.