Antitumor drugs, platinum complexes, quinoxalin ligands, DNA bindingability, cytotoxicity.

During the last decades, a number of transition-metal complexes have been utilized toprobe nucleic acid structures and in the development of DNA-cleaving agents. Amongthese complexes platinum(II) ion containing ones are renown. For this purpose, platinumcomplexes of 2,3-di(2-thienyl)-quinoxaline were synthesized in cis, asymmetric and bisgeometry in this work. Identification of the complexes was performed by usingelemental analysis and various spectroscopic techniques.The binding mode and extent of interaction of complexes was determined by UVtitration, thermal decomposition, viscometric and fluorometric measurements.Thermodynamic parameters were also determined from the UV titrations which arerepeatedly carried out at different temperaturesCytotoxicity tests of the complexes werecompleted at neutral medium and IC50 values were calculated for each complex.The DNA binding studies indicated that all the complexes interact with DNA throughgroove binding or electrostatically. Cytotoxicity experiments performed on MDA231IIcell line gave very promising results and revealed that the complex in cis geometry is themost active agent against to breast cancer.Keywords: