Isomeric platinum organometallics derived from pyrimidine, pyridazine or pyrazine and their potential as antitumor drugs

Abstract Two new organometallic compounds ( 1 and 2 ) containing multiple platinum(II) centers have been synthesized. 1 and 2 are structural isomers having the same molecular formula but they are different either in terms of the N-heterocycle present in the center or relative orientation of the two pendant arms bearing the alkynyl-Pt(PEt 3 ) 2 I units. 1 and 2 have been characterized using FTIR, NMR, HRMS and elemental analyses, besides structural characterization of one of the complex ( 1 ) using single crystal XRD. The cytotoxic potential of 1 and 2 and a previously reported di-Pt II organometallic molecule ( 3 ) have been studied against four cancer cell lines − HT-29 (colon carcinoma), MCF-7, MDA-MB-231 (breast cancer) and SK-HEP-1 (human hepatic adenocarcinoma). Comparison of IC 50 values suggests that these Pt(II) based organometallic compounds have antiproliferative activity that is comparable with that of cisplatin.