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

•Design of isomeric di-Pt(II) organometallic compounds.•Facile synthesis in moderately high yield.•Complete characterization using a suite of analytical tools such as NMR, FTIR, MS and XRD.•Pt2(II) organometallic compounds show reasonable antiproliferative activities against four cancer cells.•The positive reference cisplatin displayed comparable IC50 values in the range of 3–8 µM.