SYNTHESIS AND BIOLOGICAL-ACTIVITY OF BINUCLEAR PLATINUM COMPLEXES CONTAINING 2 MONOFUNCTIONAL CIS-[PT(NH3)(2)CL](-DIPYRIDYL SELENIDES OR SULFIDES() UNITS BRIDGED BY 4,4')

The synthesis of four binuclear platinum complexes of general formula {cis-[Pt(NH3)(2)Cl](2)(L)} (NO3)(2) [L is 4,4'-dipyridyl sulfide (comp ound I), 4,4'-dipyridyl selenide (compound II), bis(3-methyl-4-pyridyl ) sulfide (compound III) or bis(3-methyl-4-pyridyl) selenide (compound IV)] has been achieved. These compounds have been characterized by el emental analysis, IR, H-1-NMR, C-13-NMR and Pt-195-NMR spectroscopy. T he above dinuclear platinum complexes have been assayed for antitumor activity in vitro against the cisplatin-sensitive L1210 (the mice leuk emia) and cisplatin-insensitive HCT8 (the human coloadenocarcinoma) ce ll lines. The compounds show IC50 values comparable to or higher than cisplatin against L1210 cell line; however, they have lower IC50 value s than cisplatin against the cisplatin-insensitive HCT8 cell line. The complexes containing S exhibit a cytotoxicity against the two cancer cell lines superior to the Se analogues. DNA binding studies indicate the compound I possibly interacts with DNA nonintercalatively. The mod e of DNA binding of the dinuclear Pt(II) complexes bridged by 4,4'-dip yridyl selenides or sulfides may be different to that of the aliphatic diamine-bridged dinuclear Pt(II) complexes reported previously.