Biologically active platinum complexes containing 8-thiotheophylline and 8-(methylthio)theophylline

Complexes [Pt(mu-N,S-8-TT)(PPh(3))(2)](2) (1), [Pt(mu-S,N-8-TT)(PTA)(2)](2) (2), [Pt(8-TTH)(terpy)]BF(4) (3), cis-[PtCl(8-MTT)(PPh(3))(2)] (4), cis-[Pt(8-MTT)(2)(PPh(3))(2)] (5), cis-[Pt(8-MTT)(8-TTH)(PPh(3))(2)] (6), cis-[PtCl(8-MTT)(PTA)(2)] (7), cis-[Pt(8-MTT)(2)(PTA)(2)] (8), and trans-[Pt(8-MTT)(2)(py)(2)] (9) (8-TTH(2) = 8-thiotheophylline; 8-MTTH = 8-(methylthio)theophylline; PTA = 1,3,5-triaza-7-phosphaadamantane) are presented and studied by IR and multinuclear ((1)H, (31)P[(1)H]) NMR spectroscopy. The solid-state structure of 4 and 9 has been authenticated by X-ray crystallography. Growth inhibition of the cancer cells T2 and SKOV3 induced by the above new thiopurine platinum complexes has been investigated. The activity shown by complexes 4 and 9 was comparable with cisplatin on T2. Remarkably, 4 and 9 displayed also a valuable activity on cisplatin-resistant SKOV3 cancer cells.