Platinum and ruthenium complexes of new long-tail derivatives of PTA (1,3,5-triaza-7-phosphaadamantane): Synthesis, characterization and antiproliferative activity on human tumoral cell lines

The alkylation of PTA, (1,3,5-triaza-7-phosphaadamantane), with long chain alkyl iodides produced the novel ionic derivatives (PTAC12H25)I, (PTAC16H33)I and (PTAC18H37)I. Anion exchange gave the PF6− analogs (PTAC12H25)PF6, (PTAC16H33)PF6 and (PTAC18H37)PF6. The new phosphines were characterized by ESI-MS, elemental analysis, 1H, 13C, and 31P NMR spectroscopy and their coordination ability was investigated towards Pt(II) and Ru(II) cores. Complexes cis-[PtCl2(PTAR)](PF6)2 (1–3) and [CpRuCl(PPh3)(PTAR)]I (5–7) have been isolated and characterized. Antiproliferative activity, given as estimated IC50, was tested for each complex against appropriate human tumoral lines (T2, SKOV3 and SW480) in comparison with cisplatin, with the parent complexes [CpRuCl(PPh3)(PTA)] and [CpRuCl(PPh3)(PTAMe)]I and with the free ligands.