Electrophilic attack of [I(py)(2)](+)(NO3-) on three-coordinate Pt-0 precursors: Synthesis and in vitro antitumor activity of water-soluble, five-coordinate Pt-II complexes

[I(py)(2)](+)(NO3-) oxidatively adds to the three-coordinate platinum(0) pr ecursors [Pt(N,N-chelate) (olefin)] affording the cationic five-coordinate products [Pt(N,N-chelate)I(py)-(olefin)](+)(NO3-) (1) (N,N-chelate = 2,9-Me -2- 1,10-phenanthroline (dmphen), 2-methyl-6-[(phenylimino) methyl] pyridin e (pimpy)) and 2-methyl-6-[(4 -methoxyphenylimino)methyl]pyridine (mpimpy). The crystal structure of [Pt(pimpy)I(py)(dimethyl fumarate)](+)(NO3-) is r eported. The crystals are triclinic, space group P1(bar), with a = 13.511(2 ), b = 13.754(2), c = 8.678(1) Angstrom, alpha = 95.2(1)degrees, beta = 92. 5(2)degrees, gamma = 64.7(1)degrees, Z = 2. Type I complexes, which are sol uble both in chlorinated solvents and in water, were tested for cytotoxicit y against a panel of tumour cell lines of various histotypes including NSCL C H460, leukaemic HL-60, ovarian A 2780, IGROV-1, SKOV-3, and an ovarian ca rcinoma A 2780/CP selected for resistance to cis-platin [DDP = cis-diammine dichloroplatinum(II)]. [Pt(dmphen)I(py)(methyl acrylate)](+)(NO3-) was the most active in all cell lines tested, its antitumoural activity in vitro be ing comparable to that of DDP.