Interaction of diorganotin(IV) derivatives of azoles with nucleotides. Aqueous and solid-state coordination chemistry of [R2SnX2(N-2-donor)] species with nucleotides

From the reaction of [R2SnX2 {H2C(4-Mepz)(2)}] (Hpz = pyrazole; R = Me, Et or Ph; X = Cl or Br), [Me2SnBr2(4-Meim)(2)] (4-Meim = 4-methylimidazole), a nd [Me2SnCl2{phen}] (phen = 1,1 0-phenanthroline) with the mononucleotides adenosine-5'-monophosphate monohydrate (H(2)AMP), gaanosine-5'-monophosphat e disodium salt hydrate (Na(2)GMP) or 2'-deoxyguanosine-5'-monophosphate di sodium salt hydrate (Na(2)d-GMP) in water near physiological pH, the comple xes [R2Sn(AMP)], H2O (R = Me or Et), [Me2Sn(GMP)]. H2O, [Et2Sn(d-GMP)]. H2O , [Ph2SnCl (HAMP)]. H2O, and [Ph2SnCl(NaGMP)]. H2O have been obtained. Thes e compounds have been characterized by elemental analysis, FT-IR, H-1, P-31 and Sn-119 NMR spectra. The reaction between [Me2SnCl2{phen}] and 2'-deoxy cytidine-5'-monophosphoric acid monohydrate (H(2)d-CMP) yielded the mixed l igand complex [Me2Sn(d-CMP) {phen}].H2O, whereas the reaction between [R2Sn Cl2{H2C(4-Mepz)(2)}] (R = Me, et or Ph) and (H(2)d-CMP) was unsuccessful. T he interaction of [Me2SnCl2 {H2C(4-Mepz)(2)}] with the mononucleotides H(2) AMP, H(2)d-CMP, and Na(2)d-GMP in aqueous solution near physiological pH ha s been also investigated employing H-1 and P-31-NMR. Our diorganotin(IV) co mplexes exhibit higher selectivity for binding to phosphate groups of nucle otide with respect to N-sites on purinic and pyrimidinic bases. No differen ce has been observed between the behaviour of [R2SnX2(H2C{4-Mepz)(2)}] and [Me2SnCl2{phen}] toward H(2)AMP and Na(2)GMP, whereas significant differenc e has been observed toward H(2)d-CMP. Our results imply that the anti-tumou r activity of the [R2SnX2{N-2-donor}] species may occur via a different mec hanism with respect to that of cis-platin despite of their similar structur e.