The synthesis, the structural features and the in vivo biological activity of diorganotin(IV) and triorganotin(IV) derivatives of [mesotetra(4-carboxyphenyl)porphine] (H 4 TPPC) are reported. Derivatives with general formula (R 2 Sn) 2 TPPC and (R 3 Sn) 4 TPPC (R = Me, Bu, and Ph) were obtained, and the main information extracted from the infrared and Mössbauer spectral data, in the solid state, was in favor of the occurrence of fivecoordinated tin(IV) atoms, in a polymeric trigonal-bipyramidal configuration, attained through two differently coordinated, estertype and chelating respectively, carboxylate anions in [R 2 Sn] 2 TPPC, while in [Alk 3 Sn] 4 TPPC five-coordination of the tin(IV) atom is reached through bridging carboxylate groups. 1 H and 13 C NMR spectra, in DMSO-d 6 or CDCl 3 suggested that the soluble derivatives, at room temperature or at 342 K, were present in solution as simple monomers. The interactions of (trimethyltin) 4 [mesotetra(4-carboxyphenyl)porphinate] (TMTPPC) and (tributyltin) 4 [meso-tetra(4carboxyphenyl)porphinate] (TBTPPC) with Bluescript KS( ؉ ) plasmid and cultured 3T3 fibroblasts were studied. Both compounds have a clear inhibitory effect on the growth of cultured mouse embryonal fibroblasts (NIH-3T3), TBTPPC being much more active. No evidence was found, however, for DNA cleavage by the compounds at molar ratios as high as 1:10 (TMTPPC, TBTPPC/DNA base pairs).
According to our observations, the cytotoxicity of TBTPPC and TMTPPC does not seem to be based on direct interaction with DNA.