Drug Delivery with a Calixpyrrole–trans-Pt(II) Complex

A meso-p-nitroaniline-calix­[4]­pyrrole derivative trans-coordinated to a Pt­(II) center was synthesized and its structure solved by X-ray analysis. Adenosine monophosphate (AMP) was used as a model compound to evaluate the potential for the assisted delivery of the metal to the DNA nucleobases via the phosphate anion-binding properties of the calix[4]­pyrrole unit. An NMR investigation of the kinetics of AMP complexation in the absence of an H-bonding competing solvent (dry CD3CN) was consistent with this hypothesis, but we could not detect the interaction of the calix[4]­pyrrole with phosphate in the presence of water. However, in vitro tests of the new trans-calixpyrrole–Pt­(II) complex on different cancer cell lines indicate a cytotoxic activity that is unquestionably derived from the coexistence of both the trans-Pt­(II) fragment and the calix[4]­pyrrole unit.