Self-assembly of Pt(II) based nanoscalar ionic hexagons and their anticancer potencies

Two nanoscalar and supramolecular metallacycles were self-assembled by employing a predesigned pyrazine based molecular acceptor clip with two different ditopic pyridyl donor tectons. The platina macrocycles were characterized by multinuclear NMR spectroscopy, mass spectrometry (ESI-MS), and elemental analyses. Molecular modelling using PM6 semiempirical molecular orbital method suggested these metallacycles having nanoscalar dimensions with hexagonal cavities. Additionally, interactions of these macrocycles were studied with three carcinoma cell lines. Results suggest that anticancer properties of supramolecular metallacycles were higher than their organometallic precursor. The nanoscalar supramolecular metallacycles were capable of efficiently reducing cell proliferation of different cancer lines (A549, HepG2, HeLa). The anticancer activity of the larger of the two macrocycles was higher even at lower concentrations and IC50 values are comparable with that of cisplatin. TUNEL assay suggested that macrocycles induces apoptotic cell death. These results suggest that the nanoscalar supramolecular metallacycles could find potential biomedical applications as therapeutic agents.