Evaluation of the in vitro anticancer activity of cyclometalated half-sandwich rhodium and iridium complexes coordinated to naphthaldimine-based poly(propyleneimine) dendritic scaffolds

The development of cyclometalated rhodium and iridium complexes from first- and second-generation naphthaldimine-based poly(propyleneimine) dendrimer scaffolds of the type, DAB-(NH2)n (where n = 4 or 8, DAB = diaminobutane) has been accomplished. Four metallodendrimers were synthesised, viz. (Cp*MCl)4Gn (1–4), by first reacting DAB-(NH2)n with napththaldehyde and subsequently metallating the Schiff-base dendrimers with the dimers [Cp*MCl2]2 (where M = Rh or Ir). Related mononuclear complexes [Cp*MCl(L)] (L = naphthaldimine) (5–6) were obtained in a similar manner. The molecular structures of 5 and 6 have been determined by single-crystal X-ray diffraction analysis and the in vitro anticancer activities of 1–6 were evaluated against the A2780 and A2780cisR human ovarian carcinoma cell lines.