The effect of potential supramolecular-bond promoters on the DNA-interacting abilities of copper-terpyridine compounds

Three copper(II) coordination compounds have been prepared from three different 2,2′:6′,2′′-terpyridine-based ligands, which have been selected to investigate the potential role of supramolecular interactions on the DNA-interacting and cytotoxicity properties of the corresponding metal complexes. Hence, the ligands 4′-((naphthalen-2-yl)methoxy)-2,2′:6′,2′′-terpyridine (Naphtpy) and 4′-((1H-benzo[d]imidazol-2-yl)methoxy)-2,2′:6′,2′′-terpyridine (Bimztpy) have been synthesized from commercially-available 4′-chloro-2,2′:6′,2′′-terpyridine (Cltpy), and their copper(II) complexes have been obtained by reaction with copper(II) nitrate. The DNA-interacting abilities of the corresponding compounds [Cu(Cltpy)(H2O)(NO3)2] (1), [Cu(naphtpy)(NO3)(H2O)](NO3)(MeOH) (2) and [Cu(bimztpy)(NO3)(H2O)](NO3) (3) have been investigated using different techniques, and cytotoxicity assays with several cancer cell lines have revealed interesting features, viz. the more efficient complex is 2, which although it does not act as a DNA cleaver, displays the most effective DNA-interacting and cytotoxic properties, compared to 1 and 3.PG acknowledges ICREA (Institució Catalana de Recerca i Estudis Avançats) and the Ministerio de Economía y Competitividad (MINECO) of Spain (Projects CTQ2011–27929-C02-01 and CTQ2014-55293-P). This work was partially supported by a grant from the Spanish government and the EU (FIS PI13/00089), a grant from La Marató de TV3 Foundation (20132730) and the individual grant from Fundação para a Ciência e Tecnologia of the Portuguese Ministry of Science and Higher Education to LKG (SFRH/BPD/91766/2012). The European Union (EU) through COST Action CM1105 is kindly acknowledged.Peer Reviewe