The effect of potential supramolecular-bond promoters on the DNA-interacting abilities of copper-terpyridine compoundsElectronic supplementary information (ESI) available: Crystallographic data for free ligand naphtpy and complexes 1 and 2 (Tables S1 and S2); selected bond lengths and angles for 1 and 2 in Table S3; UV-vis and fluorescence DNA-binding spectra for 2 and 3; cell-viability assays for all free ligands and complexes 1-3, at different compound concentrations and incubation times. CCDC

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′-((1 H -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 )(H 2 O)(NO 3 ) 2 ] ( 1 ), [Cu( naphtpy )(NO 3 )(H 2 O)](NO 3 )(MeOH) ( 2 ) and [Cu( bimztpy )(NO 3 )(H 2 O)](NO 3 ) ( 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 . Supramolecular interactions prevail over DNA-cleaving abilities in the cytotoxicity behaviour of terpyridine-based copper( ii ) complexes.