Linker effect of ferrocenylnaphthalene diimide ligands in the interaction with double stranded DNA

Ferrocenylnaphthalene diimide ligands 1–7 were synthesized by joining a piperazino or N-methylamino linker of the naphthalene diimide skeleton with ferrocenecarboxylic, ferroceneacetic, or ferrocenepropionic parts. Their interaction with double stranded DNA (dsDNA) was studied kinetically and electrochemically. Association rate constants of these ligands were found to correlate with their intramolecular stacking ability between the ferrocene and naphthalene diimide planes: ligands which can adopt a stacked conformation in buffer solution were unfavorable in the association with dsDNA, resulting in a smaller association rate constant. Dissociation rate constants of these ligands carrying the bulky piperazino linker were smaller than that of those carrying an N-methylamino one. Binding constants were dictated by the balance of these two factors. These ligands were applied to the electrochemical detection of the amount of dsDNA on the electrode. Ligand 6 having the highest affinity for dsDNA gave rise to the largest current increase upon dsDNA formation in the electrochemical hybridization assay.

Graphical abstractSynthetic ferrocenylnaphthalene diimide ligands 1–7 showed the redox peak current at varied potential depending on their linker types. Binding affinity of 1–7 with double stranded DNA was showed the good correlation with the current increasing based on their ligands after DNA duplex formation on the electrode.Figure optionsDownload full-size imageDownload as PowerPoint slide