Synthesis and photophysical evaluations of fluorescent quaternary bipyridyl-1,8-naphthalimide conjugates as nucleic acid targeting agents

Abstract

A family of organic molecules containing the DNA intercalating chromophores, 4-nitro-and 4-amino 1,8-naphthalamide, conjugated to a diquat derivative by an 'orthogonal' phenyl spacer have been prepared, and characterized. Their binding interactions with double-stranded DNA was studied by a variety of spectroscopic techniques. These charged organic compounds are found to exhibit excellent binding affinities to DNA with binding constants comparable to those exhibited by metal complexes.

Unexpected DNA binding properties with correlated downstream biological applications in mono vs. bis-1,8-naphthalimide Ru(ii)-polypyridyl conjugates

“…[39][40][41][42][43][44] In addition to being effective DNA intercalators or groove binders, the 1,8-naphthalimides can also act as sensitising antenna for the Ru(II)-based metal-to-ligand charge transfer (MLCT) emission, allowing for the population of the excited state using two excitation channels. 45 Herein, we present two new DNA targeting Ru(II) com- DNA in a cooperative manner, 38 and potentially enhance cellular uptake. 36 To fully explore the activity of the complexes a detailed in vitro photophysical study was completed in the absence and presence of DNA.…”

“…[22][23][24][25][26][27][28][29] We have also developed several examples of DNA targeting binders, based on the use of 1,8-naphthalimide derivatives. [30][31][32][33][34][35][36][37][38] Such structures have tuneable electronic properties, and have been shown to exhibit good DNA binding affinity through either intercalation or groove binding. [39][40][41][42][43][44] In addition to being effective DNA intercalators or groove binders, the 1,8-naphthalimides can also act as sensitising antenna for the Ru(II)-based metal-to-ligand charge transfer (MLCT) emission, allowing for the population of the excited state using two excitation channels.…”

Synthesis, Optical Properties, and DNA Interaction of New Diquats Based on Triazolopyridines and Triazoloquinolines

“…[13,14,17] Figure 10 shows the changes in fluorescence emmision spectra for compound L4 during titration with ct-DNA.O nly for diquats L3 and L4 was it possible to apply aS tern-Volmer relationship;t he value of the corresponding constant (K SV )w as higher for compound L3 (4.25 10 3 m À1 )t han for L4 (3.38 10 3 m À1 ), which can be attributed to the planarity of ligand L3 (Table 1). In all cases, an increase in absorption was observed between 200 and 300 nm owing to the intrinsic DNA absorbance in this region.…”

“…The dihedral angle between the two pyridine rings depends on the lengthof the alkyl bridge. [14] An interesting way to achieve stronger intercalativei nteractions might be to replace the bypiridiner ings with condensed aromatic moieties. [8] Diquat is knownt oi nteract with DNA owing to its aromatic structure and dicationicc harge.…”

“…Althoughd iquat was reported to interact with DNA only through electrostatic interactions, [13] the incorporation of appropriate aromatic substituents can lead to intercalative binding modes. [14] An interesting way to achieve stronger intercalativei nteractions might be to replace the bypiridiner ings with condensed aromatic moieties. As our grouph as al arge background in the study of [1,2,3]triazolo [1,5-a]pyridines (TP,F igure 1) and their derivatives, we considered that those structuresm ight be good building blocks Scheme1.Generalsynthesis of diquat.…”