Adaptable DNA-Interactive Probe Proficient at Selective Turn-On Sensing for Al3+: Insight from the Crystal Structure, Photophysical Studies, and Molecular Logic Gate

Small Molecule Interactions with Biomacromolecules: DNA Binding Interactions of a Manganese(III) Schiff Base Complex with Potential Anticancer Activities

A manganese(III) complex, [MnIII(L)(SCN)(enH)](NO3)·H2O (1•H2O) (H2L = 2-((E)-(2-((E)-2-hydroxy-3-methoxybenzylidene-amino)-ethyl-imino)methyl)-6-methoxyphenol), has been synthesized and characterized by single-crystal X-ray diffraction analysis. The interaction of 1•H2O with DNA was studied by monitoring the decrease in absorbance of the complex at λ = 324 nm with the increase in DNA concentration, providing an opportunity to determine the binding constant of the 1•H2O-ct-DNA complex as 5.63 × 103 M-1. Similarly, fluorescence titration was carried out by adding ct-DNA gradually and monitoring the increase in emission intensity at 453 nm on excitation at λex = 324 nm. A linear form of the Benesi-Hildebrand equation yields a binding constant of 4.40 × 103 M-1 at 25 °C, establishing the self-consistency of our results obtained from absorption and fluorescence titrations. The competitive displacement reactions of dyes like ethidium bromide, Hoechst, and DAPI (4',6-diamidine-2'-phenylindole dihydrochloride) from dye-ct-DNA conjugates by 1•H2O were analyzed, and the corresponding KSV values are 1.05 × 104, 1.25 × 104, and 1.35 × 104 M-1 and the Kapp values are 2.16 × 103, 8.34 × 103, and 9.0 × 103 M-1, from which it is difficult to infer the preference of groove binding over intercalation by these DNA trackers. However, the molecular docking experiments and viscosity measurement clearly indicate the preference for minor groove binding over intercalation, involving a change in Gibbs free energy of -8.56 kcal/mol. The 1•H2O complex was then evaluated for its anticancer potential in breast cancer MCF-7 cells, which severely abrogates the growth of the cells in both 2D and 3D mammospheres, indicating its promising application as an anticancer drug through a minor groove binding interaction with ct-DNA.

Experimental and computational evidence for stabilising parallel, offset π[C(O)N(H)NC]⋯π(phenyl) interactions in acetohydrazide derivatives

Stabilising π[C(O)N(H)NC]⋯π(phenyl) interactions are described.

Combined theoretical and experimental investigation of a DNA interactive poly-hydroxyl enamine tautomer exhibiting “turn on” sensing for Zn2+ in pseudo-aqueous medium

Crystallographically established (solid state structure at 150 K temperature) synthesized enamine ligand (H4L) showed interconvertible equilibrium (ΔE = 7.37 kcal) of its tautomers, displayed zinc sensing and also found to exhibit DNA binding activity at the minor groove of double-stranded (ds) DNA.

DNA intercalative trinuclear Cu(ii) complex with new trans axial nitrato ligation as an efficient catalyst for atmospheric CO2 fixation to epoxides

A trinuclear octahedral Cu^II complex was synthesized and structurally characterized by single crystal X-ray diffraction studies and behaved as a catalyst for CO₂ fixation to epoxide and as a DNA binder.