Synthesis, characterization, molecular modeling, and DNA interaction studies of a Cu(II) complex containing drug of chronic hepatitis B: adefovir dipivoxil

<div><p>A new copper(II) complex [Cu(adefovir)<sub>2</sub>Cl<sub>2</sub>], where adefovir = adefovir dipivoxil drug, was synthesized and characterized by using different physicochemical methods. Binding interaction of this complex with calf thymus DNA (ct-DNA) has been investigated by multi-spectroscopic techniques and molecular modeling study. The complex displays significant binding properties of ct-DNA. The results of fluorescence and UV–vis absorption spectroscopy indicated that, this complex interacted with ct-DNA in a groove-binding mode, and the binding constant was 4.3(±0.2)  ×  10<sup>4</sup> M<sup>−1</sup>. The fluorimeteric studies showed that the reaction between the complex and ct-DNA is exothermic (Δ<i>H</i> = 73.91 kJ M<sup>−1</sup>; Δ<i>S</i> = 357.83 J M<sup>−1</sup> K<sup>−1</sup>). Furthermore, the complex induces detectable changes in the CD spectrum of ct-DNA and slightly increases its viscosity which verified the groove-binding mode. The molecular modeling results illustrated that the complex strongly binds to the groove of DNA by relative binding energy of the docked structure −5.74 kcal M<sup>−1</sup>. All experimental and molecular modeling results showed that the Cu(II) complex binds to DNA by a groove-binding mode.</p></div>