Synthesis, crystal structure, DNA interaction, DFT analysis and molecular docking studies of copper(ii) complexes with 1-methyl-l-tryptophan and phenanthroline units

Abstract

Three new mixed-ligand copper(II) complexes [CuL(neocup)H2O]NO3·2·5H2O (1), [CuL(bathoph)H2O]NO3·2·5H2O (2) and [CuL(bathocup)H2O]NO3·2·5H2O (3) (L = 1-methyl-l-tryptophan, neocup = Neocuproine, bathoph = bathophenanthroline and bathocup = bathocuproine) have been synthesized and structurally characterized by elemental analysis, IR, EPR, UV–Vis and single crystal XRD techniques. The XRD analysis shows the complex (2) crystallized in a Triclinic system with space group P1, a = 12.5630 (5) Å, b = 8.0433 (3) Å, c = 19.7816 (7) Å, α= 68.817 (2)°, β = 79.664 (2)°, and γ = 72.016 (2)°. Crystal structure study have revealed that the coordination number of Cu(II) is five with square pyramidal geometry in complex (2). The structure of the present complex (2) has been optimized using the DFT/UB3LYP/6–31G(d,p)/LANL2DZ level of theory. The interactions of the complex with calf thymus DNA (CT-DNA) have been investigated by UV–Vis absorption titration, ethidium bromide displacement assay, viscometric titration experiment and cyclic voltametric studies. Complex (2) was shown to bind DNA by intercalative mode and cleave pBR322 DNA. Molecular docking analysis was carried out.