Substituted Fe(II)-terpyridyl complexes for DNA binding studies

Four Fe(II) complexes, 1–3 and R1 with differently substituted tpy ligands were synthesized and characterized by a set of analytical techniques including 1D (¹H, ¹³C, 135-¹³C DEPT-135), 2D (¹H-¹H COSY) NMR spectroscopies and high-resolution mass spectrometry (HRMS). The ability of each compound to bind DNA was assessed by UV–visible titration assays using DNA extracted from Pisum sativum (split peas). UV–visible titration tests were performed to ascertain the binding affinity of these complexes with DNA, and the results indicated that the complexes are groove binders with binding constants in the range of 1.23–2.66 × 10⁴. To confirm that the complexes were binding with DNA through groove-binding, molecular docking studies using 1 and 2 with Dickerson-drew dodecamer B-DNA structure (PDB ID: 1B-DNA) were carried out which showed compatibility with the experimental data.