New Sensors Based on DNA Base Pairs: DFT, QTAIM and NCI-RDG Study

Abstract The aim of this work is to identify the ability of two new suggested complexes of cobalt and copper based on thymine base pair: [thym-Co-thym] and [thym-Cu-thym] to Classify them as a sensors to capture toxic agents from the environment. [thym-Co-thym] and [thym-Cu-thym] complexes were studied theoretically at DFT/M06-2X/6-311G+(d,p) level. Orbital interaction is favored for H2S (0.058 eV, 0.35 eV) and NO (0.243 eV, 0.04 eV) with [thym-Co-thym] and [thym-Cu-thym] respectively. To predict the nature of the interaction between these complexes and toxic agents we performed natural bond orbital (NBO), quantum theory of atoms in molecules (QTAIM), non-covalent interaction analysis (NCI), reduced density gradient (RDG) and binding energy. RDG analysis proves that interaction of toxic agents is more favored with copper complex.