Synthesis, structural characterization, electrochemical, photophysical and DNA binding properties of two Anderson POM-based hybrids

Abstract

In this article, two new hybrid compounds Na(C2H7N4O)2[AlMo6(OH)6O18]·2H2O (DA) and (C4H13N5)[HAlMo6(OH)6O18].10H2O (MA) were obtained from the reaction of the organic ligands (dicyandiamide and metformin) with Anderson polyoxometalate (POM) in the water solution. Anderson POM based hybrids DA and MA were characterized by the spectroscopic methods such as, FTIR, UV–vis, photoluminescence. Crystal structures of the hybrid compounds were determined by single crystal X-ray diffraction studies. In the crystal structure of MA, Anderson type polyoxometalate anions are linked by OH·····O and NH·····O hydrogen bonds forming 2D supramolecular structure in which there are solvent accessible voids. In the structure of DA, type polyoxometalate anions are connected by Na+ ions forming 2D coordination polymer type structure. The electrochemical properties of the Anderson POM and its hybrids DA and MA were investigated in the range of -2 — (+2) V, range. It is seen that Anderson type POM has two oxidation and reduction potentials. These redox processes are reversible at the 0.3 and -0.75 V (Ipa/Ipc). On the other hand, the oxidation and reduction processes of the Anderson POM based hybrids DA and MA have shifted to the lower regions and all processes are irreversible process in this potential range. Thermal properties of the hybrids DA and MA were investigated in the 20—800 °C temperature range. UV–Vis spectral and viscosity measurements revealed that hybrids DA and MA interact with DNA via groove mode.