Synthesis of Novel Supramolecular Selenomolybdate as Anticancer Agents: An Experimental and DFT Computational Analysis

Abstract

A novel organic-inorganic material based on three-dimensional (3D) Strandberg-type polyoxoselenomolybdate, (C6H14N2)2[Se2Mo5O21]& sdot;2 & sdot;6H2O (I, where C6H14N2 = DABCO cation) was successfully synthesized by solution process and characterized by scanning electron microscopy (SEM), infrared (FT-IR) and ultraviolet (UV-vis) spectroscopies, thermogravimetric analysis (TGA), cyclic voltammetry (CV) measurement. The electronic and electrochemical behavior of the compound was further evaluated as a function of pH and time via UV-vis spectroscopy and CV. Single crystal X-Ray diffraction (XRD) technique was used for complete structure elucidation. The title compound crystallizes in the non-centrosymmetric orthorhombic space group P212121, thus resulting in non-linear optical properties. The supramolecular framework exhibits a periodic arrangement of Strandberg clusters anions [Se2Mo5O21]4- connected to each other with water molecules and dabconium cations, through a network of hydrogen bonds and van der Waals interactions. The occurrence of intermolecular interactions, ensuring the cohesion between different entities, was assessed by density functional theory (DFT) calculations and Hirshfeld surface analysis. DFT calculations with different functionals have been used to better understand several properties like as RDG, QTAIMs, ELF, MEP and NLO. A good agreement was indeed found between the experimental and computational results. Furthermore, the (C6H14N2)2[Se2Mo5O21]& sdot;2 & sdot;6H2O compound was tested for its biological activity. This selenomolybdate displayed a significant inhibitory effect on the growth of human ovarian cancer cells A2780, with an IC50 value of 4.05 +/- 0.55 mu M, being thus the first Strandberg-type polyoxometalate to show a significant anticancer activity.