Supramolecular architecture of a novel non-centrosymmetric heteromolybdate hybrid for nonlinear optical applications: structure, characterization, stability study and DFT calculations

Abstract

A novel non-linear optical organic–inorganic material based on three-dimensional (3D) Strandberg-type polyoxoselenomolybdate, (C6H14N2)2[Se2Mo5O21]·2.6 H2O (I) has been successfully obtained by solution process and characterized by scanning electron microscopy, infrared and ultraviolet spectroscopy, thermogravimetric analysis, cyclic voltammetry measurement. The electronic and electrochemical stability behaviour of the compound was evaluated as a function of pH and time via UV-visible spectroscopy and cyclic voltametry. Single X-Ray diffraction was used for complete structure elucidation which confirms the title compound crystallizes in the non-centrosymmetric orthorhombic space group P212121 thus allowing 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 organic cations through a network of hydrogen bonds. The intermolecular interactions which ensure the cohesion between different entities were ‎analysed by density functional theory calculations and Hirshfeld surface analysis. DFT ‎calculations with different functionals have been used to better understand several properties. A good agreement was found between the experimental and computational results.