Journal Article

Physico-Chemical Characterization of a New Hybrid Material (NH ₄ ) ₂ (C ₆ H ₁₈ N ₂ )H ₂ P ₂ Mo ₅ O ₂₃ ·H ₂ O: Quantum Chemical and Comparative Studies with Homologous (C ₆ H ₁₈ N ₂ ) ₂ H ₂ P ₂ Mo ₅ O ₂₃ ·H ₂ O

Abid, Sonia, Roisnel, Thierry, Hichri, Amal

2024

Overview

The synthesis and solid-state characterization of a new hybrid polyoxometalate of formula (NH ₄ ) ₂ (C ₆ H ₁₈ N ₂ )[H ₂ P ₂ Mo ₅ O ₂₃ ]·H ₂ O (POM 2) were carried out by using X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR), UV–Vis and fluorescence techniques. It crystallized in a triclinic system with space group P-1, a = 10.1868 (17), b = 10.730(2), c = 14.380(3) Å, α = 100.840(6), β = 95.868(6), γ = 114.934(6)°, and Z = 1. Analysis of the crystal structure reveals that the Strandberg anions [H ₂ P ₂ Mo ₅ O ₂₃ ] ⁴⁻are interconnected into a 3D supramolecular inorganic framework through hydrogen bonding interactions involving water molecules, ammonium cations, and the terminal oxygen atoms of polyanionic units. The organic cations are hosted within the anionic framework to balance its negative charge. Density functional theory (DFT) calculations were performed to optimize the geometry of the novel compound and its homologous compound (C ₆ H ₁₈ N ₂ ) ₂ [H ₂ P ₂ Mo ₅ O ₂₃ ]·H ₂ O (POM 1), in order to evaluate HOMO–LUMO energy parameters, molecular electrostatic potential (MEP) and non linear optical (NLO) properties. The calculated results reveal good consistency with the experimental structure. The calculated first-order hyperpolarizability of POM 1 and POM 2 are 8.71 and 15.87 times that of urea.

• Publisher: Springer
• Subject: Chemical Sciences / Material chemistry / or physical chemistry / Theoretical and