Structures, electronic properties, reactivity and dynamic studies of three new polyoxometalate compounds

Abstract

We report a complex study on the crystal structures, electronic properties, reactivity and dynamics of three polyoxometalate compounds (C₆NH₈)₄[H₂P₂Mo₅O₂₃]·5H₂O (1), (C₂H₈N)₅[HP₂Mo₅O₂₃]·(C₃H₉NO₂)_0.5·(H₂O)_1.5 (2) and (C₂H₈N)₃[PMo₁₂O₄₀]·(H₂O)_0.34 (3). These compounds were synthesized using a solution method and characterized by single-crystal X-ray diffraction. Crystallography confirmed three distinct symmetries P, P2₁/c and Rc for 1, 2, and 3, respectively, and unit cell constants a = 12.5609(2) Å, b = 13.2470(2) Å, c = 14.0353(2) Å, α = 107.1568(14)°, β = 101.2854(13)°, γ = 92.1445(14)° for 1, a = 15.8583(6) Å, b = 17.3578(5) Å, c = 14.8499 (4) Å, β = 114.933(3)° for 2, and a = 16.3798(3) Å, c = 50.2781(5) Å for 3. Semi-empirical calculations applied on the compounds provided information about their reactivity and electronic structures. In this context, several discussions concerning the frontier molecular orbitals, molecular electrostatic potential, thermodynamic properties and local ionization potential were mentioned. We also conducted molecular dynamics analysis in order to elucidate the dynamics of cations and anions and their energy variation.