A DFT Study on the Electronic and Redox Properties of [PW11O39(ReN)]n–(n = 3, 4, 5) and [PW11O39(OsN)]2–

Structure, properties and reactivity of polyoxometalates: a theoretical perspective

In the thematic review dedicated to polyoxometalate (POM) chemistry published in Chemical Reviews in 1998, no contribution was devoted to theory. This is not surprising because computational modelling of molecular metal-oxide clusters was in its infancy at that time. Nowadays, the situation has completely changed and modern computational methods have been successfully applied to study the structure, electronic properties, spectroscopy and reactivity of POM clusters. Indeed, the progress achieved during the past decade has been spectacular and herein we critically review the most important papers to provide the reader with an almost complete perspective of the field.

A DFT study on the electronic and redox properties of [X8V14O50]n– (X = SiIV, GeIV, PV, and AsV)

The electronic and redox properties of the title polyanions have been calculated by means of density functional theory (DFT). These were unrestricted open-shell systems with electronic configuration of d1 of V. In this behalf, energies and compositions of α-LUMO, β-LUMO, α-HOMO, and β-HOMO were also analyzed. First of all, electronic and redox properties of vanadosilicate [Si8V14O50]12– (system 1) were calculated and then SiIV was substituted with GeIV, PV, and AsV for further investigations of systems 2, 3, and 4, respectively. The substitution greatly modifies the electronic properties as α-LUMOs are quite different in all the studied systems. The α-LUMO is mainly composed of V and O in system 1, V and Ge in system 2, V and O in system 3, and As, O, and V in system 4. The alpha HOMO–LUMO energy gaps are greatly reduced in systems 2, 3, and 4 as compared with system 1. The system 4 [As8V14O50]4– has minimal value of total bonding energy, whereas system 2 [Ge8V14O50]12– has maximal, so energetically system 4 is more favourable than the others. After the first reduction, α-LUMO in [Si8V14O50]14– is made up of V and Si, β-LUMO in [Ge8V14O50]13– is concentrated on V and Ge, β-LUMO in [P8V14O50]5– is composed of V only, whereas β-LUMO in [As8V14O50]5– is delocalized over V, O, and As with almost the same contribution of all three atoms.