Exploring the Theoretical Landscape of the Hexalacunary Wells-Dawson Anion: A Comprehensive Study

The hexalacunary polyoxometalate (POM) [P2W12O48]14− can be used as a building block for larger POMs, such as [P8W48O184]40−, but we still know relatively little about their chemistry and only a handful of different species have been discovered. With this in mind, we modelled and ran DFT-level calculations on the known hexalacunary POM species, namely [As2W12O48]14−, [P2W12O48]14−, and [Se2W12O46]14−, with the aim of understanding key properties and improving our capacity to apply inverse design to these POMs. By creating several subfamilies of our POMs, each with different combinations of countercations and/ or protons, we discerned that there was no ‘best model’ for hexalacunaries, with some subfamilies replicating certain empirical data better than others. The dimensions of structures with countercations, such as K3[P2W12O48]11−, were the most akin to their empirical counterparts, whilst the presence of protons in the model provided a relatively accurate picture of charge-neutral electron distribution whilst keeping computational costs to a minimum. There is no benefit to including both countercations and protons in the model, and a structure with a reduced anionic charge is no more accurate a model than one with only a handful of charge balancing cations.