A "directed precursor self-assembly" strategy for the facile synthesis of heteropoly blues: crystal structures, formation mechanism and electron distribution.

Recent research studies demonstrated that heteropoly blues (reduced polyoxometalates) could act as a special kind of solid material with potential functions in antiviral activity, and photocatalytic, photothermal and semiconducting properties. In this work, we develop a "directed precursor self-assembly" strategy for the facile synthesis of heteropoly blues (HPBs), so four representative HPBs [GeW10MoO40], [GeMoMoO40], [P2W16MoO62] and [P2W12MoMoO62] have been synthesized and structurally characterized. These four heteropoly blue compounds were synthesized by the solution self-assembly reaction of a precursor [MoO4(H2O)2(ox)2]2- with vacant polyoxometalates. Electrospray ionization mass spectrometry (ESI-MS) was used to analyze the assembly mechanism of these HPBs. A detailed study on the magnetic properties was also carried out, which shows that the number of MoV and their locations are capable of adjusting the electron distribution in HPBs.