Interaction of Ru(II) polypyridyl complex cations and Keggin anions [α-SiW12O40]4− in self-assembled organic-inorganic networks

Abstract

Some Keggin polyoxometalates (POMs) have shown interesting photocatalytic properties. However, because most POMs primarily absorb ultraviolet light, their ability to use solar energy is limited. In this report, we have shown that photosensitizers such as ruthenium (II) polypyridyl complexes can be linked to POMs to form hybrid solids: ([Ru(bpy)3]2[SiW12O40] (1) (bpy = 2,2′-bypyridine) and [Ru(bpy)2(MeCN)2]2[SiW12O40]·4.5H2O (2)) with broad absorption band in the UV–visible range. X-ray crystallographic studies showed that both compounds contain the [α-SiW12O40]4− units and the ruthenium (II) polypyridyl units, which form three-dimensional frameworks through noncovalent bonds such as CH⋯O and anion-π interactions. These solids were also studied using thermogravimetric analysis, FT-IR, FL, and UV–vis spectroscopy. Additionally, compound 1 shows strong luminescence at 450 nm in its solid state at room temperature.