![]() While POMs possesses inherent photoactivity through excitation of the O → M ligand-to-metal charge transfer (LMCT) excitation, this is usually limited to the UV region with only marginal tailing into the visible region ( Cameron et al., 2018). ![]() Generally, the physical properties of the POMs are dominated and controlled by the cation, and thus, Class I hybridization is a highly attractive route toward POM-based functional materials such as POM ionic liquids (POM-ILs) ( Kibler et al., 2019), POM charge transfer salts ( Xu et al., 2010), and POM-decorated polymers ( Herrmann et al., 2015).Ī lesser explored avenue with Class I hybrids is the photosensitization of POMs using cationic organic or organometallic chromophores. Class I hybrids remain the most prolifically reported and studied due to their ease of synthesis through simple metathesis reactions and their compatibility with any anionic POM structure. This is typically achieved in one of two ways: either via the exchange of alkali metal or proton countercations with organic countercations (Class I hybrid) or via the covalent grafting of organic fragments onto the POM (Class II hybrid) ( Dolbecq et al., 2010 Kibler and Newton, 2018). Organic hybridization offers a near-limitless scope for the enhancement or modulation of the POMs properties through the intelligent design of the organic component. Organic–inorganic hybrid POMs are an emerging family of molecules that involve the inclusion of organic moieties into the inorganic structure of the POM. ![]() As such, POMs have demonstrated applicability in a wide number of research areas including redox and photoredox catalysis ( Wang and Yang, 2015), optoelectronics ( Chen et al., 2019), soft materials ( Kastner et al., 2017), molecular magnetism ( Baldoví et al., 2017), photochromic devices ( Liu et al., 2006), hybrid nanomaterials ( Jordan et al., 2019 Martin et al., 2020), and battery technologies ( Huang et al., 2020). This vast family of compounds is reputed for their rich redox properties ( Gumerova and Rompel, 2018) and photoactivity ( Cameron et al., 2018) in conjunction with high thermal and oxidative stability ( Varga et al., 1998 Lv et al., 2012). Polyoxometalates (POMs) are discrete anionic metal oxide clusters, commonly formed from Group V and Group VI transition metals in their highest oxidation state. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies of the polyoxometalate (POM) and BTD-4,7-ImH precursors, estimated through UV–vis absorption spectroscopy and cyclic voltammetry, indicate that electron transfer from the BTD cations to the POM may occur in the excited state. The UV–vis diffuse reflectance spectra indicate that the hybrid has a band gap of 3.13 eV, while the solid-state fluorescence properties of the cation are quenched in the hybrid material, suggesting the existence of electron transfer between the inorganic and organic components. X-ray crystallographic analysis shows that the inorganic and organic components form a hydrogen-bonded superstructure and that the cations are revealed to be non-equivalent with varying degrees of rotation between the BTD and imidazolium rings due to competition between weak intra- and intermolecular interactions. 3Department of Chemistry, School of Chemistry, University of Nottingham, Nottingham, United KingdomĪn organic–inorganic hybrid species based on the Wells–Dawson polyoxotungstate 6− and novel fluorescent benzothiadiazole–imidazolium cations, 2+, has been synthesized.2Laboratory of Molecular Catalysis, Institute of Chemistry, Universidade Federal do Rio Grande Do Sul, Porto Alegre, Brazil. ![]()
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