Polyoxometalates in Analytical Sciences

Abstract

Polyoxometalates (POMs) have been used for spectrophotometric determinations of silicon and phosphorus under acidic conditions, referred to as the molybdenum yellow method and molybdenum blue method, respectively. Many POMs are redox active and exhibit fascinating but complicated voltammetric responses. These compounds can reversibly accommodate and release many electrons without exhibiting structural changes, implying that POMs can function as excellent mediators and can be applied to sensitive determination methods based on catalytic electrochemical reactions. In addition, some rare-earth-metal-incorporated POMs exhibit fluorescence, which enables sensitive determination by the enhancement and quenching of fluorescence intensities. In this review, various analytical applications of POMs are introduced, mainly focusing on papers published after 2000, except for the molybdenum yellow method and molybdenum blue method.

A tetrahedron-shaped polyoxoantimotungstate encapsulating a hexanuclear octahedral lanthanide-oxo cluster for an amperometric bromate sensor

“…Due to their rich electrochemical properties and strong electrocatalytic activity for numerous small molecules, tungsten-and molybdenum-based polyoxometalates have been widely exploited in the field of electrochemical sensing. [58][59][60][61] The electrocatalytic reduction activity of 1 with respect to bromate is carefully investigated in this work.…”

Exploring the Reactivity of Polyoxometalates toward Proteins: From Interactions to Mechanistic Insights

“…Despite the promising properties of metal-oxo clusters, the lack of a clear molecular-level understanding regarding their interactions and reactivity toward biomolecules hampers further developments in the rational design of such clusters for applications in biochemistry and medicine. This can be clearly seen from the enduring unanswered questions on the mechanisms of action of POMs that give rise to their reported antiviral, antibacterial, and antitumor activity. ,, Nevertheless, the therapeutic activity of POMs has been largely attributed to their interactions and reactivity toward proteins. , Hence, elucidating the molecular aspects of the reactivity between well-defined, discrete metal-oxo clusters and proteins would offer invaluable insights to advance, for instance, essential analytical tools across the biomedical sciences, , or the development of novel types of inorganic drugs based on metal-oxo clusters . This challenge can be addressed through the judicious study of simpler systems, such as peptides, which can be very instructive by unveiling a deeper understanding that can be built up toward larger and more complex biological systems in a “bottom-up” approach.…”

“… 4 , 16 , 19 Nevertheless, the therapeutic activity of POMs has been largely attributed to their interactions and reactivity toward proteins. 4 , 19 Hence, elucidating the molecular aspects of the reactivity between well-defined, discrete metal-oxo clusters and proteins would offer invaluable insights to advance, for instance, essential analytical tools across the biomedical sciences, 22 , 23 or the development of novel types of inorganic drugs based on metal-oxo clusters. 4 This challenge can be addressed through the judicious study of simpler systems, such as peptides, which can be very instructive by unveiling a deeper understanding that can be built up toward larger and more complex biological systems in a “bottom-up” approach.…”

A voltammetric sensor based on a reduced graphene oxide/β-cyclodextrin/silver nanoparticle/polyoxometalate nanocomposite for detecting uric acid and tyrosine

“…31,32 Additionally, polyoxometalate (POM), a well-organized metal-oxygen anion cluster which could be reduced reversibly without any structural change under UV irradiation, is an attractive reduction reagent in the eld of photochemical redox processes. 33,34 For example, Wang and coworkers prepared palladium nanoparticles (PdNPs) attached onto the surface of nitrogen-doped hollow carbon spheres (NHCSs) using polyoxometalates (POMs) as both reductant and bridging molecules by a green strategy, and employed PdNP/POMs/NHCSs as an effective sensing platform for the electrochemical detection of acetaminophen. 35 Yola et al successfully conducted the sensitive and selective determination of aqueous triclosan based on gold nanoparticles on a polyoxometalate/reduced graphene oxide nanohybrid.…”