Nanocluster Polyoxometalates Functional Design
Grzhegorzhevskii LAB


Polyoxometalate (POM) chemistry spans across the coordination compounds and the hierarchical supramolecular ensembles. Only five elements (V, Mo, W, Nb and Ta) possess the unique combination of ionic radius and atom shell configuration to produce diversity in polynuclear iso- and hetero-complexes: Evans–Anderson, Keggin, Well–Dawson and even giant POM-like Keplerates, etc.

POM exhibit various scenarios when being embedded into hybrid organic structures via coordination and electrostatic interactions, weak van der Waals forces and hydrogen bonding. Along with the possibility to graft the organic linkers, the POMs are a powerful platform for the design of supramolecular architectures.

Using POM as a nano-scaled template, we create supramolecular structures for photocatalysis, biomimetics and molecular recognition applications.

Research Topics
Interaction POM-Sensitizer

The giant POM (like Keplerate-type etc.) can either induce organic dye self-assembling on its surface or participate in dynamic supramolecular ensembles formation. Using different cationic dyes (xanthene dyes, porphyrins, BODIPY etc.) we can flexibly tune the electron and energy transfer process on the POM surface to control the photocatalytic behaviour. Furthermore, POM|Dye is prominent system to answer on two essential questions:
i) how dye aggregation affects the photoeficiency on metal-oxide|dye interfaces in solar cell;
ii) how we can control the aggregation.
Giant POM Covalent Modification

Using alkoxysilanes our Lab performed pioneer research on covalently grafting of the organic molecules onto the giant POM surface and realized postfunctionalization by means of click-reaction (carbodiimide, thiol-ene, Schiff-base etc.). As a result, giant POMs surve like precise (2.5 or 3 nm diameter) nanoscaled inorganic templates to assemble desired supramolecular structures for many kind of applications: photo- and regioselective catalysis, nano-vesicles formation, Langmuir-Blodgett films etc. Our strategy suggests powerful instrument to tune the smart-materials on the supramolecular level using giant POMs.
Hybrid Hydrogel and Drug Carriers

Due to the polyfunctional surface the giant POM can be embedded into hydrogel structure via electrostatic or Wan-der-Waals forces, hydrogen bonding and covalent grafting. As a template, POM macroanion can organize macromolecules in specific fashion (like electrostatic linker for catinic polyelectrolyte e.g.). As a result, we can control the swelling behaviour of hydrogel or loaded them with desired drug bound with POM surface. During the pH-depended POM destruction, the stored drug can be released in controled fashion. Furthermore, once covalently modify the polymer chain by organic dye, we can create multifunctional POM-embedded biocomatible hydrogel for bioapplication.
Machine Learning for Supramolecular Structure Design

We combine Machine Learning and cyclic voltammetry to find the way to produce supramolecular structures in controlled fashion based on the giant POM (like Keplerate) and cationic organic dyes. The global aim is software product which can predict supramolecular behaviour in such systems based on the electrochemical data. Using robot-assisted screening experiments we believe that machine learning can solve this challenge through artificial intellegence approach.
Recent Results
Fundamental Aspects of Xanthene Dye Aggregation on the Surfaces of Nanocluster Polyoxometalates: H‐ to J‐Aggregate Switching

Chemistry – A European Journal, 26(25), 5685-5693.
The precise modification of a nanoscaled Keplerate-type polyoxometalate with NH2-groups: reactive sites, mechanisms and dye conjugation

Inorganic Chemistry Frontiers, 9(7), 1541-1555.
Gigantic supramolecular assemblies built from dynamic hierarchical organization between inorganic nanospheres and porphyrins

Chemical Communications 59, 86-89.
Covalent Grafting of Eosin Y to the Giant Keplerate {Mo132} through an Organosilicon Linker in Homogeneous Regime

Inorganics, 11(6), 239.
A polyacrylamide-chitosan semi-interpenetrating self-healing network with embedded Keplerate {Mo132 } for pH-controlled release of Eu-fluorescent tags

New Journal of Chemistry, 47, 17 007−17 019
#23-73-10158, "Multilayer photopolymerized inorganic-organic hydrogel system with fluorescent response and controlled drug release of quorum sensing inhibitors for wound dressing and regeneration" funded by Russian Science Foundation, 2023-2026.

#4.81, “Laboratory of the Nanocluster Polyoxometalates Functional Design” in frame of program “Priority 2030” of the Ministry of Science and Higher Education of the Russia Federation, 2022-2024.

#21-73-00311, “Design's strategies of nanoscaled polyoxometalates by molecules of oligopyrrole dyes: precise aggregation control of photosensitizers and creation of molecular scaffolds for photocatalytic applications” funded by Russian Science Foundation, 2021-2023.

#19-73-00177, "Durable action releasing-systems for drug delivery with feedback function based on the nanocluster polyoxometalates" funded by Russian Science Foundation, 2019-2021.

#SP-1070.2018.4 “Hybrid inorganic-organic sensory covers for biodiagnostic chips” funded by the Council for Grants of the President of the Russian Federation, 2018-2020.

#16-33-00570 “Photosensitization processes and catalytic properties of the supramolecular system based on the toroidal nanoclustered polyoxomolybdate Mo138” funded by Russian Foundation for Basic Research, 2016-2017.
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Ural Federal University
Istitute of Natural Sciences and Mathematics
Institute of Applied Physics and Mathematic

Laboratory of Nanocluster Polyoxometalates
Functional Design

Russia, Ekaterinburg, Kuybisheva street 48

*photo by Slava Kaygorodov and Anna Prokofyeva