RInaldo Poli , Laboratoire de Chimie de Coordination, Toulouse, France
“Vitrimers with inorganic crosslinks: a new playground for coordination chemistry”
All are welcome or join the Zoom Meeting
https://ithaca.zoom.us/j/91673594658?pwd=a7JolK9drygjR6jROnwLgWhvXcvBRm.1
Please email alarsen@ithaca.edu with any questions concerning the event.
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The world of polymer materials has acquired a new dimension with the development of “vitrimers” – that is adaptable networks, which combine the properties of thermoplastics (better recyclability) and thermosets (better mechanical properties). The key feature in these materials is the presence of chemically exchangeable crosslinks. When the exchange process leading to crosslink migration and materiel reshaping has an associative character, the material crosslink density is temperature-independent and an Arrhenius-type rheological behavior is observed, like in vitreous silica, hence the name “vitrimer”. Currently, a flurry of activity within the polymer community aims at developing new vitrimers, all based on organic covalent reactivity (e.g. transesterification, transamidation, etc.). In this lecture, I’ll show that this area also has tremendous opportunities for coordination chemists. I’ll present new coordination adaptable networks based on the metal cluster ([M6O4(OH)4]2+, M = Zr, Hf) as crosslinking unit and on carboxylate ligand exchange as the crosslink migration process. I’ll also show the results of a mechanistic investigation by combined experimental kinetics (dynamic NMR) and computational modeling (DFT) on a model system, which demonstrates the associative character of the exchange.4 Thus, our developed materials are the first proven vitrimers based on coordination chemistry.
References
1. (a) Denissen, W.; Winne, J. M.; Du Prez, F. E., Vitrimers: permanent organic networks with glass-like fluidity. Chem. Sci. 2016, 7 (1), 30-38. (b) Krishnakumar, B.; Sanka, R.; Binder, W. H.; Parthasarthy, V.; Rana, S.; Karak, N., Vitrimers: Associative dynamic covalent adaptive networks in thermoset polymers. Chem. Eng. J. 2020, 385, 12382. (c) Van Zee, N. J.; Nicolay, R., Vitrimers: Permanently crosslinked polymers with dynamic network topology. Progr. Polym. Sci. 2020, 104, 101233.
2. Murali, M.; Berne, D.; Joly-Duhamel, C.; Caillol, S.; Leclerc, E.; Manoury, E.; Ladmiral, V.; Poli, R., Coordination adaptable networks: zirconium(IV) carboxylates. Chem. Eur. J. 2022, 28, e202202058.
3. Murali, M.; Berne, D.; Daran, J.-C.; Bijani, C.; Manoury, E.; Leclerc, E.; Caillol, S.; Ladmiral, V.; Joly-Duhamel, C.; Poli, R., Hafnium coordination vitrimer based on carboxylate exchange: synthesis, properties, and mechanistic investigations on the [Hf6O4(OH)4(O2CMe)12]2 model compound Eur. J. Inorg. Chem. 2024, 27, e202300672.
4. Murali, M.; Bijani, C.; Daran, J.-C.; Manoury, E.; Poli, R., Acetate Exchange Mechanism on a Zr12 Oxo Hydroxo Cluster: Relevance for Reshaping Zr-Carboxylate Coordination Adaptable Networks. Chem. Sci. 2023, 14, 8152–8163.