Functionalised polyhedral oligomeric silsesquioxane with encapsulated fluoride - first observation of fluxional SiF interactions in POSS
| Autor: | Mathilde Laird, Cédric Totée, Masafumi Unno, John R. Bartlett, Arie van der Lee, Michel Wong Chi Man, Philippe Gaveau, Carole Carcel, Gilles Silly |
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| Přispěvatelé: | Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Institut Européen des membranes (IEM), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM), Gunma University, Western Sydney University |
| Rok vydání: | 2020 |
| Předmět: |
Coupling constant
010405 organic chemistry Nuclear magnetic resonance spectroscopy [CHIM.MATE]Chemical Sciences/Material chemistry 010402 general chemistry 01 natural sciences Silsesquioxane 0104 chemical sciences Ion Inorganic Chemistry chemistry.chemical_compound Crystallography [CHIM.POLY]Chemical Sciences/Polymers chemistry Covalent bond Fourier transform infrared spectroscopy Single crystal Fluoride |
| Zdroj: | Dalton Transactions Dalton Transactions, Royal Society of Chemistry, 2021, 50 (1), pp.81-89. ⟨10.1039/d0dt03057k⟩ |
| ISSN: | 1477-9234 1477-9226 |
| DOI: | 10.1039/d0dt03057k⟩ |
| Popis: | International audience; The synthesis of a styryl functionalised POSS incorporating an encapsulated fluoride ion within a (SiO1.5)8 cage (T8-F) is reported. It was characterised by single crystal XRD, MALDI-MS, FTIR, solution (29Si, 19F, 13C, 1H) and solid state (29Si, 19F) NMR. In the absence of 1H decoupling, the 29Si solution NMR spectrum exhibited a triplet of doublets. In contrast, 1H, 19F and 1H/19F double-decoupling resulted in two, three and one signal, respectively, being consistent with a single Si site whose 29Si NMR signal is modulated by both the proximal aromatic-ring protons and fluoride. The associated Si⋯F coupling constant (2.5 Hz) is substantially lower than expected for a covalent Si–F bond and arises from a fluxional Si⋯F covalent effect in which the F− interacts equivalently with all eight Si atoms. Additional variable temperature NMR studies demonstrated a threshold at −5 °C below which no Si⋯F interactions are observed, and above which an increasing Si⋯F covalent character occurs. |
| Databáze: | OpenAIRE |
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