Tytuł
Proof of ion-pair structures in ammonium-based protic ionic liquids using combined NMR and DFT/PCM-based chemical shift calculations
Autorzy
[ 1 ] Instytut Chemii Bioorganicznej Polskiej Akademii Nauk, Polska Akademia Nauk | [ P ] pracownik
Dyscyplina naukowa (Ustawa 2.0)
Rok publikacji
2017
Opublikowano w
Typ artykułu
artykuł naukowy
Język publikacji
angielski
Słowa kluczowe
Streszczenie
EN The self-assembly of triethylammonium bis(trifluoromethylsulfonyl)imide, i.e. [(C2H5)(3)NH][TFSI], in chloroform and aqueous solutions has been investigated using H-1 NMR spectroscopy and computational (DFT/PCM prediction) methods. We have examined a number of ion pairs formed between the [(C2H5)(3)NH](+) cation with different conformations of alkyl substituents as well as various dispositions of the multi-site [TFSI](-) anion. Based on the agreement between the calculated (DFT) and observed H-1 NMR chemical shifts, [(C2H5)(3)NH][TFSI] in chloroform formed lipophilic complexes with effective N+-H center dot center dot center dot N or N+-H center dot center dot center dot O hydrogen bonding, whereas hydrophilic complexes with C-alpha-H center dot center dot center dot O and C-alpha-H center dot center dot center dot F hydrogen bonding are found in aqueous solutions. This study provides a new insight into the self-aggregation of ammonium PILs incorporating the widely used [TFSI](-) anion and demonstrates the importance of solvent effects on chemical shifts. The simulations with explicit and implicit dielectric continuum solvents are found to be the most realistic method, yielding a representative ensemble of structures.
Strony (od-do)
25033 - 25043
Punktacja Ministerstwa / czasopismo
40
Punktacja Ministerstwa / czasopismo w ewaluacji 2017-2021
40
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