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An Investigation into Interactions between 1‐Butyl‐3‐methyl‐imidazolium Tetrafluoroborate Guest and Pillar[5]arene Hosts: An Experimental and Molecular Dynamics Approach
Author(s) -
Al Mamari Hamad H.,
Al Harrasi Iman,
Suliman Fakhreldin O.
Publication year - 2021
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.202003241
Subject(s) - tetrafluoroborate , ionic liquid , pillar , chemistry , nuclear magnetic resonance spectroscopy , molecular dynamics , ionic bonding , crystallography , spectroscopy , proton nmr , stereochemistry , ion , computational chemistry , organic chemistry , catalysis , physics , structural engineering , quantum mechanics , engineering
Abstract Various synthesized Pillar[5]arene macrocycles were allowed to form complexes with the ionic liquid; 1‐Butyl‐3‐methyl‐imidazolium tetrafluoroborate (IL). The pillar[5]arenes used in the study were synthesized by the established pioneering method of Ogoshi that involves treatment of 1,4‐disubstituted benzenes with paraformaldehyde in the presence of BF 3 .OEt 2 . Selected synthesized pillar[5]arenes; DMpillar[5]arene (4a), DPpillar[5]arene (4b), DPGpillar[5]arene (4c) were allowed to form complexes with the ionic liquid, and complexations were confirmed by MALDI‐TOF, ESI‐MS, 1 H NMR, and DOSY spectroscopy. ESI‐MS reveals highly intense ion peaks that correspond to [pillar[5]arene+IL] + for the complexes of the three pillar[5]arenes with the ionic liquid. Changes in characteristic peaks in hosts and guests, as a result of complexation, were studied by 1 H NMR. Results obtained suggest a formation of 1 : 1 complexes between the pillar[5]arene host and the IL guest. Host‐guest interactions in such complexes have also been studied using 1 H‐ 1 H 2D ROESY NMR spectroscopy. Obtained through‐space correlations revealed interactions between certain parts of the pillar[5]arene hosts and the ionic liquid. The complexation between the three pillar[5]arenes and the IL was studied by molecular dynamics (MD) simulations. The obtained results suggest the insertion of the IL inside the nanocavities of the hosts.