Acharige UAI, Saunders GC. The Influence of the Halide in the Crystal Structures of 1-(2,3,5,6-Tetrafluoro-4-pyridyl)-3-benzylimidazolium Halides.
Molecules 2022;
27:molecules27217634. [PMID:
36364461 PMCID:
PMC9656857 DOI:
10.3390/molecules27217634]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/21/2022] [Accepted: 10/28/2022] [Indexed: 11/09/2022] Open
Abstract
The crystal structures of 1-(2,3,5,6-tetrafluoro-4-pyridyl)-3-benzylimidazolium chloride (1) and iodide (3) have been determined by single crystal X-ray diffraction. The crystal structure of 1 is similar to that of the bromide salt (2), possessing anion···C5F5N···C6H5 motifs, whilst that of 3 contains columns of alternating iodide anions and parallel tetrafluoropyridyl rings. All three crystal structures possess C(1)−H∙∙∙X− and C(2)−H∙∙∙X− hydrogen bonding. DFT calculations reveal that the strengths of the hydrogen bonding interactions lie in the order C(1)−H···X− > C(3)−H···X− > C(2)−H···X− for the same halide (X−) and Cl− > Br− > I− for each position. It is suggested that salt 3 adopts a different structure to salts 1 and 2 because of the larger size of iodide.
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