1350571-64-0Relevant academic research and scientific papers
Arene-Perfluoroarene-Anion Stacking and Hydrogen Bonding Interactions in Imidazolium Salts for the Crystal Engineering of Polarity
Althagbi, Hanan I.,Edwards, Alison J.,Nicholson, Brian K.,Reason, Daniel A.,Saunders, Graham C.,Sim, Sophie A.,Van Der Heijden, Danielle A.
, p. 174 - 188 (2016)
The crystal structure of 1-(2,3,5,6-tetrafluoropyridyl)-3-benzylimidazolium bromide possesses C6H5···C5F4N···Br- interactions that link the cations into chains, N(C)C-H···Br- interactions that link the chains into sheets, and N2C-H···Br- interactions that link the sheets to one another. As a consequence of these, it is polar (Pna21). Density functional theory calculations indicate that the strength of the interaction between a cation and a bromide anion lies in the order N2C-H···Br- > N(C)C-H···Br- > C6H5···C5F4N···Br-. Prevention of the N2C-H···Br- interaction by substitution of the hydrogen atom with a methyl group leads to dimers linked by two C6H5···C5F4N···Br- interactions. Prevention of the N(C)C-H···Br- interaction by substitution of the hydrogen with a methyl group permits chains of cations, but because the N2C-H···Br- interactions link the chains there are no strong interactions between the sheets. Chains of cations linked by Ar···C5F4N···Br- interactions also arise when the benzyl group is replaced by 3-phenylbenzyl and 2-naphthylmethyl groups. The former also contains N2C-H···Br- and N(C)C-H···Br- interactions and is centrosymmetric. The latter does not contain N(C)C-H···Br- interactions and is chiral and polar (P21). Exchanging the positions of the aryl and polyfluoroaryl groups results in a crystal structure with no π-π stacking between the aryl and polyfluoroaryl groups although N2C-H···Br- and N(C)C-H···Br- interactions persist.
