Crystal structure and theoretical calculations of 1-(4-trifluoromethyl-2,3,5,6-tetrafluorophenyl)-3-benzylimidazolium bromide

The structures of 1-(2-halo-6-fluorophenylmethyl)-1-methylimidazolium bromide salts

“…The crystal structures of fluoroaryl-substituted imidazolium salts are a valuable source of information on a range of non-covalent interactions, in particular, π-π stacking [1][2][3][4][5] and anion-π interactions [2,3,[5][6][7][8], arising from the presence of fluorine atoms, along with charge-assisted hydrogen bonding [3,9]. These interactions have importance in crystal engineering and through the judicious choice of fluoroaryl substituents polar crystal structures can be realized [1][2][3][4][5].…”

“…It is expected that non-covalent interactions can be turned on or off for imidazolium halide salts by variation of the substituent aryl group. As an example, although the structures of the related cations of 1-pentafluorophenylmethyl-3-methylimidazolium bromide (ROTMEU) [7] and 1-(2-bromophenylmethyl)-3-methylimidazolium bromide (EVACIO) [11] adopt similar conformations, because of the difference in the electronic nature of the phenyl ring the crystal structure of the former possesses an anion-π interaction [2,3,[5][6][7][8]12], whereas that of the latter does not (Figure 1). In order to further probe these structural features and non-covalent interactions we are investigating fluoroaryl-substituted imidazolium salts.…”

The crystal structures of 1-(polyfluorophenylmethyl)-3-methylimidazolium bromide salts

“…The crystal structures of fluoroaryl-substituted imidazolium salts have provided information on a range of relatively weak non-covalent interactions, in particular π-π stacking [1][2][3][4][5] and anion-π interactions [2,3,[5][6][7][8], in the presence of much stronger charge-assisted hydrogen bonding. The dependence of the structural motifs on the combination of interactions is of importance in crystal engineering.…”

“…The majority of crystal structures of fluoroaryl-substituted imidazolium bromide salts possess a N 2 C─HꞏꞏꞏBrhydrogen bond [2,3,[9][10][11], unless this position is blocked, as is the case for 2-methyl substituted imidazolium cations [12]. Typically this charge-assisted hydrogen bonding is the strongest inter-ion interaction [3,8,[11][12][13]. Most structures also possess weaker C─HꞏꞏꞏBrhydrogen bonding involving one or both of the other hydrogen atoms of the imidazolium ring.…”

The crystal structures of 1-(4-bromo-2,3,5,6-tetrafluorophenyl)-3-benzyl-methylimidazolium bromides

“…The crystal structures of 1-polyfluoroaryl-3-benzylimidazolium bromide salts display a range of interactions which are dependent on the nature of the polyfluoroaryl substituent ( Figure 1) [1][2][3][4][5][6]. Charge-assisted hydrogen bonding [7,8] interaction [11] is evident in salt 2.…”