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Halogen bonding in a series of Br(CF 2 ) n Br–DABCO adducts ( n = 4, 6, 8)
Author(s) -
Brisdon Alan K.,
Muneer Abeer M. T.,
Pritchard Robin G.
Publication year - 2017
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s2053229617013663
Subject(s) - dabco , halogen , adduct , series (stratigraphy) , halogen bond , chemistry , medicinal chemistry , organic chemistry , octane , geology , paleontology , alkyl
Halogen bonding (XB) is a highly‐directional class of intermolecular interactions that has been used as a powerful tool to drive the design of crystals in the solid phase. To date, the majority of XB donors have been iodine‐containing compounds, with many fewer involving brominated analogues. We report the formation of adducts in the vapour phase from a series of dibromoperfluoroalkyl compounds, BrCF 2 (CF 2 ) n CF 2 Br ( n = 2, 4, 6), and 1,4‐diazabicyclo[2.2.2]octane (DABCO). Single‐crystal X‐ray diffraction studies of the colourless crystals identified 1,4‐diazabicyclo[2.2.2]octane–1,4‐dibromoperfluorobutane (1/1), C 4 Br 2 F 8 ·C 6 H 12 N 2 , (I), 1,4‐diazabicyclo[2.2.2]octane–1,6‐dibromoperfluorohexane (1/1), C 6 Br 2 F 12 ·C 6 H 12 N 2 , (II), and 1,4‐diazabicyclo[2.2.2]octane–1,8‐dibromoperfluorooctane (1/1), C 8 Br 2 F 16 ·C 6 H 12 N 2 , (III), each of which displays a one‐dimensional halogen‐bonded network. All three adducts exhibit N…Br distances less than the sum of the van der Waals radii, with butane analogue (I) showing the shortest N…Br halogen‐bond distances yet reported between a bromoperfluorocarbon and a nitrogen base [2.809 (3) and 2.818 (3) Å], which are 0.58 and 0.59 Å shorter than the sum of the van der Waals radii.