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, BrCF2(CF2)
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CF2Br (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), C4Br2F8·C6H12N2, (I), 1,4-diazabicyclo[2.2.2]octane–1,6-dibromoperfluorohexane (1/1), C6Br2F12·C6H12N2, (II), and 1,4-diazabicyclo[2.2.2]octane–1,8-dibromoperfluorooctane (1/1), C8Br2F16·C6H12N2, (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.
卤素键(XB)是一类高度定向的分子间相互作用,已被用作推动固相晶体设计的有力工具。迄今为止,大多数 XB 给体都是含碘化合物,而涉及溴化类似物的则较少。我们报告了一系列二溴全氟烷基化合物 BrCF2(CF2)
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CF2Br(n = 2、4、6)和 1,4-二氮杂双环[2.2.2]辛烷 (DABCO)。无色晶体的单晶 X 射线衍射研究确定了 1,4-二氮杂双环[2.2.2]辛烷-1,4-二溴全氟丁烷 (1/1),C4Br2F8-C6H12N2,(I),1,4-二氮杂双环[2.2.2]辛烷-1,6-二溴全氟己烷 (1/1),C6Br2F12-C6H12N2,(II) 和 1,4-二氮杂双环[2.2.2]辛烷-1,8-二溴全氟辛烷 (1/1),C8Br2F16-C6H12N2,(III),它们都显示出一维卤素键网络。所有这三种加合物的 N...Br 间距都小于范德华半径之和,其中丁烷类似物 (I) 显示了迄今所报道的溴全氟碳和氮基之间最短的 N...Br 卤素键距离 [2.809 (3) 和 2.818 (3) Å],比范德华半径之和短 0.58 和 0.59 Å。