Halogen Interactions in 2,4,5-Tribromoimidazolium Salts

Froschauer, Carmen; Kahlenberg, Volker; Laus, Gerhard; Schottenberger, Herwig

doi:10.3390/cryst2031017

Cited by 7 publications

(2 citation statements)

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“…AnionÁ Á Á interactions have been observed in related imidazolium salts (Froschauer et al, 2012). The O3Á Á Á interaction and C-HÁ Á ÁO S hydrogen bonds are shown as dashed lines (see Table 1).…”

Section: Structure Descriptionmentioning

confidence: 99%

1,3-Dimethoxy-2-methylimidazolium bis(trifluoromethanesulfonyl)imide

et al. 2016

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, was obtained by the methylation of 1-hydroxy-2-methylimidazole 3-oxide and subsequent ion metathesis. In the crystal, C-HÁ Á ÁO S hydrogen bonds and OÁ Á Á interactions are observed. Structure descriptionThe molecular structure of the title compound is shown in Fig. 1. The ions which build this salt, both 1,3-dialkyloxyimidazolium cations (Laus et al., 2010) and the bis(triflimide) anion (Bentivoglio et al., 2009;Laus et al., 2011), are known to exist as syn/anti conformers in the solid state. Thus, the methoxy substituents of the cation adopt an anti conformation with a C5-O1Á Á ÁO2-C6 torsion angle of 170.6 (4) . The bis(triflimide) anion also assumes an anti conformation with a C7-S1Á Á ÁS2-C8 torsion angle of 174.9 (2) . Each cation donates three C-HÁ Á ÁO S hydrogen bonds to three anions (Fig. 2). The hydrogen-bond parameters are summarized in Table 1. An intriguing intermolecular interaction between atom O3 of the anion and the system of the imidazolium ring is observed. The pertinent O3Á Á ÁCg distance is 2.971 Å , where Cg is the centroid of the heterocyclic ring. This interaction is directional with an S1 O3Á Á ÁCg angle of 152 . The crystal packing is shown in Fig. 3.The cation in the structure of the related 1,3-dimethoxy-2-methylimidazolium tris(-pentafluoroethyl)trifluorophosphate displayed a syn geometry (Laus et al., 2007). AnionÁ Á Á interactions have been observed in related imidazolium salts (Froschauer et al., 2012). The O3Á Á Á interaction and C-HÁ Á ÁO S hydrogen bonds are shown as dashed lines (see Table 1). The centroid of the imidazole ring is drawn as red sphere. Table 1 Hydrogen-bond geometry (Å , ). Figure 3The crystal packing of the title compound viewed along the b axis showing the O3Á Á Á interactions. Figure 1The asymmetric unit of the title compound, showing the atom labels and 50% probability displacement ellipsoids for non-H atoms. of Synthesis and crystallizationA suspension of 1-hydroxy-2-methylimidazole-3-oxide (5.09 g, 44.6 mmol) and dimethyl sulfate (9.0 ml, 100 mmol) in H 2 O (5.0 ml) was stirred at room temperature for 30 min. Calcium carbonate (6.35 g, 63.4 mmol) and H 2 O (6.0 ml) were then added to the slurry, and a slight increase of temperature was observed. The mixture was stirred for 15 h. Then hydrochloric acid (36%; 11.0 ml, 129.2 mmol) was added in portions and stirred for 2 h, resulting in a clear solution. Lithium bis(trifluoromethanesulfonyl)imide (13.0 g, 44.9 mmol) was added, whereupon crystallization of the product occurred. After stirring for 1 h, the mixture was extracted with CH 2 Cl 2 (3 Â 50 ml). The combined organic phases were then washed with H 2 O (100 ml) and dried over Na 2 SO 4 . The solvent was removed under reduced pressure, and the product was dried at 75 C in vacuum (< 1 mbar). On cooling to room temperature the product was obtained as a colourless crystalline solid (yield 97%), mp. 66 C.

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Section: Structure Descriptionmentioning

confidence: 99%

1,3-Dimethoxy-2-methylimidazolium bis(trifluoromethanesulfonyl)imide

et al. 2016

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“…Although neutral, mono-N-functionalised 2-bromoimidazoles can form halogen bonds, 5 the imidazolium cation enhances the strength of the resultant halogen bonds through inductive electronic effects. 6 2-Bromoimidazolium salts have been investigated widely for their crystal growth, 7,8 as components of ionic liquids, 9,10 and in anion binding chemistry of di-and tripodal receptors, 11,12 macrocycles, [13][14][15] and interlocked rotaxanes and catenanes. 16,17 The 2-bromoimidazolium groups have also found application as reagents for the oxidative addition to transition metals, 18,19 the activation of carbon-heteroatom bonds, 20 allene polymerisation, 21 aza-Diels-Alder reactions, 22,23 halide abstraction, 24 and Michael addition.…”

Section: Introductionmentioning

confidence: 99%

Disorder in 2-bromoimidazolium hexafluorophosphate salts: the role of halogen bonds

Wolfenden

Taylor

et al. 2023

CrystEngComm

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Four‐Center Nodes: Supramolecular Synthons Based on Cyclic Halogen Bonding

Kryukova

Ivanov

Kinzhalov

et al. 2019

Chemistry A European J

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The isocyanide trans‐[PdBr2(CNC6H4‐4‐X′)2] (X′=Br, I) and nitrile trans‐[PtX2(NCC6H4‐4‐X′)2] (X/X′=Cl/Cl, Cl/Br, Br/Cl, Br/Br) complexes exhibit similar structural motif in the solid state, which is determined by hitherto unreported four‐center nodes formed by cyclic halogen bonding. Each node is built up by four Type II C−X′⋅⋅⋅X−M halogen‐bonding contacts and include one Type I M−X⋅⋅⋅X−M interaction, thus giving the rhombic‐like structure. These nodes serve as supramolecular synthons to form 2D layers or double chains of molecules linked by a halogen bond. Results of DFT calculations indicate that all contacts within the nodes are typical noncovalent interactions with the estimated strengths in the range 0.6–2.9 kcal mol−1.

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Halogen Interactions in 2,4,5-Tribromoimidazolium Salts

Abstract: Abstract:The crystal structures of 2,4,5-tribromo-1-(prop-2-ynyl)imidazole and seven new 1,3-dialkyl-2,4,5-tribromoimidazolium salts (R 1 = propenyl, propynyl, dibromopropenyl;

Cited by 7 publications

References 54 publications

1,3-Dimethoxy-2-methylimidazolium bis(trifluoromethanesulfonyl)imide

1,3-Dimethoxy-2-methylimidazolium bis(trifluoromethanesulfonyl)imide

Disorder in 2-bromoimidazolium hexafluorophosphate salts: the role of halogen bonds

Four‐Center Nodes: Supramolecular Synthons Based on Cyclic Halogen Bonding

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