Iodine halogen-bonded complexes

Mercapto-I-methylimidazole (1) functions as an iodine sponge forming a stable halogen-bonded complex with the Pennington et al. recently reported the... 

Fig. 18.8 2D plots for halogen bonded complexes a CF3CI-DME, b CF3CI-DMS, c CF3Br-DME, d CF3Br-TMP, e CF3I-NHC, f CF3I-TMA. See Sect, 18.7.5.2 for an Interpretation of iodine compounds extra peaks... 

Figure 5,2 MP2/LANL2DZ optimized geometnes of halogen-bonded complexes (a) thIourea-diiodine (planar complex with NH---I hydrogen bond) (b) tetramethylthiourea-diiodine (perpendicular complex) (c) oxlran-2-one-lodlne monochloride (anti conformer) (d) y-butyrolactone-iodine monochloride (syn conformer). Distances are in angstroms and...

The changes in the vibrational spectrum of iodine cyanide, iodine monochloride and diiodine as these molecules form halogen-bonded complexes B- ICN, B- -ICl and B- I2 with series of Lewis bases B have been extensively studied [35, 36, 273-277]. The main perturbation is a lowering of the frequency of the I—CN, I—Cl and I—I stretching motions. These frequency shifts are greater for strong bases, such as pyridines, than for weak bases, such as benzene or dioxane. Hence correlations were attempted between frequency shifts... 

Second only to sulfur-based systems, nitrogen complexes are relatively well represented in the structural literature with 41 complexes reported. Of these, 25 are with I2 as the electron acceptor, 11 are with the interhalogen IC1, three are with Br2, and two are with IBr. As expected, in every case the halogen bond forms between the nitrogen and the softest halogen atom, i.e., iodine, in all of the complexes except those with dibromine. Most N I2 complexes, and all N Br2, N IBr, and N IC1 complexes are simple adducts, mode A. Exceptions for the diiodine complexes include bridging mode (B) observed for diazines, such as pyrazine [86], tetramethylpyrazine [86], phenazine, and quinoxaline [87], and for 9-chloroacridine [89] and the 1 1 complex of diiodine with hexamethylenetetramine [144] and amphoteric bridging mode (BA) observed for 2,2 -bipyridine [85], acridine [89], 9-chloroacridine [89], and 2,3,5,6-tetra-2/-pyridylpyrazine [91]. The occurrence of both B and BA complexes with 9-chloroacridine, and of B and A complexes and an... 

Ru(Tp)I(Ci6Hi7l)]-0.512 (Fig. 2.80) has been obtained as a cocrystal of an iodine-bearing neutral ruthenium complex and diiodine. The centrosymmetric diiodine molecule links a pair of Ru complexes via halogen bonds to the Ru-bound iodide anions, thus forming a linear I- I-I- I chain.349... 

Carbon-carbon double bonds, whether attached directly to or are distant from the phosphorus, can undergo some unusual reactions, particularly when treated with electrophilic reagents such as the halogens or pseudo-halogens, a behaviour attributable to phosphoryl nucleophilic character. Ethenylphosphonic acid and its simple derivatives add chlorine or bromine with the expected overall results, but the normal addition of the latter is rapidly accelerated by UV radiation and inhibited by added iodine, suggestive of a homolytic nature Dialkyl (pent-4-enyl)phosphonates (373 R = RO, X = CH2, n = 2) equally add bromine to give the expected dibromo adducts, but their behaviour towards iodine is more complex (Scheme 49). In reactions in CHCI3 at ambient temperature, not only are the expected 4,5-diiodo adducts 374 formed, but so is an additional species, probably a quasi-... 

Halogen bonds Directional 10-50 Sulfur-iodine complex... 

When given the possibility of hydrogen and/or halogen bonding, the preference shown may have been readily predicted. Thus, in combination with 4-iodotetrafluorophenol, a 2 1 complex formed in which a stilbazole was hydrogen bonded to the phenol and halogen bonded to the iodine (Figure 53). However, when crystallized in a 1 1 ratio, the stilbazole complexed preferentially to the phenol with the... 

Fig. 10 The stracture of [bis(pyridine)iodine] complexes utilized in the investigation of the symmetry of three-center halogen bonds in solutions [80-82]. Whereas the [bis(pyridine)halo-gen]" complex allows free adjustment of N- X bond distances and angles, the [bisfpyridiny-lethynyljbenzenejhalogen]" backbone introduces a slight geometric restraint...

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