Intermolecular halogenation

Diiodoanisole is also formed in this reaction, which has been taken178 as evidence that the reaction is intermolecular. Halogen migration during sulphonation (Jacobsen rearrangement) is also well-known163. 

We shall show both from experimental evidence about gas-phase complexes and, to a lesser extent, from the results of electronic structure calculations that a parallel definition of the intermolecular halogen bond is appropriate The halogen bond is an attractive interaction between a halogen atom X and an atom or a group of atoms in different molecule(s), when there is evidence of bond formation. ... 

Table 2 Intermolecular halogen bond distances (in A) in the iodotetrathiafulvalene salts with Cl or Br anions, measured at 293 K... 

In this and the next sections we discuss two groups of molecule-based conducting magnets at which the %-d interaction works effectively. The first approach is the use of quasi one-dimensional electronic systems as the re-electron layers, and the other strategy is to increase the magnitude of the %-d interaction by the introduction of intermolecular halogen-halogen contacts. 

The stereochemical and kinetic data for the thermal ring contraction which proceeds with inversion of configuration at the halogen-receiving carbon atom are consistent with an intermolecular halogen transfer and exclude the occurrence of a thermally allowed pericyclic reaction ... 

Molecular weight and electrical conductance measurements have shown that this class of compound exists as the monomeric molecular species in acetone and dichloromethane [79SA(A)339,69JOM(20)99], while vibrational and electronic spectroscopies indicate that they exist as the polymeric form in the solid state via the intermolecular halogen bridging [72JOM(44)317,79SA(A)339]. 

Fig. 3 Double-stranded chain structure in the halogen-bonded co-crystal 5 between 2-mercapto-l-methylimidazole (1) and 1,4-diiodotetrafluorobenzene (2). Halogen-bonding distances S-. 1=3.314(1) A. 3.342(1) A. Colors are as follows black 70%—nitrogen black 50%—iodine black 30%—fluorine and hydrogen black 10%—sulfur and carbon. Dashed lines represent intermolecular halogen and hydrogen bondings. (View this art in color at www.dekker.com)...

Fig. 11 Intermolecular halogen-bonds formed in the crystal packing of 31 selected angles [ ] C12-14 11 = 68.67(6), C6-I1 - M = 146.91(7), C8-13 12 = 76.13(6), C2-I2 13 = 166.18(6). In the crystal stmcture of compound 31, each of the four iodine substituraits is connected to neighboring molecules by one of the two kinds of halogen-bonds shown in this figure [148]...

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