Iodine interhalogen compounds

The interhalogen compounds are the bromine- and iodine-base materials. It is the larger, more positive halogen that is the reactive portion of the interhalogen molecule during the disinfection process. Although only used on a limited basis at present, there are members of this class that show great promise as environmentally safe disinfectants. 

Interhalogen compounds such as iodine monochloride have been added to fluoroalkyl-substituted alkenes. The observed unidirectional regiochemistry can be explained by the polarity ot the double bond [14] (equation 7)... 

Scheme 4.44 Activation with iodine and interhalogen compounds.

Many interhalogen compounds of chlorine with fluorine, bromine and iodine are known. These include CIF, CIF3, BrCl, ICl, and ICI3. 

Fluorine also reacts with other halogens, forming interhalogen compounds. While with bromine and iodine it reacts vigorously at ordinary temperatures, with chlorine the reaction occurs at 200°C. Such interhalogen products with these halogens include iodine heptafluoride, bromine trifluoride, bromine pentafluoride, and chlorine trifluoride. Metalloid elements, such as arsenic, silicon, selenium, and boron also inflame in a stream of fluorine, forming fluorides. 

Iodine combines with fluorine, chlorine and bromine, forming interhalogen compounds such as ICl, IBrs, IF . Fluorine successively adds on to iodine forming mono-, tri-, penta-, and heptafluorides of iodine ... 

A very large number of complexes of pyridines and quinolines with all the halogens and interhalogen compounds are known, and as they have been enumerated elsewhere (74HQ14-S2)407,77HC(32-1)319) just a few examples are illustrated (Scheme 14). Treatment of pyridine with chlorine or bromine in the presence of aluminum chloride yields 4-pyridylpyridinium salts (equation 29), but rather curiously the action of iodine chloride on pyridinium hydrochloride at 250 °C produces the 2-isomer (51 equation 30). 

Interhalogen compounds may lead to product mixtures. The products formed when 1-aminopyrazoles were treated with iodine monobromide were a 17 73 ratio of 4- and 5-bromo derivatives with iodine monochloride there was an 81% yield of the 4-iodo product with only traces of the chloro analogue [86JCS(P 1)1249]. 

Polonium dichloride reacts with bromine vapor at, room temperature to give salmon pink PoCUBra. Neither polonium dichloride nor the dibromide reacts with iodine vapor on heating, but both may form unstable interhalogen compounds on treatment with iodine in carbon tetrachloride (7, 8). 

The interhalogen compounds obey the expectations based on the VSEPR theory, and typical structures are giver in Chapter 6. Ore compound not included there is the dimeric iodine trichloride, in which the iodine atom of the monomeric species appears to act as a Lewis acid and accept an additional pair of electrons from a chlorine atom (Fig. 17.5). 

The halogenation of a wide variety of aromatic compounds proceeds readily in the presence of ferric chloride, aluminum chloride, and related Friedel-Crafts catalysts. Halogenating agents generally used are elemental chlorine, bromine, or iodine and interhalogen compounds (such as iodine monochloride, bromine monochloride, etc.). These reactions were reviewed554 and are outside the scope of the present discussion. 

The elemental halogens — fluorine, chlorine, bromine, and iodine — are all toxic. Both fluorine and chlorine are highly corrosive gases that are very damaging to exposed tissue. These elements are chemically and toxicologically similar to many of their compounds, such as the interhalogen compounds, discussed in Chapter 11. The toxicities of halogen compounds are discussed in the next two sections. 

Fluorine is a sufficiently strong oxidant to oxidize chlorine, bromine, and iodine, whereas chlorine can oxidize bromine and iodine. The compounds thus formed are called interhalogen compounds. The major interhalogen compounds are listed in Table 11.1. 

Lower valent states of iodine and chlorine in the presence of one another should generate interhalogen compounds and ions such as IC1,12C1 etc. These species, and polyanions such as IJ, should be considered in a more detailed mechanism... 

Diorgano tellurium dihalides form complexes with iodine and interhalogen compounds organic compounds with N, P, O, S, and Se donor atoms boron, aluminum, and gallium trihalides antimony pentachloride and mercury(II) halides. 

The reactions of the interhalogen compounds are not greatly different from those of the halogens themselves. Hydrolysis of compounds in basic solution yield the halide ion derived from the smaller halogen and an oxy-halogen anion derived from the larger halogen thus, hydrolysis of BrF yields a 5 1 mixture of fluoride and bromate, Iodine monochloride... 

Iodine promotes glycosylation reactions of perbenzylated thioglycosides [222]. The interhalogen compounds of iodine, IBr and ICl are more active, capable of promoting... 

Cura, P, Aloui, M, Kartha, K P R, Field, R A, Iodine and its interhalogen compounds versatile reagents in carbohydrate chemistry XII. Tuning promoter reactivity for thioglycoside activation, Synlett, 1279-1280, 2000. 

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