Iodine-chlorine complexes

Treatment with chlorine gas converts amines to chloramines, whose active chlorine oxidizes iodide to iodine. This then forms the well-known, deep blue iodine-starch complex [13]. 

Substances containing active chlorine or bromine oxidize iodide ions — if necessary under the influence of UV light - to iodine, which reacts with starch to yield the well-known intense blue starch-iodine inclusion complex. 

Fig. 14. Experimental and theoretical Mossbauer spectra of ferric chloroperoxidase and its halide complexes, (a) Native chloroperoxidase, pH 3, T = 4.2 °K, Ho = 1.3 kOe, o J. y- An identical spectrum was found for the chlorine-complex measured under the same conditions, (b) Iodine complex, pH 3, T = 1.5 °K, Ho = 1,3 kOe, Hq f. (c) Fluoride complex, pH 3, T = 4.2°K, Ho = 1.3 kOe, [Taken...

Fig. 10.3 The molecular structures of the possible molecular iodine-triiodide complexes in the aqueous glycine-Kl3-LiCl-ethanol solution. Color codes blue balls—carbon atoms, dark blue balls—nitrogen atoms, red balls—oxygen atoms, violet balls—iodine atoms, yellow balls— chlorine atoms, green balls—lithium atoms...

Mori-Ban reaction refers to a synthesis of indole derivatives by an intramolecular Heck reaction of o-halo-aniline with pendant olefin catalyzed by a low-valent metal complex Pd and Ni. The preferred ortho-haXogcn is bromine or iodine (chlorine has very low reactivity under this case). More often, the o-iodo-iV-allylaniline is more reactive than corresponding o-bromo-and o-chloro-substrate. Also, it has been found that the catalyst can be deactivated under the reaction. Therefore, a periodic provision of fresh catalyst normally gives higher overall yields than that using the same total amount of catalyst with one addition. In the past three decades, the Mori-Ban reaction has been improved and applied to variety of organic synthesis. 

The heats of formation of Tt-complexes are small thus, — A//2soc for complexes of benzene and mesitylene with iodine in carbon tetrachloride are 5-5 and i2-o kj mol , respectively. Although substituent effects which increase the rates of electrophilic substitutions also increase the stabilities of the 7r-complexes, these effects are very much weaker in the latter circumstances than in the former the heats of formation just quoted should be compared with the relative rates of chlorination and bromination of benzene and mesitylene (i 3 o6 x 10 and i a-Sq x 10 , respectively, in acetic acid at 25 °C). 

Mercurous fluoride [13967-25 ] Hg2p2, is less effective than Hgp2. The addition of chlorine or iodine to the reagent increases its reactivity owing to the formation of a complex between Hgp2 and HgX2 (4,12). 

Rhenium Halides and Halide Complexes. Rhenium reacts with chlorine at ca 600°C to produce rheniumpentachloride [39368-69-9], Re2Cl2Q, a volatile species that is dimeric via bridging hahde groups. Rhenium reacts with elemental bromine in a similar fashion, but the metal is unreactive toward iodine. The compounds ReCl, ReBr [36753-03-4], and Rel [59301-47-2] can be prepared by careful evaporation of a solution of HReO and HX. Substantiation in a modem laboratory would be desirable. Lower oxidation state hahdes (Re X ) are also prepared from the pentavalent or tetravalent compounds by thermal decomposition or chemical reduction. 

Charge-Transfer Compounds. Similat to iodine and chlorine, bromine can form charge-transfer complexes with organic molecules that can serve as Lewis bases. The frequency of the iatense uv charge-transfer adsorption band is dependent on the ionization potential of the donor solvent molecule. Electronic charge can be transferred from a TT-electron system as ia the case of aromatic compounds or from lone-pairs of electrons as ia ethers and amines. 

The reactivity pattern of some organogold derivatives is of interest. Thus, complex 90 oxidatively adds molecular chlorine, bromine, or iodine to yield the gold(III) product 103 (97JOM(544)91, 98JOM(552)69). The latter is... 

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