Halogen compounds structure

Halogenated compound A compound that contains one or more of the elements chlorine, bromine, fluorine, or iodine as a part of its structure. 

The ratios of the rates of elimination of hydrogen halides depend evidently on the structure of the halogenated compound and span many orders of magnitude The rate of dehydrofluonnation w much slower than that of dehydrochlonnation, dehydrobromination and dehydrolodination However, there are exceptions... 

Complex (16), which has a similar structure to Co11 salen, catalyzes the electrocarboxylation of arylmethyl chlorides.274 The enhancement of the catalytic life of (16) as compared to Co-salen may be due to the absence of imino bond in its ligand. The catalytic reduction of halogenated compounds has also been attempted at poly[Mn(salen)]-coated electrodes (M = Ni,253 Co275), which might have potential use for determination of organohalide pollutants.275... 

Supramolecular Aspects of Structures from Lowvalent and Divalent Chalcogen-Halogen Compounds 846... 

Supramolecular Aspects of Structures from Tetravalent Chalcogen-Halogen Compounds 859... 

Pigment Yellow 138,56300, has the chemical structure 138 with X = C1 [4], The synthesis of halogenated compounds (138), for instance P.Y.138, can also be achieved by stepwise heating of tetrachloro phthalic anhydride and 8-amino-chinaldine in molten benzoic acid from 125 to 140 and then to 160°C [5],... 

Write the structures of the following organic halogen compounds. 

Gallium(III) chloride also combines with other metal chlorides such as CaCls or CrCls to form mixed chlorides that have halogen bridge structures i.e., Cl4Ta(-Cl)2. Many such compounds are volatile. 

Figure 7.28 The structures of some nephrotoxic halogenated compounds.

Let us now look at some examples to illustrate what we have discussed so far to get a feeling of how structural moieties influence the mechanisms, and to see some rates of nucleophilic substitution reactions of halogenated hydrocarbons in the environment. Table 13.6 summarizes the (neutral) hydrolysis half-lives of various mono-halogenated compounds at 25°C. We can see that, as anticipated, for a given type of compound, the carbon-bromine and carbon-iodine bonds hydrolyze fastest, about 1-2 orders of magnitude faster than the carbon-chlorine bond. Furthermore, we note that for the compounds of interest to us, SN1 or SN2 hydrolysis of carbon-fluorine bonds is likely to be too slow to be of great environmental significance. 

If L = halogen, this type of reaction is referred to as dehydrohalogenation. Thus, when assessing the fate of halogenated compounds in natural waters, this process has to be considered in addition to nucleophilic substitution. The question then is what structural features and environmental conditions determine whether only one or both of these two competing types of reactions will be important. 

The -elimination of hydrogen halides HX from organic halogen compounds yields olefins or acetylenes, depending on the structure of the starting substance and the number of HX molecules which have split off, viz. 

Some very interesting natural halogen compounds have been discovered only recently. They are included here due to their unusual structural... 

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