Organic iodides

This technique with very high frequency resolution was used to study the population of different hyperfme structure levels of the iodine atom produced by the IR-laser-flash photolysis of organic iodides tluough multiphoton excitation ... 

The direct reaction of zinc metal with organic iodides dates back to the work of Frankland(67). Several modifications have been suggested since that time to increase the reactivity of the metal. The majority of these modifications have employed zinc-copper couples(68-72), sodium-zinc alloys(73), or zinc-silver couples(77). Some recent work has indicated that certain zinc-copper couples will react with alkyl bromides to give modest yields of dialkylzinc compounds(74,73). However, all attempts to react zinc with aryl iodides or bromides have met with failure. The primary use of zinc couples has been in the Simmons-Smith reaction. This reaction has been primarily used with diiodomethane as 1,1-dibromides or longer chain diiodides have proven to be too unneactive even with the most reactive zinc couples. 

RhCl(NH3)5]Cl2 exchanged with NaX form a highly active catalyst (RhA) for MeOH carbonylation when used with an organic iodide promoter. Systems prepared from RhCl3 are far less active. EXAFS spectroscopy from the Rh K-edge was used to follow the fate of the Rh... 

Cyclopentadienylstannanes can be used in the Migita-Kosugi-Stille reaction with organic iodides, RI, to give the cross-coupled product Cp-R, for example, Equation (117).310... 

In the second part of the paper 6.10 [143] this writer generalises his new kinetic treatment of living polymerisations [134], By applying it to data from the literature, he shows how this treatment can reveal which one of the components of a binary syncatalytic system (e.g. I2 and organic iodide) determines the concentration of the propagating species and, much more important, how the rate-constant of propagation can be calculated from readily available data. There remains here a rich mine of information to be exploited by others. 

The opposite of the stabilisation of an ester is its activation. If we include in the concept ester the alkyl halides, their Friedel-Crafts reactions provide familiar examples of this phenomenon. An unusual example especially relevant to our present considerations is provided by some results made available to me in advance of publication by Giusti and Andruzzi. Their results [38] on the polymerisation of styrene by iodine and hydrogen iodide can be interpreted in terms of an organic iodide derived from styrene, probably 1-phenylethyl iodide, being activated by the co-ordination of one or two molecules of iodine. This process appears to polarise the C—I bond to such an extent that the normally stable ester becomes activated to a chain-propagating species and induces a pseudocationic polymerisation ... 

Reaction of Vitamin (B,2r) with organic iodides (RI) in aqueous solution... 

In the chemical industry, iodine and/or iodine compounds are often used as catalysts and/or catalytic promoters for the production of value-added organic chemicals. As with other catalytic reactions, the catalyst or promoter must be removed from the products after completing the reaction. However, removing trace amounts of organic iodide contaminates from the product by conventional distillation techniques is difficult primarily due to the fact that iodine compounds are unstable and split off into various boiling ranges. 

Unfortunately, we lack measured enthalpy of formation values for most organic iodides of interest here except for ethyl, n-propyl and phenyl iodides. From equation 14 and with phenyl iodide in its reference liquid state and with ethyl and propyl iodides in their reference gaseous states, the enthalpies of formation of ethyl lithium and of n-propyl lithium are calculated to be ca —54 and —74 klmoP, respectively. The former value is the same as those from Table 1 and the latter is compatible with one of the other values for n-propyl lithium derived in earlier sections. 

Hydrogen iodide is used to prepare a number of organic iodides. Hydriodic acid is a reducing agent and is used in the preparation of inorganic iodide salts. It also is used in pharmaceuticals disinfectants, and as a reagent in chemical analysis. 

Chang et al. [71] have studied adsorption of iodine, iodobenzene, iodoheptane, and l,4-dihydroxy-2-iodobenzene on Au(lll) electrode from 0.1 M HCIO4 solutions using CV and STM. The results obtained indicate that organic iodide molecules are significantly decomposed upon their adsorption to give an iodine layer and alkyl... 

Iodine (Lugol s solution 5% iodine in 10% Kl Sodium and potassium iodide Organic iodide Colloid iodine 10% solution)... 

Although the products differ considerably in these two reactions, presumably the mechanisms are not drastically different The negative hydroxide ion attacks the most positive atom in the organic iodide. In methyl iodide this is the carbon atom (, > jyc) and the iodide ion is displaced. In Ihe trifluoromethy) iodide the fluorine atoms induce a positive charge on the carbon which increases its electronegativity until it is greater than that of iodine and thus induces a positive charge on the iodine. The latter is thus attacked hy the hydroxide km with the formation of hypoiodous acid, which then loses an H+ in the alkaline medium to form IO . 

As can be seen in Table 1.13, organic iodides, bromides, and selenides show high reactivity, over 106 s-1, and can be adequately used for organic synthesis [60-63]. The reactivity is roughly divided into the following groups ... 

Additions of various organic iodides to propionaldehyde /V-acylhydrazone 3a were examined in order to evaluate the scope of the reaction with respect to the radical component. In the presence of ZnCL, radical additions proved successful with secondary and tertiary iodides in moderate yields (Table 3, entries 1-4), while primary and allylic radicals were ineffective under these conditions (entries 5 and 6). Ethyl radicals generated from triethylborane can compete for the radical acceptor and, as a result, the separable ethyl radical adduct 12a (Scheme 2) was observed (<10% yield) in all cases. 

A comprehensive picture of alkyl iodides pyrolyses has been presented by Benson124. These substrates are sensitive and difficult to handle in homogeneous molecular HI elimination studies and this is the reason for the comparatively few gas-phase investigations. Concurrent radical and unimolecular mechanisms are frequently observed in organic iodides decomposition. 

With potassium iodide a double salt, PtI2.CO.KI, is obtained as yellowish brown scales, which melt at 150° to 180° C. with decomposition. Other salts have been prepared, both with inorganic and with organic iodides.1... 

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