Inorganic Iodine V Derivatives

Various oxygen-bonded iodine(V) derivatives are known [641-643]. Iodine pentoxide, I2O5, the most important and thermally stable iodine oxide, is prepared in the form of a hygroscopic, white solid by dehydration of iodic acid, HIO3, at 200 °C. It readily absorbs water from the atmosphere, giving the hydrate, 

Methyl 2-iodoxybenzoate can be further converted into the diacetate 490 or a similar bis(trifluoroacetate) derivative by treatment with acetic anhydride or trifluoroacetic anhydride, respectively [658]. Single-crystal X-ray diffraction of methyl 2-[(diacetoxy)iodosyl]benzoate 490 revealed a pseudo-benziodoxole stmcture with three relatively weak intramolecular l - O interactions. The esters of 2-iodoxyisophthalic acid (e.g., 491) have been prepared by oxidation of the respective iodoarenes with dimethyldioxirane. X-Ray stmctural analysis of diisopropyl 2-iodoxyisophthalate 491 showed intramolecular I - O interaction with the carbonyl oxygen of only one of the two ester groups, while NMR spectra in solution indicated equivalency of both ester groups [658]. 

Alkyl iodyl derivatives, RIO2, usually lack stability and cannot be isolated. For example, the matrix isolation and FTIR spectra was reported of the unstable iodylalkanes, generated by the co-deposition and photolysis of ozone with iodoethane, 2-iodopropane, pentafluoroiodoethane, 1,1,1-trifluoroiodoethane, 1,1,2,2-tetrafluoroiodoethane, 1,1,1,2-tetrafluoroiodoethane, or iodine cyanide in an argon matrix at 14-16 K [668-670]. A relatively stable iodyltrifluoromethane, CF3IO2, was prepared by the reaction of CF3IF4 with silicon dioxide [671]. 

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