The synthesis of organic polymers containing hypervalent Iodine

Abstract

Polyesters of the formula have been made from iodosobenzenes + acid anhydrides and from iodobenzene diacetates + dicarboxylic acids. The products do not resemble in solubility behavior the iodosobenzene esters of monocarboxylic acids, the polyesters of convential diols, or the ionic salts of dicarboxylic acids. Under the best conditions they are more stable thermally than iodobenzene diacetate or dipropionate, but none is stable above 200°C. There are indications that polymers containing hypervalent atoms represent a new class of polymers by virtue of their unusual solubility behavior and physical properties.

Responsive and Degradable Highly Branched Polymers with Hypervalent Iodine(III) Groups at the Branching Points

“…Another redox‐active functionality, which can serve to link segments in macromolecules and which degrades upon reduction, is the hypervalent (HV) iodine(III) group of the type RCO 2 ‐I(Ar)‐O 2 CR (Ar = aryl, and R = alkyl, aryl, or polymer chain), named (diacyloxyiodo)arene group, containing the almost linear O‐I‐O fragment. Although (diacyloxyiodo)arenes are commonly used in organic synthetic procedures, often as oxidants or radical sources, as described in several monographs and review papers, examples of polymers with this type of functional group serving as building blocks are very rare, and their physical characteristics and especially reactivity have not been investigated in any detail. The 2‐electron reduction of (diacyloxyiodo)arenes ArI(O 2 CR) 2 leads to the (typically irreversible) formation of the corresponding monovalent iodine compound, that is, iodoarene ArI, and carboxylate anions RCO 2 − .…”

Iodosylbenzene-Pseudohalide-Based Initiators for Radical Polymerization

“…Uses of ArIL 2 in polymer science and technology that have already been reported include (i) initiators of radical polymerization, 17−23 (ii) reagents for postpolymerization modifications (polymer-analogous reactions), 24−26 and (iii) structural elements or building blocks of complex macromolecules. 27,28 The ligand exchange reactions of the acyloxy groups in (diacyloxyiodo)arenes with (pseudo)halide anions X − or the reactions between iodosylarenes ArIO and trimethylsilyl (pseudo)halides TMSX are convenient routes to (di(pseudo)haloiodo)arenes ArIX 2 , which are typically unstable and decompose in situ with the formation of (pseudo)halogen radicals, which can react with numerous substrates, including compounds with unsaturated carbon−carbon bonds or easy to abstract hydrogen atoms. In addition to chlorination reactions in the presence of (dichloroiodo)arenes (typically not prepared by ligand exchange but by chlorination of the corresponding iodoarene), numerous synthetically useful chemical transformations have been reported involving, for example, azides and thiocyanates as the pseudohalogens.…”

“…), namely their ability to participate in both radical (e.g., bond homolysis with the formation of iodoarenes ArI and radicals L • ) , and ionic reactions (e.g., ligand exchange with nucleophiles Nu – , leading to compounds of the types ArILNu and eventually ArINu 2 ), these compounds are of importance in the synthesis of functional macromolecules. Uses of ArIL 2 in polymer science and technology that have already been reported include (i) initiators of radical polymerization, − (ii) reagents for postpolymerization modifications (polymer-analogous reactions), − and (iii) structural elements or building blocks of complex macromolecules. , …”