Synthesis of Polymers Containing Group 15 Elements via Bismetallation of Acetylenic Compounds

Abstract

Carbon-element bond formation is a key point of synthetic methodology for incorporating a wide variety of metallic or metalloid elements in polymer main chains. Radical 'bismetallation' to carbon-carbon triple bonds based on homolytic cleavage of element-element single bonds is one of the most useful and highly atom-economical methods for carbon-element bond formation. Syntheses of novel polymers containing group 15 elements have been achieved by ring-collapsed radical alternating copolymerization (RCRAC) of homocyclic compounds with rings built exclusively of group 15 elements with acetylenic compounds. Poly(vinylene-arsine)s were successfully prepared by a radical reaction between pentamethylpentacycloarsine (cyclo-(MeAs) 5 ) or hexaphenylhexacycloarsine (cyclo-(PhAs) 6 ) and mono-substituted acetylenic compounds using 2,2 0 -azobisisobutyronitrile (AIBN) as a radical initiator or irradiation with xenon lamp at room temperature. Without any radical initiator at 25 C, cyclo-(MeAs) 5 caused cleavage of the arsenic-arsenic bond spontaneously and copolymerized with phenylacetylene to give poly(vinylene-arsine)s. The copolymers obtained showed fluorescence properties which were influenced by the substituents of the acetylenic compounds. Poly(vinylene-phosphine)s and poly(vinylene-stibine)s were also prepared by RCRAC of cyclo-(MeP) 5 and cyclo-(PhSb) 6 with alkynes, respectively. Different reactivity of pnictogen radicals made it possible to construct the periodic vinylene-arsine-vinylene-stibine backbone. The radical terpolymerization of cyclo-(MeAs) 5 , phenylacetylene, and a vinyl monomer and radical copolymerization of cyclic diarsine with vinyl monomers were also described.

The Dawn of Functional Organoarsenic Chemistry

“…The obtained polymers are stable in the solid state at room temperature, and the temperatures at which a weight loss of 10 % of the polymers occurs are above 200 °C in air . No arsine oxides are observed in the obtained polymers, even after stirring with 30 % H 2 O 2 at 60 °C probably because of high oxidation resistance of the arsenic atoms.…”

Organic Arsenicals as Functional Motifs in Polymer and Biomaterials Science

“…The key step in any such process is carbon–metal bond formation, which is usually achieved by classical electrophilic/nucleophilic substitution pathways or hydrometallation . An alternative, atom economical approach to the formation of carbon–metal bonds is radical bismetallation of alkynes, which has been employed in organic synthesis for the synthesis of metal substituted 1,2‐diethylenes . This process relies on the homolysis of relatively weak metal–metal bonds, initiated thermally or photochemically, in the presence of alkynes to trap the metal radicals formed.…”

Synthesis and low-temperature dehydrating imidation polymerization of 1,4-dihydro-1,4-diarsininetetracarboxylic acid dianhydride

“…[1][2][3][4][5] For example, heteroatom-containing poly(phenylene)s, such as poly(phenyleneoxide), poly(phenylenesulfide) and polyaniline, are industrially important as engineering plastics and electrical materials. Heteroaromatic polymers, such as polythiophene and polypyrrole, have also been intensively investigated and widely applied.…”

“…[6][7][8][9][10] Organoarsenic compounds are currently being considered as ligands for transition metals because of their special properties; 11,12 however, fewer studies have been conducted with these than with their phosphorus analogs, because most organoarsenic compounds are prepared from arsenic chlorides or arsenic hydrides and require extreme caution in handling because of their volatility and toxicity. We previously reported the facile synthesis of a novel cis-1,4-diarsa-2,5-cyclohexadiene, that is, cis-1,4-dihydro-1,4-dimethyl-2,3,5,6-tetrakis(t-butoxycarbonyl)-1,4-diarsinine (cis-DHDAtBu), which was synthesized by the radical reaction of pentamethylcyclopentaarsine (cyclo-(MeAs) 5 ) and di-t-butyl acetylenedicarboxylate. 13,14 Their stability against air and moisture was high enough to allow handling in air.…”