1,4-Dihydro-1,4-diarsinine:  Facile Synthesis via Nonvolatile Arsenic Intermediates by Radical Reactions

Abstract

dro-1,4-diarsinines, were synthesized by radical reactions of pentamethylcyclopentaarsine ( 1) and acetylenic compounds. The radical reactions of 1 and acetylenic compounds such as dimethyl acetylenedicarboxylate (2a) and 4-ethynylpyridine (2b) in refluxing benzene with 2,2′-azobis(isobutyronitrile) (AIBN; 5 mol %) under a nitrogen atmosphere proVided the corresponding 1,4-dihydro-1,4-diarsinines (3). Formation of 1,4dihydro-1,4-diarsinine was confirmed by 1 H and 13 C NMR spectra and FAB-mass spectrometry. The structures of 3 were confirmed as cis(e,e) forms by X-ray crystallography. This is a facile synthesis of cyclic organodiarsenic compounds, in which no Volatile toxic intermediates such as arsenic chlorides and arsenic hydrides were used. MoreoVer, this is the first example of the synthesis of 1,4-dihydro-1,4-diarsinines.

Structural diversity in the coordination of 1,4‐dihydro‐1,4‐diarsinine as a cyclic ditopic organoarsenic ligand to metal ions

“…• from that in trans-DHDAtBu of 101.05 (10) • . The extension of the interior angles at around the coordinated arsenic atoms might be due to reduce electron density of the paired electrons on the arsenic atoms by the coordination which reduces the repulsion between the paired and unpaired electrons on the arsenic atoms.…”

“…We have synthesized 1,4-dihydro-1,4-diarsinines, 1,4-diarsa-1,4-cyclohexadienes, as cyclic ditopic organoarsenic ligands by radical reaction of pentamethylcyclopentaarsine (cyclo-(MeAs) 5 ) and acetylene derivatives [10,11]. The 1,4-dihydro-1,4-diarsinines are stable toward air and moisture.…”

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

“…and methyl moieties confirmed the polyimide structure. Analysis of PI-1 by 13 C-NMR spectroscopy in DMSO-d 6 showed only one sharp resonance for the methyl carbon at 10.8 p.p.m., suggesting that the arsenic in the polymer existed in a pure form and no oxidized arsenic was present (Figure 3b). The polyimide showed a 10% weight loss at 329 1C under air.…”

“…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. In this study, we found that cis-1,4-dihydro-1,4-dimethyl-1,4-diarsinine-2,3,5,6-tetracarboxylic acid dianhydride (cis-DHDADA) was quantitatively formed from cis-DHDAtBu treated with formic acid as a Brønsted acid.…”

The Dawn of Functional Organoarsenic Chemistry

“…During the RCRAC process, the vinyl radical can be stabilized by electron‐withdrawing substituents, such as esters, resulting in isomerization from the Z form to the E form . Dimerization of the E ‐form vinyl radical species produces cyclic diarsenic compounds, cis ‐DHDAs ( 32 ).…”