1848-85-7Relevant articles and documents
Experimental and theoretical studies of fused-ring persistent [1,2,4]thiadiazinyl radicals
Zienkiewicz, Jozef,Kaszynski, Piotr,Young Jr., Victor G.
, p. 7525 - 7536 (2004)
Five persistent radicals 1a-1e were generated by the oxidation of 4H-[1,2,4]thiadiazines 2a-2e and studied with ESR and UV-vis spectroscopy. Three of the radicals, 1a, 1d, and 1e, were generated in high yields (>90%) using either SO2Cl2/amine in toluene or AgO/K2CO 3 in a toluene/ MeCN mixture. Halogenated radicals 1d and 1e were sufficiently stable for chromatographic isolation and vacuum sublimation. The solution stability of the fluorinated 1d was measured at t1/2 ≈ 4 months in the absence of oxygen, and 1e at t1/2 ≈ 40 min in the presence of air. The crystal and molecular structures of 1d were determined by X-ray crystallography showing columns of parallel almost evenly spaced planar heterocycles connected by infinite ...N...S... chains. Cyclic voltammetry of Id and 1e shows reversible reduction waves at about 0 V and irreversible oxidations at about 1.2 V. Spectral and electrochemical properties of 1 were well reproduced by DFT methods.