Taming the Oxidative Power of SeO₃ in 1,4-Dioxane, Isolation of Two New Isomers of Mixed-Valence Selenium Oxides, and Two Unprecedented Cyclic Esters of Selenic Acid

The reaction of (SeO₃)₄ with 1,4-dioxane (diox, dioxane) with or without diluting solvent led to the isolation of the unprecedented esters of selenic acid-1,2-ethyl selenate (CH₂O)₂SeO₂ and the glyoxal diselenate O₂Se­[(OCHO)₂]­SeO₂. It was possible to isolate an unknown dimeric form of Se₂O₅ (Se₄O₁₀·(diox)₂) and a geometrical isomer of the mixed-valence oxide <i>trans</i>-Se₃O₇, both stabilized by dioxane. The dioxane adduct of monomeric selenium trioxide SeO₃·diox was obtained from the reaction of (SeO₃)₄ with dioxane in liquid SO₂. The reaction mechanism for the formation of these compounds was elucidated, and the molecular structure of the unstable form of the selenium trioxide was determined, consisting in a trimeric arrangement (SeO₃)₃

Taming the Oxidative Power of SeO₃ in 1,4-Dioxane, Isolation of Two New Isomers of Mixed-Valence Selenium Oxides, and Two Unprecedented Cyclic Esters of Selenic Acid

The reaction of (SeO₃)₄ with 1,4-dioxane (diox, dioxane) with or without diluting solvent led to the isolation of the unprecedented esters of selenic acid-1,2-ethyl selenate (CH₂O)₂SeO₂ and the glyoxal diselenate O₂Se­[(OCHO)₂]­SeO₂. It was possible to isolate an unknown dimeric form of Se₂O₅ (Se₄O₁₀·(diox)₂) and a geometrical isomer of the mixed-valence oxide <i>trans</i>-Se₃O₇, both stabilized by dioxane. The dioxane adduct of monomeric selenium trioxide SeO₃·diox was obtained from the reaction of (SeO₃)₄ with dioxane in liquid SO₂. The reaction mechanism for the formation of these compounds was elucidated, and the molecular structure of the unstable form of the selenium trioxide was determined, consisting in a trimeric arrangement (SeO₃)₃