Absorption of SO2(g) by TDAE[O2SSO2](s) to Give TDAE[O2SS(O)2SO2](s): Related Reactions of [NR4]2[O2SSO2](s) (R = CH3, C2H5)

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• 作者：Andreas Decken ; Scott Greer ; Friedrich Grein ; Aaron Mailman ; Birgit Mueller ; Tressia A. P. Paulose ; Jack Passmore ; J. Mikko Rautiainen ; Stephanie A. Richardson ; Melbourne J. Schriver ; Thomas K. Whidden
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：June 20, 2016
• 年：2016
• 卷：55
• 期：12
• 页码：5999-6009
• 全文大小：533K
• 年卷期：0
• ISSN：1520-510X

文摘

One mole equivalent of gaseous SO₂ is absorbed by purple TDAE[O₂SSO₂](s), producing red, essentially spectroscopically pure TDAE[O₂SS(O)₂SO₂](s); under prolonged evacuation, the product loses SO₂(g), regenerating TDAE[O₂SSO₂](s). Similarly, [NR₄]₂[O₂SS(O)₂SO₂](s) (R = Et, Me) can be prepared, albeit at lower purity, from the corresponding tetraalkylammonium dithionites (prepared by a modification of the known [NEt₄]₂[O₂SSO₂](s) preparation). While the [NEt₄]⁺ salt is stable at rt; the [NMe₄]⁺ salt has only limited stability at −78 °C. Vibrational spectra assignments for the anion in these salts were distinctly different from those for the anion in salts containing the long-known [O₃SSSO₃]^2– dianion, the most thermodynamically stable form of [S₃O₆]^2– (we prepared TDAE[O₃SSSO₃]·H₂O(s) and obtained its structure by X-ray diffraction and vibrational analyses). The best fit between the calculated ((B3PW91/6-311+G(3df) and PBE0/6-311G(d)) and experimental vibrational spectra were obtained with the dianion having the [O₂SS(O)₂SO₂]^2– structure. Vibrational analyses of the three [O₂SS(O)₂SO₂]^2– salts prepared in this work showed that the corresponding [O₃SSO₂]^2– salts were present as a ubiquitous decomposition product. The formation of these new [O₂SS(O)₂SO₂]^2– dianion salts was predicted to be favorable for [NMe₄]⁺ and larger cations using a combination of theoretical calculations (B3PW91/6-311+G(3df)) and volume based thermodynamics (VBT). Similar methods accounted for the greater stabilities of the TDAE²⁺ and [NEt₄]⁺ salts of [O₂SS(O)₂SO₂]^2– compared to [NMe₄]₂[O₂SS(O)₂SO₂](s) toward irreversible decomposition to the corresponding [O₃SSO₂]^2– salts. These salts represent the first known examples of a new class of poly(sulfur dioxide) dianion, [SO₂]_n^2– in which n > 2.