Radical dinitroalkane dianions from the nitration of nitroalkanes by peroxynitrite.
Radical dinitroalkane dianions from the nitration of nitroalkanes by peroxynitrite.
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DOI：
10.1021/tx0001474
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发表时间：
2000-09
影响因子：
4.1
通讯作者：
E. V. Arnold;D. Bohle;Y. Hu
中科院分区：
文献类型：
--
作者：
E. V. Arnold;D. Bohle;Y. Hu
在pH >10的碱性溶液中，过氧亚硝酸根（ONOO（-））能迅速有效地硝酸硝基烷烃阴离子RCH=NO（2）（-）（R = H，CH（3），或CH（3）CH（2）），生成二硝基阴离子RC（NO（2））（2）（2-）。这些阴离子用EPR表征，具有基于1：2：3：2：1五重态的多重态，符合与两个当量（14）N硝基核的超精细耦合，以及以下超精细耦合常数，以高斯计：R = H，a（N）= 9.96和a（H）= 1.85; R = CH（3），a（N）= 9.90和a（H）= 3.22; R = CH（3）CH（2），a（N）= 9.57，a（H）= 4.01。硝化作用是由于过氧亚硝酸根的二氧化碳加合物通过ONO-OCO（2）（-）均分解形成的二氧化氮被酸性硝基烷烃阴离子捕获。在空气中，自由基dinitrodianions被氧化为单阴离子，其形成的动力学很容易遵循的UV/维斯光谱的吸收在380 nm处的上升。本文首次成功地报道了过亚硝酸根生成二氧化氮的自旋捕集过程，为制备偕二硝基烷烃提供了一种有效的方法。
In alkaline solutions at pH >10, peroxynitrite (ONOO(-)) rapidly and efficiently nitrates aci-nitroalkane anions, RCH=NO(2)(-) (R = H, CH(3), or CH(3)CH(2)), to give the radical dinitrodianions, RC(NO(2))(2)(2-). These anions have been characterized by EPR and have multiplets based on 1:2:3:2:1 pentets consistent with a hyperfine coupling with two equivalent (14)N nuclei of the nitro groups, and the following hyperfine coupling constants, in gauss: R = H, a(N) = 9.96 and a(H) = 1.85; R = CH(3), a(N) = 9.90 and a(H) = 3.22; and R = CH(3)CH(2), a(N) = 9.57 and a(H) = 4.01. Nitration is attributed to the trapping of nitrogen dioxide, formed by ONO-OCO(2)(-) homolysis for the carbon dioxide adduct of peroxynitrite, by the aci-nitroalkane anion. In air, the radical dinitrodianions are oxidized to the monoanions, and the kinetics of its formation is readily followed by UV/vis spectroscopy of the rise in absorption at 380 nm. This report represents the first successful spin trapping of nitrogen dioxide formed from peroxynitrite, and the method may be a useful one for preparing geminal dinitroalkanes.