Formation of diazohydroxides ArN<sub>2</sub>
OH in aqueous acid solution: polarographic determination of the equilibrium constant <i>K</i>
<sub>R</sub>
for the reaction of 4-substituted arenediazonium ions with H<sub>2</sub>
O
作者:Andrzej Sienkiewicz、Marta Szymula、Jolanta Narkiewicz-Michalek、Carlos Bravo-Díaz
DOI:10.1002/poc.3194
日期:2014.4
In aqueous acid (pH <4) solutions, in the dark, and in the absence of reductants, arenediazonium ions, ArN2+ decompose spontaneously through the rate‐limiting formation of the extremely unstable aryl cation that reacts with any nucleophile present in its solvation shell (DN + AN mechanism). However, in weak acidic and alkaline solutions, ArN2+ react with H2O and OH− at the terminal nitrogen to give
在酸性水溶液(pH <4)中,在黑暗中,在没有还原剂的情况下,二氮杂zon离子,ArN 2 +通过极不稳定的芳基阳离子的限速形成自发分解,该芳基阳离子与溶剂化过程中存在的任何亲核试剂反应外壳(DN + A N机制)。然而,在弱酸性和碱性溶液,ARN 2 +用H反应2 O和OH -在末端氮,得到类型ARN的偶氮加合物2是处于平衡状态与母ARN OH 2 +。重氮氢氧化物(在这种情况下为酸)与其共轭碱和重氮酸盐ArN 2处于平衡状态Ø - 。的平衡常数与OH反应-已被确定为有限数量的ARN的2 +从动力学测量而不是用H 2 O(ķ - [R )。在这里,我们首次利用ArN 2 +的电化学性质,确定了4个取代的X–ArN 2 OH(XH,Me,MeO,Br和NO 2的形成的平衡常数K R。),其可以以几种方式含有Z-E异构化或进一步反应用OH分解- ,得到diazoate ARN 2 ö -