Direct Experimental Evidence for Alkoxyl Radicals Reacting as Hydrogen Atom Donors toward Pyridines
Direct Experimental Evidence for Alkoxyl Radicals Reacting as Hydrogen Atom Donors toward Pyridines
复制标题
烷氧基自由基作为氢原子供体与吡啶反应的直接实验证据
DOI：
10.1021/acs.joc.1c00504
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Dinnocenzo, Joseph P.
中科院分区：
文献类型：
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作者：
Mark, Analuz;Feinberg, Elizabeth C.;Dinnocenzo, Joseph P.
利用纳秒瞬态吸收光谱法生成乙氧基自由基，并证明它们与2,6-lutidine和4-苯基吡啶反应生成相应的n -氢吡啶基自由基，这是一种新型的氢原子从烷氧基自由基转移到取代吡啶的氮原子上的产物。纳秒动力学表明，两种反应在室温下在乙腈中都是快速的（k ~ 107M-1s-1）。乙氧基与5-乙氧基自由基与2,6-lutidine和4-苯基吡啶反应的速率常数测定表明，这两个反应在氢（氘）原子转移反应中都表现出初级H/D动力学同位素效应。
Nanosecond transient absorption spectroscopy was used to generate ethoxyl radicals and demonstrate that they react with 2,6-lutidine and 4-phenylpyridine to give the correspondingN-hydropyridinyl radicals—products of a novel hydrogen atom transfer from the alkoxyl radical to the nitrogen atom of the substituted pyridines. Nanosecond kinetics show that both reactions are rapid (k∼ 107M–1s–1) in acetonitrile at room temperature. Rate constants measured for reaction of the ethoxyl vs.d5-ethoxyl radical with 2,6-lutidine and 4-phenylpyridine show that both reactions exhibit primary H/D kinetic isotope effects for the hydrogen (deuterium) atom transfer reactions.