RELATIVE RATES OF H. TRANSFER FROM TRANSITION-METAL HYDRIDES TO TRITYL RADICALS
RELATIVE RATES OF H. TRANSFER FROM TRANSITION-METAL HYDRIDES TO TRITYL RADICALS
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DOI：
10.1021/ja00013a026
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发表时间：
1991-06-19
影响因子：
15
通讯作者：
NORTON, JR
中科院分区：
文献类型：
--
作者：
EISENBERG, DC;LAWRIE, CJC;NORTON, JR
三（对叔丁基苯基）甲基自由基可以通过用铜粉处理相应溴化物的甲苯溶液以定量产率制备。这个根式抽象了H.从所有常见的过渡金属化合物中分离，但不粘附到所得的金属自由基上，使得后者形成金属-金属键合的二聚体。H.转移反应已经在停流装置中直接测量。在25 ℃时，H.转移速率常数从HMn（CO）4（PEtPh 2）的< 3 M-1 s-1变化到HFe（CO）2CP的12000 M-1 s-1。这些速率常数表明，H.转移反应基本上受空间因素以及键强度的影响。
The tris(p-tert-butylphenyl)methyl radical can be made in quantitative yield by treating a toluene solution of the corresponding bromide with copper powder. This radical abstracts H. from all the common transition-metal hydrides but does not stick to the resulting metalloradicals, so that the latter form metal-metal-bonded dimers. The rates of these H. transfer reactions have been measured directly in a stopped-flow apparatus. At 25-degrees-C the H. transfer rate constants vary from < 3 M-1 s-1 for HMn(CO)4(PEtPh2) to 12000 M-1 s-1 for HFe(CO)2CP. As a whole these rate constants show that the rates or these H. transfer reactions are substantially influenced by steric factors as well as by bond strengths.