Relative Rates and Approximate Rate Constants for Inter- and Intramolecular Hydrogen Transfer Reactions of Polymer-Bound Radicals
作者:Dennis P. Curran、Fanglong Yang、Jae-ho Cheong
DOI:10.1021/ja028249z
日期:2002.12.1
Measurements of relativerates and rate constants for inter- and intramolecular hydrogen transfer reactions of polymer-bound radicals are reported. The relativerate of reaction of resin-bound primary alkyl radical with tributyltin hydride is about 2 times slower than that of the benchmark reaction in solution. The data do not reveal whether this is due to a reduced rate constant or a lower concentration
报告了聚合物结合自由基的分子间和分子内氢转移反应的相对速率和速率常数的测量。树脂键合伯烷基与氢化三丁基锡的相对反应速率比溶液中的基准反应慢约2倍。数据并未显示这是由于树脂相中速率常数降低还是氢化锡浓度降低所致。然而,固体和溶液反应之间的差异小到可以忽略不计,而且在溶液中测量的速率常数似乎可以直接应用于树脂结合的自由基。树脂结合的芳基从其自身的聚合物主链和接头中快速提取氢原子 (k = 3 x 10(6) s(-1)),并将树脂简化为“溶剂” 建议用于预测其他聚合物和接头的此类效果。树脂结合的芳基的快速环化将是可能的,但由于竞争性聚合物/接头氢转移,较慢的环化和大多数双分子反应将是困难的。