Additivity of the Electronic <i>Meta</i>-Substituent Effect in 3,5-Disubstituted Cumyl Radicals Assessed by the EPR <i>D</i> Parameter of 1,3-Arylcyclopentane-1,3-diyl Triplet Diradicals
作者:Waldemar Adam、Heinrich M. Harrer、Wiebke Maas
DOI:10.1021/jo970756p
日期:1997.10.1
experimental D values of these meta-disubstituted triplet diradicals 6 versus the 3,3'-disubstituted triplet diradicals 5 demonstrates the additivity of the electronic meta-substituent effect in the corresponding 3,5-disubstituted cumyl monoradicals 4 and is corroborated by theoretical (PM3-AUHF) spin density calculations for the latter. Thus, the combined use of the experimental D parameter and semiempirically
3,3',5,5'-四取代三重双自由基6(X = X'= H,NO(2),CH(3),OAc,OCH(3)的D参数(EPR零场分裂) ,NH(2)和OH)是在MTHF基质中于77 K下测定的,并通过其自旋密度依赖性,用作测定多取代苄基单基自由基中电子取代基效应的光谱工具。这些间二取代三元双自由基6与3,3'-二取代三元双自由基5的实验D值的线性相关性(m = 2.00 +/- 0.01,r(2)= 0.974)表明电子元的可加性在相应的3,5-二取代的枯基单自由基4中具有-取代基效应,并且通过理论(PM3-AUHF)自旋密度计算证实了后者。从而,