Characterizing Triplet States of Quinonoidal Dinitrenes as a Function of Conjugation Length
作者:Masaki Minato、Paul M. Lahti
DOI:10.1021/ja963648d
日期:1997.3.1
Photolysis of para,para‘-diazide precursors in 2-methyltetrahydrofuran gives biradical ESR spectra assignable to quinonoidal dinitrenes with excited triplet biradical states. The zero field splitting (zfs) parameters for the biradicals at 77 K are as follows: 1,4-phenylenedinitrene (|D/hc| = 0.169 cm-1, |E/hc| = 0.004 cm-1); 4,4‘-biphenyldinitrene (|D/hc| = 0.188 cm-1, |E/hc| ≤ 0.002 cm-1); 4,4‘-stilbenedinitrene
对,对'-二叠氮前体在 2-甲基四氢呋喃中的光解得到双自由基 ESR 光谱,可归属于具有激发三重双自由基状态的醌型二硝烯。77 K 双自由基的零场分裂 (zfs) 参数如下: 1,4-亚苯基二烯 (|D/hc| = 0.169 cm-1, |E/hc| = 0.004 cm-1);4,4'-联苯二甲苯(|D/hc| = 0.188 cm-1,|E/hc| ≤ 0.002 cm-1);4,4'-二苯乙烯二烯(|D/hc| = 0.122 cm-1,|E/hc| < 0.002 cm-1);1,4-双(对硝基苯)丁-1,3-二烯(|D/hc| = 0.0865 cm-1,|E/hc| < 0.002 cm-1);1,8-双(对硝基苯)八-1,3,5,7-四烯(|D/hc| = 0.0442 cm-1,|E/hc| < 0.001 cm-1)。这些 zfs 参数与局部双自由基中 ESR 光谱的简