π-Topology and Spin Alignment Utilizing the Excited Molecular Field: Observation of the Excited High-Spin Quartet (<i>S = </i>3/2) and Quintet (<i>S = </i>2) States on Purely Organic π-Conjugated Spin Systems
作者:Yoshio Teki、Sadaharu Miyamoto、Masaaki Nakatsuji、Yozo Miura
DOI:10.1021/ja001920k
日期:2001.1.1
excited triplet molecular field was realized for the first time in the purely organic pi-conjugated spin system. Furthermore, the mechanism for the generation of dynamic electron spin polarization was investigated for the observed quartet and quintet states, and a plausible mechanism of the enhanced selective intersystem crossing was proposed. Ab initio molecular orbital calculations based on density functional
作为纯有机 pi 共轭自旋系统中光诱导/光开关自旋排列的模型系统,9-[4-(4,4,5,5-四甲基-1-基氧基咪唑啉-2-基)苯基]蒽 (1a ), 9-[3-(4,4,5,5-四甲基-1-基氧基咪唑啉-2-基)苯基]蒽 (1b), 9,10-双[4-(4,4,5,5-四甲基-1-基氧基咪唑啉-2-基)苯基]蒽(2a)和9,10-双[3-(4,4,5,5-四甲基-1-基氧基咪唑啉-2-基)苯基]蒽(2b) ) 被设计和合成。在这些自旋系统中,选择 9-苯基蒽和 9,10-二苯基蒽作为光自旋耦合剂,选择亚氨基氮氧化物作为悬空稳定自由基。在 EPA 或 2-MTHF 刚性玻璃基质中观察到 1a 和 2a 的具有解析精细结构分裂的第一激发态的时间分辨电子自旋共振 (TRESR) 光谱。使用基于本征场方法的光谱模拟,观察到的 1a 和 2a 的 TRESR 光谱被明确指定为激发四重奏 (S = 3/2)