Proof for the Concerted Inversion Mechanism in the <i>trans</i>→<i>cis</i> Isomerization of Azobenzene Using Hydrogen Bonding To Induce Isomer Locking
作者:H. M. Dhammika Bandara、Tracey R. Friss、Miriam M. Enriquez、William Isley、Christopher Incarvito、Harry A. Frank、Jose Gascon、Shawn C. Burdette
DOI:10.1021/jo100866m
日期:2010.7.16
often change the isomerization behavior of azobenzene, but not always in a predictive manner. The synthesis and properties of three azobenzene derivatives, AzoAMP-1, -2, and -3, are reported. AzoAMP-1 (2,2′-bis[N-(2-pyridyl)methyl]diaminoazobenzene), which possesses two aminomethylpyridine groups ortho to the azo group, exhibits minimal trans→cis photoisomerization and extremely rapid cis→trans thermal
辐照后,偶氮苯经历可逆的顺式反光异构化。取代基经常改变偶氮苯的异构化行为,但并不总是以可预测的方式改变。报道了三种偶氮苯衍生物AzoAMP-1,-2和-3的合成和性质。AzoAMP-1(2,2'-双[ ñ - (2-吡啶基)甲基] diaminoazobenzene),其具有两个氨基甲基吡啶基团邻位的偶氮基,表现出最小反→CIS光异构化和非常快速的顺式反式→热采。AzoAMP-1采用在固体状态下的平面构象和是更为发射(Φ FL当在77 K下冷冻在1:1的乙醚/乙醇基质中时,其比偶氮苯高(= 0.003)。苯胺质子与吡啶基和偶氮氮原子之间的两个强分子内氢键是造成这些异常性质的原因。计算数据预测,由于S 1中存在能垒,AzoAMP-1在S 2 ←S 0激发后不应异构化状态。当用甲基代替苯胺基质子重新计算势能曲线时,异构化的障碍消失了。独立地合成了二甲基化的类似物AzoAMP-2,并且通过实验证