connected cyclically by methylene linkers at the meta positions, were synthesized. The effect of ring strain on the structure and the photochemical and the thermal isomerization of azobenzene were investigated. Complex formation with guest species such as alkali metal cations and solvent molecules was observed. X-ray crystal analyses revealed the crystal structure of all three isomers of 2. Compound 2(t
合成了其中两(2),三(3)和四(4)个
偶氮苯单元通过亚甲基接头在间位环状连接的
偶氮苯甲烯类。研究了环应变对
偶氮苯的结构,光
化学和热异构化的影响。观察到与客体物种(例如碱
金属阳离子和溶剂分子)形成复合物。X-射线晶体分析显示出2的所有三个异构体的晶体结构。化合物2(t,c)由于环应变而扭曲,并且2(c,c)没有变形。3和4两者均形成超分子通道结构,其中
偶氮苯并ben烷分子在分子腔中保持溶剂分子。曝光后,溶液中的2、3和4会显示逐步反式顺式光异构化。确定了所有异构化步骤2的量子产率,这些值表明生色团之间的相互作用(例如能量转移和/或空间畸变)会影响异构化过程。在室温下,2(c,c)的寿命(19.7天)比2(t,c)的寿命(6.1天)更长。这些异构体的相对稳定性通过deltaH ++和deltaS ++值之间的等动力学(或补偿)关系以及环应变的作用来解释。通过HF / 6-31G **计算估算