联二噻吩稠合的近红外BODIPY染料的合成与光谱性质

以叠氮乙酸乙酯和联二噻吩甲醛为原料,合成了联二噻吩并吡咯单体,之后在酸催化下与4-N,N-二甲基氨基苯甲醛缩合并与三氟化硼配位,得到一个新型的BODIPY染料SY。采用¹H NMR、质谱以及元素分析对其结构进行了表征。化合物SY在二氯甲烷中的最大吸收和发射波长分别为654和689 nm;采用荧光光谱滴定方法研究了它对pH值的响应,酸性条件下N,N-二甲基苯氨基团发生质子化,抑制了光诱导电子转移对BODIPY母体的荧光淬灭,其溶液的荧光显著增强,染料SY可以作为近红外的pH值荧光探针。     

Molecular dynamics of a calix[4]arene-containing polymer in dichloromethane solution: ability of the solvent molecules to fill the cavity of the macrocycle

The structure and dynamics of the dichloromethane solvent around the calix[4]arene units contained in the molecular actuator poly(calix[4]arene bis-bithiophene) have been examined using a 1-micros molecular dynamics simulation. Results indicate that a solvent molecule fills the cavity associated to the cone conformation of the macrocycle during a significant period of time, especially when the actuator is not contracted. The position of such solvent molecule presents a fourfold symmetry with a maximum orientation toward the center of each ring contained in the calix[4]arene. Frequently, the solvent molecule located inside the cavity is rapidly exchanged for another molecule of the bulk. Thus, the number of dichloromethane molecules that reside more than 0.5 ns inside the cavity is relatively small. Finally, we detected that a significant number of solvent molecules are able to migrate from the cavity of one calix[4]arene to the cavity/ies of other/s, suggesting that the dynamics of the bulk solvent is important for the formation of these inclusion complexes.