The synthesis and self-assembling properties of C3 symmetric donor–acceptor molecules containing 1,3,4-oxadiazole and bisthiophene moieties in the core functionalized with octyl (BTOX8) and dodecyl (BTOX12) substituted phenyl acetylene units at the periphery are reported. BTOX8 was found to form gels only in aliphatic solvents, whereas BTOX12 formed gels in both aliphatic and aromatic solvents. Photophysical analysis of BTOX12 solutions showed a striking effect of the solvent on the nature of the self-assembled aggregate formed. Our studies indicate that in aliphatic solvents such as n-decane the solvent molecules interact mainly with the alkyl regions of BTOX12. As a result the π–π interaction between the neighbouring molecules becomes feasible resulting in strong excitonic coupling between the neighbouring molecules leading to excimer type emission. In aromatic solvents the solvent molecules interact mainly with the chromophoric part of BTOX12 resulting in reduced π-stacking between the molecules in the aggregate leading to monomer type emission. Films prepared from aliphatic and aromatic solvents exhibited photophysical properties significantly similar to those observed in the respective solvents. Photophysical studies of the films indicated that the films prepared from n-decane exhibited an H-type molecular arrangement whereas the films prepared from toluene exhibited a slipped stack J-type arrangement.
报道了含有1,3,4-恶二唑和双
噻吩部分的C3对称施受体分子的合成及自组装特性,这些分子的核心功能化为具有八烷基(BTOX8)和
十二烷基(BTOX12)取代的
苯乙炔单元。在脂肪溶剂中,发现BTOX8仅形成凝胶,而BTOX12在脂肪和
芳烃溶剂中均形成凝胶。对BTOX12溶液的光物理分析表明,溶剂对形成的自组装聚集体的性质有显著影响。我们的研究表明,在如正
癸烷等脂肪溶剂中,溶剂分子主要与BTOX12的烷基区域相互作用。因此,临近分子之间的π-π相互作用变得可行,从而导致临近分子之间强的激子耦合,进而引发类激发二聚体的发射。而在
芳烃溶剂中,溶剂分子主要与BTOX12的发色团部分相互作用,导致聚集体中分子之间的π堆叠减少,进而产生单体型发射。从脂肪和
芳烃溶剂中制备的薄膜表现出与各自溶剂中观察到的光物理特性显著相似。薄膜的光物理研究表明,用正
癸烷制备的薄膜表现出H型分子排列,而用
甲苯制备的薄膜表现出错位堆叠的J型排列。