New dendritic gelator bearing carbazole in each branching unit: selected response to fluoride ion in gel phase
作者:Defang Xu、Xingliang Liu、Ran Lu、Pengchong Xue、Xiaofei Zhang、Huipeng Zhou、Junhui Jia
DOI:10.1039/c0ob00786b
日期:——
A new dendritic gelator with carbazole as the building block (HBCD) was synthesized. It was found that H-bonding between the amide groups and π–π interaction between the aromatic rings played predominant roles in the gel formation. Meanwhile, significant aggregation-induced emission enhancement was observed in the gel state due to the formation of J-aggregates and the restricted molecular motion. Notably, the gel state of HBCD can be destroyed upon addition of F−, accompanied by fluorescence enhancement on account of the formation of N–H⋯F−, which could further lead to the increased coplanarity of HBCD. The sensory capability of HBCD exhibited a high selectivity towards F− instead of the Cl−, Br−, I− and AcO− anions, which could be explained by the fact that the steric hindrance of the dendrimer would go against the interactions between the larger anions and HBCD.
合成了一种以咔唑为结构单元的新型树枝状凝胶剂(HBCD)。研究发现,酰胺基团之间的 H 键和芳香环之间的 π-π 相互作用在凝胶形成过程中发挥了主要作用。同时,由于 J-聚集体的形成和分子运动受限,在凝胶态中观察到了显著的聚集诱导发射增强。值得注意的是,六溴环十二烷的凝胶态在加入 F- 后会被破坏,同时由于 N-H⋯F- 的形成而导致荧光增强,这可能会进一步导致六溴环十二烷的共面性增强。HBCD 对 F- 而不是 Cl-、Br-、I- 和 AcO- 阴离子具有很高的选择性,其原因可能是树枝状聚合物的立体阻碍作用不利于较大阴离子与 HBCD 之间的相互作用。