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合成了外围修饰香豆素PAMAM树枝形分子Gm-2(m+1)C,外围和核心分别共价连接香豆素和紫精的树枝形分子EV-Gm-2(m+1)C(m=0,1),以及香豆素和紫精的模型化合物C-Model和EV,化合物均通过了1H NMR,IR和MALDI-TOF MS的鉴定.1H NMR和光物理研究结果表明,在p H=4.5的醋酸-醋酸钠缓冲溶液中,CB[7]与紫精和树枝形分子外围的香豆素基团均可形成1∶1的包结复合物,结合常数分别为3.3×106 mol-1·L和1.4~1.6×105 mol-1·L.香豆素基团中7位二乙氨基及取代侧部分香豆素环包裹在CB[7]刚性的疏水空腔内,包结复合物的形成限制了香豆素7位N,N’-二乙氨基的扭转,抑制了香豆素基团从发光的分子内电荷转移(ICT)态向不发光的扭曲的分子内电荷转移(TICT)态的转变,而且CB[7]内腔的疏水环境有利于香豆素ICT态辐射跃迁,使体系发光大大增强.EV-Gm-2(m+1)C与CB[7]的主客体作用为分步结合机制,加入的CB[7]先与紫精基团作用形成包结复合物,待体系中紫精基团与CB[7]结合后,体系中香豆素基团再与CB[7]作用形成包结复合物.无论是Gm-2(m+1)C还是EV-Gm-2(m+1)C体系,均可以通过加入CB[7]的量调节体系中香豆素基团与CB[7]形成包结复合物的多少,从而实现对Gm-2(m+1)C和EV-Gm-2(m+1)C体系发光的调控.本工作为可调控发光树枝形聚合物的发展提供了一种新的策略.
The dendrimer molecule EV-Gm-2 (m + 1) C was synthesized by the external modified coumarin PAMAM dendrimer Gm-2 (m + m = 0,1), as well as the coumarin and viologen compounds C-Model and EV, all of which were identified by 1H NMR, IR and MALDI-TOF MS.IH NMR and photophysical results show that at p H = 4.5 acetic acid - sodium acetate buffer solution, CB [7] and the purple and dendritic molecules around the periphery of the coumarin group can form a 1: 1 inclusion complex with a binding constant of 3.3 × 106 mol- 1 · L and 1.4 ~ 1.6 × 105 mol-1 · L. The coumarin group 7-diethylamino and substituted side part of the coumarin ring wrapped in a rigid hydrophobic cavity CB [7], inclusion complex The formation of the material limits the torsion of the coumarin 7-position N, N’-diethylamino, suppresses the intramolecular charge transfer of the coumarin group from the luminescent intramolecular charge transfer (ICT) state to the non-luminescent twist TICT), and the hydrophobic environment in the lumen of CB [7] is favorable for the ICT radiation transition of coumarin, which greatly enhanced the luminescence of the system.EV-Gm-2 (m + 1) C and CB [7] The object function is a step-by-step binding mechanism, and the added CB [7] first interacts with the viologen group Into the inclusion complex, the system of coumarin groups and CB [7] formed after the binding of the viologen group and CB [7] complexes formed. Inclusion Gm-2 (m +1 ) C or EV-Gm-2 (m + 1) C system, the amount of inclusion complexes of coumarin group with CB [7] in the system can be adjusted by adding CB [7] Gm-2 (m + 1) C and EV-Gm-2 (m + 1) C. This work provides a new strategy for the development of tunable luminescent dendrimers.