Department of Chemistry and Material Engineering, Faculty of Engineering, Shinshu University , 4-17-1, Wakasato, Nagano 380-8553, Japan.
Institution of Education, Shinshu University , 6-ro, Nishinagano, Nagano 380-8544, Japan.
Langmuir. 2017 Nov 28;33(47):13515-13521. doi: 10.1021/acs.langmuir.7b03460. Epub 2017 Nov 16.
A β-diketone dye was packed into the two-dimensional nanospace of a synthetic smectite (Sumecton SA), which is a cation-exchangeable layered silicate, to induce strong emission owing to molecular packing of the dye. An emissive dye, 1-(4-methoxyphenyl)-3-(4-pyridyl)-1,3-propandione, was prepared through a Claisen condensation reaction; the dye exhibited aggregation-induced emission, which is enhanced emission owing to clustering of molecules to form aggregates in poor solvents or in the solid state. The dye was nonemissive in solution. However, strong green emission was observed because of the restriction of molecular motion when the protonated dye was accommodated into the interlayer nanospace of the silicate layers through cation-exchange reactions. The restricted motion was confirmed by the smaller nonradiative relaxation rate constant obtained by time-resolved luminescence and quantum yield measurements. A moderate dye packing (0.11 mmol/g) in the interlayer space is important to obtain enhanced emission, whereas the intercalation of a large amount of dye (0.27 mmol/g) resulted in concentration quenching. Therefore, the interlayer space of the layered silicate used here was responsible for the strong emission because of moderate packing of the accommodated β-diketones.
一种β-二酮染料被包裹在合成皂石（Sumecton SA）的二维纳米空间中，皂石是一种可离子交换的层状硅酸盐，由于染料的分子堆积，诱导了强烈的发射。一种发光染料，1-（4-甲氧基苯基）-3-（4-吡啶基）-1,3-丙二酮，通过 Claisen 缩合反应制备；该染料表现出聚集诱导发射，这是由于分子在不良溶剂或固态中聚集形成聚集体而增强的发射。该染料在溶液中没有发射。然而，当质子化染料通过离子交换反应容纳在硅酸盐层的层间纳米空间中时，由于分子运动受到限制，观察到强烈的绿色发射。通过时间分辨荧光和量子产率测量获得的较小非辐射弛豫率常数证实了受限运动。在层间空间中适度的染料堆积（0.11 mmol/g）对于获得增强的发射很重要，而大量染料（0.27 mmol/g）的插层导致浓度猝灭。因此，这里使用的层状硅酸盐的层间空间由于容纳的β-二酮的适度堆积而导致了强烈的发射。
