In 2019,Angewandte Chemie, International Edition included an article by Tu, Yujie; Liu, Junkai; Zhang, Haoke; Peng, Qian; Lam, Jacky W. Y.; Tang, Ben Zhong. SDS of cas: 1539-42-0. The article was titled 《Restriction of Access to the Dark State: A New Mechanistic Model for Heteroatom-Containing AIE Systems》. The information in the text is summarized as follows:
Restriction of intramol. motion (RIM), as the working mechanism of aggregation-induced emission (AIE), cannot fully explain some heteroatom-containing systems. Now, two excited states are taken into account and a mechanism, restriction of access to dark state (RADS), is specified to elaborate RIM and complete the picture of AIE mechanism. A nitrogen-containing mol. named APA is chosen as a model compound; its weak fluorescence in solution is ascribed to the easy access from the bright (π,π*) state to the close-lying dark (n,π*) state. By either metal complexation or aggregation, the dark state is less accessible due to restriction of the mol. motion leading to the dark state and elevation of the dark state energy, thus the bright state emission is restored. RADS is powerful in elucidating the AIE effect of mols. with excited states favoring non-radiative decay, including overlap-forbidden states such as (n,π*) and CT states, spin-forbidden triplet states, and so on. The experimental process involved the reaction of Bis(pyridin-2-ylmethyl)amine(cas: 1539-42-0SDS of cas: 1539-42-0)
Bis(pyridin-2-ylmethyl)amine(cas: 1539-42-0) is a secondary amine with two picolyl substituents. As a tridentate ligand this compound provides three nitrogen donors that affords good selectivity for Zn2+ over biologically relevant metals such as Na+, K+, Mg2+ and Ca2+, and leaves coordination sites free for anion binding. SDS of cas: 1539-42-0