14802-45-0Relevant articles and documents
A dimethoxypillar[5]arene/azastilbene host-guest recognition motif and its applications in the fabrication of polypseudorotaxanes
Wang, Liyun,Xia, Danyu,Chao, Jianbin,Zhang, Junjie,Wei, Xuehong,Wang, Pi
, p. 6038 - 6042 (2019/06/24)
Pillar[n]arenes, known as the fifth generation of host macrocycles since 2008, have become a popular topic over the past ten years. Until now, the studies of pillar[n]arenes were mainly focused on pillar[5]arenes owing to their easy synthesis and high yields. In particular, 1,4-dimethoxypillar[5]arene (DMP5), which shows a simple structure, efficient synthesis and high yield, has played important roles in the construction of various advanced supramolecular architectures. However, DMP5 has only displayed host-guest binding properties towards some guests. Therefore, the investigation of the host-guest chemistry of DMP5 should be able to greatly promote the development of pillararene chemistry. Herein, a photosensitive azastilbene derivative was chosen as a neutral guest to study the host-guest binding and stimuli-responsive behavior with DMP5. In addition, the binding behavior of DMP5 towards a series of analogous neutral guest molecules was investigated to study the driving forces of the host-guest interaction between DMP5 and the azastilbene guest. Moreover, the [2]pseudorotaxane based on DMP5 and the azastilbene guest was used to construct a polypseudorotaxane via metal coordination.
Azastilbenes. 2. Photodimerization
Vansant, J.,Toppet, S.,Smets, G.,Declercq, J. P.,Germain, G.,Meerssche, M. Van
, p. 1565 - 1573 (2007/10/02)
The photochemical behavior of several azastilbenes has been followed in concentrated solution and in the solid state.In acetonitrile and benzene isomerization and dimerization occur, the reactions being generally faster in acetonitrile.In methanol, however, photoreduction as well as photoaddition of the solvent intervene and are important processes.With irradiation in the solid state, dimerization occurs only for some azastilbenes and their quaternary salts, depending on the orientations of the molecules within the crystal lattice and the distances between adjacent double bonds (3.5-4.2 Angstroem).X-ray analysis has shown that trans-1,2-di(2-pyrazinyl)ethylene crystallizes in two distinct modifications of which only one has a crystal stacking suitable for topochemical dimer formation.The dimers were characterized by 1H and 13C NMR, IR, and mass spectroscopy.The crystalline and molecular structures of five of them were determined by X-ray diffraction, namely cyclobutane dimers of 1,2-di(4-pyridyl)ethylene, 1,2-di(2-pyridyl)ethylene, 1,2-di(2-pyrazinyl)ethylene (all three r-ctt dimers), and 1-(3-pyridyl)-2-(2-pyrazinyl)ethylene (r-ctt head-to-head and head-to-tail dimers).
