13055-33-9Relevant academic research and scientific papers
Synthesis of a Chiral [2]Rotaxane: Induction of a Helical Structure through Double Threading
Tsukamoto, Toshihiro,Sasahara, Ryota,Muranaka, Atsuya,Miura, Yuzuki,Suzuki, Yu,Kimura, Masaki,Miyagawa, Shinobu,Kawasaki, Tsuneomi,Kobayashi, Nagao,Uchiyama, Masanobu,Tokunaga, Yuji
supporting information, p. 4745 - 4748 (2018/08/24)
A helically chiral [2]rotaxane featuring two ammonium ion recognition sites in the dumbbell-like component and a calix-bis-crown ether as the macrocyclic component was synthesized, but with no chirality in either individual component. The enantiomeric nat
Self-assembly of novel [3]- and [2]rotaxanes with two different ring components: Donor - Acceptor and hydrogen bonding interactions and molecular-shuttling behavior
Zhao,Jiang,Shi,Yu,Xia,Li
, p. 7035 - 7043 (2007/10/03)
Three of the first kind of hetero[3]rotaxanes, which comprise one linear component and one neutral and one tetracationic ring component, have been assembled by using the intermolecular hydrogen bonding and donor - acceptor interactions. Three neutral [2]rotaxanes and three tetracationic [2]-rotaxanes have also been synthesized as intermediate products or for the sake of property comparison. The linear molecules are incorporated with two glycine subunits, for templating the formation of the neutral tetraamide cyclophane, and one or two hydroquinone subunits, for inducing the formation of the tetracationic cyclophane. Variable-temperature 1H NMR investigation reveals that the shuttling behavior of the tetracationic ring component along the linear component is substantially influenced by the existence of the neutral ring component. The spatial repelling interaction of the neutral ring on the electron-deficient tetracationic ring simultaneously weakens the latter's "positioning" tendency at both electron-rich hydroquinone sites of the linear component. As a result, the activation energy associated with the shuttling process of the tetracationic ring between the two hydroquinone sites is remarkably reduced in comparison to that of the shuttling process of the corresponding neutral ring-free [2]rotaxanes. For the first time, the rotation of the dipyridinium subunit around the axis formed by the two methylene groups connecting them within the tetracationic cyclophane has been investigated by variable-temperature 1H NMR spectroscopy and the associated kinetic data have also been successfully obtained. Furthermore, the UV - vis and fluorescent properties of the new [2]- and [3]rotaxanes have been studied. The results demonstrate that [3]rotaxanes with different ring components possess unique kinetic features that are not available in [3]rotaxanes with identical ring components.
Araliphatic diisocyanates
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, (2008/06/13)
Novel araliphatic diisocyanates having the formula are disclosed wherein X is oxygen or a single bond and Ar is an arylene radical. The araliphatic diisocyanates are prepared from well known and readily obtainable starting materials. When X represents a single bond, the starting material is a monohydric phenol wherein a C-alkylation reaction followed by an O-alkylation reaction with acrylonitrile provides an intermediate dipropionitrile which is converted to the diisocyanate via phosgenation of the corresponding diamine. When X represents oxygen, the starting material is a dihydric phenol wherein O-alkylation with acrylonitrile provides the dipropionitrile which in turn is converted to the diisocyanate via the phosgenation of the corresponding diamine. The diisocyanates find particular utility in the preparation of color and light stable polyurethane products.
