Reactive Dendronized Copolymer of Styryl Dendron and Maleic Anhydride:  A Single Molecular Scaffold

2005 ◽  
Vol 38 (12) ◽  
pp. 5069-5077 ◽  
Author(s):  
Yanhong Zhang ◽  
Jin Huang ◽  
Yongming Chen
2019 ◽  
Author(s):  
Shengxian Cheng ◽  
Xiaoxia Ma, ◽  
Yonghe He ◽  
Jun He ◽  
Matthias Zeller ◽  
...  

We report a curious porous molecular crystal that is devoid of the common traits of related systems. Namely, the molecule does not rely on directional hydrogen bonds to enforce open packing; and it offers neither large concave faces (i.e., high internal free volume) to frustrate close packing, nor any inherently built-in cavity like in the class of organic cages. Instead, the permanent porosity (as unveiled by the X-ray crystal structure and CO<sub>2</sub> sorption studies) arises from the strong push-pull units built into a Sierpinski-like molecule that features four symmetrically backfolded (<b>SBF</b>) side arms. Each side arm consists of the 1,1,4,4-tetracyanobuta-1,3-diene acceptor (TCBD) coupled with the dimethylaminophenyl donor, which is conveniently installed by a cycloaddition-retroelectrocyclization (CA-RE) reaction. Unlike the poor/fragile crystalline order of many porous molecular solids, the molecule here readily crystallizes and the crystalline phase can be easily deposited into thin films from solutions. Moreover, both the bulk sample and thin film exhibit excellent thermal stability with the porous crystalline order maintained even at 200 °C. The intermolecular forces underlying this robust porous molecular crystal likely include the strong dipole interactions and the multiple C···N and C···O short contacts afforded by the strongly donating and accepting groups integrated within the rigid molecular scaffold.


1987 ◽  
Vol 52 (9) ◽  
pp. 2194-2203
Author(s):  
Miloslav Kučera ◽  
Dušan Kimmer ◽  
Karla Majerová ◽  
Josef Majer

In the reaction of dianions with poly(methyl methacrylate), only an insignificant amount of insoluble crosslinked product is obtained. If, however, the concentration of grafting dianions approaches that of ester groups, the amount of poly(methyl methacrylate) which may thus be crosslinked becomes quite significant. Dications, too, can bring about crosslinking of only an insignificant number of poly(methyl methacrylate) chains. Carboxylic groups in poly(acrylic acid) react with dianions and dications in an anhydrous medium similarly to ester groups. On the other hand, in the presence of a cocatalytic amount of water dications are more readily bound to carboxylic groups, forming a covalent bond. The relatively highest efficiency was observed in the bond formation between dication and the poly[styrene-alt-(maleic anhydride)], both in an anhydrous medium and in the presence of H2O.


2012 ◽  
Vol 89 (11) ◽  
pp. 2067-2075 ◽  
Author(s):  
J. M. España ◽  
L. Sánchez-Nacher ◽  
T. Boronat ◽  
V. Fombuena ◽  
R. Balart

Sign in / Sign up

Export Citation Format

Share Document