Study on the inclusion behavior between meso-tetrakis[4-(3-pyridiniumpropoxy)phenyl]prophyrin tetrakisbromide and β-cyclodextrin derivatives in aqueous solution

2007 ◽  
Vol 66 (4-5) ◽  
pp. 1189-1193 ◽  
Author(s):  
Wen-Ge Qiu ◽  
Zong-Feng Li ◽  
Guang-Mei Bai ◽  
Sheng-Nan Meng ◽  
Hong-Xing Dai ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Cyclodextrin Derivatives

Formation of Highly Stable Heterodimers in Aqueous Solution Between .beta.-Cyclodextrin Derivatives Bearing Multiple Opposite Charges

1995 ◽  
Vol 99 (51) ◽  
pp. 17877-17885 ◽  
Author(s):  
Bertrand Hamelin ◽  
Ludovic Jullien ◽  
Frederique Guillo ◽  
Jean-Marie Lehn ◽  
Alain Jardy ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Cyclodextrin Derivatives ◽  
Beta Cyclodextrin

Structures Formed by Cryoprotective Agents Used in Freezc-Etching

1971 ◽  
Vol 29 ◽  
pp. 448-449
Author(s):  
G. G. Cocks ◽  
C. E. Cluthe
Keyword(s):  
Aqueous Solution ◽  
Polyethylene Oxide ◽  
Liquid Nitrogen Temperature ◽  
Ice Crystals ◽  
Etching Technique ◽  
Structural Constituent ◽  
Cryoprotective Agents ◽  
Quick Freezing ◽  
Freeze Etching ◽  
Fractured Surface

The freeze etching technique is potentially useful for examining dilute solutions or suspensions of macromolecular materials. Quick freezing of aqueous solutions in Freon or propane at or near liquid nitrogen temperature produces relatively large ice crystals and these crystals may damage the structures to be examined. Cryoprotective agents may reduce damage to the specimem, hut their use often results in the formation of a different set of specimem artifacts.In a study of the structure of polyethylene oxide gels glycerol and sucrose were used as cryoprotective agents. The experiments reported here show some of the structures which can appear when these cryoprotective agents are used.Figure 1 shows a fractured surface of a frozen 25% aqueous solution of sucrose. The branches of dendritic ice crystals surrounded hy ice-sucrose eutectic can be seen. When this fractured surface is etched the ice in the dendrites sublimes giving the type of structure shown in Figure 2. The ice-sucrose eutectic etches much more slowly. It is the smooth continuous structural constituent surrounding the branches of the dendrites.

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