A Tetrameric Sugar-Based Azobenzene That Gels Water at Various pH Values and in the Presence of Salts
IR@IICB: CSIR-Indian Institute of Chemical Biology, Kolkata
View Archive Info| Field | Value | |
| Title |
A Tetrameric Sugar-Based Azobenzene That Gels Water at Various
pH Values and in the Presence of Salts
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| Creator |
Srivastava, Aasheesh
Ghorai, Subir Bhattacharya, Anup Bhattacharya, Santanu |
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| Subject |
Chemistry
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| Description |
A novel low-molecular mass tetrameric sugar derivative containing azobenzene core, 1, showed
pronounced hydrogelation at micromolar concentration. Based on this observation, four related
azobenzene based tetrameric sugar derivatives, 4-7, and three tetrameric sugar derivatives with
a bis-terephthalamide core, 9-11, were also synthesized. However, none of these closely related
analogues of the compound 1 showed effective gelation. The gel formed from 1 was characterized
extensively using melting temperature analysis, UV-vis, FT-IR, circular dichroism spectroscopy,
and scanning electron microscopy. The resultant gel exhibited impressive tolerance to the pH
variation of the aqueous phase and gelated water in the pH range of 4-10. While UV-vis and CD
spectroscopy indicated that pronounced aggregation of the azobenzene chromophores in 1 was
responsible for gelation, FT-IR studies showed that hydrogen bonding is also a contributing factor
in the gelation process. The melting of gel was found to depend on the pH of the aqueous medium
in which gel was formed. The gel showed considerable photostability to UV irradiation, indicating
tight intermolecular packing inside the gelated state that rendered azobenzene groups in the
resultant aggregate refractory to photoisomerization. The electron micrographs of the aqueous gels
of 1 showed the existence of spongy globular aggregates in such gelated materials. Addition of
salts to the aqueous medium led to a delay in the gelation process and also caused remarkable
morphological changes in the microstructure of the gel.
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| Publisher |
American Chemical Society
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| Date |
2005
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Identifier |
http://www.eprints.iicb.res.in/338/1/BIOORGANIC_%26_MEDICINAL_CHEMISTRY_13(16)4851%2D4863_;2005[37].pdf
Srivastava, Aasheesh and Ghorai, Subir and Bhattacharya, Anup and Bhattacharya, Santanu (2005) A Tetrameric Sugar-Based Azobenzene That Gels Water at Various pH Values and in the Presence of Salts. The Journal of Organic Chemistry, 70 (17). pp. 6574-6582. |
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| Relation |
http://dx.doi.org/10.1021/jo050297p
http://www.eprints.iicb.res.in/338/ |
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