Hydrogen bonded aromatic hydrazide foldamers for the self-assembly of vesicles and gels
摘要:
This paper describes an investigation of the structural and side-chain factors for the formation of vesicles and gels by hydrogen bonding-mediated aromatic hydrazide foldamers. Six foldamers; and one straight analog that bear discrete side chains have been synthesized. SEM and AFM studies reveal that the molecules with the appended 2-(2-(dialkyl-amino)-2-oxoethylamino)-2-oxoethoxyl chains form vesicles, hydrogels or organogels, depending on the solvents. Both the inner amide units and the terminal N,N-dialkylamide units in the chains are revealed to play essential roles in controlling the self-assembly. The former facilitates it by forming the intermolecular hydrogen bonding, while the latter modulates it by providing solubility and balancing the hydrophobicity of the whole molecules in solvents of varying polarity. (C) 2009 Elsevier Ltd. All rights reserved.
The self-assembly of six-petal microflowers by hydrogen-bonded shape-persistent triangular aromatic hydrazide derivatives
摘要:
Six-petal microflowers have been self-assembled in methanol from C(3)-symmetric shape-persistent triangular aromatic hydrazide derivatives. Nine intramolecular hydrogen bonds are used to enhance the planarity of the aromatic backbone, while six 2-(2-(2-methoxyethoxy)ethoxy)-ethoxyl groups are appended to the rigid aromatic backbone. Scanning electron microscopy (SEM) images show that the molecules form unique six-petal flower-like aggregates in methanol. A self-assembling mechanism that is similar to the formation of snowflakes has been proposed. (C) 2010 Elsevier Ltd. All rights reserved.
Vesicles and Organogels from Foldamers: A Solvent-Modulated Self-Assembling Process
作者:Wei Cai、Gui-Tao Wang、Yun-Xiang Xu、Xi-Kui Jiang、Zhan-Ting Li
DOI:10.1021/ja801618p
日期:2008.6.1
Nonamphiphilic, hydrogen-bonded hydrazide foldamers appended with four or six long flexible chains were revealed to spontaneously assemble to form vesicles in methanol and organogels in aliphatic hydrocarbons. SEM, AFM, TEM, DLS, and fluorescence microscopy were all used to identify the structures of the vesicles. It was proposed that intermolecular pi stacking of the folded frameworks and hydrogen bonding of the amide units in the appended chains induced the molecules to produce cylindrical aggregates. In polar methanol, these aggregates packed together to generate one-layered vesicles owing to hydrophobically induced entanglement of the peripheral chains, while in nonpolar hydrocarbons, the peripheral chains entwined across stacked cylinders to form three-dimensional networks and thus immobilize the liquid molecules.
Hydrogen bonded aromatic hydrazide foldamers for the self-assembly of vesicles and gels
作者:Li-Yan You、Gui-Tao Wang、Xi-Kui Jiang、Zhan-Ting Li
DOI:10.1016/j.tet.2009.07.097
日期:2009.11
This paper describes an investigation of the structural and side-chain factors for the formation of vesicles and gels by hydrogen bonding-mediated aromatic hydrazide foldamers. Six foldamers; and one straight analog that bear discrete side chains have been synthesized. SEM and AFM studies reveal that the molecules with the appended 2-(2-(dialkyl-amino)-2-oxoethylamino)-2-oxoethoxyl chains form vesicles, hydrogels or organogels, depending on the solvents. Both the inner amide units and the terminal N,N-dialkylamide units in the chains are revealed to play essential roles in controlling the self-assembly. The former facilitates it by forming the intermolecular hydrogen bonding, while the latter modulates it by providing solubility and balancing the hydrophobicity of the whole molecules in solvents of varying polarity. (C) 2009 Elsevier Ltd. All rights reserved.
The self-assembly of six-petal microflowers by hydrogen-bonded shape-persistent triangular aromatic hydrazide derivatives
作者:Jian-Bin Lin、Gui-Tao Wang、Xi-Kui Jiang、Zhan-Ting Li
DOI:10.1016/j.tetlet.2010.06.021
日期:2010.8
Six-petal microflowers have been self-assembled in methanol from C(3)-symmetric shape-persistent triangular aromatic hydrazide derivatives. Nine intramolecular hydrogen bonds are used to enhance the planarity of the aromatic backbone, while six 2-(2-(2-methoxyethoxy)ethoxy)-ethoxyl groups are appended to the rigid aromatic backbone. Scanning electron microscopy (SEM) images show that the molecules form unique six-petal flower-like aggregates in methanol. A self-assembling mechanism that is similar to the formation of snowflakes has been proposed. (C) 2010 Elsevier Ltd. All rights reserved.