Photoinduced reversible gel–sol transitions of dicholesterol-linked azobenzene derivatives through breaking and reforming of van der Waals interactions

Wu, Yeping; Wu, Si; Xie, Tian; Wang, Xin; Wu, Wenxuan; Zou, Gang; Zhang, Qijin

doi:10.1039/c0sm00330a

Cited by 59 publications

(44 citation statements)

References 43 publications

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“…As for FaDC and FaLC, they form 37 gels including 12 room temperature gels compared with 9 gels formed by the cis-isomers, MaDC and MaLC, suggesting that the trans-configuration is more helpful for the gelation, which is consistent with the results of literatures [28][29][30][31][32][33][34][35][36][37]. This may be understood by considering that the change in molecular configuration leads to the weakening of van der Waals interaction between cholesteryl moieties [30] as well as breaking or reforming of the hydrogen bonding [28,29] in cis-isomer, thus making cis-isomers dissolve or form partial gels in most of the solvents which can be gelled by trans-isomers. As for the chirality, the numbers of the gels formed by D-isomers (21) and L-isomers (25) are very similar, demonstrating that the chirality is not the main factor affecting the gelation ability of the four isomers.…”

Section: Gelation Propertiessupporting

confidence: 82%

“…One-dimensional superstructures of FaDC are driven by the van der Waals interactions between the cholesteryl units, - stacking between trans-ethylenic linkage of the fumaric acid moieties and H-bonding between N-H and C=O, thus self-assemble into thin fibers, which are further aggregated into beehive-like structures. However, in the case of MaDC, the weakening of van der Waals interaction between cholesteryl moieties [30], the breaking or reforming of the hydrogen bonding [28,29], and the vanishing of the - stacking lead to dissolution of MaDC in benzene.…”

Section: Modelmentioning

confidence: 99%

“…They also prepared bis(phenylalanine) maleic acid (1) and fumaric acid (2) amides and found that in water the non-gelling maleic acid amide (1) could be converted into gelling fumaric acid amide via photochemical treatment [37]. Zhang and colleagues [30] synthesized a series of new symmetric dicholesteryl gelators with an azobenzene unit in the linkers (DCAZO). Upon UV irradiation of a cyclopentanone gel of DCAZO, a trans-cis photoisomerization of the azobenzene structure occurred, resulting in gel-sol transition.…”

mentioning

confidence: 99%

“…Stereoisomerism, which can be classified into cis-trans isomerism (or geometric isomerism), optical isomerism and conformational isomerism, is of special importance among many properties of the functional groups. As for the cis-trans isomerism, azobenzene-based [28][29][30][31][32][33], stilbene-based [34][35][36] and butene diacid-based [37] gelators have attracted a great deal of attention due to the reversible sol-gel transition of the system achieved by the configurational change induced by light illumination. Žinić and coworkers [34][35][36] reported the first example of gelation induced by configurational isomerization, which is also the first example of gel preparation by converting a non-gelling compound to a gelator induced by light illumination.…”

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confidence: 99%

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Preparation of dicholesteryl-derivatives: The effect of spatial configuration upon gelation

Yan

Zhang

et al. 2012

Chin. Sci. Bull.

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To investigate the effect of spatial configuration on the gelation properties of low molecular mass gelators (LMMGs), four novel di-cholesteryl derivatives have been specially designed and synthesized by introducing the cis-/trans-isomers of butene diacid and the optical isomers of D/L-phenylalanine into the linker between two cholesteryl moieties. These isomers have been denoted as MaDC, FaDC, MaLC and FaLC, respectively. The gelation properties of the compounds were examined in 26 organic solvents, and it was found that the trans-configuration is more favorable for the gelation, but the chirality of the linker shows little effect to the gelation. FaDC has the strongest gelation ability among the four isomers. Interestingly, FaDC and FaLC display phase-selective gelation of benzene, toluene and xylene from their mixtures with water at room temperature, which establishes a foundation for the purification of water contaminated by oil or aromatic solvents. SEM and CD spectroscopy studies revealed that the spatial configuration of the linkers of the gelators affects significantly the aggregation mode, the morphologies and the chirality of the network of the gels. Moreover, the different aggregation behaviors also have an impact on mechanical properties of the gels, which are consistent with the results from rheological studies. Furthermore, temperature-and concentration-dependent 1 H NMR and FTIR measurements demonstrated that intermolecular hydrogen bonding and - stacking are the main driving forces for the formation of the gels.

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Section: Gelation Propertiessupporting

confidence: 82%

Section: Modelmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Preparation of dicholesteryl-derivatives: The effect of spatial configuration upon gelation

Yan

Zhang

et al. 2012

Chin. Sci. Bull.

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“…Subsequently, Smith et al [23] have reported that loading smallmolecule drugs on the layers of LbL-based system using supramolecular interaction. On another front, the light-induced drug release from a LbL-based system is the most elegant way to combine reversibly and efficiency, because light as an attractive stimulus can be applied rapidly, remotely, and locally [24,25]. While numerous well-established photoresponsive LbL-based systems are available [26,27], their applications in drug release based on polyelectrolyte multilayers or coatings is scarce and little progress.…”

mentioning

confidence: 99%

Light-controlled drug releasing polymer films combining LbL self-assembly and host-guest interactions

Li¹,

He²,

Wang³

et al. 2014

Express Polym. Lett.

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Abstract. By combining LbL (layer-by-layer) self-assembly approach and host-guest interactions, a unique multilayer film was constructed and employed for a light-controlled drug release system. The drug molecules can be loaded and released into the resulting polyelectrolyte multilayers containing azobenzene (Azo) function groups by using the irradiation of visible light and UV light alternately. The photo-sensitivity of the multilayer films was studied through UV-vis spectrum, fluorescence spectrum and confocal microscopy. The target molecules could be rapidly released from the multilayers after 300 W UV light irradiation for 20 minutes. Moreover, they could be readsorbed into the multilayers uniformly when illuminated under the 300 W visible light for 10 minutes confirmed by the observation of confocal microscopy, and the readsorption ratio exceeds 100% evidenced from UV-vis spectroscopy. After several cycles of the above-mentioned process, the multilayer films show good fatigue resistance. All these results indicate the photo-sensitivity and high-efficiency of the multilayer films, which have great potential in controlled drug delivery platform and biomedical applications. : coatings, layer-by-layer, host-guest interactions, light response, drug delivery eXPRESS Polymer Letters Vol.8, No.3 (2014) 143-153 Available online at www.expresspolymlett.com DOI: 10.3144/expresspolymlett.2014.18 * Corresponding author, e-mail: softmatter@163.com © BME-PT nating irradiation with UV and Vis light allows for reversible sliding of !-CD along the surfactant, leading to the formation of rotaxane-like vesicles. Based on this principle, light-responsive host-guest assembly and disassembly between Azo and CD hold great potential to design a reversible drug delivery profile [16,17]. Layer-by-layer (LbL) self-assembly approach is particularly well-suited for fabricating functional multilayer thin films with ultrafine nanometer-scale structure for use as drug delivery vehicles [18][19][20][21]. The traditional means of loading drugs on layers of LbL platform always uses physical adsorption or chemical bonding. However, these methods of loading drugs have a common drawback: drug loading and release is irreversible. This is a critical problem in LbL multilayers for drug delivery. Therefore, it's desired to devise a reversible LbL-based system to manipulate the drug release in a more controllable manner. In the past decade, the pioneering work on LbL assembly with supramolecular interaction has been established by Ikeda et al. [22]. Subsequently, Smith et al. [23] have reported that loading smallmolecule drugs on the layers of LbL-based system using supramolecular interaction. On another front, the light-induced drug release from a LbL-based system is the most elegant way to combine reversibly and efficiency, because light as an attractive stimulus can be applied rapidly, remotely, and locally [24,25]. While numerous well-established photoresponsive LbL-based systems are available [26,27], their applications in drug release b...

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Photochromic Bulk Materials

Morimoto

Kobatake

Irie

et al. 2016

Photochromic Materials: Preparation, Properties and Applications

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Photoinduced reversible gel–sol transitions of dicholesterol-linked azobenzene derivatives through breaking and reforming of van der Waals interactions

Cited by 59 publications

References 43 publications

Preparation of dicholesteryl-derivatives: The effect of spatial configuration upon gelation

Preparation of dicholesteryl-derivatives: The effect of spatial configuration upon gelation

Light-controlled drug releasing polymer films combining LbL self-assembly and host-guest interactions

Photochromic Bulk Materials

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