Hydrazide-based organogels and liquid crystals with columnar order

Bai, Binglian; Wang, Haitao; Xin, Hu; Zhang, Fenglong; Long, Beihong; Zhang, Xiaobing; Qu, Songnan; Li, Min

doi:10.1039/b614444f

Cited by 46 publications

(14 citation statements)

References 34 publications

(25 reference statements)

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“…The observation of hydrogen bonded N-H stretching bands at 3199 cm −1 (the absence of free N-H, a relatively sharp peak with frequency higher than 3400 cm −1 ) and intense absorption of bonded CvO stretching vibrations at 1625 cm −1 and 1676 cm −1 clearly indicates that the N-Hs of the hydrazide group are associated with the CvO groups via N-H⋯OvC intermolecular hydrogen bonding in the gelation process; such a hydrogen bonding interaction was considered to be the main driving force for the formation of the fibers. 30 In addition, the absorption bands of the antisymmetric (ν as ) and symmetric (ν s ) CH 2 stretching vibrational modes are observed at 2926 cm −1 (ν as CH 2 ) and 2856 cm −1 (ν s CH 2 ) in the gel, respectively, indicating that the alkyl chains are disordered in part, which is consistent with the XRD results. The intermolecular hydrogen bonding of the hydrazide group can also be confirmed by concentrationdependent 1 H NMR as well as temperature-dependent FT-IR measurements.…”

Section: Resultssupporting

confidence: 81%

“…The intermolecular hydrogen bonding of the hydrazide group can also be confirmed by concentrationdependent 1 H NMR as well as temperature-dependent FT-IR measurements. 30…”

Section: Resultsmentioning

confidence: 99%

“…The compound N-(3,4,5-octyloxybenzoyl)-N′-(4′-nitrobenzoyl)hydrazine (C8) was synthesized according to the route shown in the literature. 30 3,4,5-Trioctyloxy-benzoylhydrazine (2.22 g, 4.26 mmol) and 4-nitrobenzoyl chloride (0.79 g, 4.26 mmol) were dissolved in tetrahydrofuran (100 mL), pyridine (2 mL) was added, and the resulting mixture was stirred at room temperature for 8 h. The reaction mixture was poured into an excess of ice water, and the precipitate was recrystallized from anhydrous alcohol for further 1 H NMR, 13 C NMR (Fig. S1 †), MS and elemental analysis.…”

Section: Synthesis Of C8mentioning

confidence: 99%

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A simple structural hydrazide-based gelator as a fluoride ion colorimetric sensor

Bai

Wei

et al. 2014

Org. Biomol. Chem.

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A 4-nitrobenzohydrazide derivative, N-(3,4,5-octyloxybenzoyl)-N'-(4'-nitrobenzoyl)hydrazine (C8), was synthesized. It could form stable gels in some of the tested organic solvents. The wide-angle X-ray diffraction analysis showed that the xerogels exhibited a layered structure. SEM images revealed that the molecules self-assembled into fibrous aggregates in the xerogels. FT-IR studies confirmed that the intermolecular hydrogen bonding between C=O and N-H groups was the major driving force for the formation of self-assembling gel processes. The gel is utilized for a 'naked eye' detection of fluoride ions, through a reversible gel-sol transition, which is associated with a color change from colorless to red. An extended conjugated system formed through the phenyl group and a five-membered ring based on intramolecular hydrogen bonding between the oxygen atom near the deprotonation nitrogen atom and the other NH, which is responsible for the dramatic color change upon addition of fluoride ions.

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Section: Resultssupporting

confidence: 81%

“…The intermolecular hydrogen bonding of the hydrazide group can also be confirmed by concentrationdependent 1 H NMR as well as temperature-dependent FT-IR measurements. 30…”

Section: Resultsmentioning

confidence: 99%

Section: Synthesis Of C8mentioning

confidence: 99%

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A simple structural hydrazide-based gelator as a fluoride ion colorimetric sensor

Bai

Wei

et al. 2014

Org. Biomol. Chem.

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“…2a and d). It may be possible that the steric hindrance decreased and the free energy increased in the homogeneous uid solution, as reported by Min Li et al 12 Moreover, the formation of helical structure also depends upon the sample concentration, the type of solvent and the sample preparation method. The differences in the morphologies between the different organogels potentially resulted from the different strengths of the hydrophobic forces between the cholesteryl segments, p-p stacking and the steric hindrance between the aromatic spacers, which played an important role in regulating the intermolecular orderly stacking and the formation of the twisted brous structure.…”

Section: Morphological Studiesmentioning

confidence: 88%

Structure–property relationships of symmetrical and asymmetrical azobenzene derivatives as gelators and their self-assemblies

Balamurugan

Chien

et al. 2014

Soft Matter

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Two different series of symmetrical and asymmetrical azobenzenes containing terminal cholesteryl/adamantyl derivatives (SAC/SAA and AAC) with varying spacer lengths (alkyl chains) have been developed. The gelation and aggregation of these derivatives were studied relative to structural motifs, spacer lengths, solvent affinity, temperatures and light conditions. Among these derivatives, the cholesteryl derivatives that have short alkyl chains (<3) act as efficient gelators in a variety of solvents. However, the cholesteryl derivatives with longer alkyl chains (11 spacer) and adamantyl derivatives did not possess this ability. Self-assembled fibrous structures were constructed by gelators with short alkyl chains (<3), while flower-like structures were constructed by gelators with moderately longer alkyl chains (3-6) at their respective critical gelation concentrations (CGCs) according to SEM (Scanning Electron Microscopy) and TEM (Transmission Electron Microscopy) analyses. In some cases, a partial/weak gel was observed in different solvents, which exhibited uniform spherical nanoparticles at CGCs. These nanoparticles were further entangled to form interconnected fibrous structures when the concentration was increased above the CGC (according to the SEM and TEM analyses). Secondary forces (van der Waals/H-bonding) and π-π stacking played important roles in the aggregation of both series in the solvents according to variable temperature (1)H-NMR analysis. The reversibility of sol-gel transitions by light was studied with respect to solvent affinity. This study revealed that reversible transitions were only observed in the non-polar solvents, as supported by the FTIR analysis of the gelators in the various solvents. The thermal and mesomorphic behaviors of the gelators by DSC (Differential Scanning Calorimetry) and POM (Polarized Optical Microscopy) analyses revealed that the chiral nematic (N*) and cholesteric mesophase (Ch*) were exhibited by only the short and longer alkyl chain cholesteryl derivatives, respectively. However, the cholesteryl derivative without a spacer (AAC0) did not exhibit any liquid crystalline phase but acted as an efficient gelator relative to the other gelators in this study.

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“…There have been a few reports on hydrazide-based LMOGs and LCs, where intermolecular hydrogen bonding is considered as the main driving force for the formation of the mesophase and gel. Dihydrazide derivatives [14,15], such as wedge-shaped, twin-tapered and fluorescence-enhanced compounds, show both thermotropic mesomorphic behaviour and strong gelation ability in organic solvents.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, mesomorphic and gelation properties of 7-alkoxycoumarin-3-carbonyl hydrazine

Chen

2012

Liquid Crystals

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Hydrazide-based organogels and liquid crystals with columnar order

Cited by 46 publications

References 34 publications

A simple structural hydrazide-based gelator as a fluoride ion colorimetric sensor

A simple structural hydrazide-based gelator as a fluoride ion colorimetric sensor

Structure–property relationships of symmetrical and asymmetrical azobenzene derivatives as gelators and their self-assemblies

Synthesis, mesomorphic and gelation properties of 7-alkoxycoumarin-3-carbonyl hydrazine

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