Co-reporter:Wei Li, Xiangyang Che, Fangyi Chen, Chunxue Zhang, Tianren Zhang, Haitao Wang, Binglian Bai, and Min Li
The Journal of Physical Chemistry B September 21, 2017 Volume 121(Issue 37) pp:8795-8795
Publication Date(Web):August 28, 2017
DOI:10.1021/acs.jpcb.7b06965
A new bis(anhydrazide) derivative containing cyclohexyl terminal groups (compound 1) was synthesized, and its gelation process was investigated. Compound 1 showed both thermal-induced gelation (T-gel) and sonication-induced gelation (S-gel) in alcohols. We investigated the gelation process of compound 1 in ethanol by different techniques. It was demonstrated that gelator 1 in ethanol underwent a transition from a clear solution through a turbid suspension to an opaque gel. Scanning electron microscopy (SEM) observations indicated that the turbid suspension consisted of separated clew-like spheres, connected spheres, and short nanorods, whereas the opaque gel consisted of fibers or bundles of fiber networks. Molecules packed loosely into an unknown phase in the spheres, whereas they packed tightly into a hexagonal columnar phase with a = 1.62 nm in the fibers. Intermolecular H-bonding between —C═O and —N—H was revealed to be the driving force for gelation, and the strength of the H-bonding became stronger in the fibers than in the spheres. We propose that the gel of compound 1 in ethanol consisting of fibers is a stable phase compared to the turbid suspension consisting of spheres or short nanorods, which is considered to be metastable. The kinetics of gelation of gelator 1 in ethanol under sonication suggest that the gelation process is a two-stage kinetic pathway with fractal values of 1.27 and 0.84. Our study hence provides new insights into the formation of fibers and the structural evolution of the gelation process and can be exploited to achieve a detailed understanding of gels.
Co-reporter:Chunxue Zhang;Xiangyang Che;Tianren Zhang;Binglian Bai;Haitao Wang
New Journal of Chemistry (1998-Present) 2017 vol. 41(Issue 17) pp:9482-9488
Publication Date(Web):2017/08/21
DOI:10.1039/C7NJ01197K
Herein, a bent-core dihydrazide derivative (BP8-C) showed unusual solvent-induced optional self-assembly behaviour, e.g. crystalline gels obtained from ethanol (EtOH) and liquid crystalline gels obtained from chloroform (CHL) and toluene (Tol). Packing models in crystalline and liquid crystalline states are confirmed by the XRD method. It was demonstrated by fluorescence spectroscopy that gelators aggregate in EtOH in a way n = 2.13 (Avrami parameter). Interestingly, liquid crystalline gels obtained in CHL display better elastic property with 200% cross-over strain and act as Newtonian fluid at low shearing rate regions, whereas the crystalline gels show better viscidity with low cross-over strain (3%). Moreover, BP8-C xerogels obtained from CHL exhibit Tg transition followed by cold crystallization upon the first heating run, whereas an unknown mesophase, Colh phase, and a broadened and super-cooled crystallization were observed during cooling. In contrast, xerogels obtained from EtOH show enantiotropic Colh mesophase, and sharp crystallization transition. The different gelation behaviour and the liquid crystalline properties of the xerogels obtained from CHL and ethanol were attributed to different molecular aggregates due to interaction between ethanol and the gelators, as confirmed by 1H NMR and FTIR spectroscopy. We emphasize the role of solvent on the self-assembly degree of gelators, which can further influence the properties of gels and the corresponding xerogels.
Co-reporter:Xiangyang Che, Min Li, Chunling Zhang, Chunxue Zhang, Haitao Wang, Binglian Bai
Journal of Molecular Liquids 2017 Volume 241(Volume 241) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.molliq.2017.06.036
•Co-solvent (ethanol and EG) induced nucleation and growth of fibers are reported.•Exploring the different growth dynamics of fibers in mixtures and in single system.•Different morphologies of xerogels are found with the change of EG content.•The gels in the mixtures exhibit different properties compared to that in ethanol.The gelation behaviour and gel properties of the organogels based on a twin-tapered dihydrazide derivative gelator, oxalyl acid N′,N′-di (3,4,5-tripentyloxybenzoyl) hydrazide (FH-T5) in mixtures of ethanol and ethylene glycol were investigated. It was demonstrated that the xerogels in the mixtures of ethanol and ethylene glycol showed the co-existence of sphere-like particles or short rod-like aggregates and fibers, which showed Colh phase. The more ethylene glycol in the mixtures, the shorter the gelation time of FH-T5 when the volume contents of ethylene glycol increased from 0% to 30%, and the kinetics of gelation of FH-T5 showed that Df value of the fibers increased from 1.302 in ethanol to 1.426 in the mixture with 30% ethylene glycol. Gels from the mixture of ethanol and ethylene glycol showed reduced storage modulus, higher Tg and the xerogels obtained from the mixtures exhibited higher wetting angle compared to that from ethanol.The FH-T5 xerogels from the mixtures of ethanol and ethylene glycol showed the co-existence of the sphere-like particles or rod-like aggregates and fibers, which exhibited similar molecular packing (Colh). The FH-T5 gels exhibited shorter gelation time and larger growth dimension of fibers (Df value) compared to that in ethanol.Download high-res image (161KB)Download full-size image
Co-reporter:Xiangyang Che;Binglian Bai;Tianren Zhang;Chunling Zhang;Chunxue Zhang;Peng Zhang;Haitao Wang
New Journal of Chemistry (1998-Present) 2017 vol. 41(Issue 16) pp:8614-8619
Publication Date(Web):2017/08/07
DOI:10.1039/C7NJ01215B
Herein, we report the gelation behaviour and gel properties of two-component organogels consisting of 1,4-bis[(3,4-bisoctyloxyphenyl) hydrozide] phenylene (BPH-8) and a photoresponsive gelator 4-[3,5-(bisoctyloxyphenyl)]-9-anthracene formyl hydrazine (MB8). It was demonstrated that the mixture of BPH-8 and MB8 showed self-sorted aggregation behaviour in ethanol. A gradient cooling procedure was used to obtain self-sorted gels of BPH-8 and MB8. Kinetics of gelation of the two component gels showed that Df values of MB8 fibers decreased due to the presence of BPH-8 gel. The two-component gels showed visible light (λvisible light = 350–570 nm) induced gel–gel transitions due to the orthogonal self-assembly of two gelators through the trans–cis conformation transition of –CN– bond of MB8 component. In addition, the stable patterned two-component gel was achieved using a special shape mask, which enabled the gels to be irradiated by visible light in a particular area. The irradiated gels showed weak emission, reduced storage modulus, a shorter linear viscoelastic region, and higher wetting angle compared to that unirradiated region due to the collapse of the MB8 aggregates under visible light.
Co-reporter:Xiaojun Gu;Binglian Bai;Haitao Wang
RSC Advances (2011-Present) 2017 vol. 7(Issue 1) pp:218-223
Publication Date(Web):2016/12/20
DOI:10.1039/C6RA24886A
The behaviors of organogels of gelators containing hydrazide and azobenzene units connected via different flexible central spacers, 1-[4-(4′-methoxylphenylazo)phenoxy]-n-[(N-(4-nitrobenzoyl)-N′-(benzoyl-4′-oxy)hydrazine)]alkane (En, n = 5, 6, 10) have been studied. The length and parity of the central flexible spacer play crucial roles in the gelation. E6 and E10 could form a stable organogel in DMF, and the critical gelation concentration of E10 is higher than that of E6, but no gelation is observed for compound E5. Xerogels of E6 and E10 from DMF exhibited fibrous aggregates. The organogels showed a photoinduced gel-to-precipitate transition under the irradiation by UV light irradiation, which was attributed to the photoisomerization of azobenzene. The trans–cis isomerization in gels further caused the morphological change from fibrous to globular aggregates. In addition, the organogel exhibited multiple stimuli-responsive behaviors upon exposure to stimuli such as temperature, anions and pH.
Co-reporter:Chunxue Zhang, Tianren Zhang, Nan Ji, Yan Zhang, Binglian Bai, Haitao Wang and Min Li
Soft Matter 2016 vol. 12(Issue 5) pp:1525-1533
Publication Date(Web):20 Nov 2015
DOI:10.1039/C5SM02535D
In this work, a new kind of gelator, 1,3-bis[(3,4-dioctyloxy phenyl) hydrazide]phenylene (BP8-C), containing two dihydrazide units as the rigid bent-core, has been synthesized and investigated. It was demonstrated that BP8-C is an efficient gelator which can gel various organic solvents, such as ethanol, benzene, toluene, chloroform, etc. Both an opaque gel (O-gel) and a transparent gel (T-gel), which is more stable, were obtained with BP8-C in chloroform at different incubation temperatures. Kinetic data based on fluorescence spectra revealed that the T-gels showed a larger Avrami parameter (n = 1.44 at 20 °C) than that of the O-gels (n = 1.21 for gelation at temperatures below 0 °C). While BP8-C did form the opaque gel in toluene, gelation took longer at lower incubation temperatures and even precipitated out below 0 °C. The kinetic Avrami analysis on sols of BP8-C with different concentrations shows a two-phrase mechanism, i.e. the n values are between 0.88 and 1.74 followed by 1.69 and 3.01 throughout the temperature range of 5 °C and 35 °C for 5.34 mg mL−1 BP8-C in toluene, indicating that the fibers formed first and then bundled to produce compact networks. We propose that supersaturation governs the formation of gel in chloroform and that the diffusion process denominates gelation in toluene. XRD and FT-IR measurements confirmed that the xerogels prepared at different temperatures in different solvents exhibited a Colh structure and that there are three molecules in one columnar slice. Our results indicate that the gelation process, morphology of the gels and thus the final properties of the gels depend strongly on the preparation conditions such as temperature, solvent, concentration, etc.
Co-reporter:Xiaojun Gu, Binglian Bai, Zhenhua Wei, Haitao Wang, Min Li
Journal of Molecular Liquids 2016 Volume 222() pp:425-429
Publication Date(Web):October 2016
DOI:10.1016/j.molliq.2016.07.071
•The hydrazide derivatives allow highly selective response to anion.•The hydrazide derivatives with one hydrazide groups can only response to F−.•With two hydrazide groups can respond to F− and AcO−.•These responses are accompanied by changes in the status and color.•We can adjust the response to anion by changing the number of hydrazide groups.Two symmetric hydrazide derivatives with different numbers of hydrazide groups were synthesized, and their anion responsive behaviors were studied. The UV–vis spectra showed that the compounds with only one hydrazide group can allow highly selective fluoride detection, whereas the compound with two hydrazide groups can respond to F− and AcO−. This is due to the difference in the acidity of the compounds, which is caused by the quantity of hydrazide. This demonstrates that altering the number of hydrazide groups can realize the effective adjustment and control of the anionic recognition ability of compounds.
Co-reporter:Binglian Bai, Mingang Zhang, Jue Wei, Huiyu Yan, Haitao Wang, Yuqing Wu, Min Li
Tetrahedron 2016 Volume 72(Issue 35) pp:5363-5368
Publication Date(Web):1 September 2016
DOI:10.1016/j.tet.2016.07.025
An organogelator named 1-[4-(4′-dodecyloxyphenylazo)phenoxy]-5- [(N-(4-nitrobenzoyl) -N′-(benzoyl-4′-oxy)hydrazine)] pentane (EN) formed stable organogel in THF. SEM image revealed that the xerogels consisted of clumped spheroids, within which molecules self-assembled to a layered structure. Both intermolecular hydrogen bonding and π–π stacking interactions were confirmed to be responsible for the self-assembly processes and the gel formation. In addition, organogel of EN exhibited multiple stimuli-responsive behaviors upon exposure to stimuli such as temperature, light, and anion. The effect of flexible central spacer on the trans–cis photoisomerization of the azobenzene moiety was demonstrated.The organogel based on a gelator of hydrazide and azobenzene units connected via a flexible central spacer exhibited a layer structure, and this organogel exhibited multiple stimuli-responsive behaviors upon exposure to stimuli such as temperature, light, and anion.
Co-reporter:Jue Wei, Qing Chai, Lihong He, Binglian Bai, Haitao Wang, Min Li
Tetrahedron 2016 Volume 72(Issue 22) pp:3073-3076
Publication Date(Web):2 June 2016
DOI:10.1016/j.tet.2016.04.035
An anthracene-based gelator (AHP-mB8) has been designed and synthesized. AHP-mB8 can form thermo-reversible gels in some of the tested solvents. FTIR, temperature-dependent 1H NMR, UV–vis and XRD spectra indicated that the gelator self-assembles into a fibrous network possibly due to the combination of intermolecular hydrogen bonding and π–π interactions. The anion binding studies indicated that AHP-mB8 has remarkable and specific F− selectivity over other tested anions to exhibit yellow-red color changes for easy naked-eye detection. The Enhanced Fluorescence Emission has been observed after gelation although the dilute solution of AHP-mB8 was almost non-fluorescent.The organogel of an anthracene derivative exhibited gelation-induced enhanced fluorescence emission, and it was selectively fluoride-responsive among test anions, expressing gel–sol transition and yellow-red color changes for easily naked-eye detection.
Co-reporter:Zhenhua Wei, Jue Wei, Binglian Bai, Haitao Wang, Min Li
Journal of Molecular Liquids 2015 Volume 204() pp:100-105
Publication Date(Web):April 2015
DOI:10.1016/j.molliq.2015.01.049
•The dimeric hydrazide derivative with methyl groups and phenyl groups can allow highly selective fluoride detection•The nature of terminal substituents affect acidity of compounds, as a consequence they show different anion sensing property•The number of hydrazide groups and the nature of the terminal substitute don’t affect the fluoride anion responsive mechanism•By altering terminal substituent groups, the anionic recognition ability of compounds could be adjusted and controlledThree dimeric hydrazide derivatives with nitro, phenyl, and methyl terminal substituents were synthesized and their anion responsive behaviors were studied. The UV–vis spectra showed that the compounds with methyl groups and phenyl groups can allow highly selective fluoride detection, whereas the compound with terminal nitro substituent can respond to F−, AcO− and H2PO4−, due to the distinction on acidity of compounds which is caused by electronic effect and field effect of terminal substituents. The 1H NMR spectra revealed that the anion responsive mechanism for F−, AcO− and H2PO4− was different due to the much lower basicity of AcO− and H2PO4− compared to F−. Whereas the number of hydrazide groups and the nature of the terminal substitute do not affect the fluoride anion responsive mechanism. It demonstrates that, by altering terminal substituent groups, the anionic recognition ability of compounds could be adjusted and controlled.The hunt for fluoride: Three dimeric hydrazide derivatives with nitro, phenyl, and methyl terminal substituents, all have colorless solution. When different anions were added, the sensing processes change the color of solution. Different terminal substituents bring various colors, and through conjugative effects they alter the acidity of compounds, as a consequence, change the affinity to different anions, so highly selective fluoride detection achieved.
Co-reporter:Jianxi Song, Haitao Wang and Min Li
New Journal of Chemistry 2015 vol. 39(Issue 4) pp:2711-2719
Publication Date(Web):27 Jan 2015
DOI:10.1039/C4NJ02204A
Organogels that are self-assembled from simple gelators are an interesting class of nano- and mesoscale soft matter in terms of simplicity and functionality. Investigating the precise roles of the organic solvents and their effects on stabilization of the formed organogel is an important topic for the development of low-molecular weight gelators. We found that thermal gel properties of N,N′-bis(4-N-alkylo-xybenzoyl) hydrazine (4D16) can be correlated with the Kamlet–Taft parameter gaining a detailed understanding of the solvent’s role in gelation. Benzene and toluene are similar aromatic solvents, but the 4D16 gels formed from these two solvents show a large variety of physical characteristics. We studied the non-covalent force, association constant, and thermodynamic parameters of the 4D16 aggregation process in these two aromatic solvents using NMR and explained why gelator 4D16 in toluene had a lower critical gelation concentration (CGC). We select 4D7, which has a higher CGC and its microstructures are similar to 4D16 in these two solvents, to compare differences in solvents and find that gelator–solvent interaction can break up toluene oligomers, whereas this interaction does not disrupt benzene oligomers. The motion of the gelator is restricted due to the defect size provided by the vicinity of the methyl groups in toluene oligomers, thus making gelator–gelator interaction favorable.
Co-reporter:Yangfang Wu, Binglian Bai, Chunxue Zhang, Yan Zhang, Haitao Wang, Zhenhua Wei, Min Li
Tetrahedron 2015 Volume 71(Issue 1) pp:37-43
Publication Date(Web):7 January 2015
DOI:10.1016/j.tet.2014.11.045
The studies of the gel-to-sol phase transition made by low molecular weight organogelator N,N-bis(3,4,5-tris(heptyloxy)benzoyl)fumarohydrazide (T7fuma) with toluene and ethanol as the solvents were reported. T7fuma was considered as a supergelator with higher Tg and lower critical gelation concentrations because of stronger intermolecular hydrogen bond. The solvent was important in controlling the photophysical properties of the solution. The aggregation-induced enhanced emission phenomenon was found in the ethanol gel. Microscopic structures were affected by gelling solvent, the morphology of the toluene xerogel presented homogeneous distribution, while that of the ethanol xerogel presented aggregates with inhomogeneous density, which provided a rough surface having superhydrophobicity.
Co-reporter:Jianxi Song, Haitao Wang, Min Li
Journal of Molecular Structure 2015 1079() pp: 250-257
Publication Date(Web):
DOI:10.1016/j.molstruc.2014.09.014
Co-reporter:Binglian Bai, Xiyue Mao, Jue Wei, Zhenhua Wei, Haitao Wang, Min Li
Sensors and Actuators B: Chemical 2015 211() pp: 268-274
Publication Date(Web):
DOI:10.1016/j.snb.2015.01.111
Co-reporter:Haitao Wang, Huimin Liu, Fu-Quan Bai, Songnan Qu, Xiaoshi Jia, Xia Ran, Fangyi Chen, Binglian Bai, Chengxiao Zhao, Zibai Liu, Hong-Xing Zhang, Min Li
Journal of Photochemistry and Photobiology A: Chemistry 2015 Volume 312() pp:20-27
Publication Date(Web):1 November 2015
DOI:10.1016/j.jphotochem.2015.07.006
•Strong fluorescence red-shift in polar solvents was observed in symmetric 1,3,4-oxadiazole derivatives.•The intramolecular charge transfer is observed from the side alkoxyl benzene to the central bi-1,3,4-oxadiazole moiety, based on a PICT mechanism.•The symmetric DAAD arrangement can enhance intramolecular charge-transfer from the side alkoxyl benzene to the central bi-1,3,4-oxadiazole moiety.The photophysical properties of 2,2′-bis-(4-alkoxyphenyl)-bi-1,3,4-oxadiazole (BOXD-n), have been studied by a combination of spectroscopic techniques and theoretical calculations. Interestingly, strong fluorescence red-shift in polar solvents was observed in this highly symmetric molecule, which indicates an efficient charge transfer (CT) occurred in the excited state. The change of molecular dipole moment between the ground state and CT excited state was calculated to be 9.9 D. Theoretical calculations at Density Functional Theory level revealed that the first singlet excited state of BOXD-n shows both π–π* and CT characters. Clear evidence for charge transfer from alkoxy benzene to the central bi-1,3,4-oxadiazole group can be observed by analysing the atomic charge and electron density change, though it is not significant. Since BOXD-1 retained a planar conformation and became more quinoid-like in the excited state, a planar intramolecular charge transfer is assigned for it. By further comparing these results with the half molecule terminated by CH3 group (2-tetradecyloxyphenyl, 5-methyl-1,3,4-oxadiazole), it could be concluded that intramolecular charge transfer property was enhanced in this DAAD arrangement of BOXD-n.The symmetric DAAD arrangement can enhance intramolecular charge-transfer from the side alkoxyl benzene to the central bi-1,3,4-oxadiazole moiety.
Co-reporter:Binglian Bai, Jie Ma, Jue Wei, Jianxi Song, Haitao Wang and Min Li
Organic & Biomolecular Chemistry 2014 vol. 12(Issue 21) pp:3478-3483
Publication Date(Web):25 Mar 2014
DOI:10.1039/C4OB00056K
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 CO 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.
Co-reporter:Yan Zhang, Hao Ding, Yangfang Wu, Chunxue Zhang, Binglian Bai, Haitao Wang and Min Li
Soft Matter 2014 vol. 10(Issue 44) pp:8838-8845
Publication Date(Web):10 Sep 2014
DOI:10.1039/C4SM01331J
We have demonstrated ultrasound-induced organogels based on twin-tapered dihydrazide derivatives, oxalyl acid N,N-di(3,4,5-trialkoxybenzoyl)hydrazide (FH-Tn). Ultrasound irradiation has been proved to influence gel properties at micro-levels. Different self-assembled structures from entangled fibers to tube-like structures and nanoparticles can be easily manipulated by tuning irradiation time and water bath temperature. FT-IR spectra exhibit weakened hydrogen bonding interactions, and XRD studies showed different packing modes before and after sonication. In addition, ultrasound can have effects on gel properties at macro-levels. Gels obtained from ultrasound treatment possess different wetting properties, relatively worse rheological properties and thermo-stability. Kinetic studies based on dynamic fluorescence spectra, rheological studies and theoretical calculations suggest that molecular aggregation mode differed from one-dimension to two-dimension for the gel after sonication.
Co-reporter:Yan Zhang, Haitao Wang, Yangfang Wu and Min Li
New Journal of Chemistry 2014 vol. 38(Issue 10) pp:4823-4829
Publication Date(Web):10 Jul 2014
DOI:10.1039/C4NJ00605D
Two different carbon nanomaterials (CNMs), single-walled carbon nanotubes (SWNTs) and graphene oxide (GO), were successfully incorporated into a bi-1,3,4-oxadiazole derivative (BOXD-T8) in DMF and gel. Molecules of BOXD-T8 self-assembled to H- and J-aggregates in DMF within moderate concentration, and the ratio of H- and J-aggregates could be manipulated simply by changing the concentration. Energy transferred from H-aggregates to outputting CNMs may have been involved due to the incorporation of CNMs. Furthermore, the incorporation of SWNTs is better to induce the aggregation of BOXD-T8, while GO is better to induce the formation of J-aggregation, which resulted in a lower critical gelation concentration (CGC) and different morphologies compared to those of the corresponding pure BOXD-T8 organogel. The SEM morphologies showed that SWNTs-containing hybrid xerogel consisted of spherical aggregates derived from the entanglement of fibers. In contrast, both graphene sheets and entangled fibers were observed for GO-containing hybrid xerogels. In addition, the composite gel showed improved mechanical properties due to the physical enhancement effects of the incorporated CNMs as rigid materials in the organogel network.
Co-reporter:Haitao Wang, Fu-Quan Bai, Xiaoshi Jia, Di Cao, Ravva Mahesh Kumar, Jean-Luc Brédas, Songnan Qu, Binglian Bai, Hong-Xing Zhang and Min Li
RSC Advances 2014 vol. 4(Issue 94) pp:51942-51949
Publication Date(Web):09 Oct 2014
DOI:10.1039/C4RA06405D
The molecular aggregation structure of 5,5′-bis(naphthalen-2-yl)-2,2′-bi(1,3,4-oxadiazole) (BOXD-NP) was studied by computing the intermolecular interaction potential energy surface (PES) at density functional theory level based on a dimer model. All B3LYP, CAM-B3LYP and M062x functionals can yield a reliable isolated molecular geometry. The conformation of BOXD-NP obtained with all methods is perfectly planar, indicating good conjugation ability between oxadiazole and naphthalene rings. The vibrational frequencies of BOXD-NP were also calculated using the B3LYP/6-311+G** method, which showed great consistency with the experimental observations and makes the assignments of the IR spectra more solid. It was revealed that the lowest excited state of BOXD-NP should be assigned as a highly allowed π–π* state by TD-DFT calculation. Considering the non-covalent interactions in molecular aggregates, the M062x functional was applied in the construction of the PES. Besides the packing structure found in the crystals, PES also predicted several stable structures, indicating that PES has great ability in guiding molecular self-assembly. Symmetry Adapted Perturbation Theory (SAPT) analysis on these energy-minimum molecular stacking structures revealed that London dispersion forces are the strongest attractive component in the binding.
Co-reporter:Binglian Bai, Chunxue Zhang, Jue Wei, Jie Ma, Xiaolong Lin, Haitao Wang and Min Li
RSC Advances 2013 vol. 3(Issue 30) pp:12109-12116
Publication Date(Web):30 Apr 2013
DOI:10.1039/C3RA40835C
A twin-tapered (six-chained) low-molecular-mass organic gelator bearing hydrazine linkage and end-capped by phenyl, 1,4-bis[(3,4,5-trihexyloxy phenyl)hydrazide]phenylene (TC6) was designed and synthesized. Quadruple hydrogen bonds between the dihydrazide units are the main driving force in forming supramolecular liquid crystals and organogels. The association constants (K) of the quadruple hydrogen bonds between the hydrazide units in chloroform are 7.13 × 103 M−1 and 1.53 × 103 M−1 on the basis of NH-1 and NH-2, respectively. Depending on the environmental conditions, compound TC6 can self-assemble into a hexagonal columnar mesophase in the condensed state, in which two molecules constitute the slice of the column, or into a smectic mesomorphic-like organization in the presence of apolar solvents such as 1,2-dichloroethane, or into a rectangular columnar mesomorphic-like organization in the presence of polar solvents such as ethanol, in which one molecule constitutes the slice of the column. Aggregation-induced emission enhancement (AIEE) has been observed after gelation though conventional chromophore units are not incorporated in TC6.
Co-reporter:Binglian Bai, Chengxiao Zhao, Haitao Wang, Xia Ran, Dan Wang, Min Li
Materials Chemistry and Physics 2012 Volume 133(Issue 1) pp:232-238
Publication Date(Web):15 March 2012
DOI:10.1016/j.matchemphys.2012.01.015
A new series of liquid-crystalline tapered hydrazide derivatives with an amino head group, e.g. N-(3,4,5-trialkoxylbenzoyl)-N′-(4′-aminobenzoyl) hydrazine (Dn, where n is the number of carbon atoms in the alkyl chains, n = 6, 8, 16), were designed and synthesized. Results of 1H NMR diluting experiment and FTIR spectroscopy revealed that the amide protons of the central hydrazide group in Dn participated in intermolecular double hydrogen bonds based on CO and NH in liquid crystalline phase. Investigations on the liquid crystalline properties showed that the D6 exhibited non-mesophase, D8 exhibited monotropic hexagonal columnar mesophase, while D16 exhibited enantiotropic oblique columnar mesophase with increasing the length of the terminal chains.Highlights► We aimed at developing new liquid-crystalline hydrazide derivatives. ► The columnar mesophases are observed in these hydrazide derivatives. ► Experimental results revealed that the amide protons of the central hydrazide group participated in intermolecular double hydrogen bonds based on CO and NH in mesophase. ► The intermolecular hydrogen-bonding interaction among dihydrazine units is the main driving force to form the mesophase.
Co-reporter:Binglian Bai, Jue Wei, Jian Zhao, Haitao Wang, Min Li
Journal of Molecular Liquids 2012 173() pp: 108-112
Publication Date(Web):
DOI:10.1016/j.molliq.2012.07.001
Co-reporter:Haitao Wang, Fu-Quan Bai, Huimin Liu, Binglian Bai, Xia Ran, Songnan Qu, Jianhua Shi, Dajun Xie, Hui-Ying Li, Min Li and Hong-Xing Zhang
Physical Chemistry Chemical Physics 2011 vol. 13(Issue 20) pp:9697-9705
Publication Date(Web):13 Apr 2011
DOI:10.1039/C1CP20092E
A bi-thiadiazole derivative, 5,5′-bis(4- tetradecyloxyphenyl)-2,2′-bi-1,3,4-thiadiazole (BTD-14), was revealed to exhibit an extremely stable thermotropic SmC phase and very interesting aggregation behavior in solutions. H- and J-aggregates could be formed simultaneously in chloroform solutions of BTD-14 with moderate concentration (10−4 M), and the population of J-aggregates enlarges during further concentration increase. All monomers, H-aggregates and J-aggregates in solutions could be reserved in the drop-cast films, and both the presence of J-aggregates and the energy transfer path from H-aggregates to J-aggregates were considered to contribute to the relative high solid state fluorescence quantum yield (33%). The BTD-1 dimer potential energy surface (PES) was computed with M062x/6-31G** method, and the molecular packing pattern corresponding to the lowest minimum of the PES are in good agreement with the crystal structures. Exploring the effect of molecular packing on its electronic structure with the TD-M062x method revealed that J-aggregates could be formed by enlarging the intermolecular displacement along the molecular long axis by about 9.8 Å.
Co-reporter:Xia Ran, Haitao Wang, Peng Zhang, Binglian Bai, Chengxiao Zhao, Zhixin Yu and Min Li
Soft Matter 2011 vol. 7(Issue 18) pp:8561-8566
Publication Date(Web):01 Aug 2011
DOI:10.1039/C1SM05566F
A new low molecular mass organic gelator (LMOG) bearing hydrazide and azobenzene groups, namely N-(3,4,5-octanoxyphenyl)-N′-4-[(4-hydroxyphenyl)azophenyl] benzohydrazide (BNB-t8), was designed and synthesized. The organogelator has shown great ability to gel a variety of organic solvents to form stable organogels with a critical gelation concentration as low as 0.5 mg mL−1. Xerogels from chloroform exhibited entangled and dense fibrous aggregates with diameters of 50–60 nm. The organogel showed photoinduced gel-to-precipitate transition under the irradiation by 365 nm UV-light, which was attributed to trans-BNB-t8 to cis-BNB-t8 photoisomerization. The trans–cisisomerization in BNB-t8 gels further caused the morphological change from fibers to vesicles at the supramolecular level.
Co-reporter:Hong Xin, Xiaoming Zhou, Chengxiao Zhao, Haitao Wang, Min Lib
Journal of Molecular Liquids 2011 Volume 160(Issue 1) pp:17-21
Publication Date(Web):15 April 2011
DOI:10.1016/j.molliq.2011.02.002
The mesomorphic dihydrazide derivatives N,N′-bis(4-n-alkyloxybenzoyl) hydrazine (Cn) showed stable liquid crystalline properties and strong gelation ability in organic solvents, and showed environmentally tuned self-assembled structures. On heating, Cn (n = 7, 12, 16) exhibit thermotropic cubic phase with Pn3m symmetry; while in the gel phase, molecules of Cn self-assembled into higher ordered monolayer structure, which is the fundamental of the fibrous aggregates observed by SEM. Intermolecular hydrogen bonding between the dihydrazide groups was demonstrated to be the major driving force for both gelation of organic solvents and stabilization of the liquid crystalline phase.Research Highlights► Cn showed stable liquid crystalline properties and strong gelation ability in organic solvents. ► Cn showed environmentally tuned self-assembled structures. ► Intermolecular hydrogen bonding was the major driving force for self-assembling processes.
Co-reporter:Xia Ran, Peng Zhang, Songnan Qu, Haitao Wang, Binglian Bai, Huimin Liu, Chengxiao Zhao, and Min Li
Langmuir 2011 Volume 27(Issue 7) pp:3945-3951
Publication Date(Web):March 11, 2011
DOI:10.1021/la104386s
We studied hydrogen-bonding assemblies in a series of dumbbell-shaped hydrazine derivatives, namely oxalyl N′,N′-bis(3,4-dialkoxybenzoyl)-hydrazide (BFH-n, n = 4, 6, 8, 10) and oxalyl N′,N′-dibenzoyl-hydrazide (FH-0). It has been demonstrated that NH-1 protons of BFH-n precipitated from tetrahydrofuran (THF) or dimethylformamide (DMF) were involved in intramolecular H-bonding to form 6-membered rings. Meanwhile, NH-2 protons of BFH-n precipitated from THF formed intermolecular hydrogen bonds with C═O groups of neighboring molecules, while NH-2 protons of BFH-n precipitated from DMF formed intermolecular hydrogen bonds with C═O group of neighboring DMF molecules. C═O, −CH3, and −CH groups of DMF molecules participated in multiple intermolecular hydrogen bonds with the −N−H and −C═O groups of FH-0 molecules in single-crystals formed in DMF, leading to a double helix morphology with a pitch of 24.2 Å along the c direction. Both left- and right-handed helical micrometer-length ribbons with nonuniform helical pitches were observed in an achiral BFH-10 xerogel precipitated from DMF.
Co-reporter:Dr. Songnan Qu; Lijun Wang; Xingyuan Liu; Min Li
Chemistry - A European Journal 2011 Volume 17( Issue 12) pp:3512-3518
Publication Date(Web):
DOI:10.1002/chem.201003156
Abstract
We report an unprecedented hierarchical self-assembly of an achiral twin-tapered bi-1,3,4-oxadiazole derivative (2,2-bis(3,4,5-trioctanoxyphenyl)-bi-1,3,4-oxadiazole, BOXD-T8). This molecule can form a layer-structured lyotropic liquid crystal and further forms a helical fibrous organogel in DMF at concentrations above 0.6 wt %. The self-assembly process of BOXD-T8 in DMF is accompanied by a change in its fluorescence. The pitches of the helical fibers are non-uniform, and both left- and right-handed helical fibers are observed in equal quantities. Intermolecular π–π interactions between aromatic segments have been demonstrated to be the driving force for aggregate formation. This helical structure of BOXD-T8 is dependent on the solvent, concentration, and the layer-structured intermediate liquid-crystalline state.
Co-reporter:Zhixin Yu, Binglian Bai, Haitao Wang, Xia Ran, Guibao Jin, Ji Sun, Chengxiao Zhao, Min Li
Materials Science and Engineering: C 2011 Volume 31(Issue 5) pp:880-884
Publication Date(Web):20 July 2011
DOI:10.1016/j.msec.2011.02.007
We report on the self-assembly of a new two-component hydrogel of thymidine (T) and melamine (M) which formed supramolecular complex (≥ 0.1%, w/v) based on intermolecular hydrogen-bonding. The 3D morphologies were tuned by changing the molar ratio of T and M in aqueous medium from 3/1 to 1/3. The xerogels respectively showed rod, sheet and flower structures as observed under SEM. Fourier transform infrared (FT-IR) spectroscopy and wide angle X-ray scattering (WAXD) patterns confirmed that thymidine and melamine form supramolecular complexes through intermolecular hydrogen-bonding. The different structures of the complexes are proposed for the different compositions of the components.
Co-reporter:Zhixin Yu, Haitao Wang, Binglian Bai, Songnan Qu, Fan Li, Xia Ran, Ji Sun, Guibao Jin, Min Li
Materials Science and Engineering: C 2010 30(5) pp: 699-704
Publication Date(Web):
DOI:10.1016/j.msec.2010.03.001
Co-reporter:Songnan Qu, Lianjiu Zhao, Zhixin Yu, Ziyu Xiu, Chengxiao Zhao, Peng Zhang, Beihong Long and Min Li
Langmuir 2009 Volume 25(Issue 3) pp:1713-1717
Publication Date(Web):January 6, 2009
DOI:10.1021/la802995b
A twin-tapered bi-1,3,4-oxadiazole derivative (BOXD-T8) showed a monomeric feature and intramolecular charge transition at concentrations lower than 10−5 mol/L. BOXD-T8 molecules self-assembled to nanoparticles and further to helical nanofibers with blue fluorescence emission in DMSO, while nanoribbons resulted in an emission-enhanced gel in ethanol. The strong fluorescent emissions of BOXD-T8 in an isolated state in apolar solvents were attributed to the coplanar conformation of the rigid backbone and the strong fluorescent emissions of BOXD-T8 in the aggregation states were attributed to the coplanar conformation of the rigid backbone and J aggregation.
Co-reporter:Jianzhong Li, Tao Tang, Fan Li, Min Li
Dyes and Pigments 2008 Volume 77(Issue 2) pp:395-401
Publication Date(Web):2008
DOI:10.1016/j.dyepig.2007.07.008
Five, novel, meso-tetra[4-(3,4,5-trialkoxybenzoate)phenyl]porphyrins and their metal complexes were synthesized and their molecular structures were confirmed by 1H NMR, FTIR spectroscopy and elemental analysis. Mesomorphic studies using DSC, polarizing optical microscope and X-ray diffraction revealed that all compounds exhibited thermotropic columnar mesophases over a wide mesophase temperature range and low liquid crystalline–crystalline transition temperature.
Co-reporter:Hong Xin, Haitao Wang, Binglian Bai, Dongmei Pang, Min Li
Journal of Molecular Liquids 2008 Volume 139(1–3) pp:143-148
Publication Date(Web):15 March 2008
DOI:10.1016/j.molliq.2007.12.007
The mesomorphic dihydrazide derivatives N-(4-alkoxybenzoyl)-N′-(4′-biphenyl carbonyl) hydrazine (Cn-ph) showed stable liquid crystalline properties and strong gelation ability in organic solvents. Both nematic and smectic phases were found in C6-ph, while only smectic A phase in C10-ph, C12-ph and C16-ph. Cn-ph kept a head-to-tail monolayer molecular arrangement in their smectic phases. In gel phase, molecules of Cn-ph self-assembled into an interdigitated layered structure, which is the fundamental of fibrous aggregations as observed by SEM. Intermolecular hydrogen bonding between the dihydrazide groups of Cn-phs was demonstrated to be the major driving force for both gelation of organic solvents and stabilization of the liquid crystalline phase.
Co-reporter:Songnan Qu, Haitao Wang, Zhixin Yu, Binglian Bai and Min Li
New Journal of Chemistry 2008 vol. 32(Issue 11) pp:2023-2026
Publication Date(Web):05 Aug 2008
DOI:10.1039/B805593A
Achiral twin-tapered dihydrazide derivatives (FH-Tn, n = 3, 4, 5, 6, 7, 8, 10) are effective gelators in ethanol. The gelling ability in ethanol, the morphologies, packing structures and intermolecular H-bonding strength were significantly influenced by the length of the alkyl chains. FH-T6 and FH-T7 showed strong gelation ability in ethanol with critical gelation concentrations of 2.1 × 10−3 mol L−1 and 2.1 × 10−3 mol L−1, respectively. Both left- and right-handed helical ribbons with non-uniform helical pitch were observed in FH-Tn (n = 5, 6, 7) gels.
Co-reporter:Binglian Bai, Haitao Wang, Hong Xin, Fenglong Zhang, Beihong Long, Xiaobing Zhang, Songnan Qu and Min Li
New Journal of Chemistry 2007 vol. 31(Issue 3) pp:401-408
Publication Date(Web):02 Feb 2007
DOI:10.1039/B614444F
We report on the synthesis and self-assembly of a new series of compounds containing a hydrazide unit in the rigid core and three alkoxy chains with varying lengths. The compounds N-(3,4,5-cetyloxybenzoyl)-N′-(4′-nitrobenzoyl) hydrazine (C16) and N-(3,4,5-dodecyloxybenzoyl)-N′-(4′-nitrobenzoyl) hydrazine (C12) exhibited stable columnar phase and strong gelation ability in several apolar organic solvents. The columnar structure was found both in the liquid crystalline state and in the xerogels by wide-angle X-ray diffraction analysis. SEM and TEM images revealed that the molecules self-assembled into twist fibrous aggregates in the xerogels. FT-IR and 1H NMR studies confirmed that the intermolecular hydrogen bonding and van der Waals interactions were the major driving force for the formation of self-assembling both the liquid crystals and gels processes. Further detailed analysis of their aggregation modes were conducted by FT-IR spectroscopy and X-ray diffraction measurement.
Co-reporter:Jianzhong Li, Tao Tang, Xiaobing Zhang, Shiyun Li, Min Li
Materials Letters 2007 Volume 61(Issue 22) pp:4351-4353
Publication Date(Web):September 2007
DOI:10.1016/j.matlet.2007.01.103
A simple method to disperse carbon nanotubes (CNTs) has been achieved, which gives two photofunctionalized CNTs, hydrazine nanotubes (h-CNTs) and 1,3,4-oxadiazole nanotubes (o-CNTs). Results from FTIR, 1H NMR spectroscopy and TEM observations showed that the functionalization was successful. The modified nanotubes can dissolve in most of the nonpolar organic solvents and no precipitate was observed in the solution of the nanotubes even after 2 months. The functionalized nanotubes showed photo-electronic properties, which is due to the attachment of the function groups to them as proved by steady-state fluorescence spectroscopy. Both h-CNTs and o-CNTs showed good thermal stability below 300 °C and might be used as functional materials.
Co-reporter:Binglian Bai;Haitao Wang;Hong Xin;Jianhua Shi;Beihong Long
Journal of Physical Organic Chemistry 2007 Volume 20(Issue 8) pp:589-593
Publication Date(Web):28 JUN 2007
DOI:10.1002/poc.1211
Hydrazide-based non-symmetric liquid crystal dimers were synthesized. The liquid crystalline properties were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and powder X-ray diffraction (XRD). These non-symmetric liquid crystal dimers are evidenced to display the monolayer smectic C phase. The effects of the lateral intermolecular hydrogen bonding as well as the length of the terminal alkyl chains and the spacers on the mesophase are discussed. Our studies reveal that intermolecular hydrogen bonding between the hydrazide groups and microsegregation effect is the driving force for the formation of the monolayer smectic C structure. Copyright © 2007 John Wiley & Sons, Ltd.
Co-reporter:Xiaobo Sun;Dong Liu;Peng Zhang;Wenjing Tian
Journal of Applied Polymer Science 2004 Volume 91(Issue 1) pp:396-403
Publication Date(Web):11 NOV 2003
DOI:10.1002/app.13124
Two novel poly(1,4-phenylenevinylene) (PPV) derivatives containing liquid crystalline oxadiazole side chains were prepared by a dehydrochlorination process. The homopolymer poly(2-methoxy-5-((2-methoxy-phenyl)-5-hexyloxy-phenyloxy-1,3,4-oxadiazole)-1,4-phenylenevinylene) (HO–PE6) is insoluble in common solvents, whereas the copolymer poly(2-methoxy-5-((2-methoxy-phenyl)-5-hexyloxy-phenyloxy-1,3,4-oxadiazole))-(2-methoxy-5-(2′-ethylhexyloxy))-1,4-phenylenevinylene) (CO–PE6) is soluble in common solvents such as chloroform, THF, and p-xylene. The molecular structure of CO–PE6 was confirmed by FTIR, 1H-NMR, UV–vis spectroscopy, and polarized light microscopy. CO–PE6 showed a maximum emission at 556 nm in chloroform and at 564 nm in solid film, when excited at 450 nm. The maximum electroluminescence emission of the device indium–tin oxide (ITO)CO–PE6/Al is at 555 nm. The turn-on voltage of LEDs based on CO–PE6 and MEH–PPV is 6.5 and 8.5 V, respectively. The electron mobility of CO–PE6 is higher than that of MEH–PPV based on the results of current–voltage and electrochemical behavior of both MEH–PPV and CO–PE6. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 396–403, 2004
Co-reporter:Zhijun Hu;Gang Chen;Xinfang Chen;Zhijun Hu;Gang Chen;Xinfang Chen
Journal of Applied Polymer Science 2003 Volume 88(Issue 9) pp:2275-2279
Publication Date(Web):14 MAR 2003
DOI:10.1002/app.11936
Side-chain liquid-crystalline copolymethacrylates (PMm's), containing para-nitro azobenzene as the mesogenic group and 2-hydroxylethyl methacrylate (HEMA) as a comonomer, were synthesized by radical polymerization, and their corresponding liquid-crystalline elastomers (LCEm's) were prepared through chemical crosslinking. All of the polymers (PMm's) and the elastomers studied showed enantiotropic smectic A phases; the clearing temperature (Ti) of the PMm polymers decreased with increasing amount of HEMA, and the Ti of the corresponding LCEm's decreased compared to that of their precursors. Small-angle X-ray scattering studies on the copolymers quenched from their liquid-crystalline phases indicated that the characteristic distance increased with increasing amorphous component content and thus, the amorphous components were in between the smectic layers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2275–2279, 2003
Co-reporter:Haitao Wang, Fu-Quan Bai, Huimin Liu, Binglian Bai, Xia Ran, Songnan Qu, Jianhua Shi, Dajun Xie, Hui-Ying Li, Min Li and Hong-Xing Zhang
Physical Chemistry Chemical Physics 2011 - vol. 13(Issue 20) pp:NaN9705-9705
Publication Date(Web):2011/04/13
DOI:10.1039/C1CP20092E
A bi-thiadiazole derivative, 5,5′-bis(4- tetradecyloxyphenyl)-2,2′-bi-1,3,4-thiadiazole (BTD-14), was revealed to exhibit an extremely stable thermotropic SmC phase and very interesting aggregation behavior in solutions. H- and J-aggregates could be formed simultaneously in chloroform solutions of BTD-14 with moderate concentration (10−4 M), and the population of J-aggregates enlarges during further concentration increase. All monomers, H-aggregates and J-aggregates in solutions could be reserved in the drop-cast films, and both the presence of J-aggregates and the energy transfer path from H-aggregates to J-aggregates were considered to contribute to the relative high solid state fluorescence quantum yield (33%). The BTD-1 dimer potential energy surface (PES) was computed with M062x/6-31G** method, and the molecular packing pattern corresponding to the lowest minimum of the PES are in good agreement with the crystal structures. Exploring the effect of molecular packing on its electronic structure with the TD-M062x method revealed that J-aggregates could be formed by enlarging the intermolecular displacement along the molecular long axis by about 9.8 Å.
Co-reporter:Binglian Bai, Jie Ma, Jue Wei, Jianxi Song, Haitao Wang and Min Li
Organic & Biomolecular Chemistry 2014 - vol. 12(Issue 21) pp:NaN3483-3483
Publication Date(Web):2014/03/25
DOI:10.1039/C4OB00056K
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 CO 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.
![Benzoic acid, 4-(decyloxy)-, 2-[4-(decyloxy)benzoyl]hydrazide](http://img.cochemist.com/ccimg/68100/68065-20-3.png)
![Benzoic acid, 4-(decyloxy)-, 2-[4-(decyloxy)benzoyl]hydrazide](http://img.cochemist.com/ccimg/68100/68065-20-3_b.png)
![Benzoic acid, 4-(pentyloxy)-, 2-[4-(pentyloxy)benzoyl]hydrazide](http://img.cochemist.com/ccimg/68100/68065-16-7.png)
![Benzoic acid, 4-(pentyloxy)-, 2-[4-(pentyloxy)benzoyl]hydrazide](http://img.cochemist.com/ccimg/68100/68065-16-7_b.png)
![(3AR,4R,5R,6AS)-4-FORMYL-2-OXOHEXAHYDRO-2H-CYCLOPENTA[B]FURAN-5-Y<WBR />L 4-BIPHENYLCARBOXYLATE](http://img.cochemist.com/ccimg/100/72-89-9.png)
![(3AR,4R,5R,6AS)-4-FORMYL-2-OXOHEXAHYDRO-2H-CYCLOPENTA[B]FURAN-5-Y<WBR />L 4-BIPHENYLCARBOXYLATE](http://img.cochemist.com/ccimg/100/72-89-9_b.png)
