- Photo-switchable smart metal-organic framework membranes with tunable and enhanced molecular sieving performance
-
Developing a novel MOF membrane material with switchable separation performance is an exciting and challenging research project. In the present work, we report preparation of a new kind of light induced smart MOF membrane, i.e., Cu(AzDC)(4,4′-BPE)0.5 membrane, which shows (i) enhanced molecular sieving performance, and (ii) is able to respond quickly to external light stimuli. Two photo-switchable moieties are addressed in the Cu(AzDC)(4,4′-BPE)0.5 membrane: azobenzene and bis(4-pyridyl)ethylene. When the Cu(AzDC)(4,4′-BPE)0.5 membrane is in situ irradiated with Vis and UV light, the separation factor of a H2/CO2 mixture can be switched reversibly between 21.3 and 43.7. This switching effect is mainly caused by reduced CO2 adsorption in the UV-cis state as proven by independent adsorption studies. For a steric reason, adsorption of CO2 is limited for the UV-cis state. In full agreement with this model, the adsorption of other gases H2, CH4 and N2 as well as their permeation behaviour is not observably influenced by the trans-cis switching.
- Liu, Chuanyao,Jiang, Yunzhe,Zhou, Chen,Caro, Jürgen,Huang, Aisheng
-
-
Read Online
- Hypoxia-Induced Pro-Protein Therapy Assisted by a Self-Catalyzed Nanozymogen
-
The success of intracellular protein therapy demands efficient delivery and selective protein activity in diseased cells. Therefore, a cascaded nanozymogen consisting of a hypoxia-activatable pro-protein, a hypoxia-inducing protein, and a hypoxia-strengthened intracellular protein delivery nanovehicle was developed. RPAB, an enzymatically inactive pro-protein of RNase, reversibly caged with hypoxia-cleavable azobenzene, was delivered with glucose oxidase (GOx) using hypoxia-responsive nanocomplexes (NCs) consisting of azobenzene-cross-linked oligoethylenimine (AOEI) and hyaluronic acid (HA). Upon NC-mediated delivery into cancer cells, GOx catalyzed glucose decomposition and aggravated tumoral hypoxia, which drove the recovery of RPAB back to the hydrolytically active RNase and expedited the degradation of AOEI to release more protein cargoes. Thus, the catalytic reaction of the nanozymogen was self-accelerated and self-cycled, ultimately leading to a cooperative anti-cancer effect between GOx-mediated starvation therapy and RNase-mediated pro-apoptotic therapy.
- Li, Xudong,Wei, Yuansong,Wu, Yuchen,Yin, Lichen
-
-
Read Online
- CH4 storage and CO2 capture in highly porous zirconium oxide based metal-organic frameworks
-
A series of porous Zr oxoclusters-based MOFs was computationally explored for their gas storage/capture performances. The highly porous UiO-67(Zr) and UiO-68(Zr) solids show exceptionally high CH4 and CO2 adsorption capacities under operating conditions that make these thermal, water and mechanical resistant materials very promising for physisorption-based processes. The Royal Society of Chemistry 2012.
- Yang, Qingyuan,Guillerm, Vincent,Ragon, Florence,Wiersum, Andrew D.,Llewellyn, Philip L.,Zhong, Chongli,Devic, Thomas,Serre, Christian,Maurin, Guillaume
-
-
Read Online
- pH and temperature responsive redox behavior of biologically important aniline derivatives
-
The redox behavior of two biologically important aniline derivatives, 2-(4-aminophenyl) ethanol and 4-aminobenzoic acid was scrutinized in a wide pH range of 2.0-12.0 using modern electrochemical techniques. The results of cyclic voltammetric experiments conducted at different temperatures were used for the evaluation of kinetic and thermodynamic parameters such as diffusion coefficient, heterogeneous electron transfer rate constant, Gibbs free energy, enthalpy and entropy changes. Differential pulse voltammetry was employed for the determination of the acid-base dissociation constant (pKa) and evaluation of the number of electrons and protons involved in redox reactions. The comparatively more rapid and sensitive voltammetric technique, square wave voltammetry allowed the determination of quite a low limit of detection and quantification of the analytes. Computational studies were performed for the identification of the most favorable oxidizable electropores of the compounds and for developing structure-activity relationships in conjunction with the experimental results. On the basis of electrochemical and computational findings a comprehensive redox mechanism was proposed which may provide useful insights about the role by which this class of compounds exert their biological action. The proposed mechanism was found to be in line with the analysis of the product scratched from the electrode surface.
- Subhan, Hanif,Lashin, Aref,Rana, Usman Ali,Al-Arifi, Nassir,Ahmad, Khurshid,Hussain, Hidayat,Qureshi, Rumana,Ali, Saqib,Zia, Muhammad Abid,Kraatz, Heinz-Bernhard,Shah, Afzal
-
-
Read Online
- Characterizing Defects in a UiO-AZB Metal-Organic Framework
-
Exploring defect sites in metal-organic framework materials has quickly become an interesting topic of discussion in the literature. With reports of the enhancement of material properties with increasing defect sites, we were interested in probing the defect nature of UiO-AZB (UiO = University of Oslo, AZB = 4,4′-azobenzenedicarboxylate) nanoparticles. In this report, we investigate the use of acetic, formic, and benzoic acids as the modulators to prepare UiO-AZB. The results of 1H NMR techniques and BET surface area analysis elucidate the extent of defects in our samples and are provided along with detailed discussions of the observed experimental trends. Interestingly, formic acid samples resulted in the most defected structure, reaching 36%. Additionally, for benzoic acid samples, with a 33% defect level, a drastic reduction in the accessible SA from 2682 m2/g to as low as 903 m2/g was observed, as the concentration of benzoic acid was increased. This was attributed to the creation of macropores in the individual crystallites and confirmed by average pore width analysis.
- Epley, Charity C.,Love, Madeline D.,Morris, Amanda J.
-
-
Read Online
- Sequential Transformation of Zirconium(IV)-MOFs into Heterobimetallic MOFs Bearing Magnetic Anisotropic Cobalt(II) Centers
-
Heterometallic metal–organic frameworks (MOFs) allow the precise placement of various metals at atomic precision within a porous framework. This new level of control by MOFs promises fascinating advances in basic science and application. However, the rational design and synthesis of heterometallic MOFs remains a challenge due to the complexity of the heterometallic systems. Herein, we show that bimetallic MOFs with MX2(INA)4 moieties (INA=isonicotinate; M=Co2+ or Fe2+; X=OH?, Cl?, Br?, I?, NCS?, or NCSe?) can be generated by the sequential modification of a Zr-based MOF. This multi-step modification not only replaced the linear organic linker with a square planar MX2(INA)4 unit, but also altered the symmetry, unit cell, and topology of the parent structure. Single-crystal to single-crystal transformation is realized so that snapshots for transition process were captured by successive single-crystal X-ray diffraction. Furthermore, the installation of Co(NCS)2(INA)4 endows field-induced slow magnetic relaxation property to the diamagnetic Zr-MOF.
- Yuan, Shuai,Qin, Jun-Sheng,Su, Jian,Li, Bao,Li, Jialuo,Chen, Wenmiao,Drake, Hannah F.,Zhang, Peng,Yuan, Daqiang,Zuo, Jinglin,Zhou, Hong-Cai
-
-
Read Online
- Efficient azobenzene co-sensitizer for wide spectral absorption of dye-sensitized solar cells
-
Two azobenzene dyes, [Cu(azobenzene-4,4′-dicarboxylate) diethylenediamine]n (ADD), [Cd(4,4′-diazenediyldibenzoato)(H2O)]n (DDB), have been designed, synthesized, and characterized as efficient co-sensitizers for dye-sensitized solar cells (DSSC). The optical, charge-transfer, electrochemical and photovoltaic properties of ADD and DDB are investigated by UV-visible spectroscopy, transient surface photovoltage measurement, cyclic voltammetry, and photocurrent-photovoltage measurement. The combination of ADD and DDB in DSSC leads to a wide spectral absorption over the whole visible range (350-700 nm). DSSC with ADD and DDB exhibits a short-circuit photocurrent density as high as 16.96 mA cm-2, open-circuit photovoltage of 0.73 V, a fill factor of 0.57, and overall light conversion efficiency of 7.1% under standard global AM1.5 solar irradiation conditions.
- Zhang,Zou,Sun
-
-
Read Online
- Molecular recognition: Hydrogen bonding induced configurational locking of a new photoresponsive receptor by dicarboxylic acids
-
A new photoresponsive system 1 has been synthesised and recognition by the cavity of the cisisomer of 1 of dicarboxylic acids of various chain lengths has been studied on irradiation at 310 nm. The cavity of the cis form is found to be selective for adipic acid.
- Goswami, Shyamaprosad,Ghosh, Kumaresh,Halder, Mintu
-
-
Read Online
- Ultrasound-assisted synthesis and characterization of a new metal-organic framework based on azobenzene-4,4-dicarboxylic acid: Precursor for the fabrication of Co3O4 nano-particles
-
Azobenzene groups are widely known as photochromic ligands thus are particularly interesting building blocks for designing receptors for neutral or charged guests. A new metal-organic framework, [Co3(adc)3(DMF)4].2DMF (compound 1) (adc = azobenzene-4,4-dicarboxylic acid, DMF = N,N-dimethylformamide), was synthesized by solvothermal methods and structurally characterized using X-ray crystallography and a range of spectroscopic techniques. Also, nanorods of compound 1 have been synthesized by a sonochemical process and characterized by field emission scanning electron microscopy (FE-SEM) and powder X-ray diffraction (PXRD). The effect of sonication time and concentration of the initial reagents on the size and morphology of the MOF have been optimized. Results indicate that decreasing of initial concentration and increasing ultrasound radiation time lead to small size nanorods of compound 1. Thus, ultrasound radiation affects the size of nanorods. After heat treatment, the cobalt ion-based metal organic framework nanorods can be converted into porous Co3O4 nanoparticles.
- Parsa, Fatemeh,Ghorbanloo, Massomeh,Masoomi, Mohammad Yaser,Morsali, Ali,Junk, Peter C.,Wang, Jun
-
-
Read Online
- Azobenzene based 2D-MOF for high selective quinone fluorescence sensing performance
-
The present work describes development of a simple and cost-effective fluorescence sensor for determination of quinone specially 1,8-dihydroxyanthraquinone (danthron). A 2D-metal-organic framework (TMU-54) containing the azobenzene group has been synthesized and applied as an efficient fluorescent sensor for danthron detection. The key feature that has a great impact on the properties of the material is the presence and distribution of functional groups within the structure. We discuss the relationship between the nature and structure of the specifically designed organic linker as well as the properties of this framework in fluorescence recognition of quinones. TMU-54 ([Cd3(adc)6(DMF)2]) is capable of distinguishing complementary and mismatched target sequences with high sensitivity and a significant Ksv (1049) value.
- Ghorbanloo, Massomeh,Junk, Peter C.,Morsali, Ali,Parsa, Fatemeh,Retailleau, Pascal,Wang, Jun
-
-
Read Online
- Exposed Equatorial Positions of Metal Centers via Sequential Ligand Elimination and Installation in MOFs
-
Metal-organic frameworks (MOFs) provide highly designable platforms to construct complex coordination architectures for targeted applications. Herein, we demonstrate that trans-coordinated metal centers with exposed equatorial positions can be placed in a MOF matrix. A Zr-based MOF, namely, PCN-160, was initially synthesized as a scaffold structure. Postsynthetic linker labilization was subsequently implemented to partially remove the original dicarboxylate linkers and incorporate pyridinecarboxylates. A pair of neighboring pyridyl groups was arranged at proper proximity within the framework to form trans-binding sites that accommodate different metal cations including Mn2+, Fe2+, Co2+, Ni2+, Cu2+, and Pd2+. Furthermore, the trans-coordinated Ni2+ sites in porous frameworks can be readily accessed by substrates along the equatorial plane, facilitating the catalysis as manifested by the superior activity in ethylene dimerization over that observed for a cis-chelated catalyst.
- Yuan, Shuai,Zhang, Peng,Zhang, Liangliang,Garcia-Esparza, Angel T.,Sokaras, Dimosthenis,Qin, Jun-Sheng,Feng, Liang,Day, Gregory S.,Chen, Wenmiao,Drake, Hannah F.,Elumalai, Palani,Madrahimov, Sherzod T.,Sun, Daofeng,Zhou, Hong-Cai
-
-
Read Online
- Novel azobenzene nickel(II) sensitizer for dye-sensitized solar cells
-
A novel 1-D chain complex {[Ni(azobenzene-4,4′-dicarboxylic acid)(ethylenediamine)2](N,N-dimethylformamide)2}(named as Ni1) was designed, synthesized, characterized, and demonstrated as an efficient sensitizer for dye-sensitized solar cells. The structure of Ni1 was characterized by single-crystal X-ray diffraction, infrared (IR) spectra, and elemental analysis. The optical, electrochemical and photovoltaic properties of Ni1 were investigated by UV-visible spectroscopy, cyclic voltammetry, and the photocurrent-photovoltage measurement. The results show that the incident photo-to-current conversion efficiency of cells based on Ni1 was obviously improved in blue light region of solar spectra. The overall conversion efficiency of the dye-sensitized solar cells using Ni1 was increased by 62% under AM 1.5 illumination (100 mW cm-2).
- Zhang, Lingyun,Luo, Yanan,Jia, Ruokun,Sun, Xuhui,Liu, Chunguang,Zhang, Yingjie
-
-
Read Online
- Azo-Functionalized Zirconium-Based Metal?Organic Polyhedron as an Efficient Catalyst for CO2 Fixation with Epoxides
-
Chemical fixation of CO2 as C1 source at ambient temperature and low pressure is an energy-saving way to make use of the green-house gas, but it still remains a challenge since efficient catalyst with high catalytic active sites is required. Here, a novel monoclinic azo-functionalized Zr-based metal?organic polyhedron (Zr-AZDA) has been prepared and applied in CO2 fixation with epoxides. The inherent azo groups not only endow Zr-AZDA with good solubilization, but also act as basic sites to enrich CO2 showing efficient synergistic catalysis as confirmed by TPD-CO2 analysis. XPS results demonstrate that the Zr active sites in Zr-AZDA possess suitable Lewis acidity, which satisfies both substrates activation and products desorption. DFT calculation indicates the energy barrier of the rate-determining step in CO2 cycloaddition could be reduced remarkably (by ca. 60.9 %) in the presence of Zr-AZDA, which may rationalize the mild and efficient reaction condition employed (80 °C and 1 atm of CO2). The work provides an effective multi-functional cooperative method for improvement of CO2 cycloaddition.
- Ding, Shujiang,Fan, Hongbo,Tang, Jia,Wang, Xiaoxia,Wei, Fen,Xie, Guanqun
-
p. 12890 - 12899
(2021/08/09)
-
- Static Retention of Dynamic Chiral Arrangements for Achiral Shear Thinning Metal–Organic Colloids
-
Chiral compounds are known to be important not only because they are the fundamental components of living organisms, but also for their unique chiroptical properties. In recent years, scientists have fabricated several chiral organic supramolecular aggregates by using chiral physical fields, such as vortex flow. Herein, the relationship between dynamic chiroptical properties and rheological nature is discussed, suggesting the shear thinning properties of non-Newtonian fluids might help colloidal particles adopt a chiral arrangement in vortices. Furthermore, the storage modulus of colloids could be increased by adding a linking agent, which successfully kept the dynamic chiroptical properties in the static state. Moreover, the salt effect on the host–guest interaction involved in the colloids was studied, the results suggested a significant enhancement of the transferred dynamic circular dichroism for the achiral guest molecule.
- Huang, Jian-Cai,Xiao, Hui,Chen, Zhixin,Zheng, Wenxu,Huang, Chang-Cang,Wu, Shu-Ting,Xie, Zenghong,Zhuang, Naifeng
-
supporting information
p. 14017 - 14024
(2021/09/02)
-
- Unraveling the Self-Assembly of Heterocluster Janus Dumbbells into Hybrid Cubosomes with Internal Double-Diamond Structure
-
Cubosomes are bicontinuous cubic-phase particles generated by amphiphile self-assembly with bicontinuous cubic phases, which creates an intricate network of interconnected nanochannels that endow these materials with special functions for advanced applications. On the other hand, clusters are an attractive class of molecules that exhibit intriguing functions and properties that differ from those of atoms and nanoparticles. Inspired by lipid self-assembly and attracted to the new functionalities of clusters, we prepared special heterocluster Janus dumbbells (HCJDs) composed of dissimilar nanoclusters: namely, a polyoxometalate and a polyhedral oligomeric silsesquioxane. HCJDs resemble conventional amphiphiles and, as such, they self-assemble in solution into faceted hybrid cubosomes via the transformation of vesicles into spongelike aggregates. Multiple mechanisms that lead to equilibrium, including molecular self-assembly, vesicle accumulation, membrane fusion, inner-structure reorganization, and cubic crystal growth, contributed to the overall process. On the basis of these results, we proposed a strategy for self-assembly - from basic molecular design that goes beyond traditional amphiphiles to the construction of micro- or nanomaterials with hierarchical structures and advanced functions.
- Liu, Hong-Kai,Ren, Li-Jun,Wu, Han,Ma, Yong-Li,Richter, Sven,Godehardt, Michael,Kübel, Christian,Wang, Wei
-
supporting information
p. 831 - 839
(2019/01/23)
-
- Conversion of anilines into azobenzenes in acetic acid with perborate and Mo(VI): correlation of reactivities
-
Azobenzenes are extensively used to dye textiles and leather and by tuning the substituent in the ring, vivid colours are obtained. Here, we report preparation of a large number of azobenzenes in good yield from commercially available anilines using sodium perborate (SPB) and catalytic amount of Na2MoO4 under mild conditions. Glacial acetic acid is the solvent of choice and the aniline to azobenzene conversion is zero, first and first orders with respect to SPB, Na2MoO4 and aniline, respectively. Based on the kinetic orders, UV–visible spectra and cyclic voltammograms, the conversion mechanism has been suggested. The reaction rates of about 50 anilines at 20–50?°C and their energy and entropy of activation conform to the isokinetic or Exner relationship and compensation effect, respectively. However, the reaction rates, deduced by the so far adopted method, fail to comply with the Hammett correlation. The specific reaction rates of molecular anilines, obtained through a modified calculation, conform to the Hammett relationship. Thus, this work presents a convenient inexpensive non-hazardous method of preparation of a larger number of azobenzenes, and shows the requirement of modification in obtaining the true reaction rates of anilines in acetic acid and the validity of Hammett relationship in the conversion process, indicating operation of a common mechanism.
- Karunakaran,Venkataramanan
-
p. 375 - 385
(2019/02/14)
-
- Light-enhanced hypoxia-responsive nanoparticles for deep tumor penetration and combined chemo-photodynamic therapy
-
Herein, we report a light-enhanced hypoxia-responsive nanoparticle for synergic treatment of solid tumors. The conversion of oxygen in the tumor exterior induced ROS and the continuous consumption of oxygen amplified the hypoxia conditions in the tumor, which enhanced the surface-to-core penetration of nanoparticles into the hypoxia central tissue.
- Li, Zhongbao,Wu, Min,Bai, Hongzhen,Liu, Xingang,Tang, Guping
-
supporting information
p. 13127 - 13130
(2018/11/30)
-
- Synthesis and self-assembly of photoresponsive and luminescent polycatenar liquid crystals incorporating an azobenzene unit interconnecting two 1,3,4-thiadiazoles
-
Novel polycatenar liquid crystals containing two 1,3,4-thiadiazole rings interconnected by an azobenzene central linkage have been synthesized and investigated by polarizing microscopy, DSC, X-ray scattering, SEM, UV-vis spectroscopy and photoluminescence measurements. These compounds can self-assemble into SmC, Colhex/p6mm and CubI/Pm3n liquid crystalline phases in the bulk states and form multistimuli responsive organogels in organic solvents. They have reversible photoresponsive properties in solution, liquid crystalline states and gel states. They also show fluorescence emission with large Stokes shift in solution and binding selectivity to Cu2+ among a series of cations in CH3CN-CH2Cl2 solution.
- Peng, Xiongwei,Gao, Hongfei,Xiao, Yulong,Cheng, Huifang,Huang, Fanran,Cheng, Xiaohong
-
supporting information
p. 2004 - 2012
(2017/03/10)
-
- Supramolecular detection of geometrical differences of azobenzene carboxylates
-
In dynamic combinatorial chemistry, the geometry of a template can be translated into the composition of a library of interchanging components. In this study, such a dynamic combinatorial library was used for the first time to detect and evaluate differences in the geometry of isomers of photoswitchable azobenzene based templates.
- Ulatowski, Filip,D?browa, Kajetan,Jurczak, Janusz
-
supporting information
p. 1820 - 1824
(2016/04/05)
-
- An azobenzene-containing metal-organic framework as an efficient heterogeneous catalyst for direct amidation of benzoic acids: Synthesis of bioactive compounds
-
An azobenzene-containing zirconium metal-organic framework was demonstrated to be an effective heterogeneous catalyst for the direct amidation of benzoic acids in tetrahydrofuran at 70°C. This finding was applied to the synthesis of several important, representative bioactive compounds.
- Hoang, Linh T. M.,Ngo, Long H.,Nguyen, Ha L.,Nguyen, Hanh T. H.,Nguyen, Chung K.,Nguyen, Binh T.,Ton, Quang T.,Nguyen, Hong K. D.,Cordova, Kyle E.,Truong, Thanh
-
supporting information
p. 17132 - 17135
(2015/12/04)
-
- Photocatalytic reduction of nitroarenes to azo compounds over N-doped TiO2: Relationship between catalysts and chemical reactivity
-
This work deals with selective reduction of aromatic nitro compounds to corresponding symmetrical substituted azo compounds using nitrogen-doped TiO2 nanoparticles as photocatalyst in the presence of a catalytic amount of formic acid. Various azo compounds containing additional reducible substituents including halogens, and carboxyl and phenol functions have been synthesized in a single step by use of this catalyst. The conversion was reasonably fast, clean, and high yielding at room temperature. A mechanism of formation for the azo compounds is proposed. The behavior of the N/TiO2 catalyst is of particular interest because this is the first time, as far as we know, that formation of azo compounds has been catalyzed by an N-doped TiO2 photocatalyst. Nitrogen-doped TiO2 was prepared by a simple modified sol-gel process with urea as nitrogen source. The catalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy, and transmission electron microscopy. The chemical nature of N was identified by XPS as N-Ti-O in the anatase TiO2 lattice.
- Wang, Huqun,Yang, Xiaofeng,Xiong, Weifeng,Zhang, Zhimin
-
p. 3981 - 3997
(2015/06/08)
-
- Synthesis and characterization of novel electrochromic and photoresponsive materials based on azobenzene-4,4′-dicarboxylic acid dialkyl ester
-
Novel electrochromic and photoresponsive materials based on azobenzene-4,4′-dicarboxylic acid dialkyl ester derivatives (ADDEDs) were successfully prepared and characterized through nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and high-performance liquid chromatography-mass spectrometry. The electrochromic behavior, electrochromic mechanism, electro-optical properties, and photoresponsive properties of ADDEDs were investigated through cyclic voltammetry and ultraviolet-visible absorption spectra. ADDEDs displayed not only outstanding electrochromic behavior but also good and reversible photoisomerization properties even under electrochromic conditions. Electrochromic devices (ECDs) based on ADDEDs were fabricated, and their electrochromic performance was analyzed. The ECDs presented a color change from colorless to magenta between 0.0 V (bleached state) and ±3.0 V (colored state). In addition, the ECDs exhibited fast switching times, reasonable contrast, satisfactory optical memories, and redox stability. The novel redox-active azobenzene derivatives are promising candidates for full-color EC display devices, electronic paper, smart windows, optical memory devices, dual-stimuli-responsive systems, as well as other potential new applications. This journal is
- He, Li-Hua,Wang, Guo-Ming,Tang, Qian,Fu, Xiang-Kai,Gong, Cheng-Bin
-
p. 8162 - 8169
(2015/05/20)
-
- Synthesis and characterization of a new photoinduced switchable β-cyclodextrin dimer
-
This paper reports an efficient preparation of bridged bis--CD AZO-CDim 1 bearing azobenzene as a linker and exhibiting high solubility in water. The photoisomerization properties were studied by UV-vis and HPLC and supported by ab initio calculations. The cis/trans ratio of AZO-CDim 1 is 7:93 without irradiation and 37:63 after 120 min of irradiation at 365 nm; the reaction is reversible after irradiation at 254 nm. The photoinduced, switchable binding behavior of AZO-CDim 1 was evaluated by ITC, NMR and molecular modeling in the presence of a ditopic adamantyl guest. The results indicate that AZO-CDim 1 can form two different inclusion complexes with an adamantyl dimer depending on its photoinduced isomers. Both cavities of cis-AZO-CDim 1 are complexed simultaneously by two adamantyl units of the guest forming a 1:1 complex while trans-AZO-CDim 1 seems to lead to the formation of supramolecular polymers with an n:n stoichiometry.
- Hamon, Florian,Blaszkiewicz, Claire,Buchotte, Marie,Banaszak-Lonard, Estelle,Bricout, Herv,Tilloy, Sbastien,Monflier, Eric,Czard, Christine,Bouteiller, Laurent,Len, Christophe,Djedaini-Pilard, Florence
-
p. 2874 - 2885
(2015/02/19)
-
- Liquid-crystal aromatic polyesters containing azo and sulfone units
-
Two novel aromatic polyesters containing azo and sulfone units were synthesized by poly-condensation of 4,4′-azobenzene-dicarbonyl chloride with dihydroxydiphenyl sulfones at low temperature. The synthesized polymers exhibited good solubility, inherent viscosity (reaches 1.05 dL g-1), high glass transition temperature (above 200 °C) and thermal stability (≤ 5 % weight loss at 348 °C), which were characterized by Fourier transform infrared spectroscopy. The liquid crystalline and photoisomerization properties were observed by polarizing optical microscope and an ultraviolet-visible spectrophotometer.
- Qiu, Ming Yan,Niu, Yong Sheng,Yu, You Zhu,Guo, Yu Hua
-
p. 7759 - 7762
(2015/02/02)
-
- Synthesis of E-1-(alkoxy-NNO-azoxy)-2-arylethenes by the reaction of bis(alkoxy-NNO-azoxy)methanes with benzyl halides under conditions of phase-transfer catalysis
-
Reaction of bis(methoxy- and ethoxy-NNO-azoxy)methane with benzyl halides and alkali under the conditions of a phase-transfer catalysis furnishes in one stage E-1-(alkoxy-NNO-azoxy)-2-arylethene in 21-55% yields. The intermediate products, 1,1-bis(alkoxy-NNO-azoxy)-2-arylethanes under the action of alkali eliminate one of the two alkoxy-NNO-azoxy groups with the formation of a double bond. The optimum solvent is DMSO, and as benzyl halides, benzyl chlorides. In the case of 4-bromobenzyl bromide a formation was found of a side bisbenzylation product, 1,3-bis(4-bromophenyl)-2,2-bis(methoxy-NNO-azoxy)propane.
- Zyuzin
-
p. 678 - 685
(2013/07/19)
-
- ENCAPSULATES
-
The present application relates to encapsulates, compositions, products comprising such encapsulates, and processes for making and using such encapsulates. Such encapsulates comprise a core comprising a perfume and a shell that encapsulates said core, such encapsulates may optionally comprise a parametric balancing agent, such shell comprising one or more azobenzene moieties.
- -
-
Page/Page column 61
(2013/03/26)
-
- Synthesis and characterization of new copoly(amide-imide)s and copoly amides with azo groups in their main chains
-
New aromatic copoly(amide-imide)s with high inherent viscosities were prepared by direct polycondensation reaction of diacides 2 or 5 and 4-nitro-1,2-phenylendiamine and three different derivatives of diacides 7 as a second diacides using triphenyl phosphite in N-methyl-2-pyrrolidone (NMP)/pyridine solution containing dissolved CaCl2. Their decomposition temperatures at 10% weight loss in nitrogen atmosphere were above 165 °C and the anaerobic char yield at 600 °C ranged from 46% to 74%. These polymers were readily soluble in various organic solvents and by their casting into transparent, tough and flexible films can be easily achieved.
- Zomorodbakhsh, Shahab,Anaraki-Ardakani, Hossein,Tavahodi, Ehsan
-
p. 1645 - 1650
(2013/07/04)
-
- Highly efficient synthesis of aromatic azos catalyzed by unsupported ultra-thin Pt nanowires
-
Aromatic azos were synthesized using unsupported ultra-thin platinum nanowires as catalysts under mild reaction conditions and the reaction mechanism was proposed.
- Hu, Lei,Cao, Xueqin,Chen, Liang,Zheng, Junwei,Lu, Jianmei,Sun, Xuhui,Gu, Hongwei
-
supporting information; experimental part
p. 3445 - 3447
(2012/05/20)
-
- Synthesis and characterization of azo aromatic diacyl chlorides
-
A convenient and rapid method for the synthesis of azo aromatic diacyl chlorides has been developed. Eight azo aromatic diacyl chlorides have been synthesized from aromatic nitro acids by using xylene as solvent. Most reaction periods are less than 2 h and the products are obtained in excellent yields with high purity.
- Qiu, Ming Yan,Zhang, Ji Chang,Shi, Wei Yun,Jia, Qing Chao,Niu, Yong Sheng
-
experimental part
p. 2295 - 2297
(2012/09/22)
-
- A highly active nano-palladium catalyst for the preparation of aromatic azos under mild conditions
-
A worm-like Pd nanocatalyst has been prepared and used in the preparation of azo compounds from nitroaromatics under mild reaction conditions. This highly dispersible nano-Pd catalyst shows high activity toward the synthesis of both symmetric aromatic azo compounds and a range of asymmetric aromatic azo compounds.
- Hu, Lei,Cao, Xueqing,Shi, Linyan,Qi, Fenqiang,Guo, Zhiqiang,Lu, Jianmei,Gu, Hongwei
-
supporting information; experimental part
p. 5640 - 5643
(2011/12/04)
-
- Novel compounds for the prophylaxis and treatment of inflammatory bowel diseases
-
Novel compounds are disclosed for the prophylaxis and treatment of inflammatory bowel disease (IBD) via the administration of an effective amount in a suitable pharmaceutical dosage of agents that are active by themselves or can deliver tin the large intestine active forms of the drugs such as 5ASA or benzoxazole acetic acid or platelet activating factors. The mechanism of the release is based on bacterial cleavage of an azo linkage in the mammalian lower bowel to release the active compound(s).
- -
-
Page/Page column 5
(2010/11/25)
-
- An easy access to aromatic azo compounds under ultrasound/microwave irradiation
-
Chemoselective reduction of nitroarenes to azo and azoxy compounds was easily achieved using zinc powder and ammonium chloride in DMF or DMF-water (95:5) under high intensity ultrasound (US) or microwave (MW) irradiation, separately or combined. When carried out under conventional heating the reaction required much higher temperatures and gave lower yields. The addition of a small amount of water caused a dramatic increase in the reactivity, permitting the reduction of hindered nitroarenes at the expense of selectivity. A novel reactor for combined US/MW irradiation was employed which demonstrated additional beneficial effects. Georg Thieme Verlag Stuttgart.
- Cravotto, Giancarlo,Boffa, Luisa,Bia, Marco,Bonrath, Werner,Curini, Massimo,Heropoulos, Georgios A.
-
p. 2605 - 2608
(2008/09/16)
-
- Benzoxazole derivatives for the prophylaxis and treatment of inflammatory bowel diseases
-
The present invention relates to novel compounds for the prophylaxis and treatment of inflammatory bowel disease (IBD) via the administration of an effective amount in a suitable pharmaceutical dosage of agents that are active by themselves or can deliver tin the large intestine active forms of the drugs such as 5ASA or benzoxazole acetic acid or platelet activating factors. The mechanism of the release is based on bacterial cleavage of an azo linkage in the mammalian lower bowel to release the active compound(s).
- -
-
Page/Page column 8; 10
(2010/11/23)
-
- Synthesis and photoresponsive study of azobenzene centered polyamidoamine dendrimers
-
A new series of novel polyamidoamine (PAMAM) dendrimers 4, 5 and 6 possessing azobenzene units specifically at the core were prepared and their reversible trans/cis photoisomerization properties were studied. PAMAM dendritic wedges as well as azo-based PAMAM dendrimers were fully characterized by means of FT-IR, NMR (1H and 13C), mass spectrometry (MALDI-MS), thermogravimetric and elemental analysis.
- Ghosh, Samaresh,Banthia, Ajit K.,Chen, Zhu
-
p. 2889 - 2896
(2007/10/03)
-
- Mechanism and reactivity in perborate oxidation of anilines in acetic acid
-
Perborate but not percarbonate in acetic acid generates peracetic acid on standing and the peracetic acid oxidation of anilines is fast. The oxidation with a fresh solution of perborate in acetic acid is smooth and second order but the specific oxidation rate increases with increasing [perborate]0 or [boric acid]. Perborate on dissolution affords hydrogen peroxide and a borate; the latter assists the former in the oxidation. The oxidation rates of anilines under identical conditions do not conform to any of the linear free energy relationships but the reaction rates of molecular anilines do. Perborate oxidation proceeds via two reaction paths but the overall oxidation rates of molecular anilines conform to structure reactivity relationships; the transition states do not differ significantly. Analysis of the oxidation rates of perborate and percarbonate reveals that while perborate oxidation is faster than percarbonate it is at least as selective as the latter.
- Karunakaran, Chockalingam,Kamalam, Ramasamy
-
p. 2011 - 2018
(2007/10/03)
-
- Structure-reactivity correlation of anilines in acetic acid
-
The oxidation of aniline in glacial acetic acid with percarbonate, a dry carrier of hydrogen peroxide, is a second-order reaction conforming to the isokinetic relationship. The hitherto followed method of correlation of the reaction rates in terms of the structure-reactivity relationships is unsatisfactory and erroneous. But the reaction rates of molecular anilines, obtained for the first time, conform to the structure-reactivity relationships.
- Karunakaran, Chockalingam,Kamalam, Ramasamy
-
p. 1118 - 1124
(2007/10/03)
-
- Synthesis of photoresponsive polyamidoamine (PAMAM) dendritic architecture
-
Polyamidoamine (PAMAM) dendrimer 1 with an azobenzene central linker has been synthesized and found to undergo reversible trans/cis isomerization upon exposure to UV-light.
- Ghosh, Samaresh,Banthia, Ajit K.
-
p. 501 - 503
(2007/10/03)
-
- Lack of linear free energy relationship: Tungsten(VI) catalyzed perborate oxidation of anilines
-
Operation of linear free energy relationships in tungsten(VI) catalyzed perborate oxidation was studied with 29 para-, meta- and ortho-substituted anilines. The activation parameters were calculated from k*( = rate/[substrate]2) at 35, 40, 45, 50 and 55 °C using the Erying relationship by the method of least squares. The oxidation is not isoentropic; in an isoentropic series only enthalpy of activation determines the reactivity and the isokinetic temperature is at infinity. At the isokinetic temperature all the compounds of the reaction series react at equal rate, the variation of substituent at this temperature has no influence on the free energy of activation.
- Karunakaran,Palanisamy
-
p. 571 - 575
(2007/10/03)
-
- Chemical Consequences of Arylnitrenes in the Crystalline Environment
-
UV photolysis of powdered crystals of several aryl azides at cryogenic temperatures afforded azo compounds predominantly. In the cases of p-(N-methylacetamido)phenyl azide and 2-azidobiphenyl, a CH insertion product or a carbazole was formed, competing with azo formation. These products can be considered to be formed through topotactic processes when the crystal structures are taken into account. The arylnitrenes generated in the azide crystals were monitored by ESR spectroscopy; they turned out to have extremely long half life-times, compared with those in the gas phase or in solution. Such high kinetic stabilities are ascribed to the inert environment around the generated nitrenes. The decay process of arylnitrenes in the initial stage obeyed a pseudo-first order kinetics; activation parameters were evaluated by Arrhenius plots. The activation enthalpies and entropies indicate that the diffusional processes of arylnitrenes may be the vital factors determining the kinetic stability and the product distribution in the crystalline environment.
- Sasaki, Akito,Mahe, Loic,Izuoka, Akira,Sugawara, Tadashi
-
p. 1259 - 1275
(2007/10/03)
-
- Characterization of simple photoresponsive systems and their applications to metal ion transport
-
Some new photoresponsive azobenzenes (1-5) have been synthesized and characterized.On irradiation at 330 nm these systems undergo conversion from the E to the Z form to a varying extent which depends upon the nature and position of substitution on the azobenzene rings.They revert back to the E form on thermal isomerization in the dark.Photochemical equilibria have been studied and compared in acetonitrile and o-dichlorobenzene; E forms are stabilized more in o-dichlorobenzene than in acetonitrile.Two of the molecules (1 and 4) show enhanced transport of Cu2+ ions across a liquid membrane on irradiation.
- Ameerunisha, Sardar,Zacharias, Panthappally S.
-
p. 1679 - 1682
(2007/10/02)
-