Stereoregular hybrid azobenzene-cyclosiloxanes with photoinduced reversible solid to liquid transition properties

Bakirov, Artem,Buzin, Mikhail,Cherkaev, Georgij,Migulin, Dmitry,Shchegolikhina, Olga,Vysochinskaya, Yulia

, (2021)

A new type of stereoregular hybrid azobenzene-organocyclosiloxane discrete molecular structures with photoactive azobenzene groups unidirectionally connected to rigid cyclosiloxane frames through alkyl spacers of different lengths were developed for the first time. The kinetics and thermodynamics of nondegradative reversible trans-cis photoisomerization processes of the synthesized azobenzene-cyclosiloxane conjugates investigated using UV/Vis spectroscopy, DSC and XRD methods showed dependency on their molecular structures. It has been observed that room temperature UV (365 nm) irradiation of the synthesized hybrids leads to photoliquefaction effect consisting of a photoinduced phase transition of crystal solids into liquids. The photoliquefaction process was observed and confirmed with DSC, XRD and POM methods. Backward solidification process was generated with visible light and by heating. The tetra-azobenzene substituted cyclosiloxane single molecule compounds described in this work can be regarded as promising candidates for the development of new hybrid smart materials with many potential high-tech applications.

Rearrangement of azoxybenzocrowns into chromophoric hydroxyazobenzocrowns and the use of hydroxyazobenzocrowns for the synthesis of ionophoric biscrown compounds

Szarmach, Miros?aw,Wagner-Wysiecka, Ewa,Luboch, Elzbieta

, p. 10893 - 10905 (2013)

The Wallach rearrangement was used as a method for preparing p-hydroxyazobenzocrown ethers starting from different azoxybenzocrowns as substrates. Synthesis of a series of p-hydroxyazobenzocrowns under modified conditions and characterization of the obtained products are presented. o-Hydroxyazobenzocrowns were identified among the products of the photochemical rearrangement of azoxybenzocrowns. Novel biscrowns were synthesized from p-hydroxyazobenzocrown ethers. The synthesized host molecules, differing in the size of the macrocycles and in the substituents in the aromatic rings, have the same dioxymethylene linkers. They were used as potential sodium or potassium ionophores in classic and miniature (screen-printed) ion-selective electrodes. The properties (tautomerism, acid-base equilibrium) of newly prepared o-hydroxyazobenzocrown ethers and their p-substituted analogs were studied using spectroscopic methods and compared.

DNA/BSA binding studies of peripherally tetra substituted neutral azophenoxy zinc phthalocyanine

Amitha,Vasudevan, Suni

, (2020)

A tetra substituted neutral zinc phthalocyanine (ZnPc-4) bearing 4-phenylazophenoxy group at the periphery had been prepared from zinc acetate dihydrate Zn(CH3COO)2·2H2O and 4-(phenylazophenoxy)phthalonitrile. The interaction of neutral metallophthalocyanine, ZnPc-4 with Calf Thymus (CT) DNA was investigated using absorption titrations, competitive Fluorescent Intercalator Displacement (FID) assay, minor groove binding assay and viscosity measurement. The binding studies revealed a probable intercalative mode of interaction of ZnPc-4 with DNA with an appreciable binding constant. The bovine serum albumin (BSA) binding activity of ZnPc-4 was evaluated by fluorescence titration.

Fabrication of highly durable hydrophobic PBZ/SiO2 surfaces

Parveen, A. Shakila,Thirukumaran,Sarojadevi

, p. 43601 - 43610 (2015)

The structure of the synthesized precursors [4-phenyl(diazenyl)phenol (PAP)] & [N,N′-bis(4-aminophenyl)terephthalamide (APTA)] and benzoxazine monomer [bis(6-phenyl diazenyl-3,4-dihydro-2H-1,3-benzoxazinyl)terephthalamide (BZO-TA)] were confirmed by Fourier Transform Infrared (FT-IR) and Nuclear Magnetic Resonance (1H & 13C-NMR) spectroscopy. The miscibility and curing behaviour of the SiO2 nanoparticles with benzoxazine was examined by Differential Scanning Calorimetric (DSC) analysis. Polybenzoxazine-silica nano hybrids [PBZ:SiO2] with different weight ratios of SiO2 nanoparticles (1, 3 and 5 wt%) were prepared by a thermal curing method. Surface morphological studies from SEM (Scanning Electron Microscopy) and AFM (Atomic Force Microscopy) revealed that the PBZ:SiO2 hybrids with same compositions show hierarchically structured roughness. FT-IR was used to investigate the thermal-curing reactions and hydrogen bonding interactions in both polybenzoxazine and its hybrids. Contact angle analysis indicated that the hybrids have a hydrophobic nature and low wettability. The thermal and mechanical stabilities of the hybrids were studied using Thermogravimetric (TGA) and Dynamic Mechanical Analysis (DMA).

Hahn,Lee,Jaffe

, p. 4975,4978 (1967)

Synthesis and photochemical properties of cationic cyclopentadienyliron containing arylazo chromophores

Li, Guang-Lei,Ye, Hui,Chen, Yu,Zhao, Bao-Dong,Wang, Tao

, p. 1516 - 1519 (2011)

Two kinds of cationic cyclopentadienyliron complexes containing arylazo chromophores (Azo-Fc) were synthesized through the nucleophilic aromatic substitution reactions of cyclopentadienyliron chlorobenzene complexes. The synthesized Azo-Fc was characterized by LC-MS, IR, and 1H NMR. The influence of substituents and the aryl ring on spectral data of the synthesized compounds is described. Unlike other cationic cyclopentadienyliron complexes, Azo-Fc hardly underwent photolysis and showed no photo-initiating abilities in the cationic polymerization under photo-irradiation; in addition, trans/cis isomerization by irradiation is possible at different wavelengths.

Facile Synthesis of Catechol Azo Dyes

Haghbeen, Kamaldin,Tan, Eng Wui

, p. 4503 - 4505 (1998)

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Formation of asymmetric N-hydroxyaryl-N'-aryl(hetaryl)diazenes in the reaction of N-aryl(hetaryl)-N'-phosphoryldiazene-N-oxides with bases

Zlotin, S. G.,Sharashkina, M. V.,Luk'yanov, O. A.

, p. 577 - 579 (1993)

Aromatic and heterocyclic N'-phenoxyphosphoryldiazene-N-oxides react with bases to give asymmetric N-hydroxyaryl-N'-aryl- and N-hydroxyaryl-N'-hetaryldiazenes.

The in situ generation and reactive quench of diazonium compounds in the synthesis of azo compounds in microreactors

Akwi, Faith M.,Watts, Paul

, p. 1987 - 2004 (2016)

In this paper, a micro-fluidic optimized process for the continuous flow synthesis of azo compounds is presented. The continuous flow synthesis of Sudan II azo dye was used as a model reaction for the study. At found optimal azo coupling reaction temperature and pH an investigation of the optimum flow rates of the reactants for the diazotization and azo coupling reactions in Little Things Factory-MS microreactors was performed. A conversion of 98% was achieved in approximately 2.4 minutes and a small library of azo compounds was thus generated under these reaction conditions from couplers with aminated or hydroxylated aromatic systems. The scaled up synthesis of these compounds in PTFE tubing (i.d. 1.5 mm) was also investigated, where good reaction conversions ranging between 66-91% were attained.

The selective synthesis ofN-arylbenzene-1,2-diamines or 1-arylbenzimidazoles by irradiating 4-methoxy-4′-substituted-azobenzenes in different solvents

Chen, Po-Yi,Hsu, Chi-Wei,Ho, Tong-Ing,Ho, Jinn-Hsuan

, p. 6662 - 6666 (2021/02/21)

The solvent-controllable photoreaction of 4-methoxyazobenzenes to afford 1-aryl-1H-benzimidazoles orN-arylbenzene-1,2-diamines has been studied. The irradiation of 4-methoxyazobenzenes in DMF containing 0.5 M hydrochloric acid providedN2-aryl-4-methoxybenzene-1,2-diamines as the major product, while irradiation in acetal containing 0.16 M hydrochloric acid led to 1-aryl-6-methoxy-2-methyl-1H-benzimidazoles as the major product. A possible reaction mechanism explaining the selectivity was also discussed.

Synthesis method and application of novel p-aryl azophenol derivative

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Paragraph 0077-0100, (2021/07/14)

The invention provides a synthesis method of a p-aryl azophenol derivative. The synthesis method comprises the following step of: subjecting two aryl diazonium salts serving as raw materials to reacting in a mixed solvent of water under the action of an additive to generate the p-aryl azophenol derivative with a structure as shown in a formula (I) that is described in the specification. The chemical structure of the diazonium salt is as described in the specification, and in the chemical structure, R and R1 groups are selected from straight-chain or branched-chain alkyl groups, straight-chain alkoxy groups, halogen, nitryl groups, ester groups, trifluoromethyl groups and cyano groups. The additive is one or more selected from a group consisting of lithium acetate, sodium acetate, potassium acetate, cesium acetate, sodium carbonate, triethylamine, N,N-diisopropylethylamine, diazabicyclo and potassium tert-butoxide. The solvent is one or more selected from the group consisting of benzyl alcohol, acetonitrile, methanol, ethanol, acetone and water. According to the invention, a one-pot cascade reaction of aryl diazonium salt and water is realized under mild and transition metal-free conditions, and the multifunctional p-substituted azophenol derivative is conveniently and efficiently synthesized.