Azo Molecules Research Articles

Photoswitchable Azobispyrazole Crystals Achieving Near-Quantitative Crystalline-State Bidirectional E ⇆ Z Conversions.

Azo molecules, being extensively studied as photoswitches, have demonstrated versatile photoswitching performance and applications in solution-phase systems. However, the dense molecular packing and insufficient conformational freedom in the solid/crystalline state typically pose a challenge to their E ⇆ Z isomerization. This study presents a breakthrough in solid-state azo chemistry, where the investigated azobispyrazole molecules are capable of achieving high E → Z photoconversion, ranging from 85% to nearly quantitative (96%), and quantitative Z → E photoswitching in their crystalline states. To the best of our knowledge, azobispyrazoles are the first photoswitchable azo crystals that achieve high-yield bidirectional conversions, particularly the challenging thermodynamically stable-to-metastable E → Z transformation. Crystallographic and computational analyses provide in-depth insights into the photoswitching mechanism and propose that locally distributed free spaces and weak intermolecular interactions within the crystal structures are key factors contributing to the crystalline-state conversion. This work opens up new avenues for the development of promising photoswitchable azo crystals and also underscores the potential application of azobispyrazole crystals as light-responsive materials.

Engineering the novel azobenzene-based molecular photoswitches for suppressing bacterial infection through dynamic regulation of biofilm formation.

Bacterial biofilm is a strong fortress for bacteria to resist harsh external environments, which can enhance their tolerance and exacerbate the drug/pesticide resistance risk. Currently, photopharmacology provides an advanced approach via precise spatiotemporal control for regulating biological activities by light-controlling the molecular configurations, thereby having enormous potential in the development of drug/pesticides. To further expand the photopharmacology application for discovering new antibiofilm agents, we prepared a series of light-controlled azo-active molecules and explored their photo isomerization, fatigue resistance, and anti-biofilm performance. Furthermore, their mechanisms of inhibiting biofilm formation were systematically investigated. Overall, designed azo-derivative A11 featured excellent anti-Xoo activity with an half-maximal effective concentration (EC50) value of 5.45 μg mL-1, and the EC50 value could be further elevated to 2.19 μg mL-1 after ultraviolet irradiation (converted as cis-configuration). The photo-switching behavior showed that A11 had outstanding anti-fatigue properties. An in-depth analysis of the action mechanism showed that A11 could effectively inhibit biofilm formation and the expression of relevant virulence factors. This performance could be dynamically regulated via loading with private light-switch property. In this work, designed light-controlled azo molecules provide a new model for resisting bacterial infection via dynamic regulation of bacterial biofilm formation. © 2024 Society of Chemical Industry.

Synthesis, structural characterization, thermal analysis and anticorrosion properties of novel AZO-based imidazo[1,2-a]pyridine derivatives: Experimental study and theoretical approaches

In this study, innovative AZO-based imidazo[1,2-a]pyridine derivatives were synthesized using simple and efficient synthetic approach enabling large-scale production. Thermal analysis highlights their suitability for potential applications requiring resistance to moderate temperatures. These compounds were investigated as corrosion inhibitors for MS in a 1 M HCl-medium. Corrosion inhibition studies, including weight loss, PotentioDynamic polarization and electrochemical impedance spectroscopy methods, revealed that AZOs exhibited maximum corrosion inhibition efficiencies reaching 96.13 % and 94.07 %, respectively, at a concentration of 10−3 M and a temperature of 298 K, with both compounds acting as mixed-type inhibitors. The study also delved into the influence of temperature and immersion time on inhibitory performance, revealing stable inhibition within the temperature range of 298–328 K. The calculated standard free energy of adsorption was −42.06 and −40.62 kJ/mol for AZO 1 and AZO 2, respectively, suggesting mixed-type adsorption, with adsorption behavior following the Langmuir isotherm. Morphological analysis through SEM and AFM, showed a reduction in surface roughness in the presence of the inhibitors, while water contact angle measurements indicated a significant increase in surface hydrophobicity. UV–visible and FT-IR analyses confirmed the interaction of AZOs with the MS surface, suggesting the formation of a protective layer composed of adsorbed AZO molecules. Furthermore, computational investigations employing DFT, Monte Carlo, and Molecular Dynamic simulation revealed the formation of coordinate bonds between the studied inhibitors and the metal surface, confirming adsorption on the metallic surface. These findings align well with experimental outcomes, and a possible corrosion inhibition mechanism process was discussed.

Synthesis and characterization of aniline-based azo molecules: In vitro pharmacological and emission studies.

The present work involves the synthesis of novel dispersed mono-azo dyes using different coupling components and 2-methoxy-5-nitro aniline as amine through a simple and convenient diazo-coupling method. The structures of the newly synthesized mono azo dyes were confirmed by using various spectral techniques such as 1H NMR, Fourier transform infrared, and high-resolution mass spectrometry. At room temperature, the electronic absorption spectra and fluorescence spectra of the synthesized mono azo dyes were recorded with different solvents. The global reactive parameters for the synthesized azo molecules were evaluated by performing density functional theory through the 6-311++G (d, p) basis set. The anti-microbial activities for the synthesized azo compounds were carried out, and the compounds G1 and G2 exhibited good antibacterial and anti-fungal activities. The in silico molecular docking studies of the azo molecules revealed that all the compounds exhibited extraordinary binding affinity as that of the standard drug. Further, the anti-tuberculosis study against the Mycobacterium tuberculosis for the synthesized azo dyes was evaluated, and from the results, it was revealed that the compound G4 showed good sensitivity among the other synthesized azo compounds.

Synthesis, Solvatochromic Studies, DFT Calculations, Characterization, and In Silico Molecular Docking Studies of Azo Dyes of 3‐Methyl‐1‐phenyl‐1H‐pyrazol‐5‐amine

AbstractIn this work, the four azo dyes (A1–A4) were synthesized using 5‐amino‐3‐methyl‐1‐phenyl pyrazole with four different coupling components by the conventional, simple diazo‐coupling method. These synthesized azo molecules were confirmed by various spectroscopic methods viz, FT‐IR spectra, HR‐MS spectra, 1H NMR spectra, and 13C NMR spectra. The electronic absorption and fluorescence spectra of synthesized azo compounds were recorded at room temperature, with different solvents. The DFT calculations were performed using 6‐311++G (d, p) basis set to evaluate the global reactive parameters of the synthesized azo dyes. The anti‐microbial activities were studied; the compound A1 exhibited a good antibacterial and anti‐fungal activities. The study of in silico molecular docking of the azo compounds revealed that all the compounds found to possess were extraordinary binding affinity as compared to the standards. The anti‐tuberculosis study was carried against mycobacterium tuberculosis and the results have shown that, the compound A2 showed good sensitivity to the studied azo compounds.

Traditional, one-pot three-component synthesis and anti-bacterial evaluations of some new pyrimidine derivatives

In this study, a novel series of pyrimidine compounds featuring azo linkages was synthesized via a sequence of stepwise and one-pot three-component reactions. The synthetic process commenced with the diazotization of 3-chloro-4-methyl aniline, followed bycoupling reaction with 4-hydroxy acetophenone, yielding the azo molecule denoted as 1-(3-((3-chloro-4-methylphenyl)diazenyl)-4-hydroxyphenyl)ethan-1-one. Subsequently, this compound underwent benzylation with benzyl bromide by Williamson ether synthesis, leading to the formation of 1-(4-(benzyloxy)-3-((3-chloro-4-methylphenyl)diazenyl)phenyl)ethan-1-one. The resultant azo-benzyloxy compound was then subjected to both classical and one-pot methodologies to synthesize pyrimidine derivatives, from results obtained from one pot reaction were in good yield. Structural elucidation of the newly synthesized compounds was characterized by spectral analysis, including FT-IR, 1H NMR, 13C NMR, and 13C-DEPT-135-NMR. The spectroscopic data confirmed the integrity of the molecular structures. Lastly, certain pyrimidine derivatives were evaluated for their antimicrobial activity against two strains of bacteria, namely Staphylococcus aureus and Escherichia coli. The results revealed that as the increasing of concentration, the sensitivity increased as reached 800 µg /mL no growth of bacterial was seen, It is also notable that the synthesized compounds have antimicrobial efficacy against both bacterial types.

Potentially Bioactive Novel Isophthalic Acid Based Azo Molecules: Synthesis, Characterization, Quantum Chemical Calculations, ADMET Properties, Molecular Docking and Molecular Dynamics Simulations

We report here the synthesis of the two novel molecules 5-((5-hexyl-2,4-dihydroxyphenyl)diazenyl)isophthalic acid (3a) and 5-((5-ethyl-2,4-dihydroxyphenyl)diazenyl)isophthalic acid (3b). The structures of the 3a and 3b were confirmed by using 1H-NMR,13C-NMR, FT-IR, UV-vis, and HR-ESI-MS techniques. The optimized molecular geometry, vibrational frequency,1H- and 13C-NMR spectra calculations were performed using the DFT/B3LYP method with a 6-311G(d,p) basis set. The frontier molecular orbitals and electronic transition wavelengths were calculated at the level of TD-DFT/CAM-B3LYP/6-311G(d,p). The experimental data obtained for the synthesized molecules were in good agreement with the theoretical ones. The calculated HOMO-LUMO band gap revealed that 3a has a softer character and may be more reactive in chemical reactions. Important ADMET parameters of the compounds were also calculated, and the obtained physicochemical, pharmacokinetic, drug similarity, and toxicity data were at the desired level for a candidate bioactive compound. In order to examine the potential anticancer or antibacterial properties of newly synthesized azo molecules, molecular docking studies were performed using four different proteins. The best interaction was determined to be between 3a and VEGFR2 (PDB ID: 2XIR) with a binding energy of 9.0 kcal/mol. Moreover, a 50 ns MD simulation study for 3a-2XIR revealed that the complex maintained both its structural integrity and molecular interactions throughout the simulation.

Synthesis, Characterization, and Photophysical Probing Interaction Studies on Azo‐Sulfonamides Acting as Potent Anti‐Tubercular Agents

AbstractBy utilizing the sulfamethizole component via the diazo‐coupling approach by electrophilic substitution process, an unprecedented series of four mono‐azo sulfonamide molecules were synthesized in good yield. Spectroscopic investigation unambiguously confirmed the structures of the newly synthesized mono‐azo sulfonamide derivatives, including FT‐IR, NMR (1H and 13C), HRMS, Uv‐Vis, and Photoluminescence (PL). In a variety of organic solvents, the 3‐diethylaminophenol coupled azo‐sulfonamide T3 showed a maximum bathochromic shift of λmax in the range 462–479 nm and in the region of 88–142 nm, a derivative of 2‐hydroxy‐1,4‐naphthoquinone T4 coupled azo colourant showed a significant Stokes shift. Conceptual density function theory was also used to build a new family of high energy density energetic mono‐azo sulfonamides. Frontier molecular orbitals (HOMO‐LUMO) and global reactivity descriptors were identified to analyze how molecules interact with one another. Further, the potency of the anti‐tubercular activity of the colorants was examined with the standards such as Isoniazid, Ethambutol, Pyrazinamide, Rifampicin, and Streptomycin. The results indicated that‐ Lawsone pigment (2‐hydroxy‐1,4‐naphthoquinone) incorporated azo molecule T4 displayed the sensitivity at 3.12 μg/mL compared with other the three mono‐azo molecules.

Synthesis, Characterization and Thermal Analysis of Cu (II), Co (II), Ru(III) and Rh(III) Complexes of a New Acidic Ligand

Hippuric acid and 3-amino phenol were used to make the 4-(2-Amino-4-hydroxy-phenylazo)-benzoylamino-acetic acid diazonium salt, a new Azo molecule that is a derivative of the (4-Amino-benzoylamino)-acetic acid diazonium salt. We found out what the ligand's chemical structures were by using information from 1HNMR, FTIR, CHN, UV-Vis, LC-mass spectroscopy, and thermal analyses. To make metal complexes of the azo ligand with Co(II), Cu(II), Ru(III), and Rh(III) ions, extra amounts of each azo ligand were mixed with metal chloride salts in a 2:2 mole ratio. The stereochemical structures and geometries of the metal complexes that were studied were guessed based on the fact that the ligand exhibited tetradentate bonding behavior when combined with the metalions. The azodye ligand is coordinated with the metal ions (Co(II), Cu(II),Ru(III), and Rh(III)) through (NNOO) the N atoms of azo and amine groups and the oxygen of carboxylic and phenolic hydroxyl groups. According to analytical results, the Ru(III) and Rh(III) complexes have binuclear octahedral geometry, whereas the Cu(II) and Co(II) complexes have binuclear distorted octahedral and binuclear tetrahedral geometry, respectively. The results indicated that the following formulas for ligand complexes should be used: [Ru2Cl2(H2O)2(LI)2], [Rh2Cl2(H2O)2(LI)2], [Co2(LI)2], and [Cu2(LI)2]. The thermal analysis conducted by TG, DTG, and DTA demonstrated partial breakdown at temperatures between 820°C and 850°C.

Molecular design on dual stimuli-responsive azobenzene-containing ionic complexes toward self-healing materials under photoirradiation or humid condition at room temperature

Self-healing materials working at room temperature are attractive in the field of materials chemistry. Compared to those requiring one specific external stimulus, one smart material that can launch the self-healing process under multiple stimuli would accommodate more various working conditions. In this work, a double-chain azobenzene-containing surfactant AZO with good molecular flexibility and hydrophilicity is designed for developing self-healing materials with dual responses to light and humidity. By mixing AZO and surfactants containing linear aliphatic chains, the resulted composites gain crystal-to-isotropic liquid phase change ability under the trigger of either light or humidity, thanks to the formation of sufficient free volume for AZO molecules. This leads to the light-/humidity-induced self-healing materials at room temperature. Meanwhile, the composite of AZO and double-chain surfactant has been proved with better responsive sensitivity to light and humidity by forming a homogeneous molecular distribution. This study provides a new designing strategy for gaining dual self-healing materials working via an athermal way, promoting the development of smart materials with multiple stimuli-responsive property.

A novel imidazole-based azo molecule: synthesis, characterization, quantum chemical calculations, molecular docking, molecular dynamics simulations and ADMET properties.

Today, the treatment or prevention of cancer, which is one of the most important causes of death, has a very important place. On the other hand, the discovery of new antimicrobial agents is also important because of antibiotic resistance that can occur in humans. For these reasons, in this study, the synthesis, quantum chemical calculations, and in silico studies of a novel azo molecule with high bioactive potential were carried out. In the first step of the synthesis part, (3-(4-methyl-1H-imidazol-1-yl)-5-(trifluoromethyl)aniline compound, which is the raw material of the drug used in cancer treatments, was synthesized. In the second step, a novel product 2-hydroxy-5-((3-(4-methyl-1H-imidazol-1-yl)-5-trifluoromethyl)phenyl)diazenyl)benzaldehyde (HTB) was obtained as a result of the reaction of salicylaldehyde coupling to this compound. Then, as it was being spectroscopically described, its geometry was optimized. In order to perform quantum chemical calculations, the molecular structure, vibrational spectroscopic data, electronic transition absorption wavelengths, HOMO and LUMO analyses, molecular electrostatic potential (MEP) and potential energy surface (PES) of the molecule were all taken into consideration. Using molecular docking simulations, in silico interactions of theHTB molecule with some anticancer and antibacterial-related proteins were studied. In addition, the ADMET parameters of the HTB were also predicted. The structure of the synthesized compound was elucidated using 1H-NMR, 13C-NMR (APT), 19F-NMR, FT-IR and UV-vis spectroscopic methods. The optimized geometry, molecular electrostatic potential diagram and vibrational frequencies of the HTB molecule were calculated at the DFT/B3LYP/6-311G(d,p) level. The TD-DFT method was used to calculate HOMOs-LUMOs and electronic transitions, and the GIAO method was used to calculate chemical shift values. It was observed that the experimental spectral data were in good agreement with the theoretical ones. Molecular docking simulations of the HTB molecule using 4 different proteins were investigated. Two of these proteins were involved in simulating anticancer activity and the other two in simulating antibacterial activity. According to molecular docking studies, the binding energies of the complexes formed by the HTB compound with the 4 selected proteins were between -9.6 and -8.7 kcal/mol. HTB showed the best affinity with VEGFR2 protein (PDB ID: 2XIR) and the binding energy of this interaction was found to be -9.6 kcal/mol. The HTB-2XIR interaction was examined with molecular dynamics simulation for 25 ns and it was determined that this complex was stable during this time. In addition, the ADMET parameters of the HTB were also calculated, and from these values, it was determined that the compound has very low toxicity and high oral bioavailability.

Kinetics of the dark cis–trans isomerization of azobenzene and azo pyridine derivatives in ethanol and chloroform solutions

The paper presents a series of azobenzene and azo pyridine compounds containing hydroxyl or 6-hydroxyhexyloxyl substituents. The nitrogen atom is located at the ortho-, meta- or para-position in the structure of azo pyridine derivatives. The impact of the structural features of azo chromophores on their thermal (DSC, TGA) and optical (UV–Vis) properties was investigated. The dark cis–trans isomerization kinetics was studied in ethanol and chloroform at 298 K. The formation of noncovalent hydrogen bonds between azo molecules and/or chromophore-solvent was monitored using the 1H NMR spectroscopy and estimated by density functional theory (DFT) calculations. Based on experimental and computational studies we proposed the mechanism of the dark cis–trans isomerization for hydroxy-substituted azo compounds.

Self-Assembly and Photoinduced Deformation of Microspheres of an Azo Molecule Containing a 1,4,3,6-Dianhydrosorbitol Core and Cinnamate Peripheral Groups

Self-Assembly and Photoinduced Deformation of Microspheres of an Azo Molecule Containing a 1,4,3,6-Dianhydrosorbitol Core and Cinnamate Peripheral Groups

Azobenzene as Antimicrobial Molecules.

Azo molecules, characterized by the presence of a -N=N- double bond, are widely used in various fields due to their sensitivity to external stimuli, ch as light. The emergence of bacterial resistance has pushed research towards designing new antimicrobial molecules that are more efficient than those currently in use. Many authors have attempted to exploit the antimicrobial activity of azobenzene and to utilize their photoisomerization for selective control of the bioactivities of antimicrobial molecules, which is necessary for antibacterial therapy. This review will provide a systematic and consequential approach to coupling azobenzene moiety with active antimicrobial molecules and drugs, including small and large organic molecules, such as peptides. A selection of significant cutting-edge articles collected in recent years has been discussed, based on the structural pattern and antimicrobial performance, focusing especially on the photoactivity of azobenzene and the design of smart materials as the most targeted and desirable application.

Synthesis, characterization, theoretical calculations of novel benzoic acid based azo molecules and their use in effective extraction of Hg(II) ions from aqueous medium

In this study, two series of benzoic acid derivative azo compounds were synthesized using coupling reaction and characterized by various spectroscopic techniques. By using o-, m-, p-chloroaniline and o-, m-, p-nitroaniline as starting materials, the effects of the directing groups on the color intensity of azo dyes were investigated. It was concluded that the nitro group increased both the reaction efficiency and the color intensity. Optimized molecular structures, vibrational and electronic transition spectra, NMR chemical shift values, frontier molecular orbitals and MEP diagrams of each molecule were calculated using the 6-311G(d,p) basis set. All calculations were performed and compared with both Density Functional Theory (DFT) and Hartree-Fock (HF) methods. Experimental and theoretical results were found to be quite compatible with each other. The extraction capabilities of all synthesized azo derivatives were investigated using various transition metal picrates such as Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+, Pb2+ cations. Solvent extraction studies of azo derivatives revealed that all compounds showed strong binding ability against Cu2+ and especially Hg2+ ions and were able to remove the Hg2+ cation from aqueous medium at a high rate (97.3%).

Predicting the maximum absorption wavelength of azo dyes using an interpretable machine learning strategy

The maximum absorption wavelength (λmax) is one of the most important properties of azo dyes. It is essential to obtain λmax of azo dyes for the development of new molecules in a short time. Herein, the machine learning algorithm “XGBoost” was used to establish a model for predicting λmax of azo dyes. It was found that the coefficient of determinations (R2) of leave-one-out cross-validation (LOOCV) and test set were 0.87, 0.73, respectively. According to SHapley Additive exPlanations (SHAP) analysis, the number of sulfur atoms of R2 group has a strong positive correlation with λmax. The more C–N pairs of topological distance 4 appear in R1 group, the more likely the molecular λmax is red-shifted. Further, the high-throughput screening strategy was adopted to screen out 26 azo molecules with larger λmax from nearly 20,000 virtual samples. These molecular λmax are expected to be red shifted from the 610 nm in the dataset. Our study provides a convenient way to search for azo dyes with larger λmax.

Synthesis, characterization and theoretical studies of the photovoltaic properties of novel bifunctional reactive disperse dyes based on aminothiazole derivatives

This article comprises synthesis and characterization of two polyfunctional diazo reactive-disperse dyes with aminothiazole moiety for application in dye-sensitized solar cells (DSSC). The characterization techniques employed were Gas chromatography-mass spectrometry (GC-MS), Fourier-transform infrared spectroscopy (FT-IR), Ultraviolet-visible spectroscopy (UV-vis), and Nuclear magnetic resonance (NMR) to determine the different functional groups, molecular connectivities and molecular weight of the various fragments of the synthesized dyes. Theoretical Density Functional Theory (DFT) and Time-Dependent TD-DFT calculations were performed using B3LYP/6-311+g(d,p). It can be observed that the HOMO energy levels of the respective dyes have lower values than I−/I3− redox couple level (around -4.80 eV) in the four different phases studied, which is crucial for the regeneration of the oxidized dye molecule and efficient charge separation. Furthermore, the HOMO-LUMO energy gaps of DYES F and S are within the range 2.38-5.40 eV, where all LUMO-CB of TiO2 energy gap values are sufficient for generating enough driving force for effective electron injection. The promising results of Light-harvesting efficiency (LHE) (values ranging from 0.81 to 0.89 except for DYE S in chloroform phase where it has an unusual value of 0.21) and Open-circuit voltage (VOC) values gotten compared with other organic, and natural sensitizers were due to the better interaction between the carboxyl and carbonyl groups of aryl azo molecule joined to the thiazolyl nucleus and the surface of TiO2 permeable film. DYE S exhibits the lowest band gap (2.374eV), which designates the highest chemical activity of the two dyes. Results from the quantum theory of atoms-in-molecules indicate that DYES F and S exhibit additional stability due to their relatively high H-bond interactions as well as certain additional intra-atomic bonds among the atoms of the investigated compounds. The outcome of the Natural bond orbital (NBO) analysis suggests that the strongest charge transfer occurs in DYE S as compared to DYE F. The types and modes of excitations for the first five excited states of the synthesized dyes were observed from the results of the hole-electron excitation analysis. First hyperpolarizability values of the dye F and dye S were determined to be 47.24 and 46.90 times the hyperpolarizability value of urea, demonstrating its excellent non-linear optical (NLO) response.

Physicochemical Properties of a Bi-aromatic Heterocyclic-Azo/BSA Hybrid System at the Air-Water Interface.

The interaction of a heterocyclic azo compound with itself and with bovine serum albumin (BSA) is realized by probing the structural modifications in Langmuir (L) monolayers and Langmuir–Blodgett (LB) films. It was found from the pressure–area/molecule isotherms that the elastic, thermodynamic, and hysteretic properties of the pure azo L monolayer were strongly altered due to the variation of temperature and pH of subphase water. In addition to that, the modification of such properties of the azo L monolayer due to mixing with BSA was also studied. The incorporation of BSA within the azo molecular assembly reduced the elasticity of that assembly. Such reduction of in-plane elasticity of the pure azo monolayer can also be achieved by reducing the temperature and pH of subphase water without adding BSA. A reduction in area per molecule of the azo assembly at the air–water interface associated with the conformational change from horizontal to vertical orientation facilitating π–π interaction was observed with increase in temperature and pH of the subphase. Such parameters also affected the interactions between azo and BSA molecules within the azo/BSA binary system. The structures of pure azo and binary films can be determined after they are transferred to hydrophilic and hydrophobic Si surfaces using the LB technique. Their out-of-plane and in-plane structures, as extracted from two complementary surface sensitive techniques, X-ray reflectivity and atomic force microscopy, were found to be strongly dependent on mixing with BSA, subphase pH, temperature, and substrate nature.

Photoisomerization kinetics of a novel photoswitchable film based on methyl red doped with sodium hexachloroplatinate hosted in polyethylene oxide

AbstractThis work proposes a novel dopant material to improve the energy storage in azo molecules. Organometallic material with platinum base atom (sodium hexachloroplatinate (IV) (Na2PtCl6)) was used as a dopant material in polyethylene oxide‐methyl red (PEO‐MR) films. The photoisomerization kinetics, the energy storage, and the electrical conductivity distribution of PEO‐(MR‐Na2PtCl6) films are investigated and studied. In addition, the effect of Na2PtCl6 on the chemical and crystal structure is also premeditated. It can be concluded that adding Na2PtCl6 to PEO‐MR film improves the energy storage in the azo molecules. Therefore, the addition of Na2PtCl6 into PEO‐MR films can be proposed for different applications, especially in molecular solar thermal energy storage media.

All-optical modulation of quantum states by nonlinear metasurface

Metasurfaces have proven themselves an exotic ability to harness light at nano-scale, being important not only for classical but also for quantum optics. Dynamic manipulation of the quantum states is at the heart of quantum information processing; however, such function has been rarely realized with metasurfaces so far. Here, we report an all-optical dynamic modulation of the photonic quantum states using the nonlinear metasurface. The metasurface consists of a metallic nanostructure combined with a photoisomerizable azo layer. By tuning the plasmonic resonance through optically switching the azo molecules between their binary isomeric states, we have realized dynamic control of transmission efficiencies of orthogonally polarized photons and also the phase delay between them, thereby an entangled state was efficiently controlled. As an illustration, a quantum state distillation has been demonstrated to recover a Bell state from a non-maximally entangled one to that with fidelities higher than 98%. Our work would enrich the functions of the metasurface in the quantum world, from static to dynamic modulation, making the quantum metasurface going practical.