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Substrate transport within biological tissues is diverse, with the most fundamental process being transport across cell membranes, which plays a crucial role in sustaining life. In this study, an artificial substrate transport system based on hydrogels by utilizing molecular recognition and stimuli‐responsive substrates is developed. α‐ and β‐Cyclodextrins are selected as host molecules, while adamantane serves as the guest molecule, enabling the adhesion of two hydrogels through self‐assembly. Under light stimulation, the light‐responsive dye, azobenzene derivative, is transported between the two hydrogels. This research provides new insights into the development of light‐controlled substance transport systems, which can be applied to biological substance delivery and the creation of smart materials. [ABSTRACT FROM AUTHOR]

This study investigates the photoresponsive behavior of substituted azobenzenes with a specific focus on their nonlinear optical response. This study suggests that azoimidazole substitution is a better alternative to azobenzene derivatives for nonlinear optical responses. The synthesis, characterization, photophysical property and isomerization pathway of 2-[(E)-(4-fluorophenyl)diazenyl]-1H-imidazole (E-2g) are presented as an optical limiter through a comprehensive blend of experimental and theoretical approaches. Notably, E-2g exhibited a lower energy barrier than reported azobenzenes. The trans-to-cis photostationary state was reached in 75 min, while the cis-to-trans state was achieved in 60 min at 354 nm. The study further explores the photoisomerization pathway of E-2g, highlighting its nonlinear absorption, which has a nonlinear absorption coefficient (βeff) of 8.8 × 10–11 m/W at 20 μJ, as determined by Z-scan measurements. The results suggest that E-2g exhibits significant nonlinear absorption characteristics, which helps in applications requiring protection from intense light sources. [ABSTRACT FROM AUTHOR]

The reactions occurred at excited states are promising and flourished. Many strategies have been discovered reactions initiated by visible light and without transition metals and organic dyes. Diboron ester (B2cat2) has special activity towards unsaturated bonds at excited states. In this work, azobenzene and derivatives are reduced to hydrazo with high yield and high selectivity by a very convenient and rapid reaction. Only three factors, B2cat2, water and 400 nm lighting or sunlight are necessary. Density functional theory (DFT) studies and NMR results show that azobenzene is excited and a trans to cis isomerization occurs under 400 nm and B2cat2 reacts with cis azobenzene through B−B bond cleavage rather than with ground state trans azobenzene. Hydrazo compounds are obtained after hydrolysis with water. Gram level hydrazobenzenes are obtained under sunlight with moderate yields. This strategy is benefit to sustainable chemistry. [ABSTRACT FROM AUTHOR]

In supramolecular chemistry, photostimulants are generally combined with a static solution under thermodynamic equilibrium with no time progression. After reaching the thermodynamic state, self‐assembly events contain various species–a mixture of component molecules, intermediate species, and completed assemblies–which light reaches uniformly. In this study, snapshot control of supramolecular polymerization was first combined with pinpoint photoirradiation using a microflow system. Employing the azobenzene derivative trans‐C3NO as a monomer, a snapshot moment of supramolecular polymerization along a microflow channel was selectively irradiated with UV light at 365 nm in a space‐resolved manner, so that the monomers, intermediates (oligomers), or extended supramolecular polymers were selectively exposed to light stimuli. We found that a pinpoint photostimulus to each snapshot moment had a pronounced effect on the kinetic pathway by tuning the timing at which the snapshot moment of cis‐C3NO was generated. Upon irradiation in the upstream region, in the very early stages before initiating polymerization, supramolecular polymerization was suppressed by generating a less reactive cis‐C3NO monomer. However, photoirradiation does not affect the supramolecular polymers in the downstream region because of their stiff nature. Remarkably, when irradiating the middle stream region involving a soft‐natured intermediate species, supramolecular copolymerization occurred through in situ conversion from trans‐ and cis‐C3NO inside the primitive supramolecular polymer. Loose monomer stacking in the primitive aggregate endows it with mechanoresponsiveness. Under the influence of shear force in a Hagen–Poiseuille flow, the resultant supramolecular copolymers containing geometrically different cis‐isomers were rolled up and transformed into a micrometer‐sized disk‐like structure. During the in situ supramolecular copolymerization and transformation to the disk structure, a liquid–liquid interface generated in the laminar flow acted as a template to fix the orientation of the monomers and supramolecular polymers, leading to the uniform disk formation. Furthermore, monomers' orientation in the aligned supramolecular polymers are fixed on the interface, on which light is always irradiated in an anisotropic manner. This results in both complexity at the molecular level and long‐range structural order such as regular rolling up at the micrometer range over the molecular scale. By incorporating the photostimulus system, microflow extends its potential for supramolecular chemistry. [ABSTRACT FROM AUTHOR]

The activation of inert C–H bonds remains a challenge in current chemistry. Here, we report the excellent reactivity of the anionic gallylene species [LGa:][Na(THF)3] (L = [(2,6-iPr2C6H3)NC(CH3)]22−, 1) that allows the selective activation one ortho sp2 C–H bond of several azobenzene and azide derivatives at ambient temperature, with the transfer of the hydrogen atom to one of the nitrogen atoms. The process leads to the formation of the aryl amido products [LGa-κ2N,C-PhNN(H)(p-R-C6H3)][Na(solvent)3] (2, R = H solvent = DME (1,2-Dimethoxyethane); 3, R = –OMe, solvent = DME; 4, R = –NMe2 solvent = THF), [LGa-κ2N,C-(m-CH3-C6H4)NN(H)(m-CH3-C6H3)][Na(15-C-5)2] (5) with new Ga–C and Ga–N bonds. Moreover, 1 is also effective for the C–H activation of two azides RN3 (R = 2,4,6-Me3C6H2 or 2,6-iPr2C6H3), resulting in the formation of gallium amides [LGa(NH-2-(CH2)-4,6-Me2C6H2)][Na(15-C-5)2] (6) and [LGa(NH-2,6-iPr2C6H3)2][Na(THF)5] (7) through intra- or intermolecular sp3 C–H amination. Significantly, these reactions occur for the highly challenging activation of inert C(sp2)–H and C(sp3)–H bonds, thus demonstrating the excellent reactivity of the Ga(I) species 1. The products 2–7 were characterized by X-ray crystallography, 1H and 13C NMR, UV–vis spectroscopy, and density functional theory (DFT) calculations. [ABSTRACT FROM AUTHOR]

Developing hydroscopic actuators with simultaneous high elasticity, shape programmability and tunable actuating behaviors are highly desired but still challenging. In this study, we propose an orthogonal composite design to develop such a material. The developed composite elastomer comprises carboxyl group-grafted polystyrene-block-poly(ethylene-co-butylene)-block-polystyrene (SEBS-g-COOH) as the elastic substrate, and a synthesized azobenzene derivative as the functional filler (Azo12). By surface treatment using acidic and base solutions, the carboxyl groups on the surface can reversibly transform into carboxylate groups, which render the composite tunable hygroscopic actuating functionality. On another aspect, the added filler undergoes trans-to-cis isomerization when exposed to UV light irradiation, leading to liquefaction of the crystalline aggregates formed by Azo12 molecules. The liquefied Azo12 molecules can autonomously resotre their trans form and reform the crystalline structure. This reversible change in crystralline structure is utilized to realize the shape memory property, and 5 wt% of Azo12 addition is adequate for the composite to exhibit photo-responsive shape memory behavior without compromising much of the elasricity. The regualtion of external geometry by shape memory effect is effective in altering the actuating behavior. The proposed method can be extend to designing different composites with the demonstrated functionalities. [ABSTRACT FROM AUTHOR]

Molecular photoswitches provide interesting tools to reversibly control various biological functions with light. Thanks to its small size and easy introduction into the biomolecules, azobenzene derivatives have been widely employed in the field of photopharmacology. All visible‐light switchable azobenzenes with controllable thermostability are highly demanded. Based on the reported tetra‐o‐chloroazobenzenes, we synthesized push‐pull systems, by introducing dialkyl amine and nitro groups as strong electron‐donating and electron‐withdrawing groups on the para‐positions, and then transformed to push‐push systems by a simple reduction step. The developed push‐pull and push‐push tetra‐o‐chloroazobenzene derivatives displayed excellent photoswitching properties, as previously reported. The half‐life of the Z‐isomers can be tuned from milliseconds for the push‐pull system to several hours for the push‐push system. The n‐π* and π‐π* transitions have better resolution in the push‐push molecules, and excitation at different wavelengths can tune the E/Z ratio at the photostationary state. For one push‐pull molecule, structure and absorption spectra obtained from theoretical calculations are compared with experimental data, along with data on the push‐push counterpart. [ABSTRACT FROM AUTHOR]

This paper proposes a molecular model of covalent grafting of azobenzene derivatives with graphite-like carbon nitride based on hydrogen bond regulation to improve the azobenzene photothermal energy storage density. The enthalpy of isomerization (Δ H) of azobenzene molecular cis - trans isomers is calculated using density functional theory, and the magnitude of Δ H is used to evaluate the photothermal storage performance of the azobenzene graphite-like carbon nitride model. The results showed that the molecular Δ H value increased by 0.105–0.243 eV after the azobenzene derivatives were covalently grafted to the graphitic carbon nitride template. In addition, when the donator group replaced the active benzene ring ortho-site of azobenzene, its value was 0.069–0.295 eV higher than that of the electron-withdrawing groups. Moreover, intramolecular hydrogen bonds can stabilize cis - trans isomers and increase the energy of azobenzene. Compared with unsubstituted azobenzene, the energy of azobenzene Δ H containing one intramolecular hydrogen bond increased by 0.295 eV, while the energy of azobenzene Δ H containing multiple intramolecular hydrogen bonds increased by 0.775 eV. [Display omitted] • A molecular model for covalent grafting of azobenzene onto g-C 3 N 4 with hydrogen bond was developed. • The energy conversion density of azobenzene synthetic was determined using density functional theory. • The grafting effect was evaluated by considering intramolecular hydrogen bond, substitution location, and electron group. [ABSTRACT FROM AUTHOR]

Compounds from the homologous series of (E)-4-[(4-heptyloxyphenyl)diazenyl]phenyl alkanoates (7OABOOCm) for m = 1–19, were synthesised. The phase behaviour was investigated by differential scanning calorimetry, polarised light (optical) microscopy, and thermo-optical analysis. The enantiotropic nematic, smectic C and crystal G phases were found for derivatives with m = 1–18, m = 7–17, and m = 4, respectively. In addition, during cooling, smectic F, crystal G, and unknown X phases were observed for derivatives with m = 7–9, m = 3,8,9, and m = 4, respectively. The X-ray diffraction results suggest that the X phase is presumably monotropic crystal H or a second crystal phase. The E–Z photoisomerisation process was observed during UV light irradiation. A photostationary state was reached after exposure time equal to approximately 80 s. The derived kinetic constant k of this process was of the order of 10−2 s−1. [ABSTRACT FROM AUTHOR]

Azobenzene compounds are putative solar thermal fuels (STF) due to the excellent photostability and structural control of isomerization rates. Azobenzenes, in which both Z‐ and E‐isomers are liquid at room temperature, are promising candidates for STF flow technology. A literature survey of melting points led to the synthesis and isomer separation of ortho‐ and meta‐monosubstituted azobenzenes with fluoro, methyl, ethyl, trifluoromethyl and methoxy substituents and several dimethyl substituted azobenzenes. Four of the compounds are liquid azobenzenes with higher specific energy than literature work with higher molar mass, liquid compounds. Eight of the compounds unexpectedly displayed a higher melting point for the Z‐isomer which is rarely observed. Intermolecular close contacts in the crystal lattice of the Z‐isomer are the main factor responsible for the higher melting temperatures. [ABSTRACT FROM AUTHOR]

Among azobenzene derivatives, azothiophenes represent a relatively recent family of compounds that exhibit similar characteristics as dyes and photoreactive systems. Their technological applications are extensive thanks to the additional design flexibility conferred by the heteroaromatic ring. In this study, we present a comprehensive investigation of the structural and electronic properties of novel dyes derived from 3-thiophenamine, utilizing a multilevel approach. We thoroughly examined the potential energy surfaces of the E and Z isomers for three molecules, each bearing different substituents on the phenyl ring at the para position relative to the diazo group. This exploration was conducted through quantum chemistry calculations at various levels of theory, employing a continuum solvent model. Subsequently, we incorporated an explicit solvent (a dimethyl sulfoxide–water mixture) to simulate the most stable isomers using classical molecular dynamics, delivering a clear picture of the local solvation structure and intermolecular interactions. Finally, a hybrid quantum mechanics/molecular mechanics (QM/MM) approach was employed to accurately describe the evolution of the solutes' properties within their environment, accounting for finite temperature effects. [ABSTRACT FROM AUTHOR]

The structure and absorption properties of a series of azobenzene derivatives are investigated using the density functional theoretical methods. The study showed that π → π* transitions of azobenzene undergo red shift after mono- and di- substitutions at para positions. Considering the fact that o-fluoro and o-methoxy derivatives of azobenzene have long living cis isomers, the effect of ortho substitution on the excitation energies is examined. An investigation on the azo-protonation revealed prominent red shift for n → π* and π → π* transitions bringing both absorptions in visible region. The effect of substitution on the cis to trans thermal relaxation is also analysed. [ABSTRACT FROM AUTHOR]

ReaxFF reactive force fields have been parameterized for the ground and first excited states of azobenzene and its derivatives. In addition, an extended set of ab initio reference data ensures wide applicability, including to azosystems in complex environments. Based on the optimized force fields, nonadiabatic surface hopping simulations produce photoisomerization quantum yields and decay times of azobenzene, both in the gas phase and in n-hexane solution, in reasonable agreement with higher level theory and experiment. The transferability to other azo-compounds is illustrated for different arylazopyrazoles as well as ethylene-bridged azobenzene. Moreover, it has been shown that the model can be easily extended to adsorbates on metal surfaces. The simulation of the ring-opening of cyclobutene triggered by the photoisomerization of azobenzene in a macrocycle highlights the advantages of a reactive force field model. [ABSTRACT FROM AUTHOR]

The chemistry of light dipnictenes has been widely investigated in the last century with remarkable achievements especially for azobenzene derivatives. In contrast, distibenes and dibismuthenes are relatively rare and show very limited reactivity. Herein, we have designed a protocol using visible light to enhance the reactivity of heavy dipnictenes. Exploiting the distinctive π–π* transition, we have been able to isolate unique examples of dipnictene‐cobalt complexes. The reactivity of the distibene complex was further exploited using red light in the presence of a diazoolefin to access an unusual four‐membered bicyclo[1.1.0]butane analog, containing only a single carbon atom. These findings set the bases to a conceptually new strategy in heavy element double bonds chemistry where visible light is at the front seat of bond activation. [ABSTRACT FROM AUTHOR]

With the rapid development of intelligent materials in recent years, intelligent hydrophobic materials have become a new research direction, and hydrophobic surfaces with adjustable wettability have enormous application potential in many fields. Generally speaking, surface wettability is determined by the combined effect of surface chemical composition and surface morphology. Therefore, the photoresponsive wettability of azobenzene-modified surfaces can be achieved by constructing rough surface of micro-nano scale and reducing the surface free energy. In this paper, we synthesized two photo responsive hydrophobic azobenzene derivatives (AAAB-PFDT and UAAB-PFDT), characterized their structure, thermal degradation behavior, and microscopic morphology. The light conversion performance of the two materials in dispersion was also studied using a UV–Vis spectrometer. By depositing the materials on the glass slide, the measurements of the water contact angle (WCA) under different lighting conditions were performed, demonstrating that both materials exhibit excellent photoswitchable hydrophobicity and reversibility. [ABSTRACT FROM AUTHOR]

o‐Aminoazotoluene (OAT), capable of photoisomerization, and o‐vanillin, a potent comutagen, have been used to synthesize a new ligand, HL, [C6H4(CH3)N=NC6H3(CH3)N=CHC6H3(OH)(OCH3)], which, upon complexation with copper(II), results in a new copper(II) complex‐Cu(L)2, [Cu{C6H4(CH3)N=NC6H3(CH3)N=CHC6H3(OCH3)O}2]. Both HL and Cu(L)2 have been characterized by single‐crystal X‐ray diffraction measurements along with other analytical techniques, for example, IR spectroscopy, NMR spectroscopy, UV–Vis spectroscopy, elemental analysis and mass spectrometry. These compounds were tested with different in vitro anticancer assay as well as with in silico studies. A comparative study has been demonstrated on anticancer activity of HL and Cu(L)2 with the ligand HAZ, {C6H5N=NC6H4N=CHC6H3(OH)(OCH3)} and its Cu‐complex, [Cu(AZ)2, Cu{C6H5N=NC6H4N=CHC6H3(OCH3)O}2]. The sensing properties of HAZ, along with the synthesis and structural properties of both HAZ and Cu(AZ)2, have been reported by our group earlier. Cytotoxicity measurements on MCF7 cell lines show that Cu(L)2 and Cu(AZ)2 have higher anticancer activity than their corresponding ligands. The apoptotic effect of Cu‐complex was studied through nuclear fragmentation assay and AO/EB dual‐staining assay on MCF7 cell line. The IC50 value of Cu(L)2 in 0.01% DMSO/water after 24‐h treatment was found 4.2 μM, which is one of the lowest values with this response time compared to the other analogous anticancer compounds. Finally, we have evaluated the expression of hERα protein with respect to Cu‐complexes, and it was observed that Cu(L)2 caused more down‐regulation of hERα as compared to Cu(AZ)2. [ABSTRACT FROM AUTHOR]

Understanding the interactions between hosts and guests in two‐component systems remains a formidable challenge due to the diverse array of adjusting factors at play. Particularly intriguing within the realm of two‐component systems are those incorporating a photoswitchable molecule within a porous metal‐organic framework (MOF) host. In such configurations, the non‐covalently attached guest molecule undergoes distinct physicochemical changes influenced by factors like guest structure, guest density, and the shape of the MOF pores. In this study, fluorinated azobenzenes (Fx‐AZB) were introduced into the rigid UiO‐66 host, and the resulting optical properties were examined with a focus on the degree of fluorination. The photoisomers of all examined compounds exhibited remarkable stability under repetitive light exposure, showing no signs of fatigue. Moreover, both photoisomers remained stable at room temperature, defying the typical T‐type photochromism associated with azobenzenes. Most notably, all fluorinated azobenzene derivatives displayed nearly complete photoswitching upon exposure to visible light within the UiO‐66 MOF host. This positions these composite materials as leaders in the realm of azobenzene‐based switch@MOF systems. [ABSTRACT FROM AUTHOR]

We performed computational simulations of the photodynamics of a self-assembled monolayer (SAM) of an azobenzene derivative (azobiphenyl, ABPT) on a gold surface. An excitonic approach was adopted in a semiempirical framework, which allowed us to consider explicitly the electronic degrees of freedom of 12 azobenzene chromophores. The surface hopping scheme was used for nonadiabatic molecular dynamics simulations. According to our results for an all trans-ABPT SAM, the excitation energy transfer between different chromophores, very fast in the ππ∗ manifold, does not occur between nπ∗ states. As a consequence, the excitation transfer does not play an important role in the quenching of the azobenzene photoisomerization in the SAM (experimentally observed and reproduced by our calculations) which, instead, has to be attributed to steric effects. [ABSTRACT FROM AUTHOR]

The potential of azobenzene derivatives that can undergo photoinduced solid-to-liquid transition at room temperature has been demonstrated in many fields such as photo-actuators, energy storage and photo-switchable adhesives. However, both their natural yellowish colour and slow liquid-to-solid phase transition restoration limit their universality in applications. Here, a colourless N-benzylideneaniline derivative molecule with asymmetric side-group substitution (MCN) is synthesized. The small molecular crystal of MCN achieves a reversible photoinduced crystal-to-isotropic liquid transition at room temperature. Due to the short half-life of MCN metastable isomers, the phase transition restoration rate here is significantly faster than that of azobenzene derivatives. As a result, only a single wavelength light source is needed to achieve complete phase change control. The phase transition behaviour of MCN is in situ monitored by using a UV-vis absorption spectrometer in a time-driven mode and a polarizing optical microscope, and its phase transition mechanism is proposed. Furthermore, a smart glass with photo-switchable transmittance is developed by mixing an MCN crystal with a commercial liquid crystal (5CB). [ABSTRACT FROM AUTHOR]

Irradiation of azobenzene-containing polymer materials with light causes cis–trans isomerization and reorientation of azobenzene moieties and thereby changes in the optical properties of the materials. In this study, the film of poly(ethyl methacrylate) doped with the azobenzene derivative Disperse Red 1 (DR1) has been irradiated with the linearly polarized light of 546 nm. The time profiles of optical anisotropy and absorbance measured during irradiation have been analyzed using a kinetic model. Based on the analysis of the time profiles, we conclude that the light-induced reorientation of DR1 molecules occurs in confined environments where trans → cis isomerization is hindered, while in roomy environments, there is no reorientation. In the confined environment, reorientation occurs due to the environmental changes caused by the isomerization attempts of the DR1 molecule. The polymer environment affects thermal cis → trans and light-induced trans → cis isomerizations of the DR1 molecule differently, suggesting that the spatial requirements for these processes to proceed are different. The thermal isomerization does not result in the reorientation of DR1 molecules in roomy environments. [ABSTRACT FROM AUTHOR]

When exposed to light at a specific wavelength, azobenzene and its derivatives experience a transformation from trans form to cis form through isomerization. Due to its ability to change color upon illumination, azobenzene finds extensive use in various molecular devices and functional materials. However, despite significant researches focused on practical applications, there are still ongoing investigations into the underlying mechanisms governing azobenzene's photochemical reactions and isomerization. In this study, we employ femtosecond stimulated Raman spectroscopy (FSRS), and transient absorption spectroscopy, in conjunction with quantum chemical calculations, to elucidate the ultrafast isomerization dynamics of an azobenzene derivative known as trans-AZOTIPS ((E)-1-phenyl-2-((triisopropylsilyl)ethynyl)diazene). The results demonstrate that upon photoexcitation, rapid isomerization occurs along the C−N=N bonds via the singlet excited state S1 to hot ground state ( S 0 * ) state transition. Additionally, we explore the impact of solvent viscosity on the isomerization process and find that the duration of isomerization remains unaffected by variations in solvent viscosity. These results suggest that the isomerization pathway involves a volume-conserving motion known as "hula twist". After that, the vibrational cooling process is obtained in S0 state. [ABSTRACT FROM AUTHOR]

This report describes the synthesis of a pseudo‐tetrahedral chromium alkyne complex supported by a bidentate phosphinimide ligand and its reactivity with an azobenzene derivative. Characterization of the former by structural and computational methods reveals an unprecedented extent of alkyne activation by a formal chromium(II) center, suggesting that this complex is best described as a chromium(IV)‐metallocyclopropene. Exposure of this compound to 4,4′‐difluoroazobenzene results in the formation of a chromium(VI) diimido complex, which constitutes a rare 4‐electron oxidative addition of an N=N double bond. The isolation of a chromium(IV)‐hydrazido intermediate enabled mechanistic investigations of this challenging bond cleavage process. This work substantiates the notion that terminal phosphinimide ligands can engender first‐row transition metal ions with exceptional reactivity. [ABSTRACT FROM AUTHOR]

Controllable and on‐demand delivery of supramolecular systems have received considerable attention in modern agricultural management, especially for managing intractable plant diseases. Here, an intelligent photoresponsive pesticide delivery system is reported based on β‐cyclodextrin (β‐CD) and azobenzene, which overcomes the resistance of phytopathogens caused by the irrational use of conventional pesticides. Antibacterial bioassays illustrated that designed azobenzene derivative 3a possesses the most efficient bioactivity with EC50 values of 0.52–25.31 µg mL−1 toward three typical phytopathogens. Moreover, the assembly of the supramolecular binary complex 3a@β‐CD is successfully elucidated and displays exceptional inhibitory activity on biofilm formation. Of note, this supramolecular binary complex significantly improves the water solubility, foliar surface wettability, and shows marked light‐responsive properties. In vivo anti‐Xoo assays reveal that 3a@β‐CD has excellent control efficiency (protective activity: 51.22%, curative activity: 48.37%) against rice bacterial blight pathogens, and their control efficiency can be elevated to values of 55.84% (protective activity) and 52.05% (curative activity) by UV–vis exposure. In addition, the 3a@β‐CD are non‐toxic toward various non‐target organisms. This study therefore offers new insights into the potential of host‐guest complexes as a feasible pesticide discovery strategy characterized by a safe, biocompatible, light‐responsive release, and antibiofilm properties for overcoming intractable plant bacterial diseases. [ABSTRACT FROM AUTHOR]

Glutamate ionotropic receptors mediate fast excitation processes in the central nervous system of vertebrates and play an important role in synaptic plasticity, learning, and memory. Here, we describe the action of two azobenene-containing compounds, AAQ (acrylamide–azobenzene–quaternary ammonium) and QAQ (quaternary ammonium–azobenzene–quaternary ammonium), which produced rapid and fully reversible light-dependent inhibition of glutamate ionotropic receptors. The compounds demonstrated voltage-dependent inhibition with only minor voltage-independent allosteric action. Calcium-impermeable AMPA receptors had weaker sensitivity compared to NMDA and calcium-permeable AMPA receptors. We further revealed that the compounds bound to NMDA and calcium-permeable AMPA receptors in different modes. They were able to enter the wide selectivity filter of AMPA receptors, and strong negative voltages caused permeation into the cytoplasm. The narrow selectivity filter of the NMDA receptors did not allow the molecules to bypass them; therefore, QAQ and AAQ bound to the shallow channel site and prevented channel closure by a foot-in-the-door mechanism. Computer simulations employing available AMPA and NMDA receptor structures readily reproduced the experimental findings, allowing for the structure-based design of more potent and selective drugs in the future. Thus, our work creates a framework for the development of light-sensitive blockers of calcium-permeable AMPA receptors, which are desirable tools for neuroscience. [ABSTRACT FROM AUTHOR]

Neoadjuvant chemotherapy has become an indispensable weapon against high-risk resectable cancers, which benefits from tumor downstaging. However, the utility of chemotherapeutics alone as a neoadjuvant agent is incapable of generating durable therapeutic benefits to prevent postsurgical tumor metastasis and recurrence. Herein, a tactical nanomissile (TALE), equipped with a guidance system (PD-L1 monoclonal antibody), ammunition (mitoxantrone, Mit), and projectile bodies (tertiary amines modified azobenzene derivatives), is designed as a neoadjuvant chemo-immunotherapy setting, which aims at targeting tumor cells, and fast-releasing Mit owing to the intracellular azoreductase, thereby inducing immunogenic tumor cells death, and forming an in situ tumor vaccine containing damage-associated molecular patterns and multiple tumor antigen epitopes to mobilize the immune system. The formed in situ tumor vaccine can recruit and activate antigen-presenting cells, and ultimately increase the infiltration of CD8+ T cells while reversing the immunosuppression microenvironment. Moreover, this approach provokes a robust systemic immune response and immunological memory, as evidenced by preventing 83.3% of mice from postsurgical metastasis or recurrence in the B16–F10 tumor mouse model. Collectively, our results highlight the potential of TALE as a neoadjuvant chemo-immunotherapy paradigm that can not only debulk tumors but generate a long-term immunosurveillance to maximize the durable benefits of neoadjuvant chemotherapy.

Azo compounds are efficient electron acceptors. Upon one‐electron reduction they generally isomerize forming the thermodynamically most stable radical anion. Herein we show that the size of the central ring in 1,2‐diazocines and diazonines has a ruling influence on the configuration of the one‐electron reduced species. Markedly, diazonines, which bear a central nine membered heterocycle, show light‐induced E/Z isomerization, but retain the configuration of the diazene N=N moiety upon one‐electron reduction. Accordingly, E/Z isomerization is not induced by reduction. [ABSTRACT FROM AUTHOR]

Herein we report the synthesis of nonsymmetrically substituted azobenzene derivatives with meta -alkyl substituents on one side and meta -aryl moieties with electron-donating or electron-withdrawing groups on the other side. The half-lives for the thermal (Z)- to (E)-isomerization of these molecules were measured in n -octane, which allows investigation of the strength of the aryl–alkyl interactions between their substituents. It was found that the London dispersion donor strength of the alkyl substrate is the decisive factor in the observed stabilization, whereas the electronic structure of the aryl fragment does not influence the isomerization in a significant way. [ABSTRACT FROM AUTHOR]

Azobenzene derivatives are a unique class of photo-switch molecules with promising potential for nanoscale optical applications. We have studied the self-assembly and photo-induced mechanical switching of azobenzene derivatives on Au(111) at the single-molecule level by using scanning tunneling microscope (STM). 4,4′-Dibromo-azobenzene (Br-AB) molecules are assembled into two types of well-ordered structures on Au(111) surfaces in the trans-isomer configuration. Br-AB molecules experienced configurational changes from trans-to-cis photo-isomerization upon the exposure to the UV light. This photo-isomerization of Br-AB molecules was observed to occur at random sites of ordered structure, evidenced by the appearance of bright protrusions with the height increment. Our results may open up new routes to engineer nanoscale photo-switch molecular devices. [ABSTRACT FROM AUTHOR]

We present a toolkit that allows for the preparation of QM/MM input files from a conformational ensemble of molecular geometries. The package is currently compatible with trajectory and topology files in Amber, CHARMM, GROMACS and NAMD formats, and has the possibility to generate QM/MM input files for Gaussian (09 and 16), Orca (≥4.0), NWChem and (Open)Molcas. The toolkit can be used in command line, so that no programming experience is required, although it presents some features that can also be employed as a python application programming interface. We apply the toolkit in four situations in which different electronic‐structure properties of organic molecules in the presence of a solvent or a complex biological environment are computed: the reduction potential of the nucleobases in acetonitrile, an energy decomposition analysis of tyrosine interacting with water, the absorption spectrum of an azobenzene derivative integrated into a voltage‐gated ion channel, and the absorption and emission spectra of the luciferine/luciferase complex. These examples show that the toolkit can be employed in a manifold of situations for both the electronic ground state and electronically excited states. It also allows for the automatic correction of the active space in the case of CASSCF calculations on an ensemble of geometries, as it is shown for the azobenzene derivative photoswitch case. [ABSTRACT FROM AUTHOR]

The development of new approaches to suppressing cardiac arrhythmias requires a deep understanding of spiral wave dynamics. The study of spiral waves is possible in model systems, for example, in a monolayer of cardiomyocytes. A promising way to control cardiac excitability in vitro is the noninvasive photocontrol of cell excitability mediated by light-sensitive azobenzene derivatives, such as azobenzene trimethylammonium bromide (AzoTAB). The trans-isomer of AzoTAB suppresses spontaneous activity and excitation propagation speed, whereas the cis isomer has no detectable effect on the electrical properties of cardiomyocyte monolayers; cis isomerization occurs under the action of near ultraviolet (UV) light, and reverse isomerization occurs when exposed to blue light. Thus, AzoTAB makes it possible to create patterns of excitability in conductive tissue. Here, we investigate the effect of a simulated excitability gradient in cardiac cell culture on the behavior and termination of reentry waves. Experimental data indicate a displacement of the reentry wave, predominantly in the direction of lower excitability. However, both shifts in the direction of higher excitability and shift absence were also observed. To explain this effect, we reproduced these experiments in a computer model. Computer simulations showed that the explanation of the mechanism of observed drift to a lower excitability area requires not only a change in excitability coefficients (ion currents) but also a change in the diffusion coefficient; this may be the effect of the substance on intercellular connections. In addition, it was found that the drift direction depended on the observation time due to the meandering of the spiral wave. Thus, we experimentally proved the possibility of noninvasive photocontrol and termination of spiral waves with a mechanistic explanation in computer models. [ABSTRACT FROM AUTHOR]

Neoadjuvant chemotherapy has become an indispensable weapon against high-risk resectable cancers, which benefits from tumor downstaging. However, the utility of chemotherapeutics alone as a neoadjuvant agent is incapable of generating durable therapeutic benefits to prevent postsurgical tumor metastasis and recurrence. Herein, a tactical nanomissile (TALE), equipped with a guidance system (PD-L1 monoclonal antibody), ammunition (mitoxantrone, Mit), and projectile bodies (tertiary amines modified azobenzene derivatives), is designed as a neoadjuvant chemo-immunotherapy setting, which aims at targeting tumor cells, and fast-releasing Mit owing to the intracellular azoreductase, thereby inducing immunogenic tumor cells death, and forming an in situ tumor vaccine containing damage-associated molecular patterns and multiple tumor antigen epitopes to mobilize the immune system. The formed in situ tumor vaccine can recruit and activate antigen-presenting cells, and ultimately increase the infiltration of CD8+ T cells while reversing the immunosuppression microenvironment. Moreover, this approach provokes a robust systemic immune response and immunological memory, as evidenced by preventing 83.3% of mice from postsurgical metastasis or recurrence in the B16–F10 tumor mouse model. Collectively, our results highlight the potential of TALE as a neoadjuvant chemo-immunotherapy paradigm that can not only debulk tumors but generate a long-term immunosurveillance to maximize the durable benefits of neoadjuvant chemotherapy. A kind of reduction responsive tactical nanomissiles as neoadjuvant chemo-immunotherapy setting promoted the formation of in situ tumor vaccines and PD-1/PD-L1 pathway blockage, and successfully inhibited postoperative tumor recurrence and metastasis. [Display omitted] [ABSTRACT FROM AUTHOR]

The stimuli-responsive, low molecular weight, dynamically tunable photophysical features have long been an important objective that challenges chemists in synthesizing liquid crystal (LC) compounds. Herein, the effect of core fluorination on the mesomorphic behavior of fan-like azobenzene derivatives was reported. Two new series of azobenzene derivatives which differ from each other in the length of the terminal alkoxy side chain as well as fluorine (-F) group substitution on the azobenzene moiety were synthesized (3a-3c, 4a-4c) and molecular structures of the compounds were confirmed using various analytical techniques. Absorption spectra of the LC compounds 3b and 3c are characterized by ππ∗ transitions around 350–410 nm. The self-assembly of these LC compounds was investigated using polarized optical microscope (POM) and differential scanning colorimetry (DSC). The trans -to- cis photoisomerization of the LC compounds 3b and 3c occurs in these absorption bands. The trans -to- cis photoisomerization of LC compounds 3b and 3c showed 4 h and 24.5 h whereas, thermal cis -to- trans isomerization rates were found to be 90s and 100s resulting in tuning of mesophases. Room temperature photoluminescence (RTPL) of LC compounds 3b and 3c when excited at 220 nm, 230 nm and 240 nm showed several sharp/weak emission intensity bands. Both the LC compounds (3b, 3c) showed sharp blue emission bands and yellow/green/orange colored bands correspond to weak emission spectra when excited at 220 nm. Further, steady state photoluminescence (SSPL) spectra of these both LC compounds revealed sharp near edge emission bands and broad violet emission peaks with higher Stoke's shift as well as full width half maximum (FWHM). Fluorescence lifetime decay (FLD) studies of compound 3 b unveiled an average lifetime (τ) shuttle between 17.24 ns and 103.60 ns at various excitation wavelengths. However, FLD of LC compound 3c unveiled that the τ fluctuates between 27.00 ns and 102.56 ns at various excitation wavelengths. Quantum yield (QY) decreases for both the LC compounds with an increase in excitation wavelengths. The study proved the importance of the alkoxy side chain at one end of the aromatic ring and core fluorination as a significant tool to modify the LC behavior of azobenzene derivatives. Thus, synthesized azobenzene derivatives are potentially useful for developing permanent optical storage and display devices. [Display omitted] • A new series of azobenzene derivatives with terminal alkoxy side chains were synthesized. • Self-assembly and textures of LC compounds 3b and 3c were investigated using POM and DSC. • Photoisomerization times for LC compounds 3b and 3c were found to be 4 h and 24.5 h, respectively, with thermal back relaxation times of 90 s and 100 s. • Emission properties of LC compounds 3b and 3c included sharp and weak intensity peaks under RTPL and multicolor emissions (blue, yellow, green, orange) under SSPL. • LD for LC compounds 3b and 3c ranged between 17.24 ns to 103.60 ns and 27.00 ns to 102.56 ns, respectively, with QY decreasing as excitation wavelengths increased. [ABSTRACT FROM AUTHOR]

The study demonstrates the influence of ethanol as a stabilizer in chloroform on the thermal cis-trans isomerization kinetics of photochromic compounds based on azobenzene and azopyridine derivatives. The significance of the addition of ethanol as a stabilizer in chloroform-based solutions on the isomerization reaction of the hydroxy- and the 6-hydroxylalkoxy-substituted azo compounds was investigated. The results have revealed that the presence of a polar stabilizer in a solvent can significantly reduce the reaction rate constant of the dark cis-trans isomerization due to the formation of hydrogen bonds at both ends of the azo-chromophore, thereby inhibiting the isomerization. Furthermore, a stabilizer can facilitate the reversion of azo-hydrazone tautomers of azophenols to their azobenzene form, resulting in a decrease in the reaction rate constant. The research presented in this paper can be essential for scientists who study the kinetics of the trans-cis and the cis-trans isomerization reactions of azo-chromophores. The results show that the use of solvents with polar stabilizers should be rather avoided, as their usage without information about stabilizers can lead to different experimental data. The authors should ensure that detailed information about stabilizers used in unstable solvents is included in the experimental section of their works (a detail currently often omitted in the literature). [Display omitted] • The kinetics of the trans -cis and cis -trans isomerization of azodyes in unstable solvents can be affected by the addition of a polar stabilizer. • The thermal cis - trans isomerization of azophenols in chloroform is hindered by the presence of ethanol stabilizer. • 1H NMR spectra showed the presence of hydrogen bonds between azocompounds and chloroform stabilizer molecules. • Azophenols transform to azo-hydrazone forms detected by 1H NMR spectra. [ABSTRACT FROM AUTHOR]

The physicochemical properties of light-responsive polymers have attracted widespread attention due to their ability to be precisely and conveniently modulated by light without additives or contact. Here, we report a thermo/light dual-responsive polymer, PNMA, synthesized through the free radical copolymerization of azobenzene derivative (mAzo) and N -isopropylacrylamide (NIPAM) monomers. By switching between 365 nm UV light and 450 nm visible light, the E / Z photoisomerization of the light-responsive mAzo can be reversibly controlled, and thereby adjusting the conformational changes of the PNMA polymer chain. Significantly, the stretching and contraction conformations of PNMA polymer chains can be manipulated by incorporating different types of cyclodextrins. A comprehensive comparative study was conducted to determine the light-controlled binding and dissociation processes between the azobenzene units and CDs (α -CD, β -CD and γ -CD), the influences of CDs on the photoisomerization kinetics and complexation constants of azobenzene with CDs, as well as the effect of CDs on the light-responsive phase transition behaviors of PNMA. Our results highlight the superior advantage of α -CD in constructing light-responsive systems with significant changes in hydrophilicity. Notably, by tuning the concentration of α -CD and the proportion of mAzo in PNMA, the range of light-induced thermosensitive response is significantly expanded. This study is the first to present a comparative study on the effects of three CDs on the thermo/light dual-responsive properties of polymer systems based on PNIPAM and azobenzene, providing new ideas for CD selection in the design and construction of advanced light-responsive materials based on light-responsive guest-host dissociation or hydrophilic changes of azobenzene/CD complexes. [Display omitted] • A thermo/light dual-responsive polymer based on PNIPAM and azobenzene is prepared. • PNMA/ α -cyclodextrin binary systems enable a light-responsive LCST shift within 20 °C. • Light-responsive host-guest interaction of PNMA/cyclodextrins is quantitatively studied. [ABSTRACT FROM AUTHOR]

Simulations based on molecular dynamics coupled to excitation energy calculations were used to generate simulated absorption spectra for a family of halide derivatives of azobenzene, a family of photoswitch molecules with a weak absorption band around 400–600 nm and potential uses in living tissue. This is a case where using the conventional approach in theoretical spectroscopy (estimation of absorption maxima based on the vertical transition from the potential energy minimum on the ground electronic state) does not provide valid results that explain how the observed band shape extends towards the low energy region of the spectrum. The method affords a reasonable description of the main features of the low-energy UV-Vis spectra of these compounds. A bathochromic trend was detected linked to the size of the halide atom. Analysis of the excitation reveals a correlation between the energy of the molecular orbital where excitation starts and the energy of the highest occupied atomic orbital of the free halide atom. This was put to the test with a new brominated compound with good results. The energy level of the highest occupied orbital on the free halide was identified as a key factor that strongly affects the energy gap in the photoswitch. This opens the way for the design of bathochromically shifted variants of the photoswitch with possible applications. [ABSTRACT FROM AUTHOR]

Heteroaryl azobenzene molecular switches often have superior performance compared to their parent azobenzene derivatives. Herein, we report the efficient photoswitching of phenylazopyridine 5‐methoxy‐2‐(2‐phenyldiazenyl)pyridine using 1H NMR and UV/vis spectroscopy demonstrating >92 % Z at the photostationary state and a thermal half‐life of 6.3 days at room temperature. Kinetic studies are in good agreement with the DFT predicted isomerization barrier. [ABSTRACT FROM AUTHOR]

Herein, density functional theory was used to study the isomerization mechanism of azobenzenesulfonamide at the ωB97XD/6-31G(d) level. The similarities and differences among the isomerization of single- and bi-molecular azobenzenesulfonamide derivatives with silicon substrates are discussed. The calculated results show that azobenzenesulfonamide (PhN1＝N2SO2NH2Ph) has two rotation-assisted inversion isomerism modes: N1 inversion and N2 inversion. These two isomerization pathways are closely related to the substituents on the benzene ring connected to the N1 atom. The stronger the electron-withdrawing ability of the substituent, the easier it is for the N1 inversion to occur. In addition, the cis–trans isomerization mechanism of a single molecular azobenzenesulfonamide derivative with a silicon substrate is similar to that without a silicon substrate. However, the isomerization pathway of a bi-molecular azobenzenesulfonamide derivative on a silicon substrate is different from that of single-molecule isomerization. Among them, the first molecular functional group of azobenzenesulfonamide undergoes N2 inversion, the second molecular functional group then adopts the N1 inversion mode, and the free energy barriers of isomerization of the two molecular functional groups are 26.88 and 13.99 kcal mol−1, respectively. This may be related to the steric hindrance of the groups in the conversion isomers. Interestingly, compared to the isomerization of the first and second azobenzenesulfonamide molecular functional groups, the energy barrier of the second group is significantly reduced. This will provide theoretical insights into the design of azobenzene and the action of its derivatives as molecular switches in polymerization systems. [ABSTRACT FROM AUTHOR]

In this study, amino‐functionalized mesoporous silica (MS) particles were synthesized and loaded with the anticancer drug, 5‐Fu. In a post‐modification reaction, the pores were gated by an azobenzene derivative to act as an enzyme‐responsive drug delivery system. The synthesis and characterization of the MS structure were validated using various instrumental techniques such as XRD, N2 adsorption/desorption, and FE‐SEM and TEM. The loading efficiency and capacity of 5‐Fu adsorption onto MS were evaluated; the adsorption isotherm graphs were plotted. The enzyme responsiveness feature of this nanocarrier was tested in the 5‐Fu release study. The 5‐Fu release from MS and the azo‐capped compound was measured, and when sodium dithionite was used as a reducing agent and an azoreductase enzyme mimicker, the controlled release was observed. Finally, the cytotoxicity of 5‐Fu loaded and azo‐capped MS in normal medium and sodium dithionate‐containing medium was evaluated and compared with the cytotoxicity of the free drug. [ABSTRACT FROM AUTHOR]

Drug nanoencapsulation increases the availability, pharmacokinetics, and concentration efficiency for therapeutic regimes. Azobenzene light-responsive molecules experience a hydrophobicity change from a polar to an apolar tendency by trans–cis photoisomerization upon UV irradiation. Polymeric photoresponse nanoparticles (PPNPs) based on azobenzene compounds and biopolymers such as chitosan derivatives show prospects of photodelivering drugs into cells with accelerated kinetics, enhancing their therapeutic effect. PPNP biocompatibility studies detect the safe concentrations for their administration and reduce the chance of side effects, improving the effectiveness of a potential treatment. Here, we report on a PPNP biocompatibility evaluation of viability and the first genotoxicity study of azobenzene-based PPNPs. Cell line models from human ventricular cardiomyocytes (RL14), as well as mouse fibroblasts (NIH3T3) as proof of concept, were exposed to different concentrations of azobenzene-based PPNPs and their precursors to evaluate the consequences on mitochondrial metabolism (MTT assay), the number of viable cells (trypan blue exclusion test), and deoxyribonucleic acid (DNA) damage (comet assay). Lethal concentrations of 50 (LC50) of the PPNPs and their precursors were higher than the required drug release and synthesis concentrations. The PPNPs affected the cell membrane at concentrations higher than 2 mg/mL, and lower concentrations exhibited lesser damage to cellular genetic material. An azobenzene derivative functionalized with a biopolymer to assemble PPNPs demonstrated biocompatibility with the evaluated cell lines. The PPNPs encapsulated Nile red and dofetilide separately as model and antiarrhythmic drugs, respectively, and delivered upon UV irradiation, proving the phototriggered drug release concept. Biocompatible PPNPs are a promising technology for fast drug release with high cell interaction opening new opportunities for azobenzene biomedical applications. [ABSTRACT FROM AUTHOR]

Cilia are of vital importance for myriad of natural functions such as the propulsion of microorganisms or the cleaning of the mammalian respiratory system. These cilia often show coupled 3D shape changes, such as waves, to perform their function. Here, we present a versatile platform to fabricate artificial micrometer‐sized azobenzene‐doped liquid crystal polymer cilia by replica molding from a track‐etched polyimide membrane. The cilia are tuneable in their size and show excellent homogeneity and high number densities over large areas. By electrically aligning the liquid crystal monomers in a splay alignment during photopolymerization, the symmetry in most cilia is broken, which allows them to reversibly bend toward a predetermined side when exposed to heat or UV light. When the applied stimulus is carefully controlled, the response can be tuned in speed and magnitude. Addressing both the trans‐ and cis‐isomers of the azobenzene derivative simultaneously makes the cilia oscillate out of plane continuously in a preprogrammed pattern with a frequency and amplitude of choice, without any obvious signs of fatigue. Thanks to the versatility of this cilia platform, a wide range of applications such as transporting loads in confined spaces, self‐cleaning surfaces, haptics, or energy generation is foreseen. [ABSTRACT FROM AUTHOR]

In this report, the design and synthesis of cholesterol-based sugar azobenzene derivatives as photo-responsive organogelators have been carried out. The gel formation in different solvents was examined, and a minimum CGC of 0.5 % (w/v) was attained in toluene. The mechanism of self-assembly of organogels was characterized by using 1H NMR, UV–Vis, FT-IR, and PXRD. These organogelators show photo-isomerization and photo-reversible properties, which were studied using absorption spectra. Computational studies studied the optimized dimer structures and geometries of the trans and cis isomers. The prominent nature of this designed structure makes it an outstanding, intelligent soft material with plausible applications. [Display omitted] [ABSTRACT FROM AUTHOR]

This study presents the synthesis, development, and comprehensive evaluation of a series of novel azobenzene derivatives – DMAC, DMAF, and DMAT – engineered with push-pull configuration by varying π-bridge substituents (benzene, furan, and thiophene, respectively). The research employs a combination of computational and experimental methods, including density functional theory (DFT) and time-resolved UV–Vis absorption spectroscopy, to explore the impact of these π-bridge modifications on the electronic, photophysical, and isomerization properties of the derivatives. Interestingly, the findings suggest that the π-bridge structure significantly influences the charge transfer characteristics, with DMAC exhibiting the most effective charge transfer and the highest photoisomerization efficiency. Time-resolved UV–Vis absorption spectroscopy demonstrates that all derivatives exhibit rapid initial E -to- Z isomerization upon light irradiation, followed by a slower approach to the photostationary state (PSS). Thermal Z -to- E isomerization kinetics are consistent with the activation energy barriers predicted by potential energy surface (PES) scans, with DMAC showing the slowest reversion due to its highest activation energy. This study contributes valuable insights into the structural influences on the photochemical dynamics of azobenzene derivatives, with implications for their applications in photoresponsive technologies. • Tailered push-pull azobenzene derivatives with diverse π-bridges were developed for tunable photophysical properties. • Unique photoisomerization behaviors were analyzed under irradiation and dark conditions. • Synthesized compounds were evaluated for photoresponsive uses in actinometry and photovoltaics. [ABSTRACT FROM AUTHOR]

• Dual-responsive resin enables shape changes via light and heat. • AZO-enhanced resin offers strong, flexible 3D structures. • UV resins with 4D printing reduce manufacturing costs. 4D printing, combining the advantages of 3D printing and stimuli-responsive materials, provides a precise and rapid fabrication method for complex-shaped smart objects. In this study, the photoisomerization characteristic of azobenzene is used to develop 4D printable resins composed of azobenzene-based acrylates (AZO) and other acrylate compounds, which can be UV-cured and 3D printed into objects with photo and thermal dual responsiveness. UV-curing kinetics reveal that AZO competes with the photoinitiator for photons during photopolymerization, reducing the generation of reactive oxygen species and subsequently affecting the mechanical properties of UV-cured resin. The optimum content of AZO in 4D printing resins is 0.5 wt%, producing 3D printed objects with excellent mechanical properties, including a maximum stress of 25.2 MPa and a strain of 100 %. This ensures the successful formation of complex-shaped objects in the 3D printing process. Moreover, the objects printed with this photosensitive resin demonstrate exceptional shape memory capabilities, achieving a 100 % shape recovery ratio over three cycles of thermal stimulation. The printed openwork spheroid with a concave shape can successfully revert to its original form after 48 s of irradiation with 365 nm UV light. The degree of shape recovery can be precisely controlled by adjusting the UV irradiation time and position. Therefore, these photo/thermal dual-responsive 4D objects show great application prospects in medical devices and smart materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • H-daa, F-daa, Cl-daa and Br-daa were calculated on b3lyp/g/def2-tzvp. • The transition states of H-TS-daa, F-TS-daa, C-TSl-daa and Br-TS-daa were found in the ground state. • The PESs of H-daa, F-daa, Cl-daa and Br-daa were calculated in S 0 , S 1 and S 2 , respectively. • The isomerization mechanisms are different in the ground state and excited state. This article investigates the geometric structure and isomerization mechanism of 4,4-acetamidazobenzene molecules with halogen atoms (F, Cl, Br) substituted at four ortho positions through density functional theory (DFT) calculations. The calculation method was b3lyp/g, and the base set was def2-tzvp. According to DFT calculations, the ortho substitution of the halogen atoms differently distorted the molecular plane of the trans isomers, resulting in obvious absorption peaks in the visible range, giving them visible-light driven properties. In addition, the transition state (TS) of the cis–trans isomerization reaction in the ground state was also found. To study the molecular isomerization mechanism, the potential energy surfaces (PESs) of the ground state (S 0), first excited state (S 1), and second excited state (S 2) of halogen substituted azobenzene derivatives were scanned separately. Through the potential energy surface curve of the ground state, the mechanism of isomerization reaction in the ground state of the four molecules is realized through a rotation-assisted inversion pathway, which is consistent with the calculation of TS. When the molecules are in the excited states, the isomerization pathways are realized through rotation pathways. [ABSTRACT FROM AUTHOR]

Light-induced chemical processes are ubiquitous in nature and have widespread technological applications. For example, photoisomerization can allow a drug with a photo-switchable scaffold such as azobenzene to be activated with light. In principle, photoswitches with desired photophysical properties like high isomerization quantum yields can be identified through virtual screening with reactive simulations. In practice, these simulations are rarely used for screening, since they require hundreds of trajectories and expensive quantum chemical methods to account for non-adiabatic excited state effects. Here we introduce a diabatic artificial neural network (DANN), based on diabatic states, to accelerate such simulations for azobenzene derivatives. The network is six orders of magnitude faster than the quantum chemistry method used for training. DANN is transferable to azobenzene molecules outside the training set, predicting quantum yields for unseen species that are correlated with experiment. We use the model to virtually screen 3100 hypothetical molecules, and identify novel species with high predicted quantum yields. The model predictions are confirmed using high-accuracy non-adiabatic dynamics. Our results pave the way for fast and accurate virtual screening of photoactive compounds. The authors introduce a diabatic neural network to accelerate excitedstate, non-adiabatic simulations of azobenzene derivatives. The model predicts quantum yields for unseen species that are correlated with experiment. [ABSTRACT FROM AUTHOR]