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Gold nanoparticles (AuNPs) have been synthesized directly inside liposomes using honey as a reducing agent. The obtained aggregates, named Cassyopea® Gold due to the method used for their preparation, show remarkable properties as reactors and carriers of the investigated AuNPs. A mean size of about 150 nm and negative surface charge of -46 mV were measured for Cassyopea® Gold through dynamic light scattering and zeta potential measurements, respectively. The formation of the investigated gold nanoparticles into Cassyopea® liposomes was spectroscopically confirmed by the presence of their typical absorption band at 516 nm. The catalytic activity of the combined liposome-AuNP nanocomposites was tested via the thermal cis-trans isomerization of resonance-activated 4-methoxyazobenzene (MeO-AB). The kinetic rate constants (kobs) determined at 25 °C in the AuNP aqueous solution and in the Cassyopea® Gold samples were one thousand times higher than the values obtained when performing MeO-AB cis-trans conversion in the presence of pure Cassyopea®. The results reported herein are unprecedented and point to the high versatility of Cassyopea® as a reactor and carrier of metal nanoparticles in chemical, biological, and technological applications.

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Astaxanthin (AST), the natural pigment in Litopenaeus vannamei, is susceptible to oxidation and isomerization, leading to the fading of the orange-red color in ready-to-eat (RTE) shrimps. This study specifically investigated the changes mechanism in AST content, including geometric and stereoisomers, as well as oxidation degradation, throughout the storage process of RTE shrimps. The results showed that the total amount of AST decreased by 46.76 % after 45 days of storage at 40 °C. The levels of geometric isomers (all-E, 9-Z, 13-Z) and stereoisomers (3S,3'S, 3S,3'R, 3R,3'R) gradually decreased over time. Notably, 9-Z and 3S,3'S isomers, known for their strong antioxidant activity, were reduced by 83.57 % and 61.64 % respectively. Additionally, AST underwent oxidative degradation, forming short-chain compounds (astaxanthinal or astaxanthinone), with the main products being Apo-14'-astaxanthinal and Apo-7-astaxanthinone DHA ester. These findings provide a theoretical foundation for further research on the degradation mechanism of AST, and offer valuable insights into the color protection of RTE shrimps.

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D-Glucose-to-L-sorbose isomerization on Lewis acidic zeolite is a highly attractive avenue for sorbose production. But the L-sorbose yield is limited by the competing D-glucose-to-D-fructose isomerization and reaction equilibrium. In this work, it is suggested that ethanol directs the glucose conformation for selective D-glucose-to-L-sorbose isomerization. It also reacts with the produced L-sorbose to form ethyl-sorboside, which allows the D-glucose-to-L-sorbose isomerization to proceed beyond the thermodynamic equilibrium limit.  It is shown that a bifunctional zeolite Beta containing framework titanium (Ti) and boron (B) is a selective catalyst for this tandem reaction: Lewis acidic framework Ti catalyzes the D-glucose-to-L-sorbose isomerization via an intramolecular 5,1-hydride shift process as confirmed by isotopic tracing experiments followed by 13C-NMR, while weak Brønsted acid framework B selectively promotes the sorbose ketalization with ethanol. A remarkably high yield of L-sorbose with a high fraction of sugar (>95%: 27% unreacted glucose, 11.4% fructose, 57% sorbose) was obtained after the mixture produced in ethanol was hydrolyzed.

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Isomerization, the process by which a molecule is coherently transformed into another molecule with the same molecular formula but a different atomic structure, is an important and well-known phenomenon of organic chemistry, but has only recently been observed for inorganic nanoclusters. Previously, CdS nanoclusters were found to isomerize between two end point structures rapidly and reversibly (the α-phase and ß-phase), mediated by hydroxyl groups on the surface. This observation raised many significant structural and pathway questions. One critical question is why no intermediate states were observed during the isomerization; it is not obvious why an atomic cluster should only have two stable end points rather than multiple intermediate arrangements. In this study, we report that the use of amide functional groups can stabilize intermediate phases during the transformation of CdS magic-size clusters between the α-phase and the ß-phase. When treated with amides in organic solvents, the amides not only facilitate the α-phase to ß-phase isomerization but also exhibit three distinct excitonic features, which we call the ß340-phase, ß350-phase, and ß367-phase. Based on pair distribution function analysis, these intermediates strongly resemble the ß-phase structure but deviate greatly from the α-phase structure. All phases (ß340-phase, ß350-phase, and ß367-phase) have nearly identical structures to the ß-phase, with the ß340-phase having the largest deviation. Despite these intermediates having similar atomic structures, they have up to a 583 meV difference in band gap compared to the ß-phase. Kinetic studies show that the isomers and intermediates follow a traditional progression in the thermodynamic stability of ß340-phase/ß350-phase < α-phase < ß367-phase < ß-phase. The solvent identity and polarity play a crucial role in kinetically arresting these intermediates. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy studies paired with simple density functional theory calculations reveal that the likely mechanism is due to the multifunctional nature of the amides that form an amphoteric surface binding bond motif, which promotes a change in the carboxylic acid binding mode. This change from chelating binding modes to bridging binding modes initiates the isomerization. We propose that the carbonyl group is responsible for the direct interaction with the surface, acting as an L-type ligand which then pulls electron density away from the electron-poor nitrogen site, enabling them to interact with the carboxylate ligands and initiate the change in the binding mode. The isomerization of CdS nanoclusters continues to be a topic of interest, giving insight into fundamental nanoscale chemistry and physics.

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Understanding the interfacial composition in heterostructures is crucial for tailoring heterogenous electrochemical and photoelectrochemical processes. This work aims to elucidate the structure of a series of Co-Fe Prussian blue analogue modified ZnO (PBA/ZnO) electrodes with interface-sensitive vibrational sum frequency generation (VSFG) spectroscopy. Our measurements revealed, for the first time, a cyanide linkage isomerism at the PBA/ZnO interface, when the composite is fabricated at elevated temperatures. In situ VSFG spectro-electrochemistry measurements correlate the CoII➝CoIII oxidation with the flip of the bridging CN ligand from Co-NC-Fe coordination mode to a Co-CN-Fe one.  Photoluminescence measurements and X-ray photoelectron spectroscopy reveal that this unprecedented linkage isomerism originates from surface defects, which act as oxidation sites for the PBA. The presence of such surface defects is correlated with the fabrication temperature for PBA/ZnO. Thus, this contribution identifies the interplay between the surface states of the ZnO substrates and the chemical composition of PBA at the ZnO surface, suggesting an easily accessible approach to control the chemical composition of the interface.

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Optically-controlled phase change materials, which are prepared by introducing molecular photoswitches into traditional phase change materials (PCMs), can convert and store solar energy into photochemical enthalpy and phase change enthalpy. However, the thermophysical properties of optically controlled PCMs, which are crucial in the practical, are rarely paid attention to. 4-(phenyldiazenyl)phenyl decanoate (Azo-A-10) is experimentally prepared as an optically-controlled PCMs, whose energy storage density is 210.0 kJ·kg-1, and the trans single crystal structure is obtained. The density, phase transition temperature, thermal conductivity, and other parameters in trans state are measured experimentally. Furthermore, a microscopic model of Azo-A-10 is established, and the thermophysical properties are analyzed based on molecular dynamics. The results show that the microstructure parameter (order parameters) and thermophysical properties (density, radial distribution function, self-diffusion coefficient, phase change temperature, and thermal conductivity) of partially or completely isomerized Azo-A-10, which are challenging to observe in experiments, can be predicted by molecular dynamics simulation. The optically-controlled phase change mechanism can be clarified according to the differences in microstructure. The optically-controlled switchability of thermophysical properties of an optically-controlled PCM is analyzed. This study provides ideas for the improvement, development, and application of optically-controlled PCMs in the future.

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The interactions between the electron donors and electron acceptors (D/A) play important roles for the performance of organic solar cells (OSCs). While the isomerization strategy is known to optimize molecular geometries and properties, the impacts of isomerization on the donors or acceptors in D/A interactions have not been extensively investigated. Here in, we innovatively investigated the impacts of donor isomerism on the D/A interactions by synthesizing two small molecule donors m-ph-ZnP2 and p-ph-ZnP2 by linking two functionalized porphyrins at the meta and para positions of phenyl groups, respectively. Compared with p-ph-ZnP2, m-ph-ZnP2 displays reduced self-aggregation but  with PC61BM. Consequently, a much higher power conversion efficiency (PCE) of 5.43% is achieved for the m-ph-ZnP2 binary OSCs than the p-ph-ZnP2 devices with a PCE of 2.03%. The enhanced performance of m-ph-ZnP2-based device can be primarily attributed to the stronger intramolecular charge transfer (ICT), the enhanced D/A interactions, the improved charge transfer, and the suppressed charge recombination. Furthermore, the ternary devices based on m-ph-ZnP2:Y6:PC61BM achieve a PCE of 8.34%. In short, this work elucidates the relationship among the chemical structure, D/A interactions and device performance, providing valuable guidelines for designing efficient OSCs materials.

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Non-activated linear α-olefins are valuable building blocks for organic transformation or olefin (co)polymerization, but they are recognized as textbook knowledge for non-homopolymerizable monomers under radical conditions. In this article, we disclose our effort to achieve an unprecedented library of all carbon-bonded sequence-regulated polymers via radical isomerization homopolymerization of α-olefin derivatives. The success of this distinctive polymerization is attributed to the remarkable efficiency and selectivity exhibited during the cyano group migration or hydrogen atom transfer, which is greatly enhanced by the precise engineering of their monomer structures. This polymerization process enables the elongation of polymer chains by five, six, or seven carbon atoms at each propagation step. These polymers, obtained through the cyano group migration or hydrogen atom transfer involved radical isomerization polymerization processes, emerge as promising candidates resembling polyethylene or polyacrylonitrile copolymers.

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A concise hydrosilylation of alkynes for synthesizing ß-(E)-vinylsilanes catalyzed by dirhodium(II)/XantPhos has been developed. In this reaction, ß-(E)-vinylsilanes were generated from the isomerization of ß-(Z)-vinylsilanes catalyzed by dirhodium(II) hydride species rather than the direct insertion of triple bond into M-H or M-Si bond (traditional Chalk-Harrod mechanism or modified Chalk-Harrod mechanism). The hydrosilylation displayed a broad substrate scope for alkynes and tertiary silanes, tolerating diverse functional groups including halides, nitrile, amines, esters, and heterocycles.

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The synthesis of group IV metallocene precatalysts for the polymerization of propylene generally yields two different isomers: The racemic isomer that produces isotactic polypropylene (iPP) and the meso isomer that produces atactic polypropylene (aPP). Due to its poor physical properties, aPP has very limited applications. To avoid obtaining blends of both polymers and thus diminish the mechanical and thermal properties of iPP, the meso metallocene complexes need to be separated from the racemic ones tediously-rendering the metallocene-based polymerization of propylene industrially far less attractive than the Ziegler/Natta process. To overcome this issue, we established an isomerization protocol to convert meso metallocene complexes into their racemic counterparts. This protocol increased the yield of iPP by 400 % while maintaining the polymer's excellent physical properties and was applicable to both hafnocene and zirconocene complexes, as well as different precatalyst activation methods. Through targeted variation of the ligand frameworks, methoxy groups at the indenyl moieties were found to be the structural motifs responsible for an isomerization to take place-this experimental evidence was confirmed by density functional theory calculations. Liquid injection field desorption ionization mass spectrometry, as well as 1H and 29Si nuclear magnetic resonance studies, allowed the proposal of an isomerization mechanism.

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Nitrones are widely used as 1,3-dipoles in organic synthesis, but control of their reactions is not always easy. This review outlines our efforts to make the reactions of nitrones more predictable and easier to use. These efforts can be categorized into (1) 1,3-nucleophilic addition reaction of ketene silyl acetals to nitrones, (2) geometry-controlled cycloaddition of C-alkoxycarbonyl nitrones, (3) stereo-controlled cycloaddition using double asymmetric induction, and (4) generation of nitrones by N-selective modification of oximes.

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Growing evidence indicates that the intake of trans fatty acids (TFAs) increases the risk of numerous diseases, such as cardiovascular diseases. Recently, our group found that certain natural sulfur compounds (allyl isothiocyanate [AITC] and diallyl disulfide [DADS]) promote cis to trans isomerization of fatty acid esters during heat treatment. However, little information is available on the fatty acid isomerization with them. In this study, we investigated the effects of oxygen and α-tocopherol (antioxidant) on isomerization of oleic acid (18:1) methyl ester (OA-ME) in the presence of AITC and DADS. Furthermore, the effect of the simultaneous use of AITC and DADS was evaluated. Our results indicate that oxygen enhances the AITC-induced trans isomerization, and DADS was found to promote trans isomerization but inhibit AITC-induced trans isomerization during heating. Both AITC- and DADS-induced trans isomerization were inhibited by α-tocopherol. These results indicate that the trans isomerization of fatty acids induced by sulfur compounds can be controlled by devising a cooking process and the food ingredients used together.

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A Pd-catalyzed asymmetric isomerization-hydroamidocarbonylation of amide-containing alkenes was developed, affording a variety of chiral a-alkyl succinimides in moderate to good yields with high enantioselectivities. The key to success was introducing bulky 1-adamentyl P-substitution and 2,3,5,6-tetramethoxyphenyl group into the rigid P-chirogenic bisphosphine ligand to create stronger steric hinderance and deeper catalytic pocket. By this approach, regio- or stereo-convergent synthesis of enantiomeric succinimides from the mixture of olefin isomers was achieved.

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3,4-disubstituted maleimides find wide applications in various pharmacologically active compounds. This study presents a highly effective approach for synthesizing derivatives of 3,4-disubstituted maleimides through the direct isomerization of α-succinimide-substituted allenoates, followed by a cascade γ'-addition and aryl imines using PR3 as a catalyst. The resulting series of 3,4-disubstituted maleimides exhibited excellent stereoselectivities, achieving yields of up to 86%. To our knowledge, the phosphine-mediated γ'-addition reaction of allenoates is seldom reported.

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A spectroscopic setup for isomerization quantum yield determination is reported. The setup combines fiber-coupled LEDs, a commercially calibrated thermopile detector for measurement of the photon flux, and a fiber-coupled UV-vis spectrometer. By solving the rate equations numerically, isomerization quantum yields can be obtained from the UV-vis absorption spectra. We show that our results for the prototypical photoswitch azobenzene are in excellent agreement with the literature. The analysis of the errors showed that the quantum yields determined using this method are in the same order of magnitude as when using actinometry, thus demonstrating the reliability of our setup.

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The isomerization of glucose is a crucial step for biomass valorization to downstream chemicals. Herein, highly dispersed MgO doped biochar (BM-0.5@450) was prepared from rice straw via a solvent-free ball milling pretreatment and pyrolysis under nitrogen conditions. The nano-MgO doped biochar demonstrated enhanced conversion of glucose in water at low temperatures. A 31 % yield of fructose was obtained from glucose over BM-0.5@450 at 50 °C with 80.0 % selectivity. At 60 °C for 140 min, BM-0.5@450 achieved a 32.5 % yield of fructose. Compared to catalyst synthesized from conventional impregnation method (IM@450), the BM-0.5@450 catalyst shows much higher fructose yields (32.5 % vs 25.9 %), which can be attributed to smaller crystallite size of MgO (11.32 nm vs 19.58 nm) and homogenous distribution. The mechanism study shows that the activated MgOH+·OH- group by water facilitated the deprotonation process leading to the formation of key intermediate enediol.

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Photoisomerization is a key photochemical reaction in microbial and animal rhodopsins. It is well established that such photoisomerization is highly selective; all-trans to 13-cis, and 11-cis to all-trans forms in microbial and animal rhodopsins, respectively. Nevertheless, unusual photoisomerization pathways have been discovered recently in microbial rhodopsins. In an enzymerhodopsin NeoR, the all-trans chromophore is isomerized into the 7-cis form exclusively, which is stable at room temperature. Although, the 7-cis form is produced by illumination of retinal, formation of the 7-cis form was never reported for a protonated Schiff base of all-trans retinal in solution. Present HPLC analysis of retinal oximes prepared by hydroxylamine reaction revealed that all-trans and 7-cis forms cannot be separated from the syn peaks under the standard HPLC conditions, while it is possible by the analysis of the anti-peaks. Consequently, we found formation of the 7-cis form by the photoreaction of all-trans chromophore in solution, regardless of the protonation state of the Schiff base. Upon light absorption of all-trans protonated retinal Schiff base in solution, excited-state relaxation accompanies double-bond isomerization, producing 7-cis, 9-cis, 11-cis, or 13-cis form. In contrast, specific chromophore-protein interaction enforces selective isomerization into the 13-cis form in many microbial rhodopsins, but into 7-cis in NeoR.

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Morphology control is crucial in achieving high-performance organic solar cells (OSCs) and remains a major challenge in the field of OSC. Solid additive is an effective strategy to fine-tune morphology, however, the mechanism underlying isomeric solid additives on blend morphology and OSC performance is still vague and urgently requires further investigation. Herein, two solid additives based on pyridazine or pyrimidine as core units, M1 and M2, are designed and synthesized to explore working mechanism of the isomeric solid additives in OSCs. The smaller steric hindrance and larger dipole moment facilitate better π-π stacking and aggregation in M1-based active layer. The M1-treated all-small-molecule OSCs (ASM OSCs) obtain an impressive efficiency of 17.57%, ranking among the highest values for binary ASM OSCs, with 16.70% for M2-treated counterparts. Moreover, it is imperative to investigate whether the isomerization engineering of solid additives works in state-of-the-art polymer OSCs. M1-treated D18-Cl:PM6:L8-BO-based devices achieve an exceptional efficiency of 19.70% (certified as 19.34%), among the highest values for OSCs. The work provides deep insights into the design of solid additives and clarifies the potential working mechanism for optimizing the morphology and device performance through isomerization engineering of solid additives.

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Typically catalysed by transition metals, alkene isomerisation is a powerful methodology for preparation of internal olefins. In contrast, the use of more earth abundant main group reagents is limited to activated substrates, requiring high temperatures and excess stoichiometric amounts. Opening a new avenue for progressing this field, here we report applications of bulky sodium amide NaTMP (TMP=2,2,6,6-tetramethylpiperidide) when partnered with tridentate Lewis donor PMDETA (N,N,N',N'',N''-pentamethyldiethylenetriamine) in catalytic alkene isomerisation of terminal olefins under mild reaction conditions. An array of distinct olefins could successfully be isomerised, including unactivated olefins, allylamines, and allylethers, showing the high activity of this partnership. In-depth mechanistic insights provided by X-ray crystallography, real-time nuclear magnetic resonance (NMR) monitoring, and density functional theory (DFT) calculations have unveiled the crucial role of in situ-generated TMP(H) in facilitating efficient isomerisation, and the choice of alkali-metal. Additionally, theoretical studies shed light on the observed E/Z selectivity, particularly accounting for the selective formation of Z-vinyl ethers. The versatility of our method is further demonstrated through the isomerisation of unactivated cycloalkenes, which undergo hydrogen isotope exchange to produce deuterated compounds.

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Responsiveness of liposomes to external stimuli, such as light, should allow a precise spatial and temporal control of release of therapeutic agents or ion transmembrane transport. Here, some aryl-azo derivatives of thymol are synthesized and embedded into liposomes from 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine to obtain light-sensitive membranes whose photo-responsiveness, release behaviour, and permeability towards Cl- ions are investigated. The hybrid systems are in-depth characterized by dynamic light scattering, atomic force microscopy and Raman spectroscopy. In liposomal bilayer the selected guests undergo reversible photoinduced isomerization upon irradiation with UV and visible light, alternately. Non-irradiated hybrid liposomes retain entrapped 5(6)-carboxyfluorescein (CF), slowing its spontaneous leakage, whereas UV-irradiation promotes CF release, due to guest trans-to-cis isomerization. Photoisomerization also influences membrane permeability towards Cl- ions. Data processing, according to first-order kinetics, demonstrates that Cl- transmembrane transport is enhanced by switching the guest from trans to cis but restored by back-switching the guest from cis to trans upon illumination with blue light. Finally, the passage of Cl- ions across the bilayer can be fine-tuned by irradiation with light of longer λ and different light-exposure times. Fine-tuning the photo-induced structural response of the liposomal membrane upon isomerization is a promising step towards effective photo-dynamic therapy.

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