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On the basis of the higher order perturbation formulas of g-factors for a 4d1 group in tetragonally compressed octahedra, the g-factors, optical absorption, local structure and their concentration dependences of pentavalent molybdenum in 40PbO-(10-x)Y2 O3 -50P2 O5 :xMoO3 (1 ≤ x ≤ 5 mol%) glass are uniformly investigated. The experimental optical absorption spectra and g factors for Mo5+ at various concentrations x are reasonably regenerated by using the reasonable exponential concentration functions of the cubic field parameter Dq, covalent factor N and relative tetragonal compression ratio ρ. The tetragonal compression ratio ρ due to the Jahn-Teller effect was found in the range of 3.8-4.2%. The decreasing trend of Dq and N and the increasing trend of ρ with concentration can be interpreted as the fact that the variations of MoO3 and Y2 O3 concentrations lead to the modulations of local structure and electron cloud distribution around Mo5+ , associated with the adjustment of the glass network. The concentration dependence of optical basicity is also analyzed for the above glass systems.

BACKGROUND Curcumin has become increasingly popular in functional foods and beverages field as a result of its high biological activity. Nevertheless, the application of curcumin is usually limited by its poor water solubility, low absorption, rapid metabolism and instability. Accordingly, the development of an appropriate wall material is crucial for its effective use. In the present study, curcumin-octenyl succinic anhydride modified pullulan (Cur-OSAP) micelles were successfully prepared by an anti-solvent co-precipitation method. RESULTS Octenyl succinic anhydride modified pullulan (OSAP) micelles exhibited the highest encapsulation efficiency (57.31%) and loading capacity (5.73%) of curcumin when the mass ratio of OSAP to curcumin was 10:1 and the degree of substitution of OSAP was 0.0469, at which point Cur-OSAP micelles formed via hydrogen binding and hydrophobic interactions, as confirmed by Fourier transform infrared and fluorescence techniques. The transmission electron microscopy results showed that the Cur-OSAP micelles were roughly spherical in shape with diameters in the approximate range 30-60 nm. CONCLUSION The encapsulation of OSAP greatly improved photostability and sustained release properties of curcumin in Cur-OSAP micelles. These findings suggest that OSAP can be used as a carrier to encapsulate and protect hydrophobic food ingredients. © 2021 Society of Chemical Industry.

Conjugated organic radical polymers with stable radical features are difficult to design because the π conjugation in the polymer backbones makes the radicals readily delocalize and tend to undergo covalent bonding processes. In this work, we report an electronic isolation strategy to design stable porous radical polymers by homocoupling reaction from a meta-position active monomer. The meta linkage ensures less conjugation in the polymer skeletons, localizes the resonant radicals, and prevents them from recombination. The resulting porous radical polymer exhibits exceptional radical characters with ultralow band gap of 0.68 eV, strong yet extended UV/Vis-NIR absorption up to 1800 nm, and high spin density. The above features make the polymer very promising in the photothermal conversion with record-high photothermal temperature increment of ≈∼240 °C and striking solar-driven water evaporation efficiency of 96.8 %. Our results demonstrate the feasibility of electronic isolation of radicals for producing outstanding photothermal materials.

Herein, we report a detailed structural, electric, thermal and optical analysis of a titanium and tantalum phosphate LiNaTiTa2 P2 O13 . The title compound is comprised of typical ReO3 -type layers constituted by corner-sharing TiO6 and TaO6 octahedra, bridged by PO4 tetrahedra, and the structure is closely related to monophosphate niobium bronzes. The existence of pentagonal tunnels, hosting the Li+ and Na+ ions, endows LiNaTiTa2 P2 O13 a moderate ion transportation behavior (4.67×10-4 S/cm at 823 K). In addition, the successful substitution of Nb for Ta in LiNaTiTa2 P2 O13 results in the optical absorption red-shift towards visible range with a narrowing band gap, which may provide a route of isomorphic replacement to band engineering for photo-catalysis.

We report the synthesis, characterization, and photophysical properties of novel metal oxide nanoparticles (NPs) coated with specially designed fluorescein substituents which are capped with electron‐withdrawing groups. The fluorescein‐coated nanoparticles were synthesized in excellent yields, and their structures were confirmed using various advanced spectroscopic, instrumental, and surface analysis techniques, revealing the formation of the target functionalized nanoparticles (FNPs) which show superior chemical and thermal stabilities. In addition, the photophysical properties of the FNPs were examined using UV‐visible absorption and fluorescence spectroscopy. These latter techniques disclosed aggregation‐induced emission (AIE) properties for most of the target FNPs, namely those which are soluble in common organic solvents at selective concentration ranges of water fractions in the solvent mixture., Novel metal oxide functionalized nanoparticles (FNPs) coated with specially designed fluorescein substituents capped with electron‐withdrawing groups were synthesized. Most of the FNPs disclose aggregation‐induced‐emission (AIE) properties, namely, those which are soluble in common organic solvents at selective concentration ranges of water fractions in the solvent mixture.

A new acentric borate, K2 Na3 [{B6 O10 (OH)}-{B3 O4 (OH)3 }] ⋅ H2 O (1) has been made under solvothermal condition. 1 has layered structure made by B6 O13 (OH)-based chains and B3 O5 (OH)3 -bridging clusters. Second-harmonic generation (SHG) measurements reveal that 1 is a phase-matchable nonlinear optical (NLO) material, showing the SHG signal intensity of 1.8 times that of KDP (KH2 PO4 ). Besides, UV-Vis diffuse reflectance spectrum shows that 1 has the short deep UV (DUV) absorption cutoff edge of 198 nm. Thermogravimetric analysis reveals it has good thermal stability. Also 1 represents firstly mixed oxoboron clusters-made 2D layered borate with NLO property.

In order to comparing and explaining the experimental infrared, electronic absorption and emission spectra of tris (4-methyl-1-(1-methyl-1H-benzo [d] imidazol-2-yl) -4H-benzo [d] imidazo[1,5-a]imidazol-3-yl) methyl (L6), density functional theory calculations were performed to systematically study the spectral properties of several species with different electronic states (L6+ , L6 and HL6+ ), as well as the axial substituted derivative with methoxy group (L6-OCH3 ). The main peaks in the vibrational, electronic absorption and emission spectra were assigned in detail. Roles of molecular electronic states and axial substitution on the spectral properties are revealed. The calculated spectra are compared with experimental results to distinguish the nature of L6 in crystal and solvent. This work combing experiment and theoretical calculations would be good example for clarifying molecular electronic states and, thus, promising the practice application of such kind of novel molecules.

A new nonheme iron(II) complex, FeII (Me3 TACN)((OSiPh2 )2 O) (1), is reported. Reaction of 1 with NO(g) gives a stable mononitrosyl complex Fe(NO)(Me3 TACN)((OSiPh2 )2 O) (2), which was characterized by Mossbauer (δ=0.52 mm s-1 , |ΔEQ |=0.80 mm s-1 ), EPR (S=3/2), resonance Raman (RR) and Fe K-edge X-ray absorption spectroscopies. The data show that 2 is an {FeNO}7 complex with an S=3/2 spin ground state. The RR spectrum (λexc =458 nm) of 2 combined with isotopic labeling (15 N, 18 O) reveals ν(N-O)=1680 cm-1 , which is highly activated, and is a nearly identical match to that seen for the reactive mononitrosyl intermediate in the nonheme iron enzyme FDPnor (ν(NO)=1681 cm-1 ). Complex 2 reacts rapidly with H2 O in THF to produce the N-N coupled product N2 O, providing the first example of a mononuclear nonheme iron complex that is capable of converting NO to N2 O in the absence of an exogenous reductant.

A series of novel 2,6-functionalized azulene molecules Azu1-3 with varied fluorene substituents at the 1- and 3-positions of azulene as well as at the 5'-position of 2-thiophene group were synthesized. Their electronic absorption and emission spectra at neutral and protonated states were examined. It was found that after functionalization with fluorenyl groups, Azu1-3 exhibited absorption maxima at 445, 451 to 468 nm, respectively. In contrast, their corresponding protonated species showed much redshifted absorption maxima at 560, 582 to 643 nm, respectively, mainly due to the extension of conjugation length and the large dipole moment along the C2v axis of 2,6-substituted azulene molecules. Azu1-3 are non-fluorescent in their neutral forms, but became emissive in their protonated states. Analysis of absorption and emission spectra shows that substitution of the 1- or 3-position of azulene led to decrease in response to trifluoroacetic acid.

A dissymmetric backbone and selenophene substitution on the central core was used for the synthesis of symmetric or dissymmetric A-DA'D-A type non-fullerene small molecular acceptors (NF-SMAs) with different numbers of selenophene. From S-YSS-Cl to A-WSSe-Cl and to S-WSeSe-Cl, a gradually red-shifted absorption and a gradually larger electron mobility and crystallinity in neat thin film was observed. A-WSSe-Cl and S-WSeSe-Cl exhibit stronger and tighter intermolecular π-π stacking interactions, extra S⋅⋅⋅N non-covalent intermolecular interactions from central benzothiadiazole, better ordered 3D interpenetrating charge-transfer networks in comparison with thiophene-based S-YSS-Cl. The dissymmetric A-WSSe-Cl-based device has a PCE of 17.51 %, which is the highest value for selenophene-based NF-SMAs in binary polymer solar cells. The combination of dissymmetric core and precise replacement of selenophene on the central core is effective to improve Jsc and FF without sacrificing Voc .

The association behavior of apoferritin species with the anionic porphyrins, 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (H2 TPPS4- ) and its zinc(II) complex (ZnTPPS4- ), which are water-soluble even in acidic solutions, was investigated for the first time through UV-Vis absorption and fluorescence spectroscopy in order to evaluate a potential ability of apoferritin as a stimuli-responsive molecular capsule. The absorption maximum wavelengths of both porphyrins were redshifted and the fluorescence intensity decreased, indicating the effective association between apoferritin species and the porphyrins, although it depended on the pH adjustment procedure. At pH 2, the ZnTPPS4- associated with apoferritin subunits without demetallating and protonating, while the free base porphyrin formed the J-aggregate of the diprotonated species (H4 TPPS2- )n , with extremely low fluorescence. As the concentration of apoferritin subunits increased, the H2 TPPS4- -subunits associates were formed accompanied by recovering the fluorescence. The association stoichiometries of 1 or 2 subunits/porphyrin obtained under neutral and acidic conditions. The significantly large association constant of ZnTPPS4- as compared with that of H2 TPPS4- indicated that the coordination to the zinc(II) center strongly contributes to the association in addition to the electrostatic interaction between apoferritin subunits and the porphyrin under acidic conditions.

We report the synthesis of a unique cubic metal–organic framework (MOF), Fe‐HHTP‐MOF, comprising hexahydroxytriphenylene (HHTP) supertetrahedral units and FeIII ions, arranged in a diamond topology. The MOF is synthesized under solvothermal conditions, yielding a highly crystalline, deep black powder, with crystallites of 300–500 nm size and tetrahedral morphology. Nitrogen sorption analysis indicates a highly porous material with a surface area exceeding 1400 m2 g−1. Furthermore, Fe‐HHTP‐MOF shows broadband absorption from 475 up to 1900 nm with excellent absorption capability of 98.5 % of the incoming light over the visible spectral region. Electrical conductivity measurements of pressed pellets reveal a high intrinsic electrical conductivity of up to 10−3 S cm−1. Quantum mechanical calculations predict Fe‐HHTP‐MOF to be an efficient electron conductor, exhibiting continuous charge‐carrier pathways throughout the structure., Fe‐HHTP‐MOF, a unique cubic metal–organic framework (MOF) comprising hexahydroxytriphenylene (HHTP) supertetrahedral units and FeIII ions arranged in a diamond topology is reported. Fe‐HHTP‐MOF is a highly crystalline, porous and deep black material featuring high electrical conductivity.

Divergent interpretations have appeared in the literature regarding the structural nature and evolutionary behavior for photoluminescent CdSe nanospecies with sharp doublets in optical absorption. We report a comprehensive description of the transformation pathway from one CdSe nanospecies displaying an absorption doublet at 373/393 nm to another species with a doublet at 433/460 nm. These two nanospecies are zero-dimensional (0D) magic-size clusters (MSCs) with 3D quantum confinement, and are labeled dMSC-393 and dMSC-460, respectively. Synchrotron-based small-angle X-ray scattering (SAXS) returns a radius of gyration of 0.92 nm for dMSC-393 and 1.14 nm for dMSC-460, and indicates that both types are disc shaped with the exponent of the SAXS form factor equal to 2.1. The MSCs develop from their unique counterpart precursor compounds (PCs), which are labeled PC-393 and PC-460, respectively. For the dMSC-393 to dMSC-460 transformation, the proposed PC-enabled pathway is comprised of three key steps, dMSC-393 to PC-393 (Step 1), PC-393 to PC-460 (Step 2 involving monomer addition), and PC-460 to dMSC-460 (Step 3). The present study provides a framework for understanding the PC-based evolution of MSCs and how PCs enable transformations between MSCs.

NO2 can participate in the photochemical reactions of aromatics, change components, and optics of secondary organic aerosol (SOA). Different from the carbonyls measured in p‐xylene SOA without NO2, nitrophenols, nitrocatechols, and their derivatives via the nitration of phenolic products of p‐xylene are detected as the major components of SOA with NO2. The increase of electrophilic nitro groups in the SOA strengthens absorption ability. Aromatic SOA particles with high concentrations of NOx may contribute to the radiative balance in urban atmosphere.

Polycyclic aromatic hydrocarbons (PAHs) have found strong interest for their electronic properties and as model systems for graphene. While PAHs have been studied intensively as single units, here PAHs were constructed in ladder-type arrangements using cross-conjugated fulvalene and dithiafulvalene motifs as connecting units and moving forward a convenient synthetic approach for dimerizing (thio)ketones into olefins by the action of Lawesson's reagent. Some of the PAHs can also be regarded as "super-extended" tetrathiafulvalenes (TTFs) with some of the largest cores ever explored, being multi-redox systems that exhibit both reversible oxidations and reductions. Concomitant absorption redshifts were observed when expanding the ladder-type structures from one to two to three indenofluorene units, and optical and electrochemical HOMO-LUMO gaps were found to correlate linearly. Various conformations (and solid-state packing arrangements) were studied by X-ray crystallography and computations.

The σ-dimer of a kinetically protected olympicenyl radical, which evaded the experimental detection, was revealed by conversion into biolympicenylidene with E-configuration in a regioselective manner. The complicated stereochemistry and energetics of the σ-dimers derived from C2v symmetry and uneven spin distribution of the olympicenyl radical were revealed by the theoretical calculations, and the energetic preference of π-dimer over σ-dimer by a minute gap was disclosed. The E-biolympicenylidene, a polycyclic ene structure previously considered as reactive intermediate in the phenalenyl radical system, exhibited exceptional stability, which allowed for a detailed investigation on its singlet diradical character and physical properties by means of X-ray crystallography, UV-vis-NIR absorption/emission spectroscopy and cyclic voltammetry, and assisted by theoretical calculations. The E-biolympicenylidene showed high resistance towards both thermal and photochemical ring-cyclization reactions, which was attributed to high activation energies for the rate-determining electrocyclization operated on both disrotatory and conrotatory mode, as well as a small spin density at the bonding sites for the radical-radical coupling process.

The fracture of polymer materials is a multiscale process starting with the scission of a single molecular bond advancing to a site of failure within the bulk. Quantifying the bonds broken during this process remains a big challenge yet would help to understand the distribution and dissipation of macroscopic mechanical energy. We here show the design and synthesis of fluorogenic molecular optical force probes (mechanofluorophores) covering the entire visible spectrum in both absorption and emission. Their dual fluorescent character allows to track non‐broken and broken bonds in dissolved and bulk polymers by fluorescence spectroscopy and microscopy. Importantly, we develop an approach to determine the absolute number and relative fraction of intact and cleaved bonds with high local resolution. We anticipate that our mechanofluorophores in combination with our quantification methodology will allow to quantitatively describe fracture processes in materials ranging from soft hydrogels to high‐performance polymers., A new platform of dual fluorescent mechanofluorophores that display covalent bond scission during material breakage by changing their optical properties was synthesized. The absorption and emission characteristics were tuned to cover the entire visible spectrum. Using photon quantitative confocal fluorescence microscopy, these new mechanofluorophores enabled the quantification of bond scission events with μm resolution.

Chromatomembrane process represents a universal approach to the separation of compounds in liquid-gas and liquid-liquid phases systems. However, the broad application of chromatomembrane separation methods in chemical analysis is restricted by the absence of serially produced chromatomembrane flow cells and the difficulties of their laboratory production. The present work addresses the preparation of chromatomembrane flow cell by using 3D printing. Fused deposition modeling and stereolithography were modes for the production of the flow cell using acrylonitrile-butadiene-styrene and polyacrylate-based Anycubic UV resins respectively. The separation and analytical performance of the 3D-printed flow cell were compared with a polyimide unit fabricated by a milling machine, the trial addressing the determination of phenol in the air. The method is based on chromatomembrane absorption of the analytes in 95 µL of the aqueous phase positioned in the cell. RP HPLC with fluorimetric detection was applied for the determination of the absorbed analytes. The detection limit of phenols (phenol and m-cresol) in the air was 0.9 µg·m-3 by absorption pre-concentration time of 10 min. The volumetric flow rate of the analyzed air through the chromatomembrane cell using an electro-driven aspirator was 0.1 L·min-1 . This article is protected by copyright. All rights reserved.

Control of fluorescent molecular assemblies is an exciting area of research with large potential for various important applications, such as, fluorescence sensing/probing, cell imaging and monitoring drug-delivery. In the present contribution, we have demonstrated control on the extent of aggregation of a dye-polyelectrolyte assembly using a macrocyclic host molecule, sulfobutylether-β-cyclodextrin (SBE-β-CD). Initially, a cationic molecular rotor based organic dye, Auramine-O (AuO), undergoes aggregation in the presence of an anionic polyelectrolyte, polystyrene sulfonate (PSS), and displays a broad intense new emission band along with large variation in its absorption features and excited-state lifetime. A manipulation of the monomer-aggregate equilibrium of the dye-polyelectrolyte assembly has been achieved by introducing a cyclodextrin based supramolecular host, SBE-β-CD, which leads to relocation of AuO molecules from polyelectrolyte (PSS) to supramolecular host cavity, owing to the formation of a host-guest complex between AuO and SBE-β-CD. A reversible control on this manipulation of monomer-aggregate equilibrium is further achieved by introducing a competitive guest for the host cavity i. e., 1-Adamantanol. Thus, we have demonstrated an interesting control on the dye-polyelectrolyte aggregate assembly using a supramolecular host molecule which open up exciting possibilities to construct responsive materials using a repertoire of various host-specific guest molecules.

Can the active kernels in ultrasmall metal nanoparticles (nanoclusters, NCs) react with one another, or can the internanocluster reaction occur when they are in close enough proximity? To resolve this fundamental issue, we investigated the solid-state internanocluster reaction of the most studied gold NC Au 25 (SR) 18 (SR: thiolate) and revealed that a novel NC was produced by increasing the pressure to 5 GPa, whose composition was determined to be Au 32 (SC 2 H 4 Ph) 24 by mass spectrometry and thermogravimetric analysis. As revealed by single-crystal X-ray crystallography, the structure consisting of a bicuboid Au 14 kernel and three pairs of interlocked trimetric staples, has not been previously reported and endows the NC with obvious photoluminescence. DFT calculations also indicate the staples contribute substantially to the absorption properties. Further experiments reveal the pressure (internanocluster distance) can tune the internanocluster reaction, and the resulting product is not necessarily the thermodynamic product. Thus, the introduced high-pressure method would have great potential for synthesizing unconventional metal NCs with enhanced properties for applications.

Extensive recent efforts have been put on the design of high-performance organic near-infrared (NIR) photothermal agents (PTAs), especially over NIR-II bio-window (1000-1350 nm). So far, the development is mainly limited by the rarity of molecules with good NIR-II response. Here, we report organic nanoparticles of intermolecular charge-transfer complexes (CTCs) with easily programmable optical absorption. By employing different common donor and acceptor molecules to form CTC nanoparticles (CT NPs), absorption peaks of CT NPs can be controllably tuned from the NIR-I to NIR-II region. Notably, CT NPs formed with perylene and TCNQ have a considerably red-shifted absorption peak at 1040 nm and achieves a good photothermal conversion efficiency of 42 % under 1064 nm excitation. These nanoparticles were used for antibacterial application with effective activity towards both Gram-negative and Gram-positive bacteria. This work opens a new avenue into the development of efficient PTAs.

The present study analyzes the features of chemical CO2 absorption using tertiary amine solvents by comparing the absorption performance and electrical properties between methyl‐di‐ethanolamine (MDEA) and tri‐ethanolamine (TEA) systems. The results are mostly attributed to the different structures of the two amine molecules. Absorption performance is significantly affected by the molecular structure and water concentration in the amine solution. The absorption performance of the MDEA system is better than that of TEA, which is basically ascribed to the MDEA molecule's more asymmetric and irregular shape than that of TEA, which thus enhances the catalytic activity of MDEA and the reactivity of the −OH moiety in water. The difference of electrical properties such as ionic conductivities (ICs) of the two protonated amines and real ionic activity coefficients (RIAC) between the two systems might be also caused by the different molecular structures of the two amines. The IC of protonated MDEA is estimated to be 23.70% higher than that of protonated TEA, because of the higher ionic mobility and charge density of MDEA. The RIAC of the MDEA system is higher than that of TEA, which is explained by the different physicochemical interactions between the molecules in the two systems. Since water is one of the reactants in the absorption, its concentration in solution significantly affects the results of the systems. In addition, the absorption using tertiary amine is a base‐catalyzed reaction, and thus variations of the overall absorption rate follow a parabolic curve. Therefore, it is maximized to be 14.2 and 9.8 mmol CO2·L−1·min−1 in the 15 wt% MDEA and TEA solutions, respectively. Finally, the correlated equations for in situ estimation of chemical absorption capacity by electrical conductivity measured during the absorption are derived in the two systems. © 2021 The Authors. Greenhouse Gases: Science and Technology published by Society of Chemical Industry and John Wiley & Sons, Ltd.

This work exposes for the first time the remarkable influence of intramolecular group rotation on third-order nonlinear optical (NLO) performance. In order to prove the role of group rotation, we designed and synthesized two photo-response compounds tetramethyl 5,5'-(((diazene-1,2-diylbis(4,1-phenylene))bis(oxy))bis (methylene)) diisophthalate (1) and 5,5'-(((diazene-1,2-diylbis(4,1-phenylene))bis(oxy))bis (methylene)) diisophthalic acid (2) and investigated their NLO performance under different substituent (benzyloxy group) rotation states. 1 and 2 have dynamic benzyloxy group rotation in dilute solution and shows reverse saturated absorption (RSA). When the benzyloxy group rotation of 1 and 2 was restricted by PMMA, their NLO performance not only converted into saturated absorption (SA) and NLO refraction behaviours, but also hardly changed after isomerization. Interestingly, we also restricted the benzyloxy group rotation in solution to a certain extent through photo-induced trans → cis isomerization, and found that the NLO performances of cis isomers of 1 and 2 exhibit SA and positive refraction and are similar to those of 1 -PMMA and 2 -PMMA. This work provides a new exploratory method for studying the influencing factors of third-order NLO performance.

The formation of high-nuclearity silver(I) clusters remains elusive and their potential applications are still underdeveloped. Herein, we firstly prepared a chain-like thiolated AgI complex {[Ag18 (St Bu)10 (NO3 )8 (CH3 CN)2 (H2 O)2 ] ⋅ [Ag18 (St Bu)10 (NO3 )8 (CH3 CN)6 ]}n (abbreviated as Ag18 ) in which two similar Ag18 clusters are assembled by NO3 - anions. The solution containing Ag18 reacted with hydrogen sulfide with controlled concentration, promptly producing another identifiable and bright red-emitting high-nuclearity silver(I) cluster, Ag62 (S)13 (St Bu)32 (NO3 )4 (abbreviated as Ag62 ). We tracked the transformation using time-dependent electrospray ionization mass spectrometry (ESI-MS), UV/Vis absorption and photoluminescence spectra. Based on this cluster transformation, we further developed an ultra-sensitive turn-on sensor detecting H2 S gas with an ultrafast response time (30 s) at a low detection limit (0.13 ppm). This work opens a new way of understanding the growth of metal clusters and developing their luminescent sensing applications.

Although the Turing structures, or stationary reaction-diffusion patterns, have received increasing attention in biology and chemistry, making such unusual patterns on inorganic solids is fundamentally challenging. We report a simple cation exchange approach to produce Turing-type Ag2 Se on CoSe2 nanobelts relied on diffusion-driven instability. The resultant Turing-type Ag2 Se-CoSe2 material is highly effective to catalyze the oxygen evolution reaction (OER) in alkaline electrolytes with an 84.5 % anodic energy efficiency. Electrochemical measurements show that the intrinsic OER activity correlates linearly with the length of Ag2 Se-CoSe2 interfaces, determining that such Turing-type interfaces are more active sites for OER. Combing X-ray absorption and computational simulations, we ascribe the excellent OER performance to the optimized adsorption energies for critical oxygen-containing intermediates at the unconventional interfaces.

Synthesis and properties of anthracene-based cyclic π-clusters which possess two and four anthracene units are discussed. The optimal cyclization conditions were determined based on a nickel(0)-mediated reaction that afforded a cyclic anthracene dimer as the major product. Bringing two anthracene planes in close proximity in a face-to-face manner resulted in red-shifted absorption owing to the narrowing of the HOMO-LUMO gap. The cyclic anthracene dimer exhibits multi-stimuli responsiveness due to high π-congestion. For example, photoirradiation on the anthracene dimer affords its photoisomer having C-C bonds that are longer than 1.65 Å, which can undergo thermal reversion under gentle heating. This enabled mechanochromism of the photoisomer (colorless) to the original anthracene dimer (red). Photoisomerization was also observed in the crystalline state, accompanied by crystal jumping or collapsing, that is, the photosalient effect.

Polycyclic aromatic compounds consisting of four or five fused anthracene units were synthesized by PtCl2 -catalyzed cycloisomerization as novel long expanded helicenes. These compounds have helical structures with significant stacking of the terminal anthracene moieties at 0.33 nm interlayer distance. In the UV-vis and fluorescence spectra, the absorption and emission bands were red-shifted as the number of fused anthracene units was increased. The characteristic broad and long-lived emission bands of the long analogues are explained by the excimer-like stabilization of the excited state. These photophysical data as well as their cyclic voltammetric data are discussed on the basis of the π-conjugation and interlayer π⋅⋅⋅π interactions in the molecular structures and the molecular orbitals. The barrier and mechanism of helical inversion are also reported.

The carriers of the diffuse interstellar bands (DIBs) are still largely unknown although polycyclic aromatic hydrocarbons, carbon chains, and fullerenes are likely candidates. A recent analysis of the properties of n‐acenes of general formula C4n+2H2n+4 suggested that these could be potential carriers of some DIBs. Dehydrogenation reactions of n‐acenes after absorption of an interstellar UV photon may result in dehydroacenes. Here the reaction energies and barriers for formation of n‐cyclacenes from 2,3‐didehydroacenes (n‐DDA) by intramolecular Diels–Alder reaction to dihydro‐etheno‐cyclacenes (n‐DEC) followed by ejection of ethyne by retro‐Diels–Alder reactions are analyzed using thermally assisted occupation density functional theory (TAO‐DFT) for n=10–20. It is found that the barriers for each of the steps depend on the ring strain of the underlying n‐cyclacene, and that the ring strain of n‐DEC is about 75 % of that of the corresponding n‐cyclacene. In each case, ethyne extrusion is the step with the highest energy barrier, but these barriers are smaller than CH bond dissociation energies, suggesting that formation of cyclacenes is an energetically conceivable fate of n‐acenes after multiple absorption of UV photons., n ‐Acenes (C4n+2H2n+4) are potential carrier candidates for diffuse interstellar bands. Their conversion into n‐cyclacenes (C4nH2n) through UV photon‐initiated dehydrogenation followed by Diels–Alder cycloaddition and acetylene expulsion appears energetically plausible. Analysis of the conversion through TAO‐DFT reveals dependency of the energy barriers on ring strains of the primary n‐cyclacene.

The use of sodium salts of aqueous solutions of different amino acids (glycinate and prolinate) for carbon dioxide (CO2) separation by chemical absorption is analyzed in a bubble-column reactor under different experimental conditions of solvent concentration and gas flow rate. The differences in absorption rate and reaction mechanism caused by the presence of carboxylic groups in comparison to the case without (monoethanolamine and pirrolidine) are evaluated. Glycinate solvent reaches a similar behavior than monoethanolamine aqueous solutions but with a higher destabilization of carbamate that allows to increase CO2 loading. Prolinate exhibits a similar behavior than pirrolidine at low CO2 loadings. Both solvents show a significant reduction in absorption capacity when stripping regeneration is carried out.

Synthetic routes for heteroatom-containing polycyclic aromatic hydrocarbons (H-PAHs) with alkyl and aryl substitution are demonstrated. Three H-PAHs, including heteroatom-containing rubicenes (H-rubicenes), angular-benzothiophenes (ABTs), and indenothiophene (IDTs) were successfully synthesized by two key steps, including polysubstituted olefin formation and cyclization. Specifically, ABT and H-rubicenes were comprehensively investigated by single-crystal X-ray diffraction, NMR spectroscopy, UV-vis absorption, cyclic voltammetry, transient absorption, and single-crystal OFET measurements.

In this report, we develop a dual-output sensor with fluorometric and colorimetric responses, for the rapid and simple detection of berberine hydrochloride (BRH) in 100% aqueous solution based on an anionic polythiophene derivative, poly(2-(2-(4-methylthiophen-3-yloxy)-ethyl) malonic acid) (PTMA). The sensing performance and mechanism were carefully examined by absorption and emission spectra. It can be applied to quantitatively detect BRH in aqueous solution with a detection limit 0.27 μM. The appealing performance of the sensor was demonstrated to originate from the electrostatic and π-π interactions between PTMA and BRH, which promoted the conformational change and aggregation of the PTMA backbone. Moreover, this method allowed rapid detection of BRH in urine samples and BRH tablets with high accuracy.

The interaction between hyperoside and human serum albumin was studied in vitamin C (VC ) and VC -free environments using ultraviolet (UV)-vis absorption, fluorescence, circular dichroism spectra, and molecular docking techniques under simulated physiological conditions. The two environments had different influences on the secondary structure of human serum albumin (HSA). The α-helix content was slightly increased from 50% to 51% in the VC environment and increased from 50% to 55% in the VC -free environment. The thermodynamic parameters were ΔH° = -30.7 kJ⋅mol-1 and ΔS° = -23.4 mol-1 ⋅K-1 in the VC environment and ΔH° = -25.4 kJ⋅mol-1 and ΔS° = -11.4 J⋅mol-1 ⋅K-1 in the VC -free environment. Through thermodynamics parameters, hydrophobic force played a dominant role in the whole environment. The binding constants were calculated to be 7.25 × 105 mol⋅L-1 and 9.76 × 105 mol⋅L-1 at 298 K and they declined with the rise in temperature. The two binding distances were 2.6 nm and 2.5 nm respectively at 298 K, indicating that fluorescence energy transfer occurred. The UV-vis spectra indicated that fluorescence quenching of the HSA-hyperoside complex was a static quenching process. Hyperoside could spontaneously bind to HSA at site I (subdomain IIA). Molecular docking elucidated the way to binding basically through hydrophobic and van der Waals force interactions. Moreover, molecular docking showed that the VC environment could influence binding of HSA and hyperoside by more H-binding and less hydrophobic forces.

The phycocyanin trimer structure is the basic building block of the rod of phycobilisome (PBS). However, PBS is composed of one higher hierarchical structure, a unit of hexamer structure that combines two trimers. In this study, we clarify the functional role of the hexamer structure from the viewpoint of light absorption properties and energy transfer of chromophore β155., Cyanophyta‐phycocyanin (C‐PC) is the main constituent of the rod of phycobilisome (PBS), which is a highly ordered and large peripheral light‐harvesting protein complex present on the cytoplasmic side of the thylakoid membrane in cyanobacteria and red algae. The C‐PC monomer comprises two chains, α‐ and β‐subunits, and aggregates to form ring‐shaped trimers (αβ)3 with rotational symmetry. The ring‐shaped trimer (αβ)3 is a structural block unit (SBU) that forms the rod of PBS. Two (αβ)3 SBUs are arranged in a face‐to‐face manner to form an (αβ)6‐hexamer. In this study, the electronic states of three phycocyanobilins, α84, β84, and β155 in C‐phycocyanin, constituting the rod of the PBS, were calculated for both the trimer and hexamer models by considering the effect of the electrostatic field of protein moieties and water molecules. For the hexamer, the absorption wavelengths of α84, β84, and β155 were similar to those obtained experimentally; however, for the trimer, only the absorption wavelength of β155 shifted toward a shorter‐wavelength. The nature of the hexamer structure as a hierarchical structure is revealed by considering the calculated absorption wavelength and energy transfer.

In this work, the effect of the calcination temperature on the TiO2 synthesis using Pechini's method was reported. The adopted calcination temperatures were 500, 600, and 700°C. XRD measurements indicated the composition of crystalline phases, and from there, the conversion of the anatase phase to rutile. TiO2 Evonik® was used as a reference standard and sodium diclofenac as a standard for photodegradation assessment. The average crystalline size increased. In both cases, this trend accompanied the increase in calcination temperature. The optical properties were performed using diffuse UV-Vis reflectance. Results obtained indicated maximum absorption wavelength values more intense and displaced to the visible region. Also, the estimated band gap energy values decreased. The photocatalytic performance of TiO2 samples was superior to the reference catalyst (TiO2 Evonik® ). Especially in the first 10 minutes, the comparative photodegradation was up to approximately 58% higher. The photodegradation kinetic constants were also higher, and by comparison, up to approximately 73% higher. Toxicity measurements, using Artemias salina, also indicated similar decay behavior in the first 10 minutes, with a performance of up to approximately 60%.

Squaraine dyes are well known for their strong absorption in the visible regime. Reports on chiral squaraine dyes are, however, scarce. To address this gap, we here report two novel chiral squaraine dyes and their achiral counterparts. The presented dyes are aggregated in solution and in thin films. A detailed chiroptical study shows that thin films formed by co‐assembling the chiral dye with its achiral counterpart exhibit exceptional photophysical properties. The circular dichroism (CD) of the co‐assembled structures reaches a maximum when just 25 % of the chiral dye are present in the mixture. The solid structures with the highest relative CD effect are achieved when the chiral dye is used solely as a director, rather than the structural component. The chiroptical data are further supported by selected spin‐filtering measurements using mc‐AFM. These findings provide a promising platform for investigating the relationship between the dissymmetry of a supramolecular structure and emerging material properties rather than a comparison between a chiral molecular structure and an achiral counterpart., Helicity control: An unexpected outcome of the co‐assembly of achiral squaraine dye a‐SQ‐1 with its chiral counterpart S ‐SQ‐1 is reported. A maximum in optical activity is observed in the supramolecular aggregates of a 3:1 mixture with a‐SQ‐1 as the major component. Intriguingly, the highest spin‐selective electron transport is observed for this mixing ratio as well, illustrating the direct relationship between optical activity and spin‐selective electron transport.

We report the single-crystal synthesis of a chlorine-centered bimetallic cluster, Cl@Ag22 Au6 (4-TBBT)28 (PPh4 ), which bears a quatrefoil-structured Cl@Ag22 (SR)16 core studded by six Au(SR)2 staples showing a quasi Td symmetry. This cluster bears 28 metal atoms and 28 ligands, with a chlorine atom hosted in the center of the metallic Ag22 Au6 core. Single-crystal analysis shows that this cluster possesses essentially a different bonding nature compared with other monolayer-protected metal clusters (MPCs) or traditional metal-sulfur complexes. We fully dissect the structure evolution in forming such a chlorine-centered cluster. Interestingly, this cluster, Cl@Ag22 Au6 (4-TBBT)28 (PPh4 ), displays a fluorescence emission at 570 nm and supports the solid emission with a minor red shift at 574 nm. On the other hand, we have tested the nonlinear optical property and observed unambiguous nonlinear optical property with a normal valley-shaped transmittance curve corresponding to reverse saturated absorption (RSA) of the cluster.

Both E‐ and Z‐isomers of lycopene are encountered in nature. Although they were separated on C30‐HPLC by the mobile phase consisting of CH3CN‐MeOH (A) and MTBE (B), the quantification of Z‐isomers cannot be archived at present because either their commercially available reference samples are currently lacking, or they are unstable. In this study, both the specific and molar absorption coefficients of 5, 9, and 13 Z‐isomers in the mobile phase were determined on the analytical C30‐HPLC‐PDA‐ELSD, and further verified on the preparative C30‐HPLC‐PDA. The specific and molar absorption coefficients of 5, 9, and 13 Z‐isomers were finally verified to be A1cm1% = 3,422 and ε mol = 183,717, A1cm1% = 2,183 and ε mol = 117,199, and A1cm1% = 1,119 and ε mol = 60,076, respectively, in the mobile phase. With these determined coefficients, the quantifications of 5, 9, and 13 Z‐isomers were able to be archived on C30‐HPLC‐PDA with the mobile phase applied in this investigation., This is the first study reporting the values of 5, 9, and 13 Z‐isomers of lycopene. It revealed that the absorption coefficient of lycopene isomer corresponded to the location of geometrical isomerization in the molecule. The specific and molar absorption coefficients of 5, 9, and 13Z‐isomers determined in this study have great potential to be applied in the Z‐isomer quantification in the fields of life sciences, food quality control, animal and human metabolism research, and pharmacology.

An original method for determining the handedness of individual non-centrosymmetric crystals in a mixture using a tightly-focused, circularly polarized X-ray beam is presented. The X-ray natural circular dichroism (XNCD) spectra recorded at the metal K-edge on selected crystals of [Δ-M(en)3 ](NO3 )2 and [Λ-M(en)3 ](NO3 )2 (M=CoII , NiII ) show extrema at the metal pre-edge (7712 eV for Co, 8335 eV for Ni). A mapping of a collection of some 220 crystals was performed at the respective energies by using left and right circular polarizations. The difference in absorption for the two polarizations, being either negative or positive, directly yielded the handedness of the crystal volume probed by the beam. By using this technique, it was found that the addition of l-ascorbic acid during the synthesis of [Co(en)3 ](NO3 )2 resulted in an enantiomeric enrichment of the Λ-isomer of 67±13 %, whereas the Ni analogue was similarly, but conversely, enriched in the Δ-isomer (65±22 %).

A new strategy was devised for estimating and screening pKa values among different carbon acids under ambient conditions by using the UV/Vis absorption spectrum of persistent radical pairs (PRPs), which are generated from an N-substituted naphthalimide (NNI) derivative in the presence of various carbanions in organic solutions. The electron paramagnetic resonance (EPR) spectroscopy was used to examine the presence of radicals. Unexpectedly, it was discovered that the UV/Vis spectrum of PRPs reveals a distinct linear relationship between the PRP absorption and the pKa value of a corresponding carbon acid, which is likely due to the energy difference among different RPRs. The finding may offer organic chemists an alternative reference to conduct carbanion-mediated reactions in various organic solutions.

Six porphycenes have been synthesized, bearing one, two, or three fluorine atoms attached directly to the 18-π-electron system at the meso positions. These novel compounds have been characterized by structural, electrochemical, and spectral techniques, combined with quantum chemical calculations. In three fluoroporphycenes, the unsymmetric substitution pattern leads to the presence of two nonequivalent trans tautomeric forms. They have been identified using electronic absorption, emission, and magnetic circular dichroism spectroscopies. Their relative energies have been estimated for the ground and lowest excited electronic states. Tautomerization potential is quasi-symmetric in S0 , but becomes strongly nonsymmetric in S1 . Femtosecond transient absorption studies allowed determination of tautomerization rates, larger and similar for both directions of the double hydrogen transfer in S0 , lower and disparate in S1 . Fluoroporphycenes emerge as good candidates for detailed studies of mechanisms of double hydrogen transfer, as well as processes responsible for rapid radiationless excited state depopulation.

A first series of fluorinated [n]helical compounds (n=5 and 6) with the dihydroindenofluorene scaffold was prepared in 5 or 9 (octafluorinated dihydroindenofluorene) steps and their photophysical properties were determined. Rh-catalyzed intramolecular [2+2+2] cyclotrimerization of triyndiols, which were prepared in a modular fashion from simple starting material such as fluorinated haloarylcarbaldehydes, to the intermediate [n]helical dihydroindeno[2,1-c]fluorene-5,8-diols was the crucial synthetic step and proceeded with high efficacy. Their further transformation gave the desired selectively fluorinated bispirodihydroindeno[2,1-c]fluorenes. Their absorption and emission spectra were recorded. The fluorescence quantum yields were up to 92 % and the emission maxima were red-shifted in comparison with their non-fluorinated counterparts (386-413 nm).

The application of single-atom catalysts (SACs) to high-temperature hydrogenation requires materials that thermodynamically favor metal atom isolation over cluster formation. We demonstrate that Pd can be predominantly dispersed as isolated atoms onto TiO2 during the reverse water-gas shift (rWGS) reaction at 400 °C. Achieving atomic dispersion requires an artificial increase of the absolute TiO2 surface area by an order of magnitude and can be accomplished by physically mixing a precatalyst (Pd/TiO2 ) with neat TiO2 prior to the rWGS reaction. The in situ dispersion of Pd was reflected through a continuous increase of rWGS activity over 92 h and supported by kinetic analysis, infrared and X-ray absorption spectroscopies and scanning transmission electron microscopy. The thermodynamic stability of Pd under high-temperature rWGS conditions is associated with Pd-Ti coordination, which manifests upon O-vacancy formation, and the artificial increase in TiO2 surface area.

The inclusion interaction between hydroxypropyl-β-cyclodextrin (HP-β-CD) and 21 2-aryl carboxylic acids was investigated by UV (ultraviolet) spectrophotometer. The inclusion constant of each 2-aryl carboxylic acids with HP-β-CD was determined by Benesi-Hildebrand's equation. According to our previous work, it was found that a high inclusion constant for inclusion complex formed by a racemate and cyclodextrin was always observed with the fact that a high enantioseparation factor was achieved for the racemate in enantioseparation by liquid-liquid chromatography, which suggested that high binding combination between racemate and cyclodextrin is very important for a successful enantioseparation in enantioselective liquid-liquid extraction. Among all the studied subjects, mandelic acid enantiomer, 2,3-diphenylpropionic acid enantiomer, and naproxen enantiomer were selected for the further study. The inclusion constants of enantiomers of these three subjects were determined by UV spectra, which indicated that a necessary difference in inclusion constants between enantiomer and cyclodextrin was also essential. It was found in UV spectra that the absorbance of the analytes with the addition of cyclodextrin would increase or decrease, which was determined by the type of electron excitation. The conformation changes of small molecules can lead to the changes of chromophore valence electron clouds distribution, causing the HOMO-LUMO energy difference decreased. Thus, a red shift of the wavelength of the maximum absorption was produced indicating that the possibility of the molecular interaction of enantiomers with HP-β-CD exists.

The main objective of this research is to improve the CO2 solubility and absorption rate of conventional alkanolamines including monoethanolamine (MEA) and methyldiethanolamine (MDEA) by 1,4–diaminobutane (DAB) as a promoter. Typically, the presence of two primary functional groups, lack of strict hindrance, and low molecular weight make DAB an efficient solvent to absorb CO2. In the first step, the absorption kinetic of DAB is investigated theoretically and a rate equation is proposed based on the zwitterion mechanism. In the second step, the equilibrium capacity of MEA and MDEA is promoted by DAB experiment in an isothermal stirred batch reactor in the pressure range 20–100 kPa, temperature range 303–313 K, and promoter volume fraction 0–10%. Then, the effective loading and regenerability of prepared samples are investigated by continuous cyclic absorption and regeneration in the designed reactor. The experimental results show that increasing DAB concentration in the MEA and MDEA as base solutions increases the CO2 absorption rate and equilibrium capacity. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd.