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New HLCT fluorophores are synthesized and successfully applied as non-doped emissive layers in solution-processed double-layered OLEDs. These devices exhibit intense yellow-green emission colors with superior performance.

The soil-derived fungus Talaromyces thailandensis PSU-SPSF059 produced one new vermistatin derivative, talarostatin, and seven known compounds including two vermistatins, two chrodrimanins, two diphenyl ethers and one penicillide derivative. Extensive spectroscopic analysis was performed to identify their structures. The absolute configuration of talarostatin was determined by comparing the experimental and calculated electronic circular dichroism data. The antimicrobial and cytotoxic activities of the isolated secondary metabolites were also evaluated.

Acylphloroglucinols are well-known

The pursuit of high energy density has promoted the development of high-performance lithium metal batteries. However, it faces a serious security problem. Ionic liquids have attracted great attention due to their high ionic conductivity, non-flammability, and the properties of promoting the formation of stable SEI films. Deeply understanding the problems existing in lithium metal batteries and the role of ionic liquids in them is of great significance for improving the performance of lithium metal batteries. This article reviews the effects of the molecular structure of ionic liquids on ionic conductivity, Li+ ion transference number, electrochemical stability window, and lithium metal anode/electrolyte interface, as well as the application of ionic liquids in Li-high voltage cathode batteries, Li-O2 batteries and Li-S batteries. The molecular design, composition and polymerization will be the main strategies for the future development of ionic liquid-based electrolytes for high performance lithium metal battery.

This work presents a simple hydrothermal synthesis of nitrogen-doped carbon dots (N-CDs), fabrication of microfluidic paper-based analytical device (μPAD), and their joint application for colorimetric determination of total cholesterol (TC) in human blood. The N-CDs were characterized by various techniques including transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRD), and the optical and electronic properties of computational models were studied using the time-dependent density functional theory (TD-DFT). The characterization results confirmed the successful doping of nitrogen on the surface of carbon dots. The N-CDs exhibited high affinity toward 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)-diammonium salt (ABTS) with the Michaelis-Menten constant (KM) of 0.018 mM in a test for their peroxidase-like activity. Particularly, since hydrogen peroxide (H2O2) is the oxidative product of cholesterol in the presence of cholesterol oxidase, a sensitive and selective method of cholesterol detection was developed. Overall, the obtained results from TD-DFT confirm the strong adsorption of H2O2 on the graphitic N positions of the N-CDs. The laminated three-dimensional (3D)-μPAD featuring a 6 mm circular detection zone was fabricated using a simple wax screen printing technique. Classification of TC according to the clinically relevant criteria (healthy, 6.2 mM) could be determined by the naked eye within 10 min by simple comparison using a color chart. Overall, the proposed colorimetric device serves as a low-cost, rapid, simple, sensitive, and selective alternative for TC detection in whole blood samples that is friendly to unskilled end users.

Seven new polyketides including a phenol (1), two diphenyl ethers (2 and 3), two depsidones (4 and 5), and two phthalides (6 and 7) were isolated from the fungus Aspergillus unguis PSU-MF16 along with 27 known compounds. Their structures were determined by extensive spectroscopic analysis. The absolute configurations of 1 and 4-7 were established using comparative analyses of calculated and experimental ECD spectra. Among the new metabolites, 2 exhibited the best antimicrobial activity against Staphylococcus aureus, methicillin-resistant S. aureus, and Microsporum gypseum with equal MIC values of 16 μg/mL. In addition, known emeguisin A displayed potent antimicrobial activity against S. aureus, methicillin-resistant S. aureus, and Cryptococcus neoformans with equal MIC values of 0.5 μg/mL, compared with the standard drugs, vancomycin and amphotericin B. The structure-activity relationship study of the isolated compounds for antimicrobial activity is discussed.

Three new pyrrolobenzoxazine sesquiterpenoids, talatrachyoxazines A – C (1 – 3), together with fourteen known compounds (4 – 17), were isolated from the fungus Talaromyces trachyspermus EU23. Their structures were identified by spectroscopic evidence and mass spectrometry. The absolute configurations of 1 – 3 were determined by NOESY data and comparison of their calculated and experimental electronic circular dichroism (ECD) spectra. Compound 1 showed cytotoxic activity against HelaS3, KB, HT-29, MCF-7, and HepG2 cell lines with IC50 values of 7, 11, 10, 12, and 10 µM, respectively. Compounds 1 and 14 showed weak antibacterial activity against the gram-positive bacteria Bacillus cereus and Bacillus subtilis, while 1 – 3 and 14 showed weak antibacterial activity against the gram-negative bacterium Pseudomonas aeruginosa. In addition, compound 1 showed weak antibacterial activity against Escherichia coli.

A microcrystalline Cd(II)-MOF, [Cd(NH2-bdc)(azp)]·DMF (NH2-H2bdc = 2-amino-1,4-benzenedicarboxylic acid and azp = 4,4′-azopyridine), namely 1-NH2 was rationally designed and synthesized as a fluorescent sensor in the off state utilizing the photo-induced electron transfer (PET) process. The crystal structure of 1-NH2 features a porous 2-fold interpenetrated 3D framework with 1D channels decorated with open Lewis basic amino and azo groups for recognizing the target species. Time-dependent density functional theory (TD-DFT) calculations were performed to gain insight into the PET process that induces the fluorescent quenching of 1-NH2. The proposed 1-NH2 is the first MOF that presents highly selective and sensitive visual turn-on fluorescence detection of glyphosate and Cr3+ with very low detection limits of 25 nM and 0.6 μM, respectively. The amino moiety in 1-NH2 plays a key role for the selective binding of Cr3+ to facilitate the sensitivity and selectivity of the detection. The fluorescent enhancement mechanism is associated with the inhibition of the PET process stimulated by the dissociation of the framework of 1-NH2 in the presence of glyphosate and Cr3+.

Herein, bismuth molybdate (Bi2MoO6) nanocatalysts containing oxygen vacancies (OVs) are found to considerably promote the photocatalytic performance toward oxidative coupling of benzylamine to N-benzylidenebenzylamine under visible light irradiation. The structure-activity relationship for this interesting catalyst is revealed for the first time. The oxygen-deficient Bi2MoO6 nanoplatelets (BMO-NPs) are synthesized using ethylene glycol-ethanol solvent mixture as a reaction medium in solvothermal method. A comparison with hydrothermally prepared Bi2MoO6 square-like sheets (BMO-SHs) suggests that the nanoplatelets are much smaller in size and contain higher amount of OVs. Benzylamine conversion over the BMO-NPs is ca. 4.0 times higher than that over the BMO-SHs and ca. 3.8 and ca. 34.6 times higher than that over the commercial benchmark TiO2 P25 and BiVO4 catalysts, respectively. The BMO-NPs achieve more than 80% product yield within 2 h of irradiation regardless of substituents of benzylamine derivatives. The enhanced activity of BMO-NPs is due to synergistic roles of high surface-to-volume ratio and OVs, providing enlarged active area, extended light absorption range and improved charge separation and transfer efficiency as evidenced from UV–vis DRS, BET surface area, photocurrent response, electrochemical impedance spectroscopy, and time-resolved fluorescence decay measurements. EPR-trapping and radical scavenging experiments indicate O2 − as a main active species rather than 1O2 and a plausible imine formation mechanism via O2 −-assisted charge transfer is proposed accordingly. The work offers an alternative facile preparation method to design efficient semiconductor photocatalysts and for the first time reveals a possible benzylamine coupling mechanism over the oxygen-deficient Bi2MoO6 nanocatalyst.

In this work, we theoretically evaluated the complete catalytic oxidation of formaldehyde (HCHO) catalyzed by a cobalt embedded sulfur vacant MoS2 (COSv–MoS2) monolayer. The density functional theory calculations demonstrate that the Co atom is strongly anchored at the S vacancy site of the MoS2 monolayer forming a single-atom catalyst without metal clustering. From the study of all possible elementary steps, we propose two possible catalytic pathways for HCHO oxidation; (1) consecutive path: HCHO dehydrogenation followed by CO oxidation with O2, and (2) co-adsorption path: HCHO oxidation by O2 through the Langmuir–Hinshelwood mechanism. Compared to the catalysts reported in the literature, this catalyst presents lower activation energy barriers for C–H bond cleavage. At room temperature, the consecutive path is found to be dominant, and the calculated activation free energy barrier is only 0.46 eV (44.38 kJ mol−1). Our kinetic analyses show that HCHO oxidation can easily occur at room temperature with a rate of 1.12 × 105 s−1. Therefore, this non-noble metal single atom COSv–MoS2 catalyst demonstrates excellent activity for HCHO catalytic oxidation at low temperatures.

The adsorption properties of the hydrogen atom on our newly designed materials were investigated using density functional theory (DFT) calculations, focusing on the role of dopants in modulating the binding properties of the metal. We proposed decorating Ti4 on pristine, B- and N-doped graphene surfaces for preparing a large-capacity hydrogen-storage device. Computational results indicate that the doping of B on graphene enhances the interaction between the metal cluster and the supporting substrate with a very strong binding energy of −6.45 eV, which is the strongest interaction among our proposed catalysts. This binding energy prevents the aggregation and formation of Ti–metal clusters. Dissociative chemisorption of the first H2 molecule occurs on all materials. Metal hydrides preferentially exhibit strong hybridization between the H-1s and Ti-3d orbitals. Furthermore, Ti4 decorated B-graphene is the most effective, with a high capacity of hydrogen adsorption which could be released under practical conditions. We confirmed that eight H2 molecules could stably adsorb on Ti4/BGr with six reversible hydrogen adsorptions. Our proposed B-doped graphene-based material, Ti4/BGr, offers high cluster-stability on the substrate with high-capacity hydrogen storage compared to various other surfaces in the previous work. Therefore, Ti4 decorated B-graphene is a promising candidate material for use as a reversible hydrogen storage material.

A single palladium (Pd) atom embedded in a high curvature defective carbon nanocone (Pd/dCNC) is investigated for formic acid (FA) decompositions using DFT calculations. We used Pd/dCNC as the catalyst for either trans-FA or cis-FA decomposition. FA is stably adsorbed on Pd/dCNC with very high adsorption energy compared to the Pd/dG surface. For the reaction mechanisms, the preferable FA dehydrogenation mechanisms proceed via the formate pathway, with a rate-determining step of only 0.50 eV (trans-FA) and 0.54 eV (cis-FA), which are less than that on active Pd (111) catalysts. The rate of hydrogen (H2) production is dependent on the FA concentration. The active neighboring C atom plays a significant role in facilitating FA dehydrogenation into H2. The side reaction producing CO and H2O via the formyl or carboxyl pathway cannot occur on Pd/dCNC due to a high energy-barrier and low production rate obtained by microkinetic simulations. Thus, our proposed catalysts effectively provide excellent activity and selectivity for FA dehydrogenation into H2.

A number of groups have invested considerable time synthesizing double-decker silsesquioxane (DD SQ) copolymers; however, to our knowledge, no one has sought to explore through-chain electronic com...

Two undescribed sesquiterpenoids, namely dysoticans A and B, and three undescribed sesquiterpenoid dimers, namely dysoticans C-E, together with six analogs, were isolated from the stem bark of Dysoxylum parasiticum (Osbeck) Kosterm. (Meliaceae), growing in West Java, Indonesia. Their structures were elucidated based on extensive spectroscopic analysis and theoretical simulations of ECD spectra and

Four donor–acceptor (D–A) type organic semiconductors, consisting of 5-hexylthiophene with thiophene/furan flanked benzothiadiazole/naphthothiadiazole, were investigated for organic field effect transistor (OFET) application. Despite being an analogue of thiophene, furan has received less attention in organic electronics due to its dissimilar properties to thiophene and instability in photochemical oxidation. Nevertheless, this study determines that furan could display comparable charge transport properties to its analogue. The extension of the electron-accepting thiadiazole core with the benzo group and different heteroatom flanking groups were investigated to show that the performance of OFETs is dependent on the molecular orbital, geometry, and packing. Bottom-gate bottom-contact device configuration was used to study the OFET transport properties of all the molecules. We successfully proved that a furan unit is a promising building block with a mobility (μmax) of 0.0122 cm2 V−1 s−1 for devices employing furan-substituted benzothiadiazole as the channel layer.

Hydrogen sulfide (H2S) leads to corrosion in transport lines and poisoning of many catalysts. Meanwhile, H2S is an inexhaustible potential source of hydrogen, which is a very valuable chemical reagent and an environmentally friendly energy product. Therefore, removal of H2S and producing hydrogen gas using potential catalysts has been intensively studied, according to the equation: H2S(g) + CO(g) → COS(g) + H2(g). In this study, hydrogen sulfide (H2S) decomposition in the presence of CO over transition metal-doped ZSM-12 clusters (TM-ZSM-12) has been investigated based on DFT calculations at the B3LYP-D3/6-31G(d,p) level. The calculation results reveal that the proposed reaction mechanism is controlled by 4 key steps, (i) hydrogen dissociation (Ea1 = +0.04 eV for the 1st hydrogen and Ea2 = +0.22 eV for the 2nd hydrogen), (ii) COS desorption (the rate-determining step of this H2S removal process, Edes = +1.18 eV), (iii) hydrogen diffusion to the transition metal with an energy barrier (Ea3) of +0.62 eV, and (iv) the H2 formation step (Ea4 = +0.94 eV). Our results indicate that in the presence of CO, the Cu–ZSM-12 cluster has a potential application as a highly active catalyst for H2S removal together with hydrogen production.

In this work, we investigate the catalytic role of platinum-decorated defective CNC (Pt/dCNC) in CO2 hydrogenation to formic acid (FA) by a density functional theory (DFT) approach. The reaction follows the equation CO2(g) + H2(g) → HCOOH(g). Combining highly reactive Pt atoms with defective CNC provides Pt/dCNC, a reactive monodispersed atomic catalyst for CO2 hydrogenation. We propose our new mechanism of CO2 hydrogenation over the Pt/dCNC catalyst involving a H2 dissociation and H spillover sequence that is energetically favorable. The rate-determining step is formic acid desorption that requires an energy barrier of 1.11 eV. Furthermore, our findings show that the rate of FA production is dependent on H2 concentration. Altogether, the theoretical results support the concept of the spillover mechanism, playing a key role in promoting CO2 hydrogenation via a formate intermediate. These results improve our understanding of the mechanism involving H2 dissociation with the H spillover process and the catal...

We investigated metal-free dyes based on isoindigo by performing density functional theory and Time-dependent density functional theory calculations to improve the efficiency of dye-sensitized solar cells. The D–π′–A′–π–A organic dyes (TIDP and TIDT) used triphenylamine as donor, thiophene as the π′-linker between the donor and auxiliary acceptor, and a phenyl or thiophene ring as the π-linker between the auxiliary acceptor and acceptor. TIDP and TIDT exhibit good charge-transfer properties. The TIDP-based device provides better device performance with a PCE of 4.11%. Calculated results reveal that the phenyl ring directly linking the auxiliary acceptor and acceptor causes a small tilt angle in the TiO2–adsorped dye, resulting in enhanced electron-injection rates, more efficient packing of adsorbed dye molecules, and slow charge recombination at the TiO2 surface. The performance of the TIDT-based device (η = 2.46%), arises from decreased electron-injection rates and fast charge recombination caused by the large dihedral angle of the adsorbed dye. This research identifies a potential π′-linker group and reveals the influence of the π-linker on photovoltaic performance in organic dyes. The phenyl ring directly linking the auxiliary acceptor and acceptor causes a smaller tilt angle in the TiO2-absorbed dye compared to thiophene ring resulting in enhanced electron-injection rates with increasing short-circuit current density (Jsc) as well as slow charge recombination at the TiO2 surface with increasing open-circuit voltage (Voc).

A coordination complex, lithium hepta(i-butyl)silsesquioxane trisilanolate (1; Li-T7), a stable intermediate in silsesquioxane (SQ) syntheses, was successfully isolated in 65% yield and found to be...

Bromination and iodination of title double decker (DD) phenylsilsesquioxane macromonomers occurs at ortho and para positions, respectively, as in PhT8,10,12 cages. Heck cross-coupling with 4-Me/CNs...

Macromonomers [RPhSiO1.5]8,10,12 and [RCH═CHSiO1.5]8,10,12, where R is a conjugated group, have previously been shown to offer photophysical properties wherein excitation promotes an electron from ...

The adsorption properties of the hydrogen atom on our newly designed materials were investigated using density functional theory (DFT) calculations, focusing on the role of dopants in modulating the binding properties of the metal. We proposed decorating Ti

Seven new polyketides including a phenol (

Indacenodithiophene (IDT) is a major building block for the design of advanced functional π-conjugated polymers and nonfullerene electron-acceptor materials for organic photovoltaics. Preliminary results of a synthetic approach aiming at the modulation of the electronic properties of IDT-based acceptors by modification of the mode of linkage of the thiophene rings with the median phenyl ring are presented. The synthesis of three acceptor-donor-acceptor (A-D-A) structures corresponding to the different possible modes of thiophene-phenyl connection (1–3) is described and their electronic properties are discussed on the basis of the results of UV–Vis absorption spectroscopy, cyclic voltammetry and theoretical calculations.

Fourteen undescribed phloroglucinol-meroterpenoids, namely eucalypcamals A-N, were isolated from a CH

A new fluorescence probe based on [5]helicene derivative (MT) was designed and synthesized. The chemical structure of the probe was fully characterized by NMR, mass spectrometry and X-ray crystallography. MT which is the combination of thioamide [5]helicene with Schiff base-thiophene moiety, exhibited a high selectivity to detect Hg2+ through irreversible desulfurization reaction with “Turn ON” fluorescence response and large Stokes shift of 110 nm in aqueous methanol solution. The detection limit of MT was 1.2 ppb (6.0 × 10−3 µM), which is lower than the limit of Hg2+ level in drinking water, as specified by WHO (6.0 ppb) and U.S. EPA (2.0 ppb). The Hg2+ detection range of the probe was 0.07–1.6 µM with good linearity. Under UV irradiation, MT possessed the capability to detect Hg2+ in diverse context of real samples, including drinking and sea waters, vegetable tissue and brain tumor cell. In addition, MT could be used as a paper test strip for monitoring and screening of Hg2+ contamination in environment.

The synthesis of a dyad involving a small arylamine-dicyanovinyl push-pull system as donor block and C60 fullerene as acceptor, connected by a flexible insulating linker formed by esterification of a β-hydroxymethylthiophene spacer is described. Unlike previously reported parent dyads with linkers connected at the 2-position of the thienyl spacer, this mode of connection allows the preservation of a free carbaldehyde group and thus the possibility to modulate the energy levels of the push-pull donor block. The electronic properties of the new dyad are analyzed by UV–Vis absorption spectroscopy, cyclic voltammetry, and theoretical calculations. A preliminary evaluation of this compound as active material for single-material organic solar cells is reported and discussed with reference to the mode of linkage of donor and C60 blocks.

Multiple studies have explored using cage silsesquioxanes (SQs) as backbone elements in hybrid polymers motivated by their well-defined structures, physical and mechanical properties. As part of this general exploration, we reported unexpected photophysical properties of copolymers derived from divinyl double decker (DD) SQs, [vinyl(Me)Si(O 0.5 ) 2 ][PhSiO 1.5 ] 8 [(O 0.5 ) 2 Si(Me)vinyl] (vinylDDvinyl). These copolymers exhibit strong emission red-shifts from model compounds and implying unconventional conjugation, despite vinyl(Me)Si(O-) 2 siloxane bridges. In an effort to identify minimum SQ structures that do/do not offer extended conjugation; we explored Heck catalyzed co-polymerization of vinyl-ladder(LL)-vinyl compounds, vinyl(Me/Ph)Si(O 0.5 ) 2 [PhSiO 1.5 ] 4 (O 0.5 ) 2 Si(Me/Ph)vinyl, with Br-Ar-Br where Br-Ar-Br = 1,4-dibromobenzene, 4,4'-dibromo-1,1'-biphenyl, 4,4''-dibromo- p -terphenyl, 4,4'-dibromo- trans -stilbene, 2,7-dibromo-9,9-dimethyl-9H-fluorene, 2,5-dibromothiophene, 5,5'-dibromo-2,2'-bithiophene and 2,5-dibromo-thieno[3,2- b ]thiophene. Most surprising, the resulting oligomers show 30-60 nm emission red-shifts beyond those seen with vinylDDvinyl analogs despite lacking a true cage . Further evidence for unconventional conjugation includes apparent integer charge transfer (ICT) between LL-co-thiophene, bithiophene and thienothiophene with 10 mol% F 4 TCNQ, suggesting potential as p-type doped organic/inorganic semiconductors. Brominating DD/LL-co-phenyl polymer vinyl groups eliminates emission red-shifts. Zn debromination thereafter restores vinyl groups and emission red-shifts but brominated phenyls remain providing potential access to families of "hairy" conjugated SQ polymers.

The synthesis of a series of four donor-π-acceptor (D-π-A) compounds involving pyrene derivatized with hexylcyanoacetate acceptor groups connected by phenyl or thienyl π-conjugating spacers is described. The electronic properties are characterized by UV–Vis absorption spectroscopy, cyclic voltammetry theoretical calculations and solvatochromism experiments. The results indicate that the thienyl connectors leads to D-π-A systems with smaller optical gaps and stronger internal charge transfers attributed to the combined effects of the lower resonance energy of thiophene, the smaller twist angles between the pyrene block and the π-connector and the deformability of the thiophene ring.

Hydrogen sulfide (H

This study reports UV–Visible spectra and electronic structures of indigo (IG) in aqueous solution using a combination of experimental and theoretical methods. In the visible region, the experimental absorption spectrum of the solution showed a broad peak with the longest wavelength of maximal absorption (λmax) value at 708 nm. For the theoretical method, a trans-IG monomer and a trans-IG bound with two water molecules (IG.2W) were optimized in the ground state using the B3LYP and B3LYP-D3 calculations with the 6-31 + G(d,p) basis set and the SCRF-CPCM model for taking solvent effect into account was also applied. Sequentially, the UV–Visible spectra and λmax of the optimized trans-IG and IG.2W models in the implicit water were simulated by the time-dependent density functional theory (TD-DFT) calculations. The TD-DFT methods including BLYP, B3LYP, PBE0, CAM-B3LYP, M06-2X, ωB97XD, LC-BLYP, and LC-ωPBE functionals without and with the D3 correction and the 6-31 + G(d,p) basis set were selected. The results pointed out that BLYP and BLYP-D3 were the best methods because they could reproduce the experimental λmax value of IG in aqueous solution. The predicted λmax values of IG.2W were almost equal to 708 nm (the experimental data), indicating that IG.2W could be responsible for optical properties of IG.