Narrowband emission from fully-bridged triphenylamine derivatives: insights into effects of structure modification and pressure.

Triphenylamine derivatives with narrowband emission have attracted growing attention in purely organic thermally-activated fluorescence (TADF) materials owing to their enhanced color purity and flexible molecular design strategy. Combined time-dependent density functional theory (TD-DFT) and ONIOM (QM/MM) calculations indicate that the excellent planarity of the experimentally developed DQAO could result in gradually decreased intermolecular interactions in the aggregated state at ambient pressure and upon compression, which is unfavorable for suppressing structural relaxation and achieving narrowband emission in its non-doped practical application. Therefore, three structure-modified derivatives, DQAO-Cb, DQAO-Ph, and DQAO-PhCb, were theoretically designed by introducing the spherical o-carborane and dangling phenyl units positioned para to the N atom of the DQAO to provide additional geometrical distortion and steric hindrance. The explorations on the reported DQAO, OQAO, and SQAO found that small structural relaxations, suppressed low-frequency vibrations, and noticeable short-range charge-transfer (SR-CT) natures of DQAO and OQAO are responsible for their much narrower emission spectral full-width at half-maxima (FWHMs) compared to that of SQAO. Introducing the o-carborane unit directly at the para position of the N atom could result in additional scissoring and stretching vibrations of the corresponding DQAO-Cb while the presence of the phenyl unit in DQAO-Ph is beneficial for suppressing the high-frequency vibrations of the pristine DQAO. More importantly, the bridged phenyl unit incorporated in DQAO-PhCb is of particular importance to inhibit the undesired low-frequency scissoring and high-frequency stretching vibrations of the o-carborane unit, which is crucial to reduce the reorganization energy of DQAO-PhCb and achieve narrowband emission. Also, the phenyl unit in DQAO-Ph and DQAO-PhCb helps to shorten charge transfer distances and improve ISC and RISC processes. Since the o-carborane unit is an adopted building block to achieve piezochromic behaviors, the theoretically structure-modified DQAO-PhCb is expected to exhibit narrowband emission, TADF, and piezochromic features all together. Our findings will hopefully provide ideas for designing triphenylamine-based TADF emitters with narrowband emission and piezochromic behaviors.

Selective Four-Electron Reduction of Oxygen by a Nonheme Heterobimetallic CuFe Complex.

We report herein the first nonheme CuFe oxygen reduction catalyst ([CuII (bpbp)(µ-OAc)2 FeIII ]2+ , CuFe-OAc), which serves as a functional model of cytochrome c oxidase and can catalyze oxygen reduction to water with a turnover frequency of 2.4×103  s-1 and selectivity of 96.0 % in the presence of Et3 NH+ . This performance significantly outcompetes its homobimetallic analogues (2.7 s-1 of CuCu-OAc with %H2 O2 selectivity of 98.9 %, and inactive of FeFe-OAc) under the same conditions. Structure-activity relationship studies, in combination with density functional theory calculation, show that the CuFe center efficiently mediates O-O bond cleavage via a CuII (µ-η1 : η2 -O2 )FeIII peroxo intermediate in which the peroxo ligand possesses distinctive coordinating and electronic character. Our work sheds light on the nature of Cu/Fe heterobimetallic cooperation in oxygen reduction catalysis and demonstrates the potential of this synergistic effect in the design of nonheme oxygen reduction catalysts.

Heterobimetallic NiFe Cooperative Molecular Water Oxidation Catalyst.

We reported herein the development of heterobimetallic NiFe molecular platform to understand NiFe synergistic effect in water oxidation catalysis. Compared to homonuclear bimetallic compounds (NiNi and FeFe), NiFe complex possesses more remarkable catalytic water oxidation performance. Mechanistic studies suggest that this remarkable difference is attributed to the fact that NiFe synergy can effectively promote O-O bond formation. The generated NiIII (µ-O)FeIV =O is the key intermediate and O-O bond was formed via intramolecular oxyl-oxo coupling between bridged O radical and terminal FeIV =O moiety.

"Three-in-One" Structural-Building-Mode-Based Ti16-Type Titanium Oxo Cluster Entirely Protected by the Ligands Benzoate and Salicylhydroxamate.

Titanium oxo clusters (TOCs) with accurate molecular structures have potential applications in photocatalysis, such as photocatalytic degradation, hydrogen production, and water oxidation. The hydrolytic stability and light absorption ability of TOCs have important impacts on photocatalysis, where the selection of peripheral organic ligands plays a significant role. In this regard, salicylhydroxamic acid (abbreviated as H3L) attracts our attention, acting as a ligand for its multidentate and dye-functional features, which can increase the hydrolytic stability and broaden light absorption for TOCs. Herein, two TOCs were solvothermally synthesized and structurally characterized using H3L, formulated as [Ti8(µ2-O)2(µ3-O)2(OiPr)12(L)4]·2CH3CN (1) and [Ti16(µ2-O)10(µ3-O)4(PhCOO)14(L)6(HL)2]·4CH3CN·2iPrOH (2). Complex 2 was obtained by adding excessive benzoic acid over the reaction system of 1, resulting in enhanced hydrolytic stability via the replacement of all alkoxy ligands by multidentate ligands for protection. Interestingly, for the first time, the "three-in-one" structural building mode with {Ti6} + {Ti4} + {Ti6} by the common subunits in 2 was observed among all reported TOCs. Moreover, complex 2 can strongly absorb visible light reaching up to 700 nm and exhibit obvious activity for the photodegradation of methyl orange.

Memory Suppression Ability can be Robustly Predicted by the Internetwork Communication of Frontoparietal Control Network.

Memory suppression (MS) is essential for mental well-being. However, no studies have explored how intrinsic resting-state functional connectivity (rs-FC) predicts this ability. Here, we adopted the connectome-based predictive modeling (CPM) based on the resting-state fMRI data to investigate whether and how rs-FC profiles in predefined brain networks (the frontoparietal control networks or FPCN) can predict MS in healthy individuals with 497 participants. The MS ability was assessed by MS-induced forgetting during the think/no-think paradigm. The results showed that FPCN network was especially informative for generating the prediction model for MS. Some regions of FPCN, such as middle frontal gyrus, superior frontal gyrus and inferior parietal lobe were critical in predicting MS. Moreover, functional interplay between FPCN and multiple networks, such as dorsal attention network (DAN), ventral attention network (VAN), default mode network (DMN), the limbic system and subcortical regions, enabled prediction of MS. Crucially, the predictive FPCN networks were stable and specific to MS. These results indicated that FPCN flexibility interacts with other networks to underpin the ability of MS. These would also be beneficial for understanding how compromises in these functional networks may have led to the intrusive thoughts and memories characterized in some mental disorders.

The changes in spatial layout of steel industry in China and associated pollutant emissions: A case of SO2.

The spatial layout of the steel industry has an impact on the regional atmospheric environment. In this study, the steel industry evolution model and the driving force analysis model were combined to analyze the evolution of spatial layout of the steel industry in China and the driving factors of this evolution. In addition, the WRF-SMOKE-CMAQ model was used to analyze the spatial dynamics of SO2 emissions from the steel industry. Our analysis presents the evolution of the steel industry in China in four stages: policy-determining, resource-oriented, economic promotion and market-oriented stage. The change in the spatial layout of the Chinese steel industry resulted in a continuously decreasing trend of pollutants in temporal characteristics and a decreasing share of emissions in North China and a continuous growth in East China in spatial characteristics. Our simulation shows that, by 2025, the pollutant SO2 emission concentration will migrate to the southeast, subject to market-oriented factors.

Redox-Active Ligand Assisted Catalytic Water Oxidation by a RuIV =O Intermediate.

Water splitting is one of the most promising solutions for storing solar energy in a chemical bond. Water oxidation is still the bottleneck step because of its inherent difficulty and the limited understanding of the O-O bond formation mechanism. Molecular catalysts provide a platform for understanding this process in depth and have received wide attention since the first Ru-based catalyst was reported in 1982. RuV =O is considered a key intermediate to initiate the O-O bond formation through either a water nucleophilic attack (WNA) pathway or a bimolecular coupling (I2M) pathway. Herein, we report a Ru-based catalyst that displays water oxidation reactivity with RuIV =(O) with the help of a redox-active ligand at pH 7.0. The results of electrochemical studies and DFT calculations disclose that ligand oxidation could significantly improve the reactivity of RuIV =O toward water oxidation. Under these conditions, sustained water oxidation catalysis occurs at reasonable rates with low overpotential (ca. 183 mV).

[Secondary metabolites from Epicoccum nigrum 14one,an endophytic fungus isolated from plant Leptogium masiaticum].

Phytochemical investigation of the culture of Epicoccum nigrum,an endolichenic fungus inhabiting Leptogium masiaticum,led to the isolation of 11 compounds. Based on NMR spectroscopy and HRESIMS data,their structures were determined as one alkaloid fusaricide( 1),and seven benzofuran derivatives including epicoccone( 2),4,6-dihydroxy-5-methoxy-7-methyl-1,3-dihydro isobenzofuran( 3),5-methyl-epicoccone B( 4),3,6,7-trihydroxy-5-methoxy-4-methylisobenzo furan-1( 3 H)-one( 5),3-methoxyepicoccone B( 6),2,3,4-trihydroxy-6-( hydroxymethyl)-5-methylbenzyl-alcohol( 7),and isoochracinic acid( 8),together with three epicoccolide analogs epicocconigrones A( 9),epicoccolide B( 10),and epicocconigrones B( 11). Compounds 1,9 and 10 showed potent microorganism inhibitory effects. These results indicated the potential perspective of this endophytic fungus as an eco-friendly biocide.

MiR-139-5p suppresses osteosarcoma cell growth and invasion through regulating DNMT1.

BACKGROUND: Accumulating evidence has suggested the crucial roles of differentially expressed miRNAs in osteosarcoma progression. MiR-139-5p was decreased in various cancers. However, the role of miR-139-5p in the development of osteosarcoma and the underlying mechanism remain to be addressed. METHODS: MiR-139-5p and DNA methyltransferase-1 (DNMT1) mRNA expressions in osteosarcoma tissues and cells were detected by qRT-PCR and western blot analysis. The effects of miR-139-5p and DNMT1 on osteosarcoma cell migration, invasion and epithelial-mesenchymal transition (EMT) were investigated through cell migration and invasion assays, and western blot analysis. The relationship between miR-139-5p and DNMT1was explored using luciferase reporter analysis and western blot. A xenograft tumor model was employed to verify the effects of miR-139-5p on osteosarcoma. RESULTS: We found that miR-139-5p was strikingly decreased in osteosarcoma tissues and cell lines. MiR-139-5p over-expression suppressed osteosarcoma cell growth, migration and invasion, while loss of miR-139-5p promoted osteosarcoma cell proliferation, migration and invasion. Following, we characterized that DNMT1 was a direct target of miR-139-5p that interacted with the 3'-untranslated region of DNMT1. MiR-139-5p regulated a down-regulation in DNMT1 protein expression levels. We also found that DNMT1 expression was increased and negatively correlated with miR-139-5p expression in osteosarcoma tissues clinically. Xenograft tumor analysis suggested that miR-139-5p over-expression reduced tumor growth in osteosarcoma in vivo through decreasing DNMT1 expressions. CONCLUSION: MiR-139-5p suppressed the osteosarcoma progression by reducing DNMT1, supplying new insight into the molecular mechanism uncovering osteosarcoma growth.

Liquid chromatography with tandem mass spectrometry method for the simultaneous determination of multiple sweet mogrosides in the fruits of Siraitia grosvenorii and its marketed sweeteners.

A high-performance liquid chromatography with electrospray ionization tandem mass spectrometry method has been developed and validated for the simultaneous quantification of eight major sweet mogrosides in different batches of the fruits of Siraitia grosvenorii and its marketed sweeteners. The sample preparation procedure and chromatographic and mass spectrographic conditions were optimized. Chromatographic separation was achieved on a reversed-phase Poroshell 120 SB C18 column in 10.0 min with gradient elution with acetonitrile and water, both of which contained 0.1% formic acid. The multiple reaction monitoring scanning mode was employed for quantification in the negative ion mode. The developed method was validated with acceptable linearity (r2 = 0.9984-0.9998) over a wide concentration range, precision (relative standard deviations = 1.09-3.91%), stability (relative standard deviations = 1.21-3.01%), and recovery in the range of 91.22-106.58% (relative standard deviations ≤ 3.79%) under optimum conditions. The proposed method was demonstrated to be simple, rapid, specific, and reliable and was successfully applied for the quality control of the fruits of S. grosvenorii and its marketed sweeteners.

In Vitro Propagation Technology for the Endangered Aquatic Species Nymphoides coronata.

Nymphoides coronata is an endangered aquatic plant species with significant medicinal and ecological importance. To preserve N. coronata from going extinct, we need to provide seedlings and efficient multiplication techniques so that it can be extensively studied. This study aimed to identify the most suitable sterilization treatment, growth medium, and substrate for the cultivation and propagation of N. coronata. Ethanol sterilization, fungicide treatment, and sterile water washing were the most important sterilization steps. A combination of 6-benzylaminopurine (6-BA) and indoleacetic acid (IAA) was the most suitable medium for bud induction and shoot proliferation. The use of α-naphthaleneacetic acid (NAA) increased the rooting rate and rooting time compared to indole-3-butyric acid (IBA). Increasing the concentration of NAA from 0.5 to 1.0 mg/L increased the rooting rate from 78 to 100% and reduced the rooting time from 7 to 5 days. The survival rate of N. coronata seedlings was 100% in a mixture of red soil and sand (1:1, w/w). As a result, the procedure mentioned above could potentially be used to safely propagate this rare species on a large scale. These findings provide valuable insights into the optimal conditions for the successful cultivation and propagation of N. coronata, which can contribute to the conservation and sustainable use of this important rare plant species.

Redox-Active Ligand Assisted Multielectron Catalysis: A Case of Electrocatalyzed CO2-to-CO Conversion.

The selective reduction of carbon dioxide remains a significant challenge due to the complex multielectron/proton transfer process, which results in a high kinetic barrier and the production of diverse products. Inspired by the electrostatic and H-bonding interactions observed in the second sphere of the [NiFe]-CODH enzyme, researchers have extensively explored these interactions to regulate proton transfer, stabilize intermediates, and ultimately improve the performance of catalytic CO2 reduction. In this work, a series of cobalt(II) tetraphenylporphyrins with varying numbers of redox-active nitro groups were synthesized and evaluated as CO2 reduction electrocatalysts. Analyses of the redox properties of these complexes revealed a consistent relationship between the number of nitro groups and the corresponding accepted electron number of the ligand at -1.59 V vs. Fc+/0. Among the catalysts tested, TNPPCo with four nitro groups exhibited the most efficient catalytic activity with a turnover frequency of 4.9 × 104 s-1 and a catalytic onset potential 820 mV more positive than that of the parent TPPCo. Furthermore, the turnover frequencies of the catalysts increased with a higher number of nitro groups. These results demonstrate the promising design strategy of incorporating multielectron redox-active ligands into CO2 reduction catalysts to enhance catalytic performance.

2-[7-Chloro-1,1-dioxo-2-(2,4,5-trifluoro-benz-yl)-3,4-dihydro-2H-1,2,4-benzothia-diazin-4-yl]acetic acid.

In the mol-ecule of the title compound, C(16)H(12)ClF(3)N(2)O(4)S, the thia-diazine ring adopts a half-chair conformation. The dihedral angle between the benzene ring of the benzothia-diazine ring system and trifluoro-phenyl group is 15.02 (7)°. In the crystal, centrosymmetrically related mol-ecules are linked into dimers via pairs of O-H⋯O hydrogen bonds, generating R(2) (2)(8) ring motifs. The dimers are further connected into a three-dimensional network by C-H⋯O hydrogen bonds.

Preparation and Study of Folate Modified Albumin Targeting Microspheres.

In this study, folate modified bovine serum albumin was successfully synthesized, while preparation of Nintedanib albumin microspheres (ND-FSA NPs) as a carrier was carried out via electrospinning technology. Folate modified albumin was used to enhance the targeting potential of the prepared microspheres. The prepared microspheres had spherical appearance and smooth outer surface. The diameters of microspheres (764.68 ± 88.46 nm) and zeta potential (- 18.38 ± 0.41 mV) were acceptable. The prepared ND-FSA NPs demonstrated a good degree of modification, wherein the modification rate was 28.1%. In vitro release was significantly increased in three different media (double deionized water-DDW, HCl-pH 1.2, and phosphate buffered solution containing 0.5% Tween 80). It is worth noting that incorporation of Nintedanib into folic acid modified albumin microspheres resulted in an enhanced uptake of the drug into MCF-7 breast cancer cells coupled with higher inhibition rate. Altogether, incorporation of Nintedanib into folate modified albumin microspheres is a new approach to improve water solubility and targeting effect of the drug.

Efficient capture and stabilization of iodine via gas-solid reaction using cyclodextrin metal-organic frameworks.

For treatment of wound infection with stabilized iodine, potassium iodide cyclodextrin metal-organic frameworks (KI-CD-MOF) was prepared to carry iodine via gas-solid reaction. Apart from highly ordered porous frameworks, KI-CD-MOF contains uniformly distributed iodide ions which stabilize iodine (I2). X-ray photoelectron spectroscopy and potentiometric titration were utilized to confirm the formation of I3- in the highly porous KI-CD-MOF as I2@KI-CD-MOF. Molecular simulation and characterizations of the synchrotron radiation Fourier transform infrared spectroscopy, differential scanning calorimeter, powder X-ray diffraction and N2 adsorption were conducted to illustrate the inclusion mechanism of iodine in I2@KI-CD-MOF. The apparent solubility of iodine in water was 3.86 times enhanced. The stability and antibacterial activity tests demonstrated that the highly-dispersed iodide ions in KI-CD-MOF are crucial in improvement to the solubility, stability, and bacteriostatic effects of active iodide. Therefore, KI-CD-MOF has broad application prospects and advantages in efficiently capturing and stabilizing iodine.

Tetra-µ(2)-acetato-diaqua-bis-(µ(2)-2-{[1,3-dihy-droxy-2-(oxidometh-yl)propan-2-yl]imino-meth-yl}phenolato)trimanganese(II,III) acetonitrile disolvate dihydrate.

In the title complex, [Mn(II)Mn(III) (2)(C(11)H(13)NO(4))(2)(CH(3)CO(2))(4)(H(2)O)(2)]·2CH(3)CN·2H(2)O, there are two Mn(III) and one Mn(II) atoms. The Mn(II) atom lies on an inversion center and the Mn(III)-Mn(II)-Mn(III) angle is therefore 180°, as required by crystallographic symmetry. The Mn(III) and Mn(II) atoms are six-coordinated in a distorted octa-hedral geometry. In the crystal, complex mol-ecules and solvent mol-ecules are linked into a three-dimensional network by O-H⋯O and O-H⋯N hydrogen-bonding inter-actions.

Task compliance predicts suppression-induced forgetting in a large sample.

Suppression-induced forgetting (SIF) refers to a memory impairment resulting from repeated attempts to stop the retrieval of unwanted memory associates. SIF has become established in the literature through a growing number of reports built upon the Think/No-Think (TNT) paradigm. Not all individuals and not all reported experiments yield reliable forgetting, however. Given the reliance on task instructions to motivate participants to suppress target memories, such inconsistencies in SIF may reasonably owe to differences in compliance or expectations as to whether they will again need to retrieve those items (on, say, a final test). We tested these possibilities on a large (N = 497) sample of TNT participants. In addition to successfully replicating SIF, we found that the magnitude of the effect was significantly and negatively correlated with participants' reported compliance during the No-Think trials. This pattern held true on both same- and independent-probe measures of forgetting, as well as when the analysis was conditionalized on initial learning. In contrast, test expectancy was not associated with SIF. Supporting previous intuition and more limited post-hoc examinations, this study provides robust evidence that a lack of compliance with No-Think instructions significantly compromises SIF. As such, it suggests that diminished effects in some studies may owe, at least in part, to non-compliance-a factor that should be carefully tracked and/or controlled. Motivated forgetting is possible, provided that one is sufficiently motivated and capable of following the task instructions.

A Novel Azaphilone Muyophilone A From the Endophytic Fungus Muyocopron laterale 0307-2.

Two known azaphilone derivatives, 4,6-dimethylcurvulinic acid (1) and austdiol (2), and their novel heterotrimer, muyophilone A (3), were isolated and identified from an endophytic fungus, Muyocopron laterale 0307-2. Their structures and stereochemistry were established by extensive spectroscopic analyses including HRMS, NMR spectroscopy, electronic circular dichroism (ECD) and vibrational circular dichroism (VCD) spectroscopic methods, as well as single crystal X-ray diffraction. In the structure of 3, two compound 2-derived azaphilone units were connected through an unprecedented five-membered carbon bridge which was proposed to be originated from compound 1. Compound 3 represents the first example of azaphilone heterotrimers.

Bis(ferrocene-carboxyl-ato-κO)bis-(2-pyridyl-methanol-κN,O)cobalt(II).

The title complex mol-ecule, [Fe(2)Co(C(5)H(5))(2)(C(6)H(4)O(2))(2)(C(6)H(7)NO)(2)], has a crystallographic imposed centre of symmetry. The Co(II) atom displays a distorted octa-hedral coordination geometry, provided by the O atoms of two monodentate ferrocene-carboxyl-ate anions and by the N and O atoms of two 2-pyridyl-methanol mol-ecule. The mol-ecular conformation is stabilized by intra-molecular C-H⋯O hydrogen bonds.

Tetra-kis{µ(3)-2-[(2-hy-droxy-eth-yl)amino]-ethano-lato}tetra-kis-[chloridonickel(II)] methanol solvate.

The complex mol-ecule of the title compound, [Ni(4)(C(4)H(10)NO(2))(4)Cl(4)]·CH(3)OH, consists of a cubane-like {Ni(4)O(4)} core in which each nickel(II) atom is six-coordinated in a distorted octa-hedral geometry by one N and four O atoms of three mono-deprotonated diethano-lamine ligands and by a chloride anion. The mol-ecular conformation is stabilized by intra-molecular O-H⋯Cl bonds. In the crystal structure, complex mol-ecules and methanol solvent mol-ecules are linked into a three-dimensional network by N-H⋯Cl, N-H⋯O and O-H⋯Cl hydrogen-bonding inter-actions.