Search

A room-temperature electrochemical strategy for hydrogenation (deuteration) and reverse dehydrogenation of N-heterocycles over a bifunctional MoNi4 electrode is developed, which includes the hydrogenation of quinoxaline using H2O as the hydrogen source with 80% Faradaic efficiency and the reverse dehydrogenation of hydrogen-rich 1,2,3,4-tetrahydroquinoxaline with up to 99% yield and selectivity. The in situ generated active hydrogen atom (H*) is plausibly involved in the hydrogenation of quinoxaline, where a consecutive hydrogen radical coupled electron transfer pathway is proposed. Notably, the MoNi4 alloy exhibits efficient quinoxaline hydrogenation at an overpotential of only 50 mV, owing to its superior water dissociation ability to provide H* in alkaline media. In situ Raman tests indicate that the NiII/NiIII redox couple can promote the dehydrogenation process, representing a promising anodic alternative to low-value oxygen evolution. Impressively, electrocatalytic deuteration is easily achieved with up to 99% deuteration ratios using D2O. This method is capable of producing a series of functionalized hydrogenated and deuterated quinoxalines.

Superelectrophilic monoanions [B12 (BO)11 ]- and [B12 (OBO)11 ]- , generated from stable dianions [B12 (BO)12 ]2- and [B12 (OBO)12 ]2- , show great potential for binding with noble gases (Ngs). The binding energies, quantum theory of atoms in molecules (QTAIM), natural population analysis (NPA), energy decomposition analysis (EDA), and electron localization function (ELF) were carried out to understand the B-Ng bond in [B12 (BO)11 Ng]- and [B12 (OBO)11 Ng]- . The calculated results reveal that heavier noble gases (Ar, Kr, and Xe) bind covalently with both [B12 (BO)11 ]- and [B12 (OBO)11 ]- with large binding energies, making them potentially feasible to be synthesized. Only [B12 (OBO)11 ]- could form a covalent bond with helium or neon but the small binding energy of [B12 (OBO)11 He]- may pose a challenge for its experimental detection.

Current research suggests that cadmium (Cd) exposure may be associated with the progression of diabetic nephropathy; however, the details of this relationship are insufficiently understood. The present study investigated the effects of elevated glucose on Cd-induced toxicity to glomerular cells using in vitro and in vivo models, and it demonstrated that Cd exposure and the hyperglycemia of diabetes acting together increased the risk of developing glomerular nephrosis . In vitro, human podocytes were exposed to a DMEM low-glucose media without (control), or with Cd (as CdCl2), or a high-glucose media plus Cd. The CCK-8, ROS, apoptosis, and mitochondrial transmembrane potential (ΔΨm) assays showed that human podocytes exposed to Cd in a high-glucose media had greater degrees of injury compared with cells treated with Cd at low (euglycemic)-glucose levels. In vivo, diabetic hyperglycemia was induced by streptozotocin in 8-week-old male C57BL/6 mice to which either CdCl2 or saline (control) was intraperitoneally injected twice weekly for 24 weeks. Compared with euglycemic saline-treated controls, the diabetic mice exposed to Cd demonstrated decreased body weight and increased blood urea nitrogen levels along with histopathological renal architecture changes including collagen fiber accumulation. The results of this study supported the hypothesis that hyperglycemia plus Cd exposure increases the risk of damage to glomerular podocytes compared with Cd exposure in euglycemia.

Recently, one η1-coordinated complex of endohedral metallofullerene (EMF) Y@C2v(9)-C82[Re(CO)5] has been synthesized and characterized with a highly efficient radical-coupling methodology by performing a photochemical reaction between Y@C2v(9)-C82 and [Re(CO)5]2 complexes. Theoretical investigations with the density functional theory reveal that this complex is stabilized by an ionic C-Re bond. The reactions of M@C2v(9)-C82 (M = Sc, Y, La) with [Re(CO)5]2 suggest that the reaction energies differ little because of similar single occupied molecular orbitals (SOMOs) of M@C2v(9)-C82. In the reactions of Y@C2v(9)-C82 with various transition-metal complexes [M'Ln]2 (M' = Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir), the C-M' bonds with Mn, Tc, Re, Fe, Ru, and Os can stably exist, whereas those with Co, Rh, and Ir are unstable. Further analyses disclose that, in each element group, the stability of the C-M' bond is mainly determined by the bond energy of the M'-M' bond, which is related to the dσ orbital of the M'Ln species. Moreover, the very-low-energy dσ orbitals and large geometrical distortions of M'(CO)4 (M' = Co, Rh, Ir) lead to poor stabilities of the C-M' (M' = Co, Rh, Ir) bonds. As comparison, the reactions of Y@Cs(6)-C82 and La@C72 have been investigated. The Y@Cs(6)-C82 structure is more reactive toward the [M'Ln]2 complexes than Y@C2v(9)-C82 thanks to a lower SOMO of Y@Cs(6)-C82 than that of Y@C2v(9)-C82, which derives from position change of the Y atom in Cs(6)-C82 during the reactions. However, the formation of [Y@Cs(6)-C82]2 suppresses the formation of several C-M' bonds. The reactivity of La@C72 is weak due to a high LUMO+1 of C72, which leads to a high SOMO of La@C72. We believe that this theoretical study provides primary principles of radical-coupling reactions of EMFs and will be valuable for future research of organometallic complexes of fullerene.

Conductive ionenes were synthesized by integrating the electron donor dialkoxynaphthalene (DAN) with the electron acceptor naphthalene diimide (NDI) using the Menshutkin reaction. The crystallinity and morphology of the films of these polymers can be optimized by varying the DAN-to-NDI ratio. These ionenes show strong charge transfer from DAN to NDI, though absent conjugated backbones, affording self-doping polymers with enhanced π-π interactions and excellent electronic properties. This is the first example where an electron donor can dope the electron acceptor in nonconjugated polymers, opening a new avenue for designing efficient interlayer materials. These ionenes markedly modify the electrode interface and promote efficient interfacial self-doping to boost the performance of fullerene-based, non-fullerene-based, and ternary organic solar cells, affording high power conversion efficiencies over a wide range of interlayer thicknesses, from ∼8 to ∼40 nm, with a maximum efficiency of 17.05%.

Contains fulltext : 251688.pdf (Publisher’s version ) (Open Access)

There is still dispute over the stability of endohedral metallofullerenes (EMFs) M2C2n, and recently, multiform lutetium-based dimetallofullerenes have been dropped in experiments. The thermodynami...

First-principles calculations have been carried out for the 20-electron transition metal complexes (Cp)2TMO and their molecular wires (Cp = C5H5, C5(CH3)H4, C5(CH3)5; TM = Cr, Mo, W). The calculation results at the BP86/def2-TZVPP level reveal that the ground state is singlet and the optimized geometries are in good agreement with the experimental values. The analysis of frontier molecular orbitals shows that two electrons in the highest occupied molecular orbital HOMO-1 are mainly localized on cyclopentadienyl and oxygen ligands. Furthermore, the nature of the TM-O bond was investigated with the energy decomposition analysis-natural orbitals for chemical valence (EDA-NOCV). The attraction term in the intrinsic interaction energies ΔEint is mainly composed of two important parts, including electrostatic interaction (about 52% of the total attractive interactions ΔEelstat + ΔEorb) and orbital interaction, which might be the major determinant of the stability of these (Cp)2TMO complexes. All of the TM-O bonds should be described as electron-sharing σ single bonds [(Cp)2TM]+-[O]- with the contribution of 53-57% of ΔEorb and two π backdonations from the occupied p orbitals of oxygen ligands into vacant π* MOs of the [(Cp)2TM]+ fragments, which are 35-40% of ΔEorb. The results of bond order and interaction energy from EDA-NOCV calculations suggest the influence of the radius of TM and methyl in the interactions between TM and O in (Cp)2TMO. Additionally, the relativistic effects slightly amplify the strength of bonding with increasing ΔEorb for the EDA-NOCV calculations on three metal complexes (C5H5)2TMO. Finally, the geometries, electronic structures, and magnetics of infinitely extended systems, [(C5H5)TMO]∞, have also been explored. The results of the density of states (DOS) and band structure revealed that [(C5H5)CrO]∞ and [(C5H5)WO]∞ are semiconductors with the narrow bands, whereas [(C5H5)MoO]∞ behaves as metal.

Thus far, all the stable singlet carbenes consist of a center carbon atom, and electron donor or withdrawing substituents with heteroatoms, such as, N, P, O, and S. Herein, carbene was generated by the lithium–bromine exchange reaction and used to functionalize C60. The reaction mechanisms, including the lithium–bromine exchange and carbene addition reactions, were studied in detail with ab initio density functional theory. The interaction between LiBr and the carbon atom was first characterized as a mainly ionic interaction, combined with the coordinate interaction and hyperconjugation. Then, a novel stable singlet fullerene carbene without the heteroatom, was primitively generated via lithium–bromine exchange and carbene addition reactions; it exhibited a remarkable stability with high singlet–triplet energy gap and HOMO–LUMO energy gap. This computational survey indicates that fullerene carbene will be a potential ligand in the coordinated compounds, and is useful for further functionalization and applications of fullerenes. Furthermore, theoretical results show that the lithium–bromine exchange reaction would be a powerful and feasible tool to functionalize the double bonds in some aliphatic and aromatic olefins, including anthracene, benzene, propylene, ethylene, 1-butene, propanal, and 3-pentanone. Based on the carbene reaction mechanisms and nature of corresponding bonds in their products, two indexes, bond length and the hybridization state of atoms, were suggested to distinguish the carbene addition and insertion to the double bond.

In comparison with the prevalent 2D material-supported single atom catalysts (SACs), the design and fabrication of SACs with single molecule substrates are still challenging. Here we introduce a new type of SAC in which a recently identified all-boron fullerene B40 is employed as the support and its catalytic performance toward the nitrogen reduction reaction (NRR) process is explored in theory. Taking advantage of the novel heptagonal ring substructure on the sphere and the electron-deficient nature of boron, the atomic metals are facile to reside on B40 to form atomically dispersed η7-B40M exohedral complexes. Among a series of candidates, originating from the proper metal-adsorbate interactions, the atomic tungsten-decorated B40W is screened out as the most feasible catalyst for the NRR with a low over-potential and high selectivity to passivate the competitive hydrogen evolution process.

Ligand engineering based on a closo-B12-cage has been practiced in this work to design a series of stable gas-phase dianions [B12(ECX)12]2− (E = N, P, and As; X = O, S, and Se) via ab initio calculations. The calculated second electron affinities ranging from 1.2 to 3.4 eV indicate that these dianions are electronically stable against electron auto-detachment. Their electronic structures were analyzed based on molecular orbitals and natural bond orbitals. We found that in these designer dianions, the ECX ligands bind the B12-cage via B–E covalent interactions. We simulated the photoelectron spectra of these dianions and discussed the potential application of [B12(NCX)12]2− (X = O, S, and Se) salts as electrolytes in Li- or Mg-ion batteries.

Carbon materials based on different hybridization of carbon atoms have drawn great attention because of their unique configurations and physical and chemical properties. Here, a previously unknown 2D carbon allotrope named L-2Gy, graphene-like carbon matryoshka graphynes (Gy) with two alkynyls (C[triple bond, length as m-dash]C) inserted into the three-fold carbon atoms of graphene, has been constructed with considerable thermal, dynamical, and mechanical stability by using ab initio density functional theory. With the increasing number of alkynyls between the three-fold carbon atoms of graphene, the stability of Gy will seriously decrease. L-2Gy has a fascinating chemical bond environment consisting of sp- and sp2-hybridized carbon atoms, and delocalized π electrons derived from the 27 three-center two-electron π bonds. This particular electronic structure plays a vital role in chemically stabilizing L-2Gy. The electronic band structure reveals the semi-metallic features of L-2Gy mainly contributed by the px/z orbitals of carbon atoms. Furthermore, compared with the acknowledged catalysts for the hydrogen evolution reaction (HER), L-2Gy, as a 2D carbon allotrope, shows excellent catalytic activity for the HER.

Non-radiative recombination loss (ΔEnon-rad) has become the main limiting factor for the power conversion efficiency (PCE) of organic solar cells (OSCs). Herein, two benzo[1,2-b:4,5-b′]difuran (BDF) polymers (P-FT and P-FP) in combination with two electron acceptors (m-ITIC and Y6) in OSCs were employed to systemically investigate the impact of molecular orientation and interaction on energy loss in OSCs. The use of the Y6 acceptor instead of ITIC provided a reduced energy loss in OSC, regardless of the donor used, and the energy loss was lower in OSC based on P-FP, as compared to that based on P-FT. ΔEnon-rad as small as 0.23 eV was obtained in the P-FP:Y6 device, due to the small energetic disorder. In addition, the P-FP:Y6 device also possessed a promising EQEmax of 86.7%. These results provide a deep understanding of the role molecular interactions between the polymer donor and acceptor play in reducing energy loss and promoting device performance through synergic selection and optimization of donor and acceptor in OSCs.

Based on the DFT calculations, the sulfonamide was explored as an efficient hydrogen-atom transfer catalyst for the C(sp3)–H alkylation. The combination of a metal-free photoredox catalyst and a su...

We designed and synthesized two isomers AOIC1 and AOIC2 by unidirectional extension of the same asymmetric precursor in different directions and separated by selectivity of Lewis-acid-mediated Frie...

N6-methyladenosine (m6A) is the most abundant inner RNA modification in eukaryotes. Due to the development of RNA sequencing technology, the distribution pattern of m6A in the transcriptome has been uncovered. Dynamically, the reversible N6-methylation is mediated by two types of proteins, which are classified as “writers” and “erasers”. Under the association of specific co-factors, writers show spatiotemporal N6-methyltransferase activity. Mechanically, m6A can be recognized by “reader” proteins or can directly modify RNA conformation, and it widely affects gene expression by mediating RNA stability, translation, splicing and export. m6A is involved in a series of physiology processes. Dysregulation of m6A is gradually defined as the pathogenesis of some diseases, e.g., cancer and cardiovascular disease. Therefore, a good understanding of m6A is essential for molecular biology and pathology research. In this article we systemically present an overview of the functions and mechanisms of identified m6A regulators. The discovered biological and pathological processes affected by m6A are also summarized. We hope that readers with related research interests benefit from our review.

We designed and synthesized a series of fused-ring electron acceptors (FREAs) based on naphthalene-fused octacyclic cores end-capped by 3-(1,1-dicyanomethylene)-5,6-difluoro-1- indanone (NOICs) using a bottom-up approach. The NOIC series shares the same end groups and side chains, as well as similar fused-ring cores. The butterfly effects, arising from different methoxy positions in the starting materials, impact the design of the final FREAs, as well as their molecular packing, optical and electronic properties, charge transport, film morphology, and performance of organic solar cells. The binary-blend devices based on this NOIC series show power conversion efficiencies varying from 7.15% to 14.1%, due to the different intrinsic properties of the NOIC series, morphologies of blend films, and voltage losses of devices.

Aims In response to vascular injury, vascular smooth muscle cells (VSMC) may change from a contractile phenotype to a proliferative phenotype and consequently become conducive to neointima formation. Apoptosis repressor with caspase recruitment domain (ARC) was initially discovered as an endogenous apoptosis inhibitor, but whether ARC plays a role in VSMCs and whether it can participate in the regulation of atherosclerosis are unknown. Methods and results Protein and mRNA levels of ARC in tissues and cells were detected by western blot and quantitative real-time PCR. Immunofluorescence staining was used to detect the protein location, and immunohistochemistry was used to detect protein expression in tissues. VSMC proliferation was analysed using Cell Counting Kit-8 (CCK-8) and EdU assays, while migration was assessed by Transwell assay. Mechanistically, the direct binding between two proteins was verified by immunoprecipitation. We found that ARC expression was stimulated in VSMCs during cell proliferation. Our results also showed that ARC promoted cell proliferation and induced phenotypic modulation of VSMCs in vitro and vivo. Mechanistic studies demonstrated that ARC increased the nuclear localization of Yes associated protein (YAP) by binding to 14-3-3e and that ARC played a role in promoting cell proliferation and phenotypic modulation. Additionally, the transcription factor p53 negatively regulated ARC expression at the transcriptional level during cell proliferation and phenotypic modulation. Conclusions Our findings define a novel role for ARC in the phenotypic transition of proliferating VSMCs, which may provide a new strategy for regulating neointimal formation.

Precise deuterium incorporation with controllable deuterated sites is extremely desirable. Here, a facile and efficient electrocatalytic deuterodehalogenation of halides using D2 O as the deuteration reagent and copper nanowire arrays (Cu NWAs) electrochemically formed in situ as the cathode was demonstrated. A cross-coupling of carbon and deuterium free radicals might be involved for this ipso-selective deuteration. This method exhibited excellent chemoselectivity and high compatibility with the easily reducible functional groups (C=C, C≡C, C=O, C=N, C≡N). The C-H to C-D transformations were achieved with high yields and deuterium ratios through a one-pot halogenation-deuterodehalogenation process. Efficient deuteration of less-active bromide substrates, specific deuterium incorporation into top-selling pharmaceuticals, and oxidant-free paired anodic synthesis of high-value chemicals with low energy input highlighted the potential practicality.

Four-electron transfer from U to the fullerene cage commonly exists in U@C2n (2n < 82) so far, while four- and three-electron transfers, which depend on the cage isomers, simultaneously occur in U@...

Poisson’s ratio is one of the fundamental features of materials, reflecting the transverse strain response to the applied certain axial strain. The materials with a negative Poisson’s ratio, also known as auxetic materials, are rare in nature and attract lots of research interest because of their unusual mechanical behavior and extensive applications in mechanical nanodevices. Here, we proposed and studied a novel hyperbolic two-dimensional graphene-like structure (GLS) showing a negative Poisson’s ratio behavior by first-principles calculation. The thermodynamic, dynamic, lattice dynamic, and mechanical stabilities of the GLS were carefully studied. In addition, we also explored the electronic structure, mechanical characteristics, and optical-electronic characteristics. The GLS not only displays a negative Poisson’s ratio in certain directions but also shows low-gap semiconductor characteristics and superior electronic conductivity. It is a potential sunscreen material because of the outstanding reflection and absorption for ultraviolet and infrared light.

Purpose To investigate the risk factors associated with retinal detachment recurrence after first vitrectomy in high myopic eyes with macular hole retinal detachment (MHRD). Methods Patients with high myopic eyes with MHRD who underwent pars plana vitrectomy and silicone oil (SO) tamponade with a follow-up period more than 12 months and more than 3 months after SO removal were included in this retrospective study. Logistic regression was performed to determine the risk factors associated with retinal re-detachment. Results A total of 45 eyes from 43 patients were included in this study (11 male and 34 female patients). The retinal re-detachment rate after the first removal of silicon oil was 35.5% (16/45) in a mean postoperative follow-up time of 35.64 ± 32.94 months. Complete macular atrophy on fundus photography (odds ratio (OR) = 17.021, 95% confidence interval (95% CI): 2.218-130.609, p = 0.006) was a risk factor for MHRD after SO removal, while internal limiting membrane (ILM) peeling (OR = 0.091, 95% CI: 0.013-0.633, p = 0.015) and duration of SO tamponade (OR = 0.667, 95% CI: 0.454-0.980, p = 0.039) were protective factors. Conclusion For high myopic eyes with MHRD, complete macular atrophy was a significant risk factor for retinal re-detachment after silicon oil removal. ILM peeling and the duration of silicon oil tamponade were protective factors.

Imines are important precursors for pharmaceutical, agricultural, and synthetic chemistry. The state-of-art synthesis of imines via condensation of amines with aldehydes or ketones often uses homog...

Site-specific fluorescent labeling of RNA is crucial for obtaining the structural and dynamic information of RNAs by fluorescence techniques. Post-synthetic modification of RNA based on N-hydroxysuccinimide (NHS) coupling reaction is an economic, efficient and simple strategy to introduce fluorophore to samples. However, this strategy are not that frequently used in RNA molecules, and the reported reaction conditions and yields varied among different systems. This study results mainly focused on screening the reaction conditions (reactants concentrations, dimethylsulfoxide concentration, solution conditions, pH and reaction time) between NHS-linked fluorophore and aminoallyl-RNA (aa-RNA) to optimize the yield of fluorescent RNA up to 55%, doubled the initial yield. What’s more, as low as one tenth of fluorescent reagent was used in our protocol compared with the reported protocols, greatly reducing the experimental cost. The protocol can be applied as a general guide potentially for RNA labeling by NHS-ester coupling reaction., Graphical Abstract

Three fused-ring electron acceptors (SIDIC, DIDIC and TIDIC) were designed and synthesized using single bond, vinylene and acetylene units linked indaceno[3,2-b]dithiophene dimers as electron-rich cores and 3-(1,1-dicyanomethylene)-5,6-difluoro-1-indanone as electron-deficient termini. These molecules exhibit strong absorption from 550 to 900 nm with large attenuation coefficients of 1.8–2.0 × 105 M−1 cm−1 and high electron mobilities of 2.2–4.9 × 10−3 cm2 V−1 s−1. In combination with wide-bandgap polymer FTAZ as a donor, organic solar cells exhibit efficiencies of 9.3–13.1%. Effects of the linking units on optical, electronic, morphologic, and photovoltaic properties were revealed. Relative to SIDIC, vinylene-bridged DIDIC shows red-shifted absorption, while acetylene-bridged TIDIC shows blue-shifted absorption. Compared with SIDIC and DIDIC, TIDIC has a lower HOMO, higher electron mobility, and higher device efficiency.

C60 was profoundly revealed as being an excellent container for stabilizing unusual Ga(I). Differently sized fullerenes performed as flexible tools for tuning the oxidation states of gallium. A fluoridation strategy was proposed for the further stabilization of Ga@Ih(1812)-C60. This will facilitate exploiting more features and applications involving rarely used Ga(I ).

Thermodynamically stable La@C2v(24 107)-C78, La@D3h(24 109)-C78, La@C1(22 595)-C78, Ce@D3h(24 109)-C78, Sm@C2v(24 107)-C78, and Sm@D3h(24 109)-C78 based on density functional theory and statistical thermodynamic analysis are studied in theory. C1(22 595)-C78, violating the isolated pentagon rule, is a second novel isomer stabilized by encaging a La atom. In addition, three- and two-electron transfers occur in M@C78 (M = La and Ce) and Sm@C78, respectively. Although there are two electrons transferred from Sm to C78, these electrons transferred to the surface of C2v(24 107)-C78 are unpaired. Thus, the surface of the endohedral metallofullerene, Sm@C2v(24 107)-C78, firstly displays diradical characteristics. Notably, the spin states of the two electrons transferred from Sm to D3h(24 109)-C78 are different from those on C2v(24 107)-C78, leading to different spin ground states. Furthermore, the natural bond orders and bond critical point analyses on thermodynamically stable M@C78 (M = La, Ce, and Sm) reveal that the distance between the metal and carbon atom plays an important role in the covalent interaction between the inner metal atoms and C78. Because of the strong ionic interaction, the studies on the magnetic character of M@C78 (M = La, Ce, and Sm) show that Sm@C78 is a promising candidate for single-molecule magnets with high isotropic susceptibility. The infrared spectra were simulated to facilitate further experimental study on the stable M@C78 (M = La, Ce, and Sm). We believe that this work will provide good guidance and assistance for the further study of mono-metallofullerenes and coordination compounds in both experiment and theory.

Fullerenes are important zero-dimensional materials in photoelectric, antioxidant, pharmaceutical, and single-molecular-magnet fields, but the fullerene-formation mechanism has been elusive since t...

Electrodynamic therapy (EDT) has recently emerged as a potential external field responsive approach for tumor treatment. While it presents a number of clear superiorities, EDT inherits the intrinsic challenges of current reactive oxygen species (ROS) based therapeutic treatments owing to the complex tumor microenvironment, including glutathione (GSH) overexpression, acidity and others. Herein for the first time, iron oxide nanoparticles are decorated using platinum nanocrystals (Fe3O4@Pt NPs) to integrate the current EDT with chemodynamic phenomenon and GSH depletion. Fe3O4@Pt NPs can effectively induce ROS generation based on the catalytic reaction on the surface of Pt nanoparticles triggered by electric field (E), and meanwhile it may catalyze intracellular H2O2 into ROS via Fenton reaction. In addition, Fe3+ ions released from Fe3O4@Pt NPs under the acidic condition in tumor cells consume GSH in a rapid fashion, inhibiting ROS clearance to enhance its antitumor efficacy. As a result, considerable in vitro and in vivo tumor inhibition phenomena are observed. This study has demonstrated an alternative concept of combinational therapeutic modality with superior efficacy.

The rapid development of digital society and artificial intelligence has triggered explosive demands for specialty plastics, especially conjugated polymers that are instrumental for flexible electronics and smart devices. The recycling and degradation of postconsumer conjugated polymers have become more important than ever to reduce the pressure to the environment. Here we report the discovery of an environmentally self-degradable conjugated polymer poly(deca-4,6-diynedioic acid), or PDDA. PDDA is stable in the dark or without oxygen when used as a functional material. However, when exposed to sunlight and air after the service life, PDDA disintegrates rapidly and fully decomposes through photooxidation in a week, yielding biocompatible, value-added succinic acid as a major degradation product. The complete degradation of PDDA into green upcycling products by sunlight in air, without leaving any microplastics, not only renders a pioneering paradigm of environmentally self-degradable conjugated polymers but also inspires developing effective strategies to completely degrade postconsumer conjugated polymers in a natural environment.

A systematic first-principles study is performed to investigate the 20-electron transition metal complexes (CH)TM(EE) (TM = Cr, Mo, W; EE = CO, N, BF). The bond dissociation energy (De) based on (CH)TM(EE) → (CH)TM(EE) + EE indicates much lower thermodynamic stability of (CH)TM(N) because of poor binding ability of N ligands. For the thermodynamic stable (CH)TM(EE) complexes (TM = Cr, Mo, W; EE = CO, BF), their 20-electron nature is derived from their occupied nonbonding molecular orbital mainly donated by ligands. Furthermore, charge transfer from TMs to the CH ligands is revealed by the atoms in molecules (AIM) theory, leading to the positive charges of the TM atoms. On the other hand, the nature of the TM-E bond has been thoroughly analyzed by the energy decomposition analysis (EDA) method. The absolute value of interaction energies (|ΔE|) between (CH)TM(EE) and EE has the same trend as the corresponding bond dissociation energy and Wiberg bond orders of TM-E bonds, following the order W > Mo > Cr with same ligands and BF > CO with same TM. Additionally, the largest contribution to the ΔE values is the repulsive term ΔE. Similar contributions from covalent and electrostatic terms to the TM-E bonds were found, which can be described as the classic dative bond with nearly same σ and π contributions. The stronger σ donations and π backdonations in (CH)TM(BF) than in (CH)TM(CO) indicate much more stability of (CH)TM(BF).

Triplet U@C1(28324)-C80, violating the isolated pentagon rule, is experimentally recognized as the stable isomer for uranium-based endohedral monometallofullerene U@C80. Here we first verified that...

The thermodynamic and dynamic stabilities of Sc3 X@C80 (X = C, N, and O) are explored via density functional theory combined with statistical thermodynamic analysis and ab initio molecular dynamics. It is the first time to comprehensively consider the effect of nonmetal atoms on trimetallic endohedral clusterfullerenes. Relative to Sc3 X@Ih (31924)-C80 (X = N and O) with general six-electron transfer, an intriguing electronic structure of unexplored Sc3 C@D5h (31923)-C80 with thermodynamic and dynamic stabilities is clearly disclosed. Natural bond orbitals and charge decomposition analysis simultaneously suggest that one unpaired electron appears on the cage for neutral Sc3 C@D5h (31923)-C80 , which could be prospectively stabilized by effective exohedral derivatization and ionization in the future. Moreover, isoelectronic endohedral clusterfullerenes, (Sc3 C@C80 )- , Sc3 N@C80 , and (Sc3 O@C80 )+ , are also uniquely taken into account. The geometries, electronic structures, reactivities, and reactive sites of isoelectronic species are examined, and it turns out that all the three isoelectronic species would rather electrophilic than nucleophilic reactions. © 2019 Wiley Periodicals, Inc.

Mixed-metal uranium-based endohedral clusterfullerenes, Sc2UX@C80 (X = C, N), which were recently reported in experiments, have been investigated considering heptagon-containing isomers by density functional theory calculations in conjunction with statistical thermodynamic analysis. The triplet Sc2UC@Ih(31924)-C80 and quartet Sc2UN@Ih(31924)-C80, named after the spiral number (31924), are found to be thermodynamically stable and satisfy aromaticity rules. Furthermore, the restricted movements of the Sc2UX (X = C, N) cluster in Ih(31924)-C80 have been demonstrated via ab initio molecular dynamics simulations. The six-electron transfer from the inner cluster to the cage results in the electronic structures (Sc2UX)6+@C806– (X = C, N), which were also confirmed by natural bond orbital analysis. On the basis of the frontier molecular orbitals, the oxidation states of uranium in Sc2UC@C80 and Sc2UN@C80 are +IV and +III, respectively, with residual electrons in 5f orbitals of U. The chemical bond between U and C...

Tea stalk was used for producing carboxymethyl cellulose (CMC), and a response surface methodology was used to model effective factors relative to the degree of substitution (DS). The optimum values of the independent variables were an alkalization time of 107 min, monochloroacetic acid at 3.11 g, and an etherification time of 171 min, at which the CMC had a DS of 0.668. The yield of CMC in optimization condition was 75.9 %. The optimized CMC was in a good agreement with the commercial CMC, as based on Fourier transform infrared spectroscopy and X-ray diffractometry analyses. The optimized CMC was used to enhance paper strength, and with economic factors and paper strength enhancement taken into account, the appropriate amount of optimized CMC was determined to be approximately 0.3 %. When the amount of optimized CMC was at 0.3 %, the tensile index, burst index, tearing index, and folding endurance were 26.7 N m/g, 1.0 kPa m 2 / g 1.0\hspace{0.1667em}\text{kPa}\hspace{0.1667em}{\text{m}^{2}}/\text{g} , 12.1 mN m 2 / g 12.1\hspace{0.1667em}\text{mN}\hspace{0.1667em}{\text{m}^{2}}/\text{g} , and 2.0, respectively. Together, these results indicated that the optimized CMC exhibited comparable paper strengthening properties relative to that of commercially available CMC.

Yogurt is a popular product worldwide partly because of the health-promoting effects of the probiotics that it contains. Probiotics with high survivability constitute a promising direction for fortified yogurt products. This study aimed to prepare Bifidobacterium breve-loaded yogurt with the bacteria surviving transit to the lower part of small intestine or colon. Bifidobacterium breve beads were prepared through an ion-crosslinking method using low methoxyl pectin as the encapsulating material. Features such as encapsulation efficiency and stability during storage and passage through the simulated gastrointestinal tract were studied in vitro. A commercial starter was used for yogurt fermentation, and B. breve with or without encapsulation was added as a probiotic supplement with the starter or 3 to 4 h after fermentation. The effects of B. breve beads on yogurt characteristics were evaluated after different fermentation processes: BC, milk fermented with marketed yogurt starter; UBFF, unencapsulated B. breve added to fresh milk and then fermented; EBFF, encapsulated B. breve added to fresh milk and then fermented; UBAF, unencapsulated B. breve added after fermentation with the starter; and EBAF, encapsulated B. breve beads added 3 to 4 h after fermentation with the starter. Evaluation was based on texture, electronic nose, and electronic tongue analyses. The particle size analysis of B. breve beads showed that they were uniform, mostly spherical, 1 to 1.5 mm in diameter with encapsulating efficiency higher than 99%. Following treatment with the simulated gastrointestinal tract conditions, the number of B. breve decreased by 1.76 and 4.82 log cfu/g for B. breve beads and unencapsulated B. breve, respectively. The EBAF group showed the lowest viscosity (2,235.67 cP) at d 0, and the lower postfermentation degree was reflected by the slow increase in yogurt viscosity. All groups kept a relatively stable pH during storage. The cohesiveness values of the EBAF and UBAF groups were significantly higher than those of the other groups. The trends in texture changes within the BC, UBFF, and EBFF groups were similar, and the UBAF and EBAF groups showed similar trends. In conclusion, B. breve beads showed good stability in vitro and improved yogurt characteristics by increasing the survival rate of the encapsulated cells. Good compatibility of low methoxyl pectin beads with yogurt was also observed.

The study investigated the effects of low cadmium (Cd) burden on the respiratory symptoms and pulmonary function in occupational workers. The study population consisted of 98 nickel-cadmium battery workers. Levels of urine cadmium, urinary creatinine (Cr), and data on the adverse respiratory symptoms and pulmonary function of the participants were measured and collected respectively. The urinary cadmium level in cadmium-exposed workers (n = 53) was within the normal range but greater than 2.4 times than those of the control group (n = 45). Compared with the control group, the cadmium-exposed workers had higher prevalence of all subjective respiratory symptoms studied in the study. The prevalence of cough (30%), phlegm (23%), and upper respiratory tract infection (URTI) (79%) in the exposure group was significantly (P

We extend thieno[3,2-b]thiophene and naphthalene cores in our previously reported fused-ring electron acceptors (FREAs) F6IC and IHIC2 to benzo[b]benzo[4,5]thieno[2,3-d]thiophene and naphtho[1,2-b:5,6-b′]dithiophene, respectively, and synthesize two new isomeric FREAs BTIC and NTIC. Both BTIC and NTIC exhibit strong absorption from 500 to 800 nm with high extinction coefficients (2.4–2.6 × 105 M−1 cm−1) and electron mobilities of 1.8–3.4 × 10−4 cm2 V−1 s−1. Paired with the polymer donor PM6, the BTIC and NTIC-based organic solar cells (OSCs) show power conversion efficiencies (PCEs) of 11.5–12.2%, much higher than those of the control devices based on IHIC2 and F6IC (7.21–7.31%). The PM6/NTIC-based OSCs afford a higher PCE of 12.2% than PM6/BTIC-based OSCs (11.5%), due to the red-shifted absorption and up-shifted HOMO of NTIC.

In this study, molded fiber products (MFPs) were prepared from lignin compounded with Lewis acid-modified fibers using enzymatic hydrolysis lignin (EHL) as a bio-phenol. The fibers were modified and compounded entirely through hot-pressing. To improve the reactivity of enzymatic lignin, hydroxylated enzymatic hydrolysis lignin (HEHL) was prepared by hydroxylation modification of purified EHL with hydrogen peroxide (H2O2) and ferrous hydroxide (Fe(OH)3). HEHL was mixed uniformly with Lewis acid-modified fibers on a pressure machine and modified during the molding process. The purpose of Lewis acid degradation of hemicellulose-converted furfural with HEHL was to generate a resin structure to improve the mechanical properties of a MFPs. The microstructure of the MFP was shown to be generated by resin structure, and it was demonstrated that HEHL was compounded on Lewis acid-modified fibers during the molding process. The thermal stability of the MFP with composite HEHL did not change significantly owing to the addition of lignin and had higher tensile strength (46.28 MPa) and flexural strength (65.26 MPa) compared to uncompounded and modified MFP. The results of this study are expected to promote the application of high lignin content fibers in molded fibers.

Water splitting is an important source of hydrogen, a promising future carrier for clean and renewable energy. A detailed understanding of the mechanisms of water splitting, catalyzed by supported metal atoms or nanoparticles, is essential to improve the design of efficient catalysts. Here, we report an infrared spectroscopic study of such a water splitting process, assisted by a C60 supported vanadium atom, C60 V+ +H2 O→C60 VO+ +H2 . We probe both the entrance channel complex C60 V+ (H2 O) and the end product C60 VO+ , and observe the formation of H2 as a result from resonant infrared absorption. Density functional theory calculations exploring the detailed reaction pathway reveal that a quintet-to-triplet spin crossing facilitates the water splitting reaction by C60 -supported V+ , whereas this reaction is kinetically hindered on the isolated V+ ion by a high energy barrier. The C60 support has an important role in lowering the reaction barrier with more than 70 kJ mol-1 due to a large orbital overlap of one water hydrogen atom with one carbon atom of the C60 support. This fundamental insight in the water splitting reaction by a C60 -supported single vanadium atom showcases the importance of supports in single atom catalysts by modifying the reaction potential energy surface. ispartof: ANGEWANDTE CHEMIE-INTERNATIONAL EDITION vol:60 issue:52 pages:27095-27101 ispartof: location:Germany status: published

A series of ternary organic photovoltaics (OPVs) are fabricated with one wide bandgap polymer D18-Cl as donor, and well compatible Y6 and Y6-1O as acceptor. The open-circuit-voltage (VOC) of ternary OPVs is monotonously increased along with the incorporation of Y6-1O, indicating that the alloy state should be formed between Y6 and Y6-1O due to their excellent compatibility. The energy loss can be minimized by incorporating Y6-1O, leading to the VOC improvement of ternary OPVs. By finely adjusting the Y6-1O content, a power conversion efficiency of 17.91% is achieved in the optimal ternary OPVs with 30 wt% Y6-1O in acceptors, resulting from synchronously improved short-circuit-current density (JSC) of 25.87 mA cm−2, fill factor (FF) of 76.92% and VOC of 0.900 V in comparison with those of D18-Cl : Y6 binary OPVs. The JSC and FF improvement of ternary OPVs should be ascribed to comprehensively optimal photon harvesting, exciton dissociation and charge transport in ternary active layers. The more efficient charge separation and transport process in ternary active layers can be confirmed by the magneto-photocurrent and impedance spectroscopy experimental results, respectively. This work provides new insight into constructing highly efficient ternary OPVs with well compatible Y6 and its derivative as acceptor., By employing the well compatible Y6 : Y6-1O as acceptor and wide bandgap polymer D18-Cl as donor, the PCE of 17.91% is achieved in optimized ternary OPVs, resulting from the simultaneously improved JSC, FF and VOC.

A new non-fullerene acceptor PDFC is prepared by introducing perylene diimide into the core of an A-DA'D-A architecture. Due to the large conjugation and electron-deficient ability of perylene diimide, PDFC shows strong absorption, suitable energy levels and favorable face-on packing. The optimal device realizes a PCE of 12.56% with one of the highest fill factors (81.3%). A PCE of 9.66% is obtained in a 570 nm thick-film device based on PDFC.

The successful isolation of cyclo-C18 in the experiment means the ground-breaking epoch of carbon rings. Herein, we studied the thermodynamic stabilities of cyclo-Cn (4 $\leq$ n $\leq$ 34) with density functional theory. When n = 4N + 2 (N is integer), cyclo-Cn (10 $\leq$ n $\leq$ 34) were thermodynamically stable. Especially, cyclo-C10 and cyclo-C14 were thermodynamically, kinetically, dynamically, and optically preferred to cyclo-C18, and were the candidates of zero-dimension carbon rings. The carbon atoms were sp hybridization in cyclo-C10, cyclo-C14 and cyclo-C18. Cyclo-C14 and cyclo-C18 had alternating abnormal single and triple bonds, but cyclo-C10 had equal bonds. Cyclo-C10, cyclo-C14, and cyclo-C18 with large aromaticities had out-plane and in-plane pi systems, which were perpendicular to each other. The number of pi electrons in out-plane and in-plane pi systems followed the Huckel rule. Simulated UV-vis-NIR spectra indicated the similar electronic structures of cyclo-C14 and cyclo-C18., Comment: 23 pages, 6 figures, 1 table

Starting from common intermediate methyl 1-hydroxy-9H-carbazole-3-carboxylate, synthetic routes toward murrayaquinone A, olivacine, and N-methylcalothrixin B were developed.

The E3 ubiquitin ligase F-box and WD repeat domain containing 7 (FBW7α) functions as a putative tumor suppressor in non-small cell lung cancer (NSCLC) due to its regulation of a set of oncogenic proteins associated with cell proliferation and mitosis. Increasing efforts have been focused on the understanding of FBW7 in determining cell cycle progression and apoptosis induction, however, the correlation between FBW7 and tumor metastasis is not fully understood. In this study, we reported a potential anti-metastatic effect of FBW7 in non-small cell lung cancer (NSCLC). In this model, FBW7 inhibited cancer cell metastasis primarily by inducing ubiquitination and proteolysis of the transcriptional factor Snail, which suppressed E-cadherin cell tight junction protein expression. Loss of FBW7 would stabilize the Snail protein, thus, inhibit E-cadherin expression and promote metastasis in vitro and in vivo. Moreover, Snail ubiquitination and degradation were also achieved by pharmacological approach, in which the FBW7 agonist oridonin treatment led to Snail proteolysis. Furthermore, FBW7 silencing stabilized Snail protein and induced epithelial-to mesenchymal transition (EMT), and acquisition of migration and invasion properties in NSCLC. Overall, our study provides new insights into the FBW7-Snail axis in regulating cell migration and invasion, and suggests that targeting FBW7 may be a potent approach to inhibit metastasis in NSCLC.