Citrinsorbicillin A(1),a novel homotrimeric sorbicillinoid,along with two new monomers citrinsor-bicillins B(2)and C(3),were isolated from the Coptis chinensis endophyte Trichoderma citrinoviride HT-9 by liquid chroma...Citrinsorbicillin A(1),a novel homotrimeric sorbicillinoid,along with two new monomers citrinsor-bicillins B(2)and C(3),were isolated from the Coptis chinensis endophyte Trichoderma citrinoviride HT-9 by liquid chromatograph mass spectrometer(LC-MS)-guided strategy.1 was the first trimeric-example from terrestrial fungi,which possessed a unique carbon skeleton with two bicyclo[2.2.2]octanedione ring connected through an enolated carbon forming by[4+2]cycloaddition.Their structures were elucidated by spectroscopic analysis and X-ray diffraction.1 exhibited moderate cytotoxicity against human colon cancer HT29 cells,and it induced significant cell cycle arrest by reducing the protein expression of cyclin D1.展开更多
A trimeric porous coordination framework [Ni_3(TPTC)(IN)_2(μ_2-H_2O)_2(CH_3OH)_2)]n· x(solvents)(1, TPTC = terphenyl-3,3?,5,5??-tetracarboxylic acid, IN = isonicotinic acid) was synthesized and characterized by ...A trimeric porous coordination framework [Ni_3(TPTC)(IN)_2(μ_2-H_2O)_2(CH_3OH)_2)]n· x(solvents)(1, TPTC = terphenyl-3,3?,5,5??-tetracarboxylic acid, IN = isonicotinic acid) was synthesized and characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, single-crystal and powder X-ray diffraction. It crystallizes in monoclinic space group C2/c with a = 33739(12), b = 14.820(5), c = 13.568(5) ?, β = 97.388(6)o, V = 6728(4) ?3, Z = 4, Mr = 965.35, Dc = 0.953 g·cm^(-3), F(000) = 1955.5, μ = 0.881 mm^(–1), GOOF = 1.072, the final R = 0.0859 and w R = 0.2424 for 5284 observed reflections with I > 2σ(I). The structure of 1 is constructed from the linkage of trinuclear {Ni_3} second building units through TPTC and IN spacers, forming a 4,8-connected network of Schl?fli symbol {32.42.52}{34.46.58.68.72}. The CO2 uptake values for 1 are 97.9 m^2·g^(-1) at 273 K and 66.2 m^2·g^(-1) at 298 K, while its N_2 adsorption values are 8.5 m^2·g^(-1) at 273 K and 4.9 m^2·g^(-1) at 298 K, respectively. These results show that 1 has high CO_2/N_2 adsorption selectivity at ambient conditions.展开更多
The trimeric phenylenevinylene with the symmetrical chiral end-groups （ChTPV） was synthesized. The liquid crystalline and luminescent properties of the ChTPV have been studied by differential scanning calorimetry （...The trimeric phenylenevinylene with the symmetrical chiral end-groups （ChTPV） was synthesized. The liquid crystalline and luminescent properties of the ChTPV have been studied by differential scanning calorimetry （DSC）, polarized optical microscopy （POM）, absorption and photoluminescence spectra. The results indicated that the ChTPV exhibits mesophase over a wide temperature range and a typical optical texture of smectic phase. In contrast with the spectra of the solution, that of the film showed blue-shift in maximal absorption and red-shift in maximal emission due to H-type aggregation with parallel alignment of the TPV transition dipole moment.展开更多
A viscoelastic system formed by the solutions of di（2-hydroxyl-dimethylene ether）-α,ω, y-triple （ dimethyloctadecylammonium chlorine ） （ 18-4 （ OH ） -18-4 （ OH ） -18 ） is proposed to solve the problems of ...A viscoelastic system formed by the solutions of di（2-hydroxyl-dimethylene ether）-α,ω, y-triple （ dimethyloctadecylammonium chlorine ） （ 18-4 （ OH ） -18-4 （ OH ） -18 ） is proposed to solve the problems of poor temperature and shear resistances of clean fracturing fluid. The apparent viscosity of 18-4（ OH）-18-4（ OH）-18 solution affected by inorganic salt, hydrotropic salt and their mixtures is investigated using steady state measurements. Meanwhile, the temperature and shear resistances of systems of 18-4（ OH）-18-4（ OH）-18 and several common single-chain surfactants are compared. The rheological experiments show that, the coexistence of NaSal and NaC1 makes it easier for the system to promote micellar growth yielding wormlike micelles than single NaSal or NaC1. The apparent vis- cosity of 18-4（OH） -18-4（OH） -18 solution maintains over 87. 5 mPa-s above 100 22. The results indi- cate that there exists a synergistic effect in solutions of 18-4 （ OH ） -18-4 （ OH ） -18 trimeric surfactant展开更多
A novel oxamide-bridged trimeric tetranuclear complex 1 incorporating a macro- cyclic oxamide of formula {[(CuL)3Mn](ClO4)2}3 (macrocyclic oxamide L = 2,3-dioxo-5,6,14,15- dibenzo-1,4,8,12-tetraazacyclopentadeca-7,12-...A novel oxamide-bridged trimeric tetranuclear complex 1 incorporating a macro- cyclic oxamide of formula {[(CuL)3Mn](ClO4)2}3 (macrocyclic oxamide L = 2,3-dioxo-5,6,14,15- dibenzo-1,4,8,12-tetraazacyclopentadeca-7,12-diene) was prepared and structurally characterized. The compound [(CuL)3Mn](ClO4)2 crystallizes in the trigonal system, space group P 3 with a = 22.434(17), b = 22.434(17), c = 18.82(2) ?, α = β = 90, γ = 120o, V = 8203(13) ?3, Z = 6, Dc = 1.751g/cm3, μ(MoKα) = 1.557, F(000) = 4392, the final R = 0.083 and wR = 0.1727 for 9604 obser- ved reflections with I > 2σ(I). The single-crystal X-ray analysis shows that 1 is a trimeric complex. There are three similar constitutes, dissimilar conformations and asymmetrically independent ‘building-block’ [(CuL)3Mn] in one crystal cell of the title complex 1.展开更多
Carbazole-based self-assembled molecules have been widely adopted as hole-transporting layers(HTLs)in high-performance organic solar cells(OSCs).However,their practical implementation has been constrained by their lim...Carbazole-based self-assembled molecules have been widely adopted as hole-transporting layers(HTLs)in high-performance organic solar cells(OSCs).However,their practical implementation has been constrained by their limited concentration in solutions and poor solvent tolerance.Herein,to address these limitations,we designed two novel trimeric molecules(TPACz-1 and TPACz-2)that synergistically integrate the structural merits of small molecules with the processing advantages of polymers.Notably,TPACz-2 showed exceptional hole-transporting capacity with uniform coverage on indium tin oxide(ITO)substrates,coupled with robust processability characterized by an extended concentration tolerance range(0.2–1.0 mg mL^(-1))and compatibility with a broad range of solvents.Binary OSCs based on TPACz-2 showed an excellent power conversion efficiency(PCE)of 19.65%with a short-circuit current density of 27.49 mA cm^(-2)and a fill factor of 80.9%.At the same time,the corresponding ternary devices exhibited a high PCE exceeding 20%.Furthermore,the TPACz-based devices demonstrated superior ambient stability,retaining~80%of their initial PCE after 680 h at 25%relative humidity,substantially outperforming conventional PEDOT:PSS-based counterparts.This work offers valuable guidance and highlights the crucial role of oligomeric molecular design as a pivotal strategy for the development of innovative HTLs in OSCs.展开更多
Influenza causes seasonal outbreaks yearly and unpredictable pandemics with high morbidity and mortality rates.Despite significant efforts to address influenza,it remains a major threat to human public health.This iss...Influenza causes seasonal outbreaks yearly and unpredictable pandemics with high morbidity and mortality rates.Despite significant efforts to address influenza,it remains a major threat to human public health.This issue is partially due to the lack of antiviral drugs with potent antiviral activity and broad reactivity against all influenza virus strains and the rapid emergence of drug-resistant variants.Moreover,designing a universal influenza vaccine that is sufficiently immunogenic to induce universal antibodies is difficult.Some novel epitopes hidden in the hemagglutinin(HA)trimeric interface have been discovered recently,and a number of antibodies targeting these epitopes have been found to be capable of neutralizing a broad range of influenza isolates.These findings may have important implications for the development of universal influenza vaccines and antiviral drugs.In this review,we focused on the antibodies targeting these newly discovered epitopes in the HA domain of the influenza virus to promote the development of universal anti-influenza antibodies or vaccines and extend the discovery to other viruses with similar conformational changes in envelope proteins.展开更多
In this theoretical study,we investigate the generation of second harmonics(SH)during the interaction of a laser beam with a metallic nanoparticle(MNP)trimer.Utilizing a classical electrodynamics framework,we explore ...In this theoretical study,we investigate the generation of second harmonics(SH)during the interaction of a laser beam with a metallic nanoparticle(MNP)trimer.Utilizing a classical electrodynamics framework,we explore the nonlinear interactions between the laser beam fields and nanoparticles(NPs),accounting for dipole-dipole interactions among the particles.Analytical expressions are derived to quantify the impact of these interactions on SH radiation power for two distinct polarizations of the laser beam.Our findings indicate that when the laser electric field is aligned parallel to the trimer's symmetry axis,there is a significant enhancement in SH radiation power compared to a single non-interacting NP,accompanied by a red-shift in the plasmon resonance peak.Conversely,when the laser electric field is perpendicular to the trimer axis,the SH radiation power from each NP decreases,and the plasmon resonance peak experiences a blue-shift.Additionally,we examine the influence of particle size and interparticle separation on SH generation.These results provide valuable insights into the role of interparticle interactions in enhancing nonlinear optical processes in NP assemblies,with potential implications for the design of nanophotonic devices.展开更多
Propylene,a readily accessible and economically viable light olefin,has garnered substantial interest for its potential conversion into valuable higher olefins through oligomerization processes.The distribution of pro...Propylene,a readily accessible and economically viable light olefin,has garnered substantial interest for its potential conversion into valuable higher olefins through oligomerization processes.The distribution of products is profoundly influenced by the catalyst structure.In this study,Fe_(2)O_(3)-doped NiSO_(4)/Al_(2)O_(3) catalysts have been meticulously developed to facilitate the selective trimerization of propylene under mild conditions.Significantly,the 0.25Fe_(2)O_(3)-NiSO_(4)/Al_(2)O_(3) catalyst demonstrates an enhanced reaction rate(48.5 mmol_(C3)/(g_(cat).·h)),alongside a high yield of C9(~32.2%),significantly surpassing the performance of the NiSO_(4)/Al_(2)O_(3) catalyst(C9:~24.1%).The incorporation of Fe_(2)O_(3) modifies the migration process of sulfate ions,altering the Lewis acidity of the electron-deficient Ni and Fe sites on the catalyst and resulting a shift in product distribution from a Schulz-Flory distribution to a Poisson distribution.This shift is primarily ascribed to the heightened energy barrier for theβ-H elimination reaction in the C6 alkyl intermediates on the doped catalyst,further promoting polymerization to yield a greater quantity of Type II C9.Furthermore,the validation of the Cossee-Arlman mechanism within the reaction pathway has been confirmed.It is noteworthy that the 0.25Fe_(2)O_(3)-NiSO_(4)/Al_(2)O_(3) catalyst exhibits remarkable stability exceeding 80 h in the selective trimerization of propylene.These research findings significantly enhance our understanding of the mechanisms underlying olefin oligomerization reactions and provide invaluable insights for the development of more effective catalysts.展开更多
As an increasingly used alternative to perfluorooctanoic acid(PFOA),hexafluoropropylene oxide trimer acid(HFPO-TA)has been widely detected in global water environments.However,little is known regarding its toxic effec...As an increasingly used alternative to perfluorooctanoic acid(PFOA),hexafluoropropylene oxide trimer acid(HFPO-TA)has been widely detected in global water environments.However,little is known regarding its toxic effects on cardiovascular development.Here,zebrafish embryos were treated with egg water containing 0,60,120,or 240 mg/L HFPO-TA.Results showed that HFPO-TA treatment led to a significant reduction in both larval survival percentage and heart rate.Furthermore,HFPO-TA exposure caused severe pericardial edema and elongation of the sinus venous to bulbus arteriosus distance(SV-BA)in Tg(myl7:GFP)transgenic larvae,disrupting the expression of genes involved in heart development and thus causing abnormal heart looping.Obvious sprouting angiogenesis was observed in the 120 and 240 mg/L exposed Tg(fli:GFP)transgenic larvae.HFPO-TA treatment also impacted the mRNA levels of genes involved in the vascular endothelial growth factor(VEGF)pathway and embryonic vascular development.HFPO-TA exposure significantly decreased erythrocyte number in Tg(gata1:DsRed)transgenic embryos and influenced gene expression associated with the heme metabolism pathway.HFPO-TA also induced oxidative stress and altered the transcriptional levels of genes related to cell cycle and apoptosis,inhibiting cell proliferation while promoting apoptosis.Therefore,HFPO-TA exposure may induce abnormal development of the cardiovascular and hematopoietic systems in zebrafish embryos,suggesting it may not be a suitable or safe alternative for PFOA.展开更多
Five novel(9,10-dihydro)phenanthrene and bibenzyl trimers,as well as two previously identified biphenanthrenes and bibenzyls,were isolated from the tubers of Bletilla striata.Their structures were elucidated through c...Five novel(9,10-dihydro)phenanthrene and bibenzyl trimers,as well as two previously identified biphenanthrenes and bibenzyls,were isolated from the tubers of Bletilla striata.Their structures were elucidated through comprehensive analyses of NMR and HRESIMS spectroscopic data.The absolute configurations of these compounds were determined by calculating rotational energy barriers and comparison of experimental and calculated ECD curves.Compounds 5b and 6 exhibited inhibitory effects on LPS-induced NO production in BV-2 cells,with IC_(50) values of 12.59±0.40 and 15.59±0.83μmol·L^(-1),respectively.A mechanistic study suggested that these compounds may attenuate neuroinflammation by reducing the activation of the AKT/IκB/NF-κB signaling pathway.Additionally,compounds 3a,6,and 7 demonstrated significant PTP1B inhibitory activities,with IC_(50) values of 1.52±0.34,1.39±0.11,and 1.78±0.01μmol·L^(-1),respectively.Further investigation revealed that compound 3a might inhibit LPS-induced PTP1B overexpression and NF-κB activation,thereby mitigating the neuroinflammatory response in BV-2 cells.展开更多
Development of degradable polyester elastomers plays an important role in the applications of soft mateirals.Noncrystalline polymenthides(PMs)from menthol derived lactone monomers are excellent soft segments for prepa...Development of degradable polyester elastomers plays an important role in the applications of soft mateirals.Noncrystalline polymenthides(PMs)from menthol derived lactone monomers are excellent soft segments for preparing degradable polyester elastomers.By using cyclic trimeric phosphazene base(CTPB)as an organocatalyst,we succesfully synthesized PMs with different molecular weights(8.2 kDa to 100.7 kDa)in high yields via ring-opening polymerization(ROP)of menthide.When a CTPB/urea binary catalytic system was adopted,the polymerizations proceeded in a more controlled manner.Using glycerol as initiator,star shaped PMs with well.defined structure were synthesized and subsequently end-capped by acrylate.UV iradiation of the terminal acrylate groups in the star-shaped PMs resulted in formation of chemically cos-linked polyester elastomers without heat or other stimuli.The obtained polyester elastomers exhibit matched modulus(3.8-5.5 MPa),tensile strength(0.56-0.68 MPa),and strain at break(280%-320%)with soft body tssues,displaying great potential in biomedical applications.展开更多
Raman vibrational spectra of the selected basic （hydroxyl OH and deuteroxyl OD） transition-metal halides, geomet- rically frustrated material series α-, β-, γ-Cu2（OH）3Cl, α-Cu2（OH）3Br, β-Ni2（OH）3Cl, β-Co...Raman vibrational spectra of the selected basic （hydroxyl OH and deuteroxyl OD） transition-metal halides, geomet- rically frustrated material series α-, β-, γ-Cu2（OH）3Cl, α-Cu2（OH）3Br, β-Ni2（OH）3Cl, β-Co2（OH）3Cl, β-Co2（OH）3Br, γ-Cu2（OD）3Cl, and β-Co2（OD）3Cl are measured at room temperature and analysed to investigate the relationship be- tween the microstructured OH environments and their respective Raman spectra. Among these selected samples, the last two are used to determine the OH stretching vibration region （3600 cm-1-3300 cm-1） and OH bending vibra- tion region （1000 cm-1-600 cm-1） of OH systems in the spectra. Through the comparative analysis of the distances d（metal-O）, d（O-halogen）, and d（OH）, the strong metal-O interaction and trimeric hydrogen bond （Car, C8 or C1 symmetry） are found in every material, but both determine simultaneously an ultimate d（OH）, and therefore an OH stretching vibration frequency. According to the approximately linear relationship between the OH stretching vibration frequency and d（OH）, some unavailable d（OH） are guessed and some doubtful d（OH） are suggested to be corrected. In addition, it is demonstrated in brief that the OH bending vibration frequency is also of importance to check the more detailed crystal microstructure relating to the OH group.展开更多
Mid-infrared absorption and Raman spectra of the geometrically frustrated material series, hydroxyl cobalt halides β-CO2（OH）3Cl and β-CO2（OH）3Br, are first, to the best of our knowledge, measured at room tempera...Mid-infrared absorption and Raman spectra of the geometrically frustrated material series, hydroxyl cobalt halides β-CO2（OH）3Cl and β-CO2（OH）3Br, are first, to the best of our knowledge, measured at room temperature, to study the corresponding relationship between their vibrational spectral properties and crystal microstructures. Through the comparative analysis of the four spectra we have categorically assigned the OH-related vibration modes of hydroxyl groups in the trimeric hydrogen bond environment （Co3 =OH）3 … Cl/Br, and tentatively suggested vibration modes of O-Co-O, Co O and Cl/Br-Co-Cl/Br units. These results can also become the basis for analysing their low-temperature spectral properties, which can help to understand the underlying physics of their exotic geometric frustration phenomena around phase transition temperatures.展开更多
We have reported previously the ultrafast energy transfer process with a time constant of 0.8 ps from a monomeric to a dimeric subunit within a perylenetetracarboxylic diimide trimer, which was derived indirectly from...We have reported previously the ultrafast energy transfer process with a time constant of 0.8 ps from a monomeric to a dimeric subunit within a perylenetetracarboxylic diimide trimer, which was derived indirectly from a model fitting into the transient absorption experimental data. Here we present a direct ultrafast fluorescence quenching measurement by employing fs time-resolved transient fluorescence spectroscopy based on noncollinear optical parametric amplification technique. The rapid decay of the monomer＇s emission due to energy transfer was observed directly with a time constant of about 0.82 ps, in good agreement with the previous result.展开更多
From an aqueous extract of“tian ma”(the steamed and dried rhizomes of Gastrodia elata),ten new compounds gastrodiben-zins A−D(1−4)and gastrotribenzins A−F(5−10),along with known analogues(11−20),having structure fea...From an aqueous extract of“tian ma”(the steamed and dried rhizomes of Gastrodia elata),ten new compounds gastrodiben-zins A−D(1−4)and gastrotribenzins A−F(5−10),along with known analogues(11−20),having structure features coupling between two and three p-hydroxybenzyl-derived units via carbon-and/or ether-bonds,were isolated and characterized by spectroscopic data analysis.Meanwhile,the new compounds 5a,6a,8a,22,and 23,as well as the known derivatives 13a,14a,15,17−21,24,25,and p-hydroxybenzyl aldehyde were isolated and identified from a refluxed aqueous solution of p-hydroxybenzyl alcohol.Methylation of 5a and 6a in methanol and ethylation of 6a,8a,13a,and 14a in ethanol produced 5 and 6 and 7,8,13,and 14,respectively.using ultra-performance liquid chromatography high-resolution electrospray ioniza-tion mass spectrometry(UPLC-HRESIMS)analysis of the refluxed solutions of p-hydroxybenzyl alcohol and the refluxed extracts of the fresh G.elata rhizome and“tian ma”extracts indicated consistent production and variation of the dimeric and trimeric derivatives of p-hydroxybenzyl alcohol upon extracting solvents and refluxing time.In various assays,the dimeric and trimeric derivatives showed more potent activities than p-hydroxybenzyl alcohol itself and gastrodin,which are the main known active constituents of“tian ma”.These results revealed for the first time that the more effective dimers and trimers can be produced through condensation of the co-occurring p-hydroxybenzyl alcohol during processing and decocting of the G.elata rhizomes,demonstrating insights into medicinal chemistry behind application protocols of traditional Chinese medicines.展开更多
One new A - type proanthocyanidin trimer, lindetannin trimer, was isolated from the stems of Lindera aggregata (Sims) Kosterm.. Its structure was elucidated by spectral and chemical methods.
A series of copolymers of thiazoloisoindigo (Tzll) with different chalcogenophene trimers were synthesized to systematicllyinvestigate the chalcogen effect on their charge transport propertes.When only the middlethiop...A series of copolymers of thiazoloisoindigo (Tzll) with different chalcogenophene trimers were synthesized to systematicllyinvestigate the chalcogen effect on their charge transport propertes.When only the middlethiophene ring of terthiphene(T-T-T)is replaced byheavier chalcogenophenes,a preference(expressed by the ratio of μe/μh)towards electron transport was observed descending from T-T-Tto T-Se-Tthen to T-Te-T(Se and Te stand for selenophene and tellurophene,respectively).On the other hand,with the increased number of heavierchalcogenophenes,a preference toward hole transport was observed descending from Se-T-Se to Se-Se-se then to Se-Te-Se.This phenomenon iswellexplained by the balance between the aromatic resonance energy of the chalcogenophenes and the electronegativity of the chalcogens.Specifically,P(TZll-T-Se-T)displayed relatively balanced ambipolar property(μh^(max)andμe^(max) of 3.77 and 1.59 cm^(2)·v^(-1)·s^(-1)with aμe/μh of 0.42).while P(Tll-Se-Te-Se)exhibited the best preference to hole transfer with a u.u,of 0.09.P(Tzll-T-Te-T)exhibited the best preference to electrontransfer with aμe/μl,of 16 and theμe^(max)of 0.64 cm^(2)·v^(-).s^(-1)which is the highest electron mobility among the known conjugated polymerscontaining tellurophenes.展开更多
基金supported by the National Natural Science Foundation of China(No.82003629)the Natural Science Foundation of Chongqing(No.cstc2021jcyj-msxmX0975)the Open Project of State Key Laboratory of Natural Medicines(No.SKLNMKF202304).
文摘Citrinsorbicillin A(1),a novel homotrimeric sorbicillinoid,along with two new monomers citrinsor-bicillins B(2)and C(3),were isolated from the Coptis chinensis endophyte Trichoderma citrinoviride HT-9 by liquid chromatograph mass spectrometer(LC-MS)-guided strategy.1 was the first trimeric-example from terrestrial fungi,which possessed a unique carbon skeleton with two bicyclo[2.2.2]octanedione ring connected through an enolated carbon forming by[4+2]cycloaddition.Their structures were elucidated by spectroscopic analysis and X-ray diffraction.1 exhibited moderate cytotoxicity against human colon cancer HT29 cells,and it induced significant cell cycle arrest by reducing the protein expression of cyclin D1.
基金supported by the National Science Foundation of Fujian Province(No.2017J01039)
文摘A trimeric porous coordination framework [Ni_3(TPTC)(IN)_2(μ_2-H_2O)_2(CH_3OH)_2)]n· x(solvents)(1, TPTC = terphenyl-3,3?,5,5??-tetracarboxylic acid, IN = isonicotinic acid) was synthesized and characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, single-crystal and powder X-ray diffraction. It crystallizes in monoclinic space group C2/c with a = 33739(12), b = 14.820(5), c = 13.568(5) ?, β = 97.388(6)o, V = 6728(4) ?3, Z = 4, Mr = 965.35, Dc = 0.953 g·cm^(-3), F(000) = 1955.5, μ = 0.881 mm^(–1), GOOF = 1.072, the final R = 0.0859 and w R = 0.2424 for 5284 observed reflections with I > 2σ(I). The structure of 1 is constructed from the linkage of trinuclear {Ni_3} second building units through TPTC and IN spacers, forming a 4,8-connected network of Schl?fli symbol {32.42.52}{34.46.58.68.72}. The CO2 uptake values for 1 are 97.9 m^2·g^(-1) at 273 K and 66.2 m^2·g^(-1) at 298 K, while its N_2 adsorption values are 8.5 m^2·g^(-1) at 273 K and 4.9 m^2·g^(-1) at 298 K, respectively. These results show that 1 has high CO_2/N_2 adsorption selectivity at ambient conditions.
基金supported by the National Science Foundation(No.20674005)the major project of Ministry Education of the People's Republic of China(No.104187).
文摘The trimeric phenylenevinylene with the symmetrical chiral end-groups （ChTPV） was synthesized. The liquid crystalline and luminescent properties of the ChTPV have been studied by differential scanning calorimetry （DSC）, polarized optical microscopy （POM）, absorption and photoluminescence spectra. The results indicated that the ChTPV exhibits mesophase over a wide temperature range and a typical optical texture of smectic phase. In contrast with the spectra of the solution, that of the film showed blue-shift in maximal absorption and red-shift in maximal emission due to H-type aggregation with parallel alignment of the TPV transition dipole moment.
文摘A viscoelastic system formed by the solutions of di（2-hydroxyl-dimethylene ether）-α,ω, y-triple （ dimethyloctadecylammonium chlorine ） （ 18-4 （ OH ） -18-4 （ OH ） -18 ） is proposed to solve the problems of poor temperature and shear resistances of clean fracturing fluid. The apparent viscosity of 18-4（ OH）-18-4（ OH）-18 solution affected by inorganic salt, hydrotropic salt and their mixtures is investigated using steady state measurements. Meanwhile, the temperature and shear resistances of systems of 18-4（ OH）-18-4（ OH）-18 and several common single-chain surfactants are compared. The rheological experiments show that, the coexistence of NaSal and NaC1 makes it easier for the system to promote micellar growth yielding wormlike micelles than single NaSal or NaC1. The apparent vis- cosity of 18-4（OH） -18-4（OH） -18 solution maintains over 87. 5 mPa-s above 100 22. The results indi- cate that there exists a synergistic effect in solutions of 18-4 （ OH ） -18-4 （ OH ） -18 trimeric surfactant
基金This project was supported by the National Natural Science Foundation of China (No. 20331010) and Natural Science Foundation of Tianjing (No. 033602011)
文摘A novel oxamide-bridged trimeric tetranuclear complex 1 incorporating a macro- cyclic oxamide of formula {[(CuL)3Mn](ClO4)2}3 (macrocyclic oxamide L = 2,3-dioxo-5,6,14,15- dibenzo-1,4,8,12-tetraazacyclopentadeca-7,12-diene) was prepared and structurally characterized. The compound [(CuL)3Mn](ClO4)2 crystallizes in the trigonal system, space group P 3 with a = 22.434(17), b = 22.434(17), c = 18.82(2) ?, α = β = 90, γ = 120o, V = 8203(13) ?3, Z = 6, Dc = 1.751g/cm3, μ(MoKα) = 1.557, F(000) = 4392, the final R = 0.083 and wR = 0.1727 for 9604 obser- ved reflections with I > 2σ(I). The single-crystal X-ray analysis shows that 1 is a trimeric complex. There are three similar constitutes, dissimilar conformations and asymmetrically independent ‘building-block’ [(CuL)3Mn] in one crystal cell of the title complex 1.
基金supported by the Ministry of Science and Technology of China(2023YFE0210400)the National Natural Science Foundation of China(22361132530,52303237)+1 种基金the Natural Science Foundation of Tianjin(24JCYBJC01540)the Fundamental Research Funds for the Central Universities(023-63253172)。
文摘Carbazole-based self-assembled molecules have been widely adopted as hole-transporting layers(HTLs)in high-performance organic solar cells(OSCs).However,their practical implementation has been constrained by their limited concentration in solutions and poor solvent tolerance.Herein,to address these limitations,we designed two novel trimeric molecules(TPACz-1 and TPACz-2)that synergistically integrate the structural merits of small molecules with the processing advantages of polymers.Notably,TPACz-2 showed exceptional hole-transporting capacity with uniform coverage on indium tin oxide(ITO)substrates,coupled with robust processability characterized by an extended concentration tolerance range(0.2–1.0 mg mL^(-1))and compatibility with a broad range of solvents.Binary OSCs based on TPACz-2 showed an excellent power conversion efficiency(PCE)of 19.65%with a short-circuit current density of 27.49 mA cm^(-2)and a fill factor of 80.9%.At the same time,the corresponding ternary devices exhibited a high PCE exceeding 20%.Furthermore,the TPACz-based devices demonstrated superior ambient stability,retaining~80%of their initial PCE after 680 h at 25%relative humidity,substantially outperforming conventional PEDOT:PSS-based counterparts.This work offers valuable guidance and highlights the crucial role of oligomeric molecular design as a pivotal strategy for the development of innovative HTLs in OSCs.
基金This work was supported by the National Natural Science Foundation of China(Nos.81822027 and 81630090)the National Key R&D Program of China(No.2019YFA0904400)+1 种基金the National Science and Technology Major Projects of Infectious Disease funds(No.2018ZX10301403)the grant from the Chinese Academy of Medical Sciences(No.2019PT350002).
文摘Influenza causes seasonal outbreaks yearly and unpredictable pandemics with high morbidity and mortality rates.Despite significant efforts to address influenza,it remains a major threat to human public health.This issue is partially due to the lack of antiviral drugs with potent antiviral activity and broad reactivity against all influenza virus strains and the rapid emergence of drug-resistant variants.Moreover,designing a universal influenza vaccine that is sufficiently immunogenic to induce universal antibodies is difficult.Some novel epitopes hidden in the hemagglutinin(HA)trimeric interface have been discovered recently,and a number of antibodies targeting these epitopes have been found to be capable of neutralizing a broad range of influenza isolates.These findings may have important implications for the development of universal influenza vaccines and antiviral drugs.In this review,we focused on the antibodies targeting these newly discovered epitopes in the HA domain of the influenza virus to promote the development of universal anti-influenza antibodies or vaccines and extend the discovery to other viruses with similar conformational changes in envelope proteins.
文摘In this theoretical study,we investigate the generation of second harmonics(SH)during the interaction of a laser beam with a metallic nanoparticle(MNP)trimer.Utilizing a classical electrodynamics framework,we explore the nonlinear interactions between the laser beam fields and nanoparticles(NPs),accounting for dipole-dipole interactions among the particles.Analytical expressions are derived to quantify the impact of these interactions on SH radiation power for two distinct polarizations of the laser beam.Our findings indicate that when the laser electric field is aligned parallel to the trimer's symmetry axis,there is a significant enhancement in SH radiation power compared to a single non-interacting NP,accompanied by a red-shift in the plasmon resonance peak.Conversely,when the laser electric field is perpendicular to the trimer axis,the SH radiation power from each NP decreases,and the plasmon resonance peak experiences a blue-shift.Additionally,we examine the influence of particle size and interparticle separation on SH generation.These results provide valuable insights into the role of interparticle interactions in enhancing nonlinear optical processes in NP assemblies,with potential implications for the design of nanophotonic devices.
文摘Propylene,a readily accessible and economically viable light olefin,has garnered substantial interest for its potential conversion into valuable higher olefins through oligomerization processes.The distribution of products is profoundly influenced by the catalyst structure.In this study,Fe_(2)O_(3)-doped NiSO_(4)/Al_(2)O_(3) catalysts have been meticulously developed to facilitate the selective trimerization of propylene under mild conditions.Significantly,the 0.25Fe_(2)O_(3)-NiSO_(4)/Al_(2)O_(3) catalyst demonstrates an enhanced reaction rate(48.5 mmol_(C3)/(g_(cat).·h)),alongside a high yield of C9(~32.2%),significantly surpassing the performance of the NiSO_(4)/Al_(2)O_(3) catalyst(C9:~24.1%).The incorporation of Fe_(2)O_(3) modifies the migration process of sulfate ions,altering the Lewis acidity of the electron-deficient Ni and Fe sites on the catalyst and resulting a shift in product distribution from a Schulz-Flory distribution to a Poisson distribution.This shift is primarily ascribed to the heightened energy barrier for theβ-H elimination reaction in the C6 alkyl intermediates on the doped catalyst,further promoting polymerization to yield a greater quantity of Type II C9.Furthermore,the validation of the Cossee-Arlman mechanism within the reaction pathway has been confirmed.It is noteworthy that the 0.25Fe_(2)O_(3)-NiSO_(4)/Al_(2)O_(3) catalyst exhibits remarkable stability exceeding 80 h in the selective trimerization of propylene.These research findings significantly enhance our understanding of the mechanisms underlying olefin oligomerization reactions and provide invaluable insights for the development of more effective catalysts.
基金supported by the Ministry of Science and Technology of China(Nos.2021YFA1101300 and 2020YFA0112500)the National Key R&D Program of China(2018YFA0801000)the National Natural Science Foundation of China(No.32170853)。
文摘As an increasingly used alternative to perfluorooctanoic acid(PFOA),hexafluoropropylene oxide trimer acid(HFPO-TA)has been widely detected in global water environments.However,little is known regarding its toxic effects on cardiovascular development.Here,zebrafish embryos were treated with egg water containing 0,60,120,or 240 mg/L HFPO-TA.Results showed that HFPO-TA treatment led to a significant reduction in both larval survival percentage and heart rate.Furthermore,HFPO-TA exposure caused severe pericardial edema and elongation of the sinus venous to bulbus arteriosus distance(SV-BA)in Tg(myl7:GFP)transgenic larvae,disrupting the expression of genes involved in heart development and thus causing abnormal heart looping.Obvious sprouting angiogenesis was observed in the 120 and 240 mg/L exposed Tg(fli:GFP)transgenic larvae.HFPO-TA treatment also impacted the mRNA levels of genes involved in the vascular endothelial growth factor(VEGF)pathway and embryonic vascular development.HFPO-TA exposure significantly decreased erythrocyte number in Tg(gata1:DsRed)transgenic embryos and influenced gene expression associated with the heme metabolism pathway.HFPO-TA also induced oxidative stress and altered the transcriptional levels of genes related to cell cycle and apoptosis,inhibiting cell proliferation while promoting apoptosis.Therefore,HFPO-TA exposure may induce abnormal development of the cardiovascular and hematopoietic systems in zebrafish embryos,suggesting it may not be a suitable or safe alternative for PFOA.
基金This research was supported by the National Natural Science Foundation of China(No.81903488)the CAMS Innovation Fund for Medical Sciences(No.CIFMS-2021-I2M-1-026)。
文摘Five novel(9,10-dihydro)phenanthrene and bibenzyl trimers,as well as two previously identified biphenanthrenes and bibenzyls,were isolated from the tubers of Bletilla striata.Their structures were elucidated through comprehensive analyses of NMR and HRESIMS spectroscopic data.The absolute configurations of these compounds were determined by calculating rotational energy barriers and comparison of experimental and calculated ECD curves.Compounds 5b and 6 exhibited inhibitory effects on LPS-induced NO production in BV-2 cells,with IC_(50) values of 12.59±0.40 and 15.59±0.83μmol·L^(-1),respectively.A mechanistic study suggested that these compounds may attenuate neuroinflammation by reducing the activation of the AKT/IκB/NF-κB signaling pathway.Additionally,compounds 3a,6,and 7 demonstrated significant PTP1B inhibitory activities,with IC_(50) values of 1.52±0.34,1.39±0.11,and 1.78±0.01μmol·L^(-1),respectively.Further investigation revealed that compound 3a might inhibit LPS-induced PTP1B overexpression and NF-κB activation,thereby mitigating the neuroinflammatory response in BV-2 cells.
基金This work was financially supported by the National Natural Science Foundation of China(No.21704048)the 111 Project(No.D17004)the Taishan Scholars Constructive Engineering Foundation(No.tsqn20161031).
文摘Development of degradable polyester elastomers plays an important role in the applications of soft mateirals.Noncrystalline polymenthides(PMs)from menthol derived lactone monomers are excellent soft segments for preparing degradable polyester elastomers.By using cyclic trimeric phosphazene base(CTPB)as an organocatalyst,we succesfully synthesized PMs with different molecular weights(8.2 kDa to 100.7 kDa)in high yields via ring-opening polymerization(ROP)of menthide.When a CTPB/urea binary catalytic system was adopted,the polymerizations proceeded in a more controlled manner.Using glycerol as initiator,star shaped PMs with well.defined structure were synthesized and subsequently end-capped by acrylate.UV iradiation of the terminal acrylate groups in the star-shaped PMs resulted in formation of chemically cos-linked polyester elastomers without heat or other stimuli.The obtained polyester elastomers exhibit matched modulus(3.8-5.5 MPa),tensile strength(0.56-0.68 MPa),and strain at break(280%-320%)with soft body tssues,displaying great potential in biomedical applications.
基金Project supported by the Grant-in-Aid for Scientific Research on Priority Area from the Ministry of Education,Culture,Sports,Science and Technology,Japan (Grant No. Tokutei 22014008)
文摘Raman vibrational spectra of the selected basic （hydroxyl OH and deuteroxyl OD） transition-metal halides, geomet- rically frustrated material series α-, β-, γ-Cu2（OH）3Cl, α-Cu2（OH）3Br, β-Ni2（OH）3Cl, β-Co2（OH）3Cl, β-Co2（OH）3Br, γ-Cu2（OD）3Cl, and β-Co2（OD）3Cl are measured at room temperature and analysed to investigate the relationship be- tween the microstructured OH environments and their respective Raman spectra. Among these selected samples, the last two are used to determine the OH stretching vibration region （3600 cm-1-3300 cm-1） and OH bending vibra- tion region （1000 cm-1-600 cm-1） of OH systems in the spectra. Through the comparative analysis of the distances d（metal-O）, d（O-halogen）, and d（OH）, the strong metal-O interaction and trimeric hydrogen bond （Car, C8 or C1 symmetry） are found in every material, but both determine simultaneously an ultimate d（OH）, and therefore an OH stretching vibration frequency. According to the approximately linear relationship between the OH stretching vibration frequency and d（OH）, some unavailable d（OH） are guessed and some doubtful d（OH） are suggested to be corrected. In addition, it is demonstrated in brief that the OH bending vibration frequency is also of importance to check the more detailed crystal microstructure relating to the OH group.
基金Project supported by the Grant-in-Aid for Scientific Research from the Japanese Society for the Promotion of Science (Grant No.Kiban-B 19340100)the Grant-in-Aid for Scientific Research on Priority Areas from the Ministry of Education,Culture,Sports,Science and Technology,Japan (Grant No.Tokutei 22014008)
文摘Mid-infrared absorption and Raman spectra of the geometrically frustrated material series, hydroxyl cobalt halides β-CO2（OH）3Cl and β-CO2（OH）3Br, are first, to the best of our knowledge, measured at room temperature, to study the corresponding relationship between their vibrational spectral properties and crystal microstructures. Through the comparative analysis of the four spectra we have categorically assigned the OH-related vibration modes of hydroxyl groups in the trimeric hydrogen bond environment （Co3 =OH）3 … Cl/Br, and tentatively suggested vibration modes of O-Co-O, Co O and Cl/Br-Co-Cl/Br units. These results can also become the basis for analysing their low-temperature spectral properties, which can help to understand the underlying physics of their exotic geometric frustration phenomena around phase transition temperatures.
基金This work was supported by the National Natural Science Foundation of China （No.20925313 and No.60438020）, the National Basic Research Program of China （No.2009CB929404）, and the Chinese Academy of Sciences Innovation Program （KJCX2-YW-W25）.
文摘We have reported previously the ultrafast energy transfer process with a time constant of 0.8 ps from a monomeric to a dimeric subunit within a perylenetetracarboxylic diimide trimer, which was derived indirectly from a model fitting into the transient absorption experimental data. Here we present a direct ultrafast fluorescence quenching measurement by employing fs time-resolved transient fluorescence spectroscopy based on noncollinear optical parametric amplification technique. The rapid decay of the monomer＇s emission due to energy transfer was observed directly with a time constant of about 0.82 ps, in good agreement with the previous result.
基金support from the National Natural Sciences Foundation of China(NNSFCGrant Nos.81730093,81630094,and 81502942)+1 种基金CAMS Innovation Fund for Medical Science of China(2017-I2M-3-010 and 2016-I2M-1-004)the Drug Innovation Major Project(2018ZX09711001-001,China)is acknowledged is acknowledged.
文摘From an aqueous extract of“tian ma”(the steamed and dried rhizomes of Gastrodia elata),ten new compounds gastrodiben-zins A−D(1−4)and gastrotribenzins A−F(5−10),along with known analogues(11−20),having structure features coupling between two and three p-hydroxybenzyl-derived units via carbon-and/or ether-bonds,were isolated and characterized by spectroscopic data analysis.Meanwhile,the new compounds 5a,6a,8a,22,and 23,as well as the known derivatives 13a,14a,15,17−21,24,25,and p-hydroxybenzyl aldehyde were isolated and identified from a refluxed aqueous solution of p-hydroxybenzyl alcohol.Methylation of 5a and 6a in methanol and ethylation of 6a,8a,13a,and 14a in ethanol produced 5 and 6 and 7,8,13,and 14,respectively.using ultra-performance liquid chromatography high-resolution electrospray ioniza-tion mass spectrometry(UPLC-HRESIMS)analysis of the refluxed solutions of p-hydroxybenzyl alcohol and the refluxed extracts of the fresh G.elata rhizome and“tian ma”extracts indicated consistent production and variation of the dimeric and trimeric derivatives of p-hydroxybenzyl alcohol upon extracting solvents and refluxing time.In various assays,the dimeric and trimeric derivatives showed more potent activities than p-hydroxybenzyl alcohol itself and gastrodin,which are the main known active constituents of“tian ma”.These results revealed for the first time that the more effective dimers and trimers can be produced through condensation of the co-occurring p-hydroxybenzyl alcohol during processing and decocting of the G.elata rhizomes,demonstrating insights into medicinal chemistry behind application protocols of traditional Chinese medicines.
文摘One new A - type proanthocyanidin trimer, lindetannin trimer, was isolated from the stems of Lindera aggregata (Sims) Kosterm.. Its structure was elucidated by spectral and chemical methods.
基金the National Natural Science Foundation of China(Nos.22075105 and 51573204)National Science Foundation of Shandong Province(No.ZR2018ZB0315)+1 种基金H.Zhang thanks the financial support from the National Natural Science Foundation of China(No.51803230)Prof.J.Wang thanks the financial support from the Opening Project of Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education,Jianghan University.The authors thank Dr.Chunming Yang for GIWAXS tests and beamline BL16B1(Shanghai Synchrotron Radiation Facility)for providing beam time.
文摘A series of copolymers of thiazoloisoindigo (Tzll) with different chalcogenophene trimers were synthesized to systematicllyinvestigate the chalcogen effect on their charge transport propertes.When only the middlethiophene ring of terthiphene(T-T-T)is replaced byheavier chalcogenophenes,a preference(expressed by the ratio of μe/μh)towards electron transport was observed descending from T-T-Tto T-Se-Tthen to T-Te-T(Se and Te stand for selenophene and tellurophene,respectively).On the other hand,with the increased number of heavierchalcogenophenes,a preference toward hole transport was observed descending from Se-T-Se to Se-Se-se then to Se-Te-Se.This phenomenon iswellexplained by the balance between the aromatic resonance energy of the chalcogenophenes and the electronegativity of the chalcogens.Specifically,P(TZll-T-Se-T)displayed relatively balanced ambipolar property(μh^(max)andμe^(max) of 3.77 and 1.59 cm^(2)·v^(-1)·s^(-1)with aμe/μh of 0.42).while P(Tll-Se-Te-Se)exhibited the best preference to hole transfer with a u.u,of 0.09.P(Tzll-T-Te-T)exhibited the best preference to electrontransfer with aμe/μl,of 16 and theμe^(max)of 0.64 cm^(2)·v^(-).s^(-1)which is the highest electron mobility among the known conjugated polymerscontaining tellurophenes.
