Acceptor-donor-acceptor(A-D-A)type molecules,of which the novel non-fused azacyclic end-group pyrazoli-nones were modified with chlorine substitution on the phenyl ring,were synthesized.The non-fused azacyclic end-gro...Acceptor-donor-acceptor(A-D-A)type molecules,of which the novel non-fused azacyclic end-group pyrazoli-nones were modified with chlorine substitution on the phenyl ring,were synthesized.The non-fused azacyclic end-group py-razolinones have the advantages of simple synthesis steps,low cost and environmental friendliness,compared to the classical end-group dicyanomethyleneindianone.The properties of the synthesized A-D-A type molecules with non-fused azacyclic end groups were characterized by theoretical calculation,UV-vis absorption,cyclic voltammetry,X-ray diffraction and space charge limited current.It is shown that the strong UV-vis absorptions of the synthesized A-D-A type molecules are located in the wavelength range of 500~700 nm,with a moderate band gap of nearly 1.7 eV.At the same time,the influence of end-group chlorination on the properties of A-D-A type molecules was compared and explored.It is proven that this kind of A-D-A type molecule with non-fused azacyclic end groups has the potential to be applied as interfacial modified layer of the active layer in perovskite solar cell devices.展开更多
This paper computes the group and character table of Trimethylborane and Cyclohaxane. Results show that the groups are isomorphic to the wreath products C3wrC2 and C2wrC6 with orders 81 and 384 and with 17 and 28 conj...This paper computes the group and character table of Trimethylborane and Cyclohaxane. Results show that the groups are isomorphic to the wreath products C3wrC2 and C2wrC6 with orders 81 and 384 and with 17 and 28 conjugacy classes respectively, where Cn denotes a cyclic group of order n.展开更多
Two-dimensional self-assemblies of four partially fluorinated molecules, 1,4-bis（2,6-difluoropyridin-4-yl）benzene, 4,4＇-bis（2,6-difluoropyridin-4-yl）-1,1＇-biphenyl, 4,4＇-bis（2,6-difluoropyridin-4-yl）-1,1＇：4...Two-dimensional self-assemblies of four partially fluorinated molecules, 1,4-bis（2,6-difluoropyridin-4-yl）benzene, 4,4＇-bis（2,6-difluoropyridin-4-yl）-1,1＇-biphenyl, 4,4＇-bis（2,6-difluoropyridin-4-yl）-1,1＇：4＇,1＇-terphenyl and 4,4＇-bis（2,6-difluoropyridin-3-yl）-1,1＇-biphenyl, involving weak intermolecular C-H···F and C-H···N hydrogen bonds were systematically investigated on Au（111） with low-temperature scanning tunneling microscopy. The inter-molecular connecting modes and binding sites were closely related to the backbones of the building blocks, i.e., the molecule length determines its binding sites with neighboring molecules in the assemblies while the attaching positions of the N and F atoms dictate its approaching and docking angles. The experimental results demonstrate that multiple weak hydrogen bonds such as C-H···F and C-H···N can be efficiently applied to tune the molecular orientations and the self-assembly structures accordingly.展开更多
Self-assembled molecules(SAMs) have shown great potential in replacing bulk charge selective contact layers in high-performance perovskite solar cells(PSCs) due to their low material consumption and simple processing....Self-assembled molecules(SAMs) have shown great potential in replacing bulk charge selective contact layers in high-performance perovskite solar cells(PSCs) due to their low material consumption and simple processing. Herein, we design and synthesize a series of donor-acceptor(D-A) type SAMs(MPA-BTCA, MPA-BT-BA, and MPA-BT-RA, where MPA is 4-methoxy-N-(4-methoxyphenyl)-N-phenylaniline;BT is benzo[c][1,2,5]-thiadiazole;CA is 2-cyanoacrylic acid, BA is benzoic acid, RA is rhodanine-3-propionic acid) with distinct anchoring groups, which show dramatically different properties. MPA-BTCA with CA anchoring groups exhibited stronger dipole moments and formed a homogeneous monolayer on the indium tin oxide(ITO) surface by adopting an upstanding self-assembling mode. However, the MPA-BT-RA molecules tend to aggregate severely in solid state due to the sp~3 hybridization of the carbon atom on the RA group, which is not favorable for achieving a long-range ordered self-assembled layer.Consequently, benefiting from high dipole moment, as well as dense and uniform self-assembled film,the device based on MPA-BT-CA yielded a remarkable power conversion efficiency(PCE) of 21.81%.Encouragingly, an impressive PCE approaching 20% can still be obtained for the MPA-BT-CA-based PSCs as the device area is increased to 0.80 cm^(2). Our work sheds light on the design principles for developing hole selecting SAMs, which will pave a way for realizing highly efficient, flexible, and large-area PSCs.展开更多
The electrochemical water splitting to produce hydrogen converts electric energy into clean hydrogen energy,which is a groundbreaking concept of energy optimization.To achieve high efficiency,numerous strategies have ...The electrochemical water splitting to produce hydrogen converts electric energy into clean hydrogen energy,which is a groundbreaking concept of energy optimization.To achieve high efficiency,numerous strategies have been developed to enhance the performance of electrocatalysts.Among these,interface engineering with molecules/ions/groups,serves as a versatile approach for optimizing the performance of electrocatalysts in water splitting.On the basis of numerous achievements in high-performance electrocatalysts engineered through molecules/ions/groups at interface,a comprehensive understanding of these advancements is crucial for guiding future progress.Herein,after providing a concise overview of the background,the interface engineering via molecules/ions/groups for electrocatalytic water splitting is demonstrated from three perspectives.Firstly,the engineering of electronic state of electrocatalysts by molecules/ions/groups at interface to reduce the Gibbs free energy of the corresponding reactions.Secondly,the modification of local microenvironment surrounding electrocatalysts via molecules/ions/groups at interface to enhance the transfer of reactants and products.Thirdly,the protection of electrocatalysts with molecule/ion/group fences improves their durability,including protecting active sites from leaching and defending them against harmful species.The fundamental principles of these three aspects are outlined for each,along with pertinent comments.Finally,several research directions and challenges are proposed.展开更多
The electrochemical CO_(2) reduction reaction(eCO_(2)RR),producing gaseous C_(2+)products such as ethylene(C_(2)H_(4)),represents a sustainable strategy to mitigate the greenhouse effect.Inspired by the promotion effe...The electrochemical CO_(2) reduction reaction(eCO_(2)RR),producing gaseous C_(2+)products such as ethylene(C_(2)H_(4)),represents a sustainable strategy to mitigate the greenhouse effect.Inspired by the promotion effect of the cyano group(-C≡N) for C-C coupling in organic chemistry,several cyano-containing organocatalysts have been found to be capable of directly converting CO_(2) into C_(2)H_(4) with-C≡N as the active center during the eCO_(2)RR.The selectivity of C_(2)H_(4) for the representative catalyst,metal-free dicyandiamide(DCD),reached 27.6 % after partial hydrogenation in KHCO_(3) solution.In addition,its selectivity can be further improved to 57.7 % when coupled with oriented Cu crystals.The experimental and computational results collectively reveal that charge redistribution between Cu{100} and DCD promotes the partial hydrogenation of the cyano group and lays the foundation for the reduced energy barrier for the CO_(2) reduction on-C≡N.This study breaks the limitations of traditional metal/metal oxide-based catalysts by using cyano-containing organocatalysts for direct C_(2+) product generation,expanding the eCO_(2)RR catalyst library.In addition,this research elucidates the role of charge redistribution and cyano group hydrogenation in lowering reaction barriers,providing fundamental guidance for the design of new organocatalysts.展开更多
Hamiltonian of an O3 molecule is classicized by using coherent states, and its potential energy surface is obtained. The surface and the contours are plotted. The calculated force constants and dissociation energies a...Hamiltonian of an O3 molecule is classicized by using coherent states, and its potential energy surface is obtained. The surface and the contours are plotted. The calculated force constants and dissociation energies are in good agreement with experimental values.展开更多
Machine learning(ML)offers considerable promise for the design of new molecules and materials.In real-world applications,the design problem is often domain-specific,and suffers from insufficient data,particularly labe...Machine learning(ML)offers considerable promise for the design of new molecules and materials.In real-world applications,the design problem is often domain-specific,and suffers from insufficient data,particularly labeled data,for ML training.In this study,we report a data-efficient,deep-learning framework for molecular discovery that integrates a coarse-grained functional-group representation with a self-attention mechanism to capture intricate chemical interactions.Our approach exploits group-contribution concepts to create a graph-based intermediate representation of molecules,serving as a low-dimensional embedding that substantially reduces the data demands typically required for training.Using a self-attention mechanism to learn the subtle but highly relevant chemical context of functional groups,the method proposed here consistently outperforms existing approaches for predictions of multiple thermophysical properties.In a case study focused on adhesive polymer monomers,we train on a limited dataset comprising only 6,000 unlabeled and 600 labeled monomers.The resulting chemistry prediction model achieves over 92%accuracy in forecasting properties directly from SMILES strings,exceeding the performance of current state-of-the-art techniques.Furthermore,the latent molecular embedding is invertible,enabling the design pipeline to automatically generate new monomers from the learned chemical subspace.We illustrate this functionality by targeting several properties,including high and low glass transition temperatures(Tg),and demonstrate that our model can identify new candidates with values that surpass those in the training set.The ease with which the proposed framework navigates both chemical diversity and data scarcity offers a promising route to accelerate and broaden the search for functional materials.展开更多
Background:Human natural killer(NK)cells have attracted widespread attention as a potential adoptive cell therapy(ACT).However,the therapeutic effects of NK cell infusion in patients with solid tumors are limited.Ther...Background:Human natural killer(NK)cells have attracted widespread attention as a potential adoptive cell therapy(ACT).However,the therapeutic effects of NK cell infusion in patients with solid tumors are limited.There is an urgent need to explore a suitable new treatment plan to overcome weaknesses and support the superior therapeutic activity of NK cells.Methods:In this study,the mechanisms underlying the susceptibility of gastric cancer(GC)cell lines AGS,HGC-27,and NCI-N87 to NK cell-mediated cytotoxicity were explored.Results:Lactic dehydrogenase(LDH)release assays showed that all three GC cell lines were susceptible to the umbilical cord blood NK(UCB-NK)cells,and HGC-27 cells with high CD56 expression were the most sensitive to UCB-NK,followed by NCI-N87 and AGS.When the expression of CD56 in HGC-27 cells decreased,the lytic activity of NK cells in HGC-27 cells was abating.In addition,combining oxaliplatin with NK cells produced additive anti-tumor effects in vitro,which may have resulted from oxaliplatin-induced NK group 2 member D(NKG2DL)upregulation in GC cells.These results of cytotoxicity activity showed that inhibition of CD56 expression might suppress the sensitivity of GC cells to NK cell-mediated cytotoxicity,and upregulation of the expression of NKG2DL on the surface of GC cells by oxaliplatin could enhance the killing sensitivity of NK cells.Conclusion:Collectively,our study provides a deeper theoretical foundation and a better therapeutic strategy for NK cell immunotherapy in the treatment of human GC.展开更多
BrCF_2SO_2Br, prepared from sulfinatodehalogenation of CF_2Br_2 followed by bromination of the intermediate BrCF_2SO_2Na, was shown to be a mild and efficient bromodifluoromethylating agent.
文摘Acceptor-donor-acceptor(A-D-A)type molecules,of which the novel non-fused azacyclic end-group pyrazoli-nones were modified with chlorine substitution on the phenyl ring,were synthesized.The non-fused azacyclic end-group py-razolinones have the advantages of simple synthesis steps,low cost and environmental friendliness,compared to the classical end-group dicyanomethyleneindianone.The properties of the synthesized A-D-A type molecules with non-fused azacyclic end groups were characterized by theoretical calculation,UV-vis absorption,cyclic voltammetry,X-ray diffraction and space charge limited current.It is shown that the strong UV-vis absorptions of the synthesized A-D-A type molecules are located in the wavelength range of 500~700 nm,with a moderate band gap of nearly 1.7 eV.At the same time,the influence of end-group chlorination on the properties of A-D-A type molecules was compared and explored.It is proven that this kind of A-D-A type molecule with non-fused azacyclic end groups has the potential to be applied as interfacial modified layer of the active layer in perovskite solar cell devices.
文摘This paper computes the group and character table of Trimethylborane and Cyclohaxane. Results show that the groups are isomorphic to the wreath products C3wrC2 and C2wrC6 with orders 81 and 384 and with 17 and 28 conjugacy classes respectively, where Cn denotes a cyclic group of order n.
基金supported by NSFC(Nos.21333001,21133001,21261130090),ChinaNRF CREATE-SPURc project(No.R-143-001-205-592),Singapore
文摘Two-dimensional self-assemblies of four partially fluorinated molecules, 1,4-bis（2,6-difluoropyridin-4-yl）benzene, 4,4＇-bis（2,6-difluoropyridin-4-yl）-1,1＇-biphenyl, 4,4＇-bis（2,6-difluoropyridin-4-yl）-1,1＇：4＇,1＇-terphenyl and 4,4＇-bis（2,6-difluoropyridin-3-yl）-1,1＇-biphenyl, involving weak intermolecular C-H···F and C-H···N hydrogen bonds were systematically investigated on Au（111） with low-temperature scanning tunneling microscopy. The inter-molecular connecting modes and binding sites were closely related to the backbones of the building blocks, i.e., the molecule length determines its binding sites with neighboring molecules in the assemblies while the attaching positions of the N and F atoms dictate its approaching and docking angles. The experimental results demonstrate that multiple weak hydrogen bonds such as C-H···F and C-H···N can be efficiently applied to tune the molecular orientations and the self-assembly structures accordingly.
基金financial support from the National Natural Science Foundation of China (NSFC)(21805128)the National Natural Science Foundation of China (21774055)+3 种基金the financial support from the National Natural Science Foundation of China(21975260)the Shenzhen Science and Technology Innovation Commission(JCYJ20180504165709042)financial support of Guangdong Provincial Key Laboratory Program(2021B1212040001) from the Department of Science and Technology of Guangdong Provincethe NSFC-CNR exchange program of NSFC(22011530391)。
文摘Self-assembled molecules(SAMs) have shown great potential in replacing bulk charge selective contact layers in high-performance perovskite solar cells(PSCs) due to their low material consumption and simple processing. Herein, we design and synthesize a series of donor-acceptor(D-A) type SAMs(MPA-BTCA, MPA-BT-BA, and MPA-BT-RA, where MPA is 4-methoxy-N-(4-methoxyphenyl)-N-phenylaniline;BT is benzo[c][1,2,5]-thiadiazole;CA is 2-cyanoacrylic acid, BA is benzoic acid, RA is rhodanine-3-propionic acid) with distinct anchoring groups, which show dramatically different properties. MPA-BTCA with CA anchoring groups exhibited stronger dipole moments and formed a homogeneous monolayer on the indium tin oxide(ITO) surface by adopting an upstanding self-assembling mode. However, the MPA-BT-RA molecules tend to aggregate severely in solid state due to the sp~3 hybridization of the carbon atom on the RA group, which is not favorable for achieving a long-range ordered self-assembled layer.Consequently, benefiting from high dipole moment, as well as dense and uniform self-assembled film,the device based on MPA-BT-CA yielded a remarkable power conversion efficiency(PCE) of 21.81%.Encouragingly, an impressive PCE approaching 20% can still be obtained for the MPA-BT-CA-based PSCs as the device area is increased to 0.80 cm^(2). Our work sheds light on the design principles for developing hole selecting SAMs, which will pave a way for realizing highly efficient, flexible, and large-area PSCs.
基金supported by the National Natural Science Foundation of China(Nos.22071069,22090050,22176180,21874121 and 21974128)the National Key Research and Development Program of China(Nos.2018YFE0206900 and 2021YFA1200400)+2 种基金Zhejiang Provincial Natural Science Foundation of China under Grant(Nos.LY20B050002 and LD21B050001)Hubei Provincial Natural Science Foundation of China(No.2020CFA037)the Foundation of Basic and Applied Basic Research of Guangdong Province(No.2019B1515120087).
文摘The electrochemical water splitting to produce hydrogen converts electric energy into clean hydrogen energy,which is a groundbreaking concept of energy optimization.To achieve high efficiency,numerous strategies have been developed to enhance the performance of electrocatalysts.Among these,interface engineering with molecules/ions/groups,serves as a versatile approach for optimizing the performance of electrocatalysts in water splitting.On the basis of numerous achievements in high-performance electrocatalysts engineered through molecules/ions/groups at interface,a comprehensive understanding of these advancements is crucial for guiding future progress.Herein,after providing a concise overview of the background,the interface engineering via molecules/ions/groups for electrocatalytic water splitting is demonstrated from three perspectives.Firstly,the engineering of electronic state of electrocatalysts by molecules/ions/groups at interface to reduce the Gibbs free energy of the corresponding reactions.Secondly,the modification of local microenvironment surrounding electrocatalysts via molecules/ions/groups at interface to enhance the transfer of reactants and products.Thirdly,the protection of electrocatalysts with molecule/ion/group fences improves their durability,including protecting active sites from leaching and defending them against harmful species.The fundamental principles of these three aspects are outlined for each,along with pertinent comments.Finally,several research directions and challenges are proposed.
基金financial support provided by the National Natural Science Foundation of China (52472304)。
文摘The electrochemical CO_(2) reduction reaction(eCO_(2)RR),producing gaseous C_(2+)products such as ethylene(C_(2)H_(4)),represents a sustainable strategy to mitigate the greenhouse effect.Inspired by the promotion effect of the cyano group(-C≡N) for C-C coupling in organic chemistry,several cyano-containing organocatalysts have been found to be capable of directly converting CO_(2) into C_(2)H_(4) with-C≡N as the active center during the eCO_(2)RR.The selectivity of C_(2)H_(4) for the representative catalyst,metal-free dicyandiamide(DCD),reached 27.6 % after partial hydrogenation in KHCO_(3) solution.In addition,its selectivity can be further improved to 57.7 % when coupled with oriented Cu crystals.The experimental and computational results collectively reveal that charge redistribution between Cu{100} and DCD promotes the partial hydrogenation of the cyano group and lays the foundation for the reduced energy barrier for the CO_(2) reduction on-C≡N.This study breaks the limitations of traditional metal/metal oxide-based catalysts by using cyano-containing organocatalysts for direct C_(2+) product generation,expanding the eCO_(2)RR catalyst library.In addition,this research elucidates the role of charge redistribution and cyano group hydrogenation in lowering reaction barriers,providing fundamental guidance for the design of new organocatalysts.
文摘Hamiltonian of an O3 molecule is classicized by using coherent states, and its potential energy surface is obtained. The surface and the contours are plotted. The calculated force constants and dissociation energies are in good agreement with experimental values.
基金supported by the U.S.Department of Energy,Office of Science,Basic Energy Sciences,Materials Sciences and Engineering Division.
文摘Machine learning(ML)offers considerable promise for the design of new molecules and materials.In real-world applications,the design problem is often domain-specific,and suffers from insufficient data,particularly labeled data,for ML training.In this study,we report a data-efficient,deep-learning framework for molecular discovery that integrates a coarse-grained functional-group representation with a self-attention mechanism to capture intricate chemical interactions.Our approach exploits group-contribution concepts to create a graph-based intermediate representation of molecules,serving as a low-dimensional embedding that substantially reduces the data demands typically required for training.Using a self-attention mechanism to learn the subtle but highly relevant chemical context of functional groups,the method proposed here consistently outperforms existing approaches for predictions of multiple thermophysical properties.In a case study focused on adhesive polymer monomers,we train on a limited dataset comprising only 6,000 unlabeled and 600 labeled monomers.The resulting chemistry prediction model achieves over 92%accuracy in forecasting properties directly from SMILES strings,exceeding the performance of current state-of-the-art techniques.Furthermore,the latent molecular embedding is invertible,enabling the design pipeline to automatically generate new monomers from the learned chemical subspace.We illustrate this functionality by targeting several properties,including high and low glass transition temperatures(Tg),and demonstrate that our model can identify new candidates with values that surpass those in the training set.The ease with which the proposed framework navigates both chemical diversity and data scarcity offers a promising route to accelerate and broaden the search for functional materials.
基金supported by the CAMS Innovation Fund for Medical Sciences(Grants:2021-I2M-1-070)National Natural Science Foundation of China(Grants 82373767).
文摘Background:Human natural killer(NK)cells have attracted widespread attention as a potential adoptive cell therapy(ACT).However,the therapeutic effects of NK cell infusion in patients with solid tumors are limited.There is an urgent need to explore a suitable new treatment plan to overcome weaknesses and support the superior therapeutic activity of NK cells.Methods:In this study,the mechanisms underlying the susceptibility of gastric cancer(GC)cell lines AGS,HGC-27,and NCI-N87 to NK cell-mediated cytotoxicity were explored.Results:Lactic dehydrogenase(LDH)release assays showed that all three GC cell lines were susceptible to the umbilical cord blood NK(UCB-NK)cells,and HGC-27 cells with high CD56 expression were the most sensitive to UCB-NK,followed by NCI-N87 and AGS.When the expression of CD56 in HGC-27 cells decreased,the lytic activity of NK cells in HGC-27 cells was abating.In addition,combining oxaliplatin with NK cells produced additive anti-tumor effects in vitro,which may have resulted from oxaliplatin-induced NK group 2 member D(NKG2DL)upregulation in GC cells.These results of cytotoxicity activity showed that inhibition of CD56 expression might suppress the sensitivity of GC cells to NK cell-mediated cytotoxicity,and upregulation of the expression of NKG2DL on the surface of GC cells by oxaliplatin could enhance the killing sensitivity of NK cells.Conclusion:Collectively,our study provides a deeper theoretical foundation and a better therapeutic strategy for NK cell immunotherapy in the treatment of human GC.
文摘BrCF_2SO_2Br, prepared from sulfinatodehalogenation of CF_2Br_2 followed by bromination of the intermediate BrCF_2SO_2Na, was shown to be a mild and efficient bromodifluoromethylating agent.
