The photo-physical characteristics of semiconductor polymer are systematically stud- ied through comparing poly （9,9-dioctylfluorene） （PFO） and poly （9,9-dioctylfluorene-co- benzothiadiazole） （F8BT）. The quant...The photo-physical characteristics of semiconductor polymer are systematically stud- ied through comparing poly （9,9-dioctylfluorene） （PFO） and poly （9,9-dioctylfluorene-co- benzothiadiazole） （F8BT）. The quantum chemical calculation shows that the introduction of benzothiadiazole unit facilitates the intrachain charge transfer （ICT） and modulates the electronic transition mechanism of polymer. The transient absorption measurement exhibits that intrachain exciton relaxation is dominant in the decay of excited PFO in a monodis- perse system and intrachain exciton interaction could appear at high excitation intensity. In F8BT solution, the ICT state exists and participates in the relaxation of excited state. The relaxation processes of PFO and F8BT in the condensed phase both accelerate and show obvious exciton-exciton annihilation behavior at high excitation intensity. At the same excitation intensity, the mean lifetime of F8BT is longer than that of PFO, which may be assigned to the excellent delocalization of charge.展开更多
The H^++CO2 reaction at high energies is relevant in atmospheric chemistry,astrophysics,and proton cancer therapy research.Therefore,we present herein a complete investigation of H^++CO2 at ELab=30 eV with the simples...The H^++CO2 reaction at high energies is relevant in atmospheric chemistry,astrophysics,and proton cancer therapy research.Therefore,we present herein a complete investigation of H^++CO2 at ELab=30 eV with the simplest-level electron nuclear dynamics(SLEND)method.SLEND describes nuclei via classical mechanics and electrons with a singledeterminantal Thouless wavefunction.The 3402 SLEND conducted simulations from 42 independent CO2 target orientations provide a full description of all the reactive processes and their mechanisms in this system:non-charge-transfer scattering(NCTS),charge-transfer scattering(CTS),and single C=O bond dissociation;all this valuable information about reactivity is not accessible experimentally.Numerous details of the projectile scattering patterns are provided,including the appearance and coalescence of primary and secondary rainbow angles as a function of the target orientation.SLEND NCTS and CTS differential cross sections(DCSs)are evaluated in conjunction with advanced semi-classical techniques.SLEND NCTS DCS agrees well with its experimental counterpart at all the measured scattering angles,whereas SLEND CTS DCS agrees well at high scattering angles but less satisfactorily at lower ones.Remarkably,both NCTS and CTS SLEND DCSs predict the primary rainbow angle signatures in agreement with the experiment.展开更多
Compared to the conventional trial-and-error approach,computational prediction is becoming an increasingly prominent approach inthe discovery of covalent organic frameworks(COFs)with specific applications,yet it has b...Compared to the conventional trial-and-error approach,computational prediction is becoming an increasingly prominent approach inthe discovery of covalent organic frameworks(COFs)with specific applications,yet it has been rarely demonstrated.Herein,we em-ployed density functional theory(DFT)to pre-screen the electronic and optical properties of thiophene-based donor-acceptor(D-A)pairs simplified from their corresponding COF structures.Theoretical calculation illustrates the BMTB-BTTC with the highest number ofthiophene units is expected to exhibit the best photocatalytic performance for hydrogen production.According to calculation predic-tion,four COFs have been prepared and their photocatalytic activities have been experimentally validated.Interestingly,the corre-sponding BMTB-BTTC-COF shows the highest photocatalytic hydrogen production rate of 12.37 mmolg^(-1)·h^(-1) among the four COFs.Combining the calculation and experimental results,it has been proven that the photocatalytic activity can be fine-tuned by modulat-ing the number of thiophene units.Our study provides a new strategy for the rational design and regulation of D-A COFs to enhancephotocatalytic activity through computational prediction.展开更多
Light-driven carbon dioxide(CO_(2))capture and utilization is one of the most fundamental reactions in Nature.Herein,we report the first visible-light-driven photocatalyst-free hydrocarboxylation of alkenes with CO_(2...Light-driven carbon dioxide(CO_(2))capture and utilization is one of the most fundamental reactions in Nature.Herein,we report the first visible-light-driven photocatalyst-free hydrocarboxylation of alkenes with CO_(2).Diverse acrylates and styrenes,including challenging tri-and tetrasubstituted ones,undergo anti-Markovnikov hydrocarboxylation with high selectivities to generate valuable succinic acid derivatives and 3-arylpropionic acids.In addition to the use of stoichiometric aryl thiols,the thiol catalysis is also developed,representing the first visible-lightdriven organocatalytic hydrocarboxylation of alkenes with CO_(2).The UV-vis measurements,NMR analyses,and computational investigations support the formation of a novel charge-transfer complex(CTC)between thiolate and acrylate/styrene.Further mechanistic studies and density functional theory(DFT)calculations indicate that both alkene and CO_(2)radical anions might be generated,illustrating the unusual selectivities and providing a novel strategy for CO_(2)utilization.展开更多
Amphiphilic polypyridyl mthenium（Ⅱ） complex cis-di（isothiocyanato）（4,4＇-di-tert-butyl-2,2＇-bipyridyl）（4,4＇- dicarboxy-2,2＇-bipyridyl）ruthenium（Ⅱ）（K005） has been synthesized and characterized by cycli...Amphiphilic polypyridyl mthenium（Ⅱ） complex cis-di（isothiocyanato）（4,4＇-di-tert-butyl-2,2＇-bipyridyl）（4,4＇- dicarboxy-2,2＇-bipyridyl）ruthenium（Ⅱ）（K005） has been synthesized and characterized by cyclic voltammetry, ^1H NMR, UV-Vis, and FT-IR spectroscopies. The sensitizer sensitizes TiO2 over a notably broad spectral range due to its intense metal-to-ligand charge-transfer （MLCT） bands at 537 and 418 nm. The photophysical and photochemical studies of K005 were contrasted with those of cis-Ru（dcbpy）2（NCS）2, known as the N3 dye, and the amphiphilic ruthenium（Ⅱ） dye Z907. A reversible couple at E1/2=0.725 V vs. saturated calomel electrode （SCE） with a separation of 0.08 V between the anodic and cathodic peaks, was observed due to the Ru^Ⅱ/Ⅲ couple by cyclic voltammetry. Furthermore, this amphiphilic ruthenium complex was successfully used as sensitizers for dye-sensitized solar cells with the efficiency of 3.72% at the 100 mW·cm^-2 irradiance of air mass 1.5 simulated sunlight without optimization of TiO2 films and the electrolyte.展开更多
A reversible dual-responsive luminescent material was introduced by our group to show the simultaneous color and lifetime switching in response to external stimuli.Pristine crystalline powder of(E)-2-(benzo[d]thiazol-...A reversible dual-responsive luminescent material was introduced by our group to show the simultaneous color and lifetime switching in response to external stimuli.Pristine crystalline powder of(E)-2-(benzo[d]thiazol-2-yl)-3-(pyren-1-yl)acrylonitrile(Py-BZTCN)shows the orderedπ–πstacking with only near-monomer-normal orange-yellow fluorescence,but it exhibits red emission with thermally activated delayed fluorescence(TADF)after grinding,which can be reversibly recovered by heating or fuming treatment.Grinding disturbs the orderedπ–πstacking of pristine powder,leading to the formation of small aggregates with compressed distance and increased overlap ofπ–πstacking between adjacent molecules.The cause of switching was verified by single-crystal X-ray diffraction experiments of two corresponding crystals.This strongπ–πinteraction effectively promotes the excited-state energy splitting and substantially decreases the singlet–triplet energy gap(ΔEST)of aggregates,resulting in the red TADF emission of aggregates through reverse intersystem crossing.This finding proposes a new route to realizing the TADF emission of aggregates through strong intermolecular interactions based on non-TADF monomer,thereby enabling a novel high-contrast dualresponsive luminescence switching.展开更多
文摘The photo-physical characteristics of semiconductor polymer are systematically stud- ied through comparing poly （9,9-dioctylfluorene） （PFO） and poly （9,9-dioctylfluorene-co- benzothiadiazole） （F8BT）. The quantum chemical calculation shows that the introduction of benzothiadiazole unit facilitates the intrachain charge transfer （ICT） and modulates the electronic transition mechanism of polymer. The transient absorption measurement exhibits that intrachain exciton relaxation is dominant in the decay of excited PFO in a monodis- perse system and intrachain exciton interaction could appear at high excitation intensity. In F8BT solution, the ICT state exists and participates in the relaxation of excited state. The relaxation processes of PFO and F8BT in the condensed phase both accelerate and show obvious exciton-exciton annihilation behavior at high excitation intensity. At the same excitation intensity, the mean lifetime of F8BT is longer than that of PFO, which may be assigned to the excellent delocalization of charge.
基金Present calculations were performed at the Texas Tech University High Performance Computer Center and the Texas Advanced Computing Center at the University of Texas at Austin.Prof.Morales acknowledges financial support from the Cancer Prevention and Research Institute of Texas(CPRIT)grant RP140478.Prof.Yan acknowledges the financial support from the National Natural Science Foundation of China(No.21373064)and the Program for Innovative Research Team of Guizhou Province(No.QKTD[2014]4021).
文摘The H^++CO2 reaction at high energies is relevant in atmospheric chemistry,astrophysics,and proton cancer therapy research.Therefore,we present herein a complete investigation of H^++CO2 at ELab=30 eV with the simplest-level electron nuclear dynamics(SLEND)method.SLEND describes nuclei via classical mechanics and electrons with a singledeterminantal Thouless wavefunction.The 3402 SLEND conducted simulations from 42 independent CO2 target orientations provide a full description of all the reactive processes and their mechanisms in this system:non-charge-transfer scattering(NCTS),charge-transfer scattering(CTS),and single C=O bond dissociation;all this valuable information about reactivity is not accessible experimentally.Numerous details of the projectile scattering patterns are provided,including the appearance and coalescence of primary and secondary rainbow angles as a function of the target orientation.SLEND NCTS and CTS differential cross sections(DCSs)are evaluated in conjunction with advanced semi-classical techniques.SLEND NCTS DCS agrees well with its experimental counterpart at all the measured scattering angles,whereas SLEND CTS DCS agrees well at high scattering angles but less satisfactorily at lower ones.Remarkably,both NCTS and CTS SLEND DCSs predict the primary rainbow angle signatures in agreement with the experiment.
基金supported by the National Natural Science Foundation of China(Nos.22371091,21975104,22150004,22201102,and 22302141)the Guangdong Major Project of Basic and Applied Research(No.2019B030302009)+4 种基金Zhejiang Provincial Natural Science Foundation of China(No.LY22E030008)the Open Fund of Guangdong Provincial Key Laboratory of Functional Supramolecular Coordination Materials and Applications(No.2020B121201005)the Postdoctoral Fellowship Program of CPSF(No.GZC20240598)China Postdoctoral Science Foundation(No.2024M751118)Q.G.is thankful for the financial support from Special Project for Peak Carbon Dioxide Emissions-Carbon Neutrality(21DZ1206900)from the Shanghai Municipal Science and Technology Commission.
文摘Compared to the conventional trial-and-error approach,computational prediction is becoming an increasingly prominent approach inthe discovery of covalent organic frameworks(COFs)with specific applications,yet it has been rarely demonstrated.Herein,we em-ployed density functional theory(DFT)to pre-screen the electronic and optical properties of thiophene-based donor-acceptor(D-A)pairs simplified from their corresponding COF structures.Theoretical calculation illustrates the BMTB-BTTC with the highest number ofthiophene units is expected to exhibit the best photocatalytic performance for hydrogen production.According to calculation predic-tion,four COFs have been prepared and their photocatalytic activities have been experimentally validated.Interestingly,the corre-sponding BMTB-BTTC-COF shows the highest photocatalytic hydrogen production rate of 12.37 mmolg^(-1)·h^(-1) among the four COFs.Combining the calculation and experimental results,it has been proven that the photocatalytic activity can be fine-tuned by modulat-ing the number of thiophene units.Our study provides a new strategy for the rational design and regulation of D-A COFs to enhancephotocatalytic activity through computational prediction.
基金Financial support was provided by the the National Natural Science Foundation of China(nos.21822108,21822303,21801176,21772129,and 21772020)the Fok Ying Tung Education Foundation(no.161013)+1 种基金Sichuan Science and Technology Program(nos.2019YJ0379 and 20CXTD0112)the Fundamental Research Funds for the Central Universities.
文摘Light-driven carbon dioxide(CO_(2))capture and utilization is one of the most fundamental reactions in Nature.Herein,we report the first visible-light-driven photocatalyst-free hydrocarboxylation of alkenes with CO_(2).Diverse acrylates and styrenes,including challenging tri-and tetrasubstituted ones,undergo anti-Markovnikov hydrocarboxylation with high selectivities to generate valuable succinic acid derivatives and 3-arylpropionic acids.In addition to the use of stoichiometric aryl thiols,the thiol catalysis is also developed,representing the first visible-lightdriven organocatalytic hydrocarboxylation of alkenes with CO_(2).The UV-vis measurements,NMR analyses,and computational investigations support the formation of a novel charge-transfer complex(CTC)between thiolate and acrylate/styrene.Further mechanistic studies and density functional theory(DFT)calculations indicate that both alkene and CO_(2)radical anions might be generated,illustrating the unusual selectivities and providing a novel strategy for CO_(2)utilization.
文摘Amphiphilic polypyridyl mthenium（Ⅱ） complex cis-di（isothiocyanato）（4,4＇-di-tert-butyl-2,2＇-bipyridyl）（4,4＇- dicarboxy-2,2＇-bipyridyl）ruthenium（Ⅱ）（K005） has been synthesized and characterized by cyclic voltammetry, ^1H NMR, UV-Vis, and FT-IR spectroscopies. The sensitizer sensitizes TiO2 over a notably broad spectral range due to its intense metal-to-ligand charge-transfer （MLCT） bands at 537 and 418 nm. The photophysical and photochemical studies of K005 were contrasted with those of cis-Ru（dcbpy）2（NCS）2, known as the N3 dye, and the amphiphilic ruthenium（Ⅱ） dye Z907. A reversible couple at E1/2=0.725 V vs. saturated calomel electrode （SCE） with a separation of 0.08 V between the anodic and cathodic peaks, was observed due to the Ru^Ⅱ/Ⅲ couple by cyclic voltammetry. Furthermore, this amphiphilic ruthenium complex was successfully used as sensitizers for dye-sensitized solar cells with the efficiency of 3.72% at the 100 mW·cm^-2 irradiance of air mass 1.5 simulated sunlight without optimization of TiO2 films and the electrolyte.
基金supported by the National Natural Science Foundation of China(nos.52073117,91833304,51873077,and 51803071)the National Basic Research Program of China(no.2016YFB0401001)+1 种基金the Postdoctoral Innovation Talent Support Project(no.BX20180121)the China Postdoctoral Science Foundation(nos.2018M641767 and 2019TQ0198).
文摘A reversible dual-responsive luminescent material was introduced by our group to show the simultaneous color and lifetime switching in response to external stimuli.Pristine crystalline powder of(E)-2-(benzo[d]thiazol-2-yl)-3-(pyren-1-yl)acrylonitrile(Py-BZTCN)shows the orderedπ–πstacking with only near-monomer-normal orange-yellow fluorescence,but it exhibits red emission with thermally activated delayed fluorescence(TADF)after grinding,which can be reversibly recovered by heating or fuming treatment.Grinding disturbs the orderedπ–πstacking of pristine powder,leading to the formation of small aggregates with compressed distance and increased overlap ofπ–πstacking between adjacent molecules.The cause of switching was verified by single-crystal X-ray diffraction experiments of two corresponding crystals.This strongπ–πinteraction effectively promotes the excited-state energy splitting and substantially decreases the singlet–triplet energy gap(ΔEST)of aggregates,resulting in the red TADF emission of aggregates through reverse intersystem crossing.This finding proposes a new route to realizing the TADF emission of aggregates through strong intermolecular interactions based on non-TADF monomer,thereby enabling a novel high-contrast dualresponsive luminescence switching.
