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CCS Chemistry 2022年第11期4卷 3516-3528页

作者： Yan-Fei Kang Wen-Kai Chen Kun-Xu Teng Ling-Yun Wang Xiao-Cheng Xu Li-Ya Niu Ganglong Cui Qing-Zheng Yang College of Chemistry Beijing Normal UniversityBeijing 100875 College of LaboratoryMedicine Hebei North UniversityZhangjiakou075000 Hebei

We report for the first time a practical and simple supramolecular approach to turn fluorophores into photosensitizers(PSs).Using boron dipyrromethene(BODIPY)as a proof-of-concept,eight BODIPY derivatives manifest bright fluorescence and generate negligible singlet oxygen in solution.In contrast,aggregation fails to emit fluorescence and enhances singlet oxygen generation.Experimentally,these aggregates have excellent photodynamic therapy(PDT)performance,and one even exhibits much stronger photocytotoxicity than the commercialized PS Ce6 under identical conditions.Theoretical studies show that this property originated from significantly reduced energy gaps between relevant excited singlet and triplet states,leading to considerably improved intersystem-crossing efficiency.Importantly,a simple disaggregation recovers the original properties of the fluorophores.This reversible switching property between fluorophores and PSs assists the development of smart PDT systems,in which singlet oxygen generation in tumors can be controlled in an intelligent manner after PDT treatment.The present work provides a novel strategy to design heavy-atom-free PSs and may pave the way to the development of smart PDT systems.

关键词： photosensitizer aggregation BODIPY photodynamic therapy intersystem crossing

Enhancing intersystem crossing by Intermolecular Dimer-Stacking of Cyanine as Photosensitizer for Cancer Therapy

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CCS Chemistry 2022年第11期4卷 3627-3636页

作者： Haiqiao Huang Dandan Ma Qiang Liu Daipeng Huang Xueze Zhao Qichao Yao Tao Xiong Saran Long Jianjun Du Jiangli Fan Xiaojun Peng State Key Laboratory of Fine Chemicals Dalian University of TechnologyDalian 116024 Ningbo Institute of Dalian University of Technology Dalian University of TechnologyNingbo 315016

Development of new photosensitizers(PSs)with high singlet oxygen quantumyield and minimal side effects is of great interest in photodynamic therapy(PDT).Herein,a facile strategy to significantly improve photosensitization has been demonstrated for the first time with two pentamethine dyes connected by a varying alkyl chain resulting in a series of cyanine dimers.The photophysical properties of the dimerswere studied with steady-state optical spectroscopies,a timecorrelated single photon counting technique,and laser flash photolysis spectrometry.X-ray crystallography confirmed that the molecular packing modes of Cy-Bu-D and Cy-He-D were dominated by H-aggregation.The H-aggregation by dimerization suppresses the radiative singlet decay,which helps to stabilize the highly efficient triplet excitation state.Moreover,the dimers show more intensewavelength absorption in the nearinfrared(ɛ1.5-2.0 times more than monomer Cy-H at 650 nm),better singlet oxygen quantum yield,and a longer triplet-state lifetime than monomer Cy-H,providing excellent performance as a triplet PS.In vivo experiments demonstrated that Cy-He-D successfully suppresses tumor growth after PDT treatment.This work is beneficial to the design of novel heavy atom free PSs for PDT-based theranostic systems.

关键词： dimer intersystem crossing photodynamic therapy photosensitizers cancer

Spin-orbit Coupling and intersystem crossing in 4H-Pyran-4-thione： CASSCF//TD-B3LYP Study

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Chinese Journal of Chemistry 2007年第10期25卷 1461-1466页

作者：吕玲玲刘新文袁琨王永成汪汉卿 College of Life Science and Chemistry Tianshui Normal University Tianshui Gansu 741001 China College of Chemistry and Chemical Engineering Northwest Normal University Lanzhou Gansu 730070 China Institute of Chemical Physics Chinese Academy of Sciences Lanzhou Gansu 730070 China

The intersystem crossing channels of gaseous 4H-pyran-4-thione were investigated using the CASSCF//TD-B3LYP methods and group theory. Using the effective one-electron spin-orbit Harniltonian, the strengths of spin-orbit coupling were estimated, which plays an essential role in the spin transitions between different spin states. Calculated results show that phosphorescence and non-radiative decay via intersystem crossing to the So state are concurrent processes occurring at the T1 state. A rapid depletion of the S1 state via intersystem crossing to the T1 state can be mediated by the T2 state, if spin relaxation is fast within the triplet levels. Our calculated results are in close agreement with experimental observations.

关键词： 4H-pyran-4-thione spin-orbit coupling intersystem crossing phosphorescence

Switching on/off phosphorescent or non-radiative channels by aggregation-induced quantum interference

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Aggregate

Aggregate 2024年第1期5卷 175-184页

作者： Yi Kong Yu-Chen Wang Xunkun Huang WanZhen Liang Yi Zhao Department of Chemistry State Key Laboratory of Physical Chemistry of Solid SurfacesiChEMFujian Provincial Key Laboratory of Theoretical and Computational Chemistryand College of Chemistry and Chemical EngineeringXiamen UniversityXiamenPeople’s Republic of China

Pure organic materials with persistent and efficient room-temperature phosphorescence have recently aroused great research interest due to their vast potential in applications.One crucial design principle for such materials is to suppress as much as possible the non-radiative decay of the triplet exciton while maintaining a moderate phosphorescent radiative rate.However,molecular engineering often exhibits similar regulation trends for the two processes.Here,we propose that the quantum interference caused by aggregation can be utilized to control the phosphorescent and non-radiative decay channels.We systematically analyze various constructive and destructive transition pathways in aggregates with different molecular packing types and establish clear relationships between the luminescence characters and the signs of the singlet and triplet excitonic couplings.It is shown that the decay channels can be flexibly switched on or off by regulating the packing type and excitonic couplings.Most importantly,an enhanced phosphorescent decay and a completely suppressed non-radiative decay can be simultaneously realized in the aggregate packed with inversion symmetry.This work lays the theoretical foundation for future experimental realization of quantum interference effects in phosphorescence.

关键词： excitonic coupling intersystem crossing organic aggregates organic room temperature phosphorescence quantum interference

Bodipy-Squaraine Dyads:Preparation and Study of the Intramolecular Energy Transfer,Charge Separation and intersystem crossing

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Bodipy-Squaraine Dyads:Preparation and Study of the Intramol...

The fsTAS study of the spin-orbital charge transfer intersystem crossing of orthogonal Bodipy dimers

中国化学会第四届卟啉与酞菁学术研讨会

作者： Yu Dong Jianzhang Zhao State Key Laboratory of Fine Chemicals Dalian University of Technology

It’s important to study the F?rster Resonance Energy Transfer（FRET）,charge transfer and other photophysical process of multi-chromophore molecules for designing triplet photosensitizers with the properties of strong ability of visible light-harvesting and efficient intersystem crossing [1,2].Two triads（BDP-SQ and Styryl-BDP-SQ） were prepared with Bodipy,styrylBodipy and Squaraine（SQ） units.SQ units show efficient intersystem crossing（ISC.（37）T = 50%）,[3] and BODIPY dyes show strong ability of visible light-harvesting.[4,5] The cascade photophysical properties of the triads were studied with steady state and time-resolved optical spectroscopies,as well as with electrochemical characterization and theoretical computations.The FRET process can be observed in both BDP-SQ and Styryl-BDP-SQ.ISC process exists in triad BDP-SQ is attributed to S1?T1 transition.But ISC is competed by fast FRET and charge separation（CS） process in Styryl-BDP-SQ.For BDP-SQ,the singlet energy transfer kinetics is associated with solvent polarity and it was found to be 1.6 and 0.6 ps in toluene and acetonitrile,respectively.Similarly,the fast CS process takes 17 ps and 2 ps in toluene and acetonitrile for Styryl-BDP-SQ,respectively.These results may be useful for future design of photosensitizers with strong visible light absorption and vectorial energy funneling.

关键词： Charge Separation Charge Recombination FRET intersystem crossing Triplet State

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The fsTAS study of the spin-orbital charge transfer intersys...

Towards Design of Room-temperature Phosphorescent Organic Molecules By Enhancing intersystem crossing via Functional Groups

第十五届全国光化学学术讨论会

作者： Ya Liu Jianhzhang Zhao Keli Han State Key Laboratory of Molecular Reaction Dynamics Dalian Institute of Chemical Physics Chinese Academy of Sciences University of Chinese Academy of Sciences State Key Laboratory of Fine Chemicals School of Chemical Engineering Dalian University of Technology

Recently, orthogonal Bodipy dimers were reported to show moderate to excellent ISC ability. In this case no heavy atom effect is required, which have some advantages for photodynamic therapy. However, the photosensitization mechanism of these Bodipy dimers remained ambiguous. Herein we present experimental evidence for the postulated spin-orbital charge transfer induced ISC of a series of Bodipy dimers with electrochemical measurement and fs transient absorption spectra.

关键词： Bodipy Charge Transfer intersystem crossing Triplet State Photochemistry

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Towards Design of Room-temperature Phosphorescent Organic Mo...

Recent Advances in Organic Room-Temperature Phosphorescence of Heteroatom(B/S/P)-Containing Chromophores

第十三届全国量子化学会议

作者： Ran Liu Guozhen Zhang Jun Jiang 中国科学技术大学

Room-temperature phosphorescent(RTP) materials have attracted an increasing number of scientific explorations because of their significant features, such as long lived excited states and higher efficiency towards energy utilization. intersystem crossing(ISC) is the prerequisite for phosphorescence and the enhancement of ISC rate is to play an important role in making RTP viable. According to perturbation theory, the efficiency of ISC can be affected by 1)spin-orbit coupling(SOC), or 2) singlet(S)-triplet(T) excited states gap. In the model systems, different functional groups with different electrophiles were added in order to tune the S-T gap.The results show that electron donating groups can improve the coefficient of ISC by narrowing the S-T gap owing to affecting the energy levels of relevant excited states. It was revealed by the electron-hole analysis that the key to enhance the coefficient of ISC via a functional group is to change the nature of the singlet and triplet excited states of interest from the localized excitation to the charge transfer excitation.

关键词： organic phosphorescent molecule intersystem crossing excited state charge transfer singlet-triplet gap

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CCS Chemistry 2023年第2期5卷 292-309页

作者： Zepeng Wang Xiaojie Cheng Yingjie Xie Shulin Liu Mengjiao Dong Jianfeng Zhao Fushun Liang Zhongfu An Wei Huang Key Laboratory of Flexible Electronics(KLOFE) Institute of Advanced Materials(IAM)School of Flexible Electronics(SoFE)Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM)Nanjing Tech University(Nanjing Tech)Nanjing 211816 College of Chemistry Institute of Organic Luminescent Materials(IOLM)Liaoning UniversityShenyang 110036 Institute of Flexible Electronics(IFE) Northwestern Polytechnical University(NPU)Xi’anShaanxi 710072 Key Laboratory for Organic Electronics and Information Displays Institute of Advanced Materials(IAM)Nanjing University of Posts and TelecommunicationsNanjing 210023

Purely organic room-temperature phosphors,which have received extensive attention as emerging stateof-the-art luminescent materials in various fields,have a longer lifetime than fluorophores.The energy gap law and El-Sayed’s rule provide clear design principles for the development of organic room-temperature phosphorescence.Therefore,the incorporation of heteroatoms(such as sulfur and phosphorus)usually promotes the intersystem crossing rate and increases the 3(π,π*)configuration to realize long lifetimes.Furthermore,boron-containing phosphors not only display excellent phosphorescence properties but also expand El-Sayed’s rule without(n,π*)transitions.This review summarizes recent work on organic phosphorescence of heterocycles with boron,sulfur,and phosphorus heteroatoms and highlights the significance of the guidelines for constructing efficient phosphorescence molecules.This work is instrumental in further diversifying the pool of phosphorescent molecules and developing new and effective design strategies.

关键词： purely organic room-temperature phosphorescence heterocyclic compounds El-Sayed’s rule intersystem crossing phosphorescence mechanism

Kinetics process of room temperature phosphorescence and fluorescence of gadolinium porphyrin in aqueous solution

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Journal of Rare Earths 2021年第10期39卷 1187-1193,I0001页

作者： Ting Liu Xiyu Zhang Honglin Zhang Hua Zhao Zhiguo Zhang Ye Tian Condensed Matter Science and Technology Institute Harbin Institute of TechnologyHarbin 150001 China School of Materials and Engineering Harbin Institute of TechnologyHarbin 150001China Division of Cardiology The First Affiliated HospitalHarbin Medical UniversityHarbin 150001China

The behavior of room temperature phosphorescence quenching and fluorescence enhancing of gadolinium labeled sinoporphyrin sodium(Gd-DVDMS) in the aqueous solution were studied.Gd-DVDMS was characterized by various techniques including mass spectra,Fourier transform infrared spectra and transmission electron microscopy.The optical behavior was monitored through UV-vis absorption spectra and photoluminescence spectra.The result shows that the phosphorescence intensity gradually quenches,almost disappears after dissolved 120 min,meanwhile the fluorescence intensity enhances 5 times.The above behavior is attributed to the decreased population of Gd-DVDMS as first excited triplet state(T1),Based on the time-invariant of both absorption spectra and phosphorescence decay curves at710 nm of Gd-DVDMS in different dissolution time,the reason for the decreased population of GdDVDMS in T1 state is that the intersystem crossing from first excited state(S1) to T1 is prevented.In addition,the fluorescent decay curves of Gd-DVDMS initially dissolved in the aqueous solution and dissolved for 120 min were also measured for comparison.The big change in fluorescent lifetime further proves the conclusion that intersystem crossing is prevented,meanwhile,the increase in fluorescence intensity is demonstrated.In this work,the possibility of decomposition of Gd-DVDMS is excluded because the phosphorescence decay curve in Gd-DVDMS aqueous solution is sensible to DVDMS.

关键词： Gd-DVDMS Phosphorescence Fluorescence Aqueous solution intersystem crossing Rare earths

Factors affecting improvement of fluorescence intensity of quartet and doublet state of NO diatomic molecule excited by glow discharge

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Chinese Physics B 2018年第8期27卷 356-363页

作者： Ahmed Asaad I Khalilt Reem A1-Tuwirqi Mohamed Gondal Noura A1-Suliman Department of Laser Sciences and Interactions National Institute of Laser Enhanced Sciences(NILES)Cairo UniversityGiza12613 Egypt Department of Physics Faculty of ScienceKing Abdulaziz UniversityJeddah 21551Saudi Arabia Department of Physics King Fahd University of Petroleum&MineralsDhahran 31261Saudi Arabia Department of Physics Faculty of Science for GirlsImam Abdulrahman Ben Faisal UniversityDammam 31441Saudi Arabia

We report on the observation of new fluorescence emission spectral transitions obtained from NO diatomic molecule in the region from ultraviolet （UV） to near infrared （NIR） in a low power glow discharge system. This glow discharge electronic excitation populates different quartet and doublet states of NO in its proximity such as the A2Z （/9 = 2）, b4∑- （υ= 3）, B2М （1） = 4）, and X2Л （u= 33-32） states. Due to inter-system crossing, emission lines originating from these levels to lower lying states are recorded and spectral line assignments are performed. The observed systems include b4∑- a4∏, B21∏-a4∏, a4∏-X2I∏, A2∑X2∏, X2∏-X2∏ （33-15）, X2∏-X2∏ （33-17）, X2∏-X2∏ （33-20）, and X2∏-X2∏ （33- 18）. This new information will conduce to the better understanding of the interesting features of NO molecule. Such parameters that affect the recording of low density of NO molecules are also discussed In addition to the factors such as the time evolution, argon gas concentration relative to NO mixture, the percentage of NO molecular gas concentration, discharge electric current signals and discharge applied voltage are studied. Those factors would enhance the fluorescence signal intensity of NO molecules. The recent results might be significant as reference data for optimizing the glow discharge spectrometer and diagnostics of NO gas.

关键词： fluorescence emission NO molecule quartet states intersystem crossing glow discharge