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Zhang X, Chen X, Sun Y, Zhao J. Radical enhanced intersystem crossing mechanism, electron spin dynamics of high spin states and their applications in the design of heavy atom-free triplet photosensitizers. Org Biomol Chem 2024; 22:5257-5283. [PMID: 38884590 DOI: 10.1039/d4ob00520a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2024]
Abstract
Heavy atom-free triplet photosensitizers (PSs) can overcome the high cost and biological toxicity of traditional molecular systems containing heavy atoms (such as Pt(II), Ir(III), Ru(II), Pd(II), Lu(III), I, or Br atoms) and, therefore, are developing rapidly. Connecting a stable free radical to the chromophore can promote the intersystem crossing (ISC) process through electron spin exchange interaction to produce the triplet state of the chromophore or the doublet (D) and quartet (Q) states when taking the whole spin system into account. These molecular systems based on the radical enhanced ISC (REISC) mechanism are important in the field of heavy atom-free triplet PSs. The REISC system has a simple molecular structure and good biocompatibility, and it is especially helpful for building high-spin quantum states (D and Q states) that have the potential to be developed as qubits in quantum information science. This review introduces the molecular structure design for the purpose of high-spin states. Time-resolved electron paramagnetic resonance (TREPR) is the most important characterization method to reveal the properties of these molecular systems, generation mechanism and electron spin polarization (ESP) of the high spin states. The spin polarization manipulation of high spin states and potential application in the field of quantum information engineering are also summarized. Moreover, molecular design principles of the REISC system to obtain long absorption wavelength, high triplet state quantum yield and long triplet state lifetime are introduced, as well as applications of the compounds in triplet-triplet annihilation upconversion, photodynamic therapy and bioimaging. This review is useful for the design of heavy atom-free triplet PSs based on the radical-chromophore molecular structure motif and the study of the photophysics of the compounds, as well as the electron spin dynamics of the multi electron system upon photoexcitation.
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Affiliation(s)
- Xue Zhang
- State Key Laboratory of Fine Chemicals, Frontiers Science Centre for Smart Materials, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, P. R. China.
| | - Xi Chen
- State Key Laboratory of Fine Chemicals, Frontiers Science Centre for Smart Materials, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, P. R. China.
| | - Yue Sun
- State Key Laboratory of Fine Chemicals, Frontiers Science Centre for Smart Materials, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, P. R. China.
| | - Jianzhang Zhao
- State Key Laboratory of Fine Chemicals, Frontiers Science Centre for Smart Materials, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, P. R. China.
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Dhami S, Khatun MN, Sengupta C, Iyer PK, Pandey R. Substitution effects on the photoinduced excited state dynamics of perylenemonoimides in solution and thin films. Phys Chem Chem Phys 2024; 26:15600-15610. [PMID: 38757930 DOI: 10.1039/d4cp00993b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
Perylene monoimide (PMI) derivatives are attracting significant attention due to their strong absorption in the visible range, thermal stability, and synthetic accessibility. These properties make them promising for application in various areas such as optoelectronic devices, photosensitizers, etc. In this work, the photophysical properties and excited state dynamics of four different PMI derivatives (PMIB, BrPMITB, PMITB, and APITB) were studied in solution and thin films utilizing steady-state and time-resolved spectroscopic techniques. Among the four PMI derivatives, APITB is designed as a donor-acceptor dyad, with thianthrene as a donor and PMI as an acceptor. The activation of the triplet state through the spin-orbit charge transfer intersystem crossing (SOCT-ISC) process in THF was observed upon substitution with the thianthrene group at the peri position of the PMI moiety. The SOCT-ISC process facilitates triplet formation in the APITB dyad within 423 ps. Meanwhile, other PMI derivatives showed fluorescence within the femtosecond timescale in THF. The PMI derivatives in thin films displayed different photo physical properties to those in THF. This discrepancy arises due to the effective intermolecular coupling between the PMI derivatives in thin films.
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Affiliation(s)
- Suman Dhami
- Department of Chemistry, Indian Institute of Technology Roorkee, 247667 Haridwar, Uttarakhand, India.
| | - Mst Nasima Khatun
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
| | - Chaitrali Sengupta
- Department of Chemistry, Indian Institute of Technology Roorkee, 247667 Haridwar, Uttarakhand, India.
| | - Parameswar Krishnan Iyer
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
- Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Ravindra Pandey
- Department of Chemistry, Indian Institute of Technology Roorkee, 247667 Haridwar, Uttarakhand, India.
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Bo Y, Zhang H, Li Y, Reva Y, Xie L, Guldi DM. Tuning the Absorption, Fluorescence, Intramolecular Charge Transfer, and Intersystem Crossing in Spiro[fluorene]acridinone. Angew Chem Int Ed Engl 2024; 63:e202313936. [PMID: 38314965 DOI: 10.1002/anie.202313936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 01/25/2024] [Accepted: 01/26/2024] [Indexed: 02/07/2024]
Abstract
In this work, we prepared a series of electron donor-acceptor systems based on spiro[fluorene-9,7'-dibenzo[c,h]acridine]-5'-one (SFDBAO). Our SFDBAOs consist of orthogonally positioned fluorenes and aromatic ketones. By fine-tuning the substitution of electron-donating pyrenes, the complex interplay among different excited-state decay channels and the overall impact of solvents on these decay channels were uncovered. Placing pyrene, for example, at the aromatic ketones resulted in a profound solvatochromism in the form of a bright charge-transfer (CT) emission spanning from yellow to red-NIR. In contrast, a dark non-emissive CT was noted upon pyrene substitution at the fluorenes. In apolar solvents, efficient triplet-excited state generation was observed for all SFDBAOs. Either charge transfer was concluded to mediate the intersystem crossing (ISC) in the case of pyrene substitution or the El-Sayed rule was applicable when lacking pyrene substitution as in the case of SFABAO. In polar solvents, charge separation is the sole decay upon pyrene substitution. Moreover, competition between ISC and CT lowered the triplet-excited state generation in SFDBAO.
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Affiliation(s)
- Yifan Bo
- Department of Chemistry and Pharmacy &, Interdisciplinary Center of Molecular Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstrasse 3, 91058, Erlangen, Germany
| | - He Zhang
- Key Laboratory for Organic Electronics and Information Displays, Institute of Advanced Materials (IAM), Center for Molecular Systems and Organic Devices (CMSOD), Nanjing University of Posts and Telecommunications, Wenyuan Road 9, Nanjing, 210023, China
- School of Materials Science and Engineering, Anhui University, Jiulong Road 111, Hefei, 230601, China
| | - Yue Li
- Key Laboratory for Organic Electronics and Information Displays, Institute of Advanced Materials (IAM), Center for Molecular Systems and Organic Devices (CMSOD), Nanjing University of Posts and Telecommunications, Wenyuan Road 9, Nanjing, 210023, China
| | - Yana Reva
- Department of Chemistry and Pharmacy &, Interdisciplinary Center of Molecular Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstrasse 3, 91058, Erlangen, Germany
| | - Linghai Xie
- Key Laboratory for Organic Electronics and Information Displays, Institute of Advanced Materials (IAM), Center for Molecular Systems and Organic Devices (CMSOD), Nanjing University of Posts and Telecommunications, Wenyuan Road 9, Nanjing, 210023, China
- School of Flexible Electronics (SoFE), Henan Institute of Flexible Electronics (HIFE), Henan University, Mingli Road 379, Zhengzhou, 450046, China
| | - Dirk M Guldi
- Department of Chemistry and Pharmacy &, Interdisciplinary Center of Molecular Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstrasse 3, 91058, Erlangen, Germany
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Maroń AM, Cannelli O, Socie EC, Lodowski P, Oppermann M, Machura B, Chergui M. Early bird or night owl? Controlling the ultrafast photodynamics of triphenylamine substituted 2,2':6',2''-terpyridine. Phys Chem Chem Phys 2024; 26:6265-6276. [PMID: 38305747 DOI: 10.1039/d3cp04492k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Abstract
Controlling the ultrafast photodynamics of metal-free organic molecules has great potential for technological applications. In this work, we use solvent polarity and viscosity as "external knobs" to govern the photodynamics of an electron-donating derivative of 2,2':6',2''-terpyridine (terpy), namely 4'-(4-(di(4-tert-butylphenyl)amine)phenyl)-2,2':6',2''-terpyridine (tBuTPAterpy). We combine femtosecond fluorescence upconversion (FlUC), transient absorption (TA) and quantum mechanical calculations to provide a comprehensive description of the tBuTPAterpy's photodynamics. Our results demonstrate that, by changing the solvent, the time scale of light-induced conformational changes of the system can be tuned over two orders of magnitude, controlling the tBuTPAterpy fluorescence spectral region and yield. As a result, depending on the local environment, tBuTPAterpy can act either as an "early bird" or a "night owl", with a tunability that makes it a promising candidate for metal-free sensors.
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Affiliation(s)
- Anna Maria Maroń
- Institute of Chemistry, University of Silesia, Szkolna 9, 40-007 Katowice, Poland.
| | - Oliviero Cannelli
- Laboratory of Ultrafast Spectroscopy (LSU) and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne, ISIC CH H1 625, Station 6, CH-1015, Lausanne, Switzerland
- Center for Free-Electron Laser Science, DESY, Notkestraße 85, 22607 Hamburg, Germany.
| | - Etienne Christophe Socie
- Laboratory of Ultrafast Spectroscopy (LSU) and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne, ISIC CH H1 625, Station 6, CH-1015, Lausanne, Switzerland
| | - Piotr Lodowski
- Institute of Chemistry, University of Silesia, Szkolna 9, 40-007 Katowice, Poland.
| | - Malte Oppermann
- Laboratory of Ultrafast Spectroscopy (LSU) and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne, ISIC CH H1 625, Station 6, CH-1015, Lausanne, Switzerland
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, 4056 Basel, Switzerland
| | - Barbara Machura
- Institute of Chemistry, University of Silesia, Szkolna 9, 40-007 Katowice, Poland.
| | - Majed Chergui
- Laboratory of Ultrafast Spectroscopy (LSU) and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne, ISIC CH H1 625, Station 6, CH-1015, Lausanne, Switzerland
- Elettra - Sincrotrone Trieste S.C.p.A., S.S.14 Km.163, 5 in Area Science Park, I - 34149, Trieste, Italy
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Xiao X, Yan Y, Sukhanov AA, Doria S, Iagatti A, Bussotti L, Zhao J, Di Donato M, Voronkova VK. Long-Lived Charge-Separated State in Naphthalimide-Phenothiazine Compact Electron Donor-Acceptor Dyads: Effect of Molecular Conformation Restriction and Solvent Polarity. J Phys Chem B 2023; 127:6982-6998. [PMID: 37527418 DOI: 10.1021/acs.jpcb.3c02595] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/03/2023]
Abstract
To study the charge separation (CS) and long-lived CS state, we prepared a series of dyads based on naphthalimide (NI, electron acceptor) and phenothiazine (PTZ, electron donor), with an intervening phenyl linker attached on the N-position of both moieties. The purpose is to exploit the electron spin control effect to prolong the CS-state lifetime by formation of the 3CS state, instead of the ordinary 1CS state, the spin-correlated radical pair (SCRP), or the free ion pairs. The electronic coupling magnitude is tuned by conformational restriction exerted by the methyl groups on the phenyl linker. Differently from the previously reported NI-PTZ analogues containing long and flexible linkers, we observed a significant CS emission band centered at ca. 600 nm and thermally activated delayed fluorescence (TADF) with a lifetime of 13.8 ns (population ratio: 42%)/321.6 μs (56%). Nanosecond transient absorption spectroscopy indicates that in cyclohexane (CHX), only the 3NI* state was observed (lifetime τ = 274.7 μs), in acetonitrile (ACN), only the CS state was observed (τ = 1.4 μs), whereas in a solvent with intermediate polarity, such as toluene (TOL), both the 3NI* (shorter-lived) and the CS states were observed. Observation of the long-lived CS state in ACN, yet lack of TADF, confirms the spin-vibronic coupling theoretical model of TADF. Femtosecond transient absorption spectroscopy indicates that charge separation occurs in both nonpolar and polar solvents, with time constants ranging from less than 1 ps in ACN to ca. 60 ps in CHX. Time-resolved electron paramagnetic resonance (TREPR) spectra indicate the existence of the 3NI* and CS states for the dyads upon photoexcitation. The electron spin-spin dipole interaction magnitude of the radical anion and cation of the CS state is intermediate between that of a typical SCRP and a 3CS state, suggesting that the long CS-state lifetime is partially due to the electron spin control effect.
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Affiliation(s)
- Xiao Xiao
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, E-208 West Campus, 2 Ling Gong Road, Dalian 116024, P. R. China
| | - Yuxin Yan
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, E-208 West Campus, 2 Ling Gong Road, Dalian 116024, P. R. China
| | - Andrey A Sukhanov
- Zavoisky Physical-Technical Institute FRC Kazan Scientific Center of RAS, Sibirsky Tract 10/7, Kazan 420029, Russia
| | - Sandra Doria
- LENS (European Laboratory for Non-Linear Spectroscopy), via N. Carrara 1, 50019 Sesto Fiorentino (FI), Firenze, Italy
- ICCOM-CNR, via Madonna del Piano 10, 50019 Sesto Fiorentino (FI), Italy
| | - Alessandro Iagatti
- LENS (European Laboratory for Non-Linear Spectroscopy), via N. Carrara 1, 50019 Sesto Fiorentino (FI), Firenze, Italy
- INO-CNR, Largo Enrico Fermi 6, 50125 Firenze (FI), Italy
| | - Laura Bussotti
- LENS (European Laboratory for Non-Linear Spectroscopy), via N. Carrara 1, 50019 Sesto Fiorentino (FI), Firenze, Italy
| | - Jianzhang Zhao
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, E-208 West Campus, 2 Ling Gong Road, Dalian 116024, P. R. China
- State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi 830017, P. R. China
| | - Mariangela Di Donato
- LENS (European Laboratory for Non-Linear Spectroscopy), via N. Carrara 1, 50019 Sesto Fiorentino (FI), Firenze, Italy
- ICCOM-CNR, via Madonna del Piano 10, 50019 Sesto Fiorentino (FI), Italy
| | - Violeta K Voronkova
- Zavoisky Physical-Technical Institute FRC Kazan Scientific Center of RAS, Sibirsky Tract 10/7, Kazan 420029, Russia
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Zhang X, Sukhanov AA, Liu X, Taddei M, Zhao J, Harriman A, Voronkova VK, Wan Y, Dick B, Di Donato M. Origin of intersystem crossing in highly distorted organic molecules: a case study with red light-absorbing N, N, O, O-boron-chelated Bodipys. Chem Sci 2023; 14:5014-5027. [PMID: 37206394 PMCID: PMC10189861 DOI: 10.1039/d3sc00854a] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 04/14/2023] [Indexed: 05/21/2023] Open
Abstract
To explore the relationship between the twisted π-conjugation framework of aromatic chromophores and the efficacy of intersystem crossing (ISC), we have studied a N,N,O,O-boron-chelated Bodipy derivative possessing a severely distorted molecular structure. Surprisingly, this chromophore is highly fluorescent, showing inefficient ISC (singlet oxygen quantum yield, ΦΔ = 12%). These features differ from those of helical aromatic hydrocarbons, where the twisted framework promotes ISC. We attribute the inefficient ISC to a large singlet-triplet energy gap (ΔES1/T1 = 0.61 eV). This postulate is tested by critical examination of a distorted Bodipy having an anthryl unit at the meso-position, for which ΦΔ is increased to 40%. The improved ISC yield is rationalized by the presence of a T2 state, localized on the anthryl unit, with energy close to that of the S1 state. The electron spin polarization phase pattern of the triplet state is (e, e, e, a, a, a), with the Tz sublevel of the T1 state overpopulated. The small zero-field splitting D parameter (-1470 MHz) indicates that the electron spin density is delocalized over the twisted framework. It is concluded that twisting of π-conjugation framework does not necessarily induce ISC, but S1/Tn energy matching may be a generic feature for increasing ISC for a new-generation of heavy atom-free triplet photosensitizers.
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Affiliation(s)
- Xue Zhang
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology Dalian 116024 P. R. China
| | - Andrey A Sukhanov
- Zavoisky Physical-Technical Institute, FRC Kazan Scientific Center of Russian Academy of Sciences Kazan 420029 Russia
| | - Xi Liu
- College of Chemistry, Beijing Normal University Beijing 100875 P. R. China
| | - Maria Taddei
- LENS (European Laboratory for Non-Linear Spectroscopy) Via N. Carrara 1 50019 Sesto Fiorentino (FI) Italy
| | - Jianzhang Zhao
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology Dalian 116024 P. R. China
| | - Anthony Harriman
- Molecular Photonics Laboratory, School of Natural and Environmental Sciences, Newcastle University Newcastle Upon Tyne NE1 7RU UK
| | - Violeta K Voronkova
- Zavoisky Physical-Technical Institute, FRC Kazan Scientific Center of Russian Academy of Sciences Kazan 420029 Russia
| | - Yan Wan
- College of Chemistry, Beijing Normal University Beijing 100875 P. R. China
| | - Bernhard Dick
- Lehrstuhl für Physikalische Chemie, Institut für Physikalische und Theoretische Chemie, Universität Regensburg D-93053 Regensburg Germany
| | - Mariangela Di Donato
- LENS (European Laboratory for Non-Linear Spectroscopy) Via N. Carrara 1 50019 Sesto Fiorentino (FI) Italy
- ICCOM, Istituto di Chimica dei Complessi OrganoMetallici Via Madonna del Piano 10 50019 Sesto Fiorentino (FI) Italy
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Heavy Atom-Free Triplet Photosensitizers: Molecular Structure Design, Photophysical Properties and Application in Photodynamic Therapy. Molecules 2023; 28:molecules28052170. [PMID: 36903415 PMCID: PMC10004235 DOI: 10.3390/molecules28052170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 02/08/2023] [Accepted: 02/22/2023] [Indexed: 03/03/2023] Open
Abstract
Photodynamic therapy (PDT) is a promising method for the treatment of cancer, because of its advantages including a low toxicity, non-drug-resistant character, and targeting capability. From a photochemical aspect, a critical property of triplet photosensitizers (PSs) used for PDT reagents is the intersystem crossing (ISC) efficiency. Conventional PDT reagents are limited to porphyrin compounds. However, these compounds are difficult to prepare, purify, and derivatize. Thus, new molecular structure paradigms are desired to develop novel, efficient, and versatile PDT reagents, especially those contain no heavy atoms, such as Pt or I, etc. Unfortunately, the ISC ability of heavy atom-free organic compounds is usually elusive, and it is difficult to predict the ISC capability of these compounds and design novel heavy atom-free PDT reagents. Herein, from a photophysical perspective, we summarize the recent developments of heavy atom-free triplet PSs, including methods based on radical-enhanced ISC (REISC, facilitated by electron spin-spin interaction), twisted π-conjugation system-induced ISC, the use of fullerene C60 as an electron spin converter in antenna-C60 dyads, energetically matched S1/Tn states-enhanced ISC, etc. The application of these compounds in PDT is also briefly introduced. Most of the presented examples are the works of our research group.
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Xiao X, Kurganskii I, Maity P, Zhao J, Jiang X, Mohammed OF, Fedin M. A long-lived charge-separated state of spiro compact electron donor-acceptor dyads based on rhodamine and naphthalenediimide chromophores. Chem Sci 2022; 13:13426-13441. [PMID: 36507154 PMCID: PMC9682887 DOI: 10.1039/d2sc04258d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 10/25/2022] [Indexed: 12/15/2022] Open
Abstract
Spiro rhodamine (Rho)-naphthalenediimide (NDI) electron donor-acceptor orthogonal dyads were prepared to generate a long-lived charge separation (CS) state based on the electron spin control approach, i.e. to form the 3CS state, not the 1CS state, to prolong the CS state lifetime by the electron spin forbidden feature of the charge recombination process of 3CS → S0. The electron donor Rho (lactam form) is attached via three σ bonds, including two C-C and one N-N bonds (Rho-NDI), or an intervening phenylene, to the electron acceptor NDI (Rho-Ph-NDI and Rho-PhMe-NDI). Transient absorption (TA) spectra show that fast intersystem crossing (ISC) (<120 fs) occurred to generate an upper triplet state localized on the NDI moiety (3NDI*), and then to form the CS state. For Rho-NDI in both non-polar and polar solvents, a long-lived 3CS state (lifetime τ = 0.13 μs) and charge separation quantum yield (Φ CS) up to 25% were observed, whereas for Rho-Ph-NDI (τ T = 1.1 μs) and Rho-PhMe-NDI (τ T = 2.0 μs), a low-lying 3NDI* state was formed by charge recombination (CR) in n-hexane (HEX). In toluene (TOL), however, CS states were observed for Rho-Ph-NDI (0.37 μs) and Rho-PhMe-NDI (0.63 μs). With electron paramagnetic resonance (EPR) spectra, weak electronic coupling between the Rho and NDI moieties for Rho-NDI was proved. Time-resolved EPR (TREPR) spectra detected two transient species including NDI-localized triplets (formed via SOC-ISC) and a 3CS state. The CS state of Rho-NDI features the largest dipolar interaction (|D| = 184 MHz) compared to Rho-Ph-NDI (|D| = 39 MHz) and Rho-PhMe-NDI (|D| = 41 MHz) due to the smallest distance between Rho and NDI moieties. For Rho-NDI, the time-dependent e,a → a,e phase change of the CS state TREPR spectrum indicates that the long-lived CS state is based on the electron spin control effect.
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Affiliation(s)
- Xiao Xiao
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials, School of Chemical Engineering, Dalian University of TechnologyDalian 116024P. R. China
| | - Ivan Kurganskii
- International Tomography Center, SB RAS Institutskaya Str., 3A, and Novosibirsk State UniversityPirogova str. 2Novosibirsk 630090Russia
| | - Partha Maity
- Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST)Thuwal 23955-6900Kingdom of Saudi Arabia
| | - Jianzhang Zhao
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials, School of Chemical Engineering, Dalian University of TechnologyDalian 116024P. R. China,State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang UniversityUrumqi 830017P. R. China
| | - Xiao Jiang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of TechnologyDalian 116024P. R. China
| | - Omar F. Mohammed
- Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST)Thuwal 23955-6900Kingdom of Saudi Arabia
| | - Matvey Fedin
- International Tomography Center, SB RAS Institutskaya Str., 3A, and Novosibirsk State UniversityPirogova str. 2Novosibirsk 630090Russia
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Zhao X, Zhu L, Li Q, Yin H, Shi Y. The Interplay between ESIPT and TADF for the 2,2'-Bipyridine-3,3'-diol: A Theoretical Reconsideration. Int J Mol Sci 2022; 23:ijms232213969. [PMID: 36430447 PMCID: PMC9696045 DOI: 10.3390/ijms232213969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 11/01/2022] [Accepted: 11/09/2022] [Indexed: 11/16/2022] Open
Abstract
Organic molecules with excited-state intramolecular proton transfer (ESIPT) and thermally activated delayed fluorescence (TADF) properties have great potential for realizing efficient organic light-emitting diodes (OLEDs). Furthermore, 2,2'-bipyridine-3,3'-diol (BP(OH)2) is a typical molecule with ESIPT and TADF properties. Previously, the double ESIPT state was proved to be a luminescent state, and the T2 state plays a dominant role in TADF for the molecule. Nevertheless, whether BP(OH)2 undergoes a double or single ESIPT process is controversial. Since different ESIPT channels will bring different TADF mechanisms, the previously proposed TADF mechanism based on the double ESIPT structure for BP(OH)2 needs to be reconsidered. Herein, reduced density gradient, potential energy surface, IR spectra and exited-state hydrogen-bond dynamics computations confirm that BP(OH)2 undergoes the barrierless single ESIPT process rather than the double ESIPT process with a barrier. Moreover, based on the single ESIPT structure, we calculated spin-orbit coupling matrix elements, nonradiative rates and electron-hole distributions. These results disclose that the T3 state plays a predominant role in TADF. Our investigation provides a better understanding on the TADF mechanism in hydrogen-bonded molecular systems and the interaction between ESIPT and TADF, which further provides a reference for developing efficient OLEDs.
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Ye K, Cao L, van Raamsdonk DME, Wang Z, Zhao J, Escudero D, Jacquemin D. Naphthalimide-phenothiazine dyads: effect of conformational flexibility and matching of the energy of the charge-transfer state and the localized triplet excited state on the thermally activated delayed fluorescence. Beilstein J Org Chem 2022; 18:1435-1453. [PMID: 36300011 PMCID: PMC9577389 DOI: 10.3762/bjoc.18.149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 09/26/2022] [Indexed: 11/23/2022] Open
Abstract
In order to investigate the joint influence of the conformation flexibility and the matching of the energies of the charge-transfer (CT) and the localized triplet excited (3LE) states on the thermally activated delayed fluorescence (TADF) in electron donor–acceptor molecules, a series of compact electron donor–acceptor dyads and a triad were prepared, with naphthalimide (NI) as electron acceptor and phenothiazine (PTZ) as electron donor. The NI and PTZ moieties are either directly connected at the 3-position of NI and the N-position of the PTZ moiety via a C–N single bond, or they are linked through a phenyl group. The tuning of the energy order of the CT and LE states is achieved by oxidation of the PTZ unit into the corresponding sulfoxide, whereas conformation restriction is imposed by introducing ortho-methyl substituents on the phenyl linker, so that the coupling magnitude between the CT and the 3LE states can be controlled. The singlet oxygen quantum yield (ΦΔ) of NI-PTZ is moderate in n-hexane (HEX, ΦΔ = 19%). TADF was observed for the dyads, the biexponential luminescence lifetime are 16.0 ns (99.9%)/14.4 μs (0.1%) for the dyad and 7.2 ns (99.6%)/2.0 μs (0.4%) for the triad. Triplet state was observed in the nanosecond transient absorption spectra with lifetimes in the 4–48 μs range. Computational investigations show that the orthogonal electron donor–acceptor molecular structure is beneficial for TADF. These calculations indicate small energetic difference between the 3LE and 3CT states, which are helpful for interpreting the ns-TA spectra and the origins of TADF in NI-PTZ, which is ultimately due to the small energetic difference between the 3LE and 3CT states. Conversely, NI-PTZ-O, which has a higher CT state and bears a much more stabilized 3LE state, does not show TADF.
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Affiliation(s)
- Kaiyue Ye
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, P. R. China
| | - Liyuan Cao
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, P. R. China
| | | | - Zhijia Wang
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, P. R. China
| | - Jianzhang Zhao
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, P. R. China
- State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi 830017, P. R. China
| | | | - Denis Jacquemin
- Nantes Université, CNRS, CEISAM UMR-6230, Nantes F-44000, France
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11
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Chen X, Sukhanov AA, Taddei M, Dick B, Zhao J, Voronkova VK, Di Donato M. Charge Separation/Recombination, Intersystem Crossing, and Unusually Slow Intramolecular Triplet-Triplet Energy Transfer in Naphthalenediimide-Anthracene Compact Energy Donor-Acceptor Dyads. J Phys Chem Lett 2022; 13:8740-8748. [PMID: 36098552 DOI: 10.1021/acs.jpclett.2c02118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Three anthracene (An)-naphthalenediimide (NDI) compact electron donor-acceptor dyads were prepared. Femtosecond transient absorption (fs-TA) spectra show fast charge separation (ca. 0.9-1.7 ps) and relatively slow charge recombination (ca. 8-565 ps) upon photoexcitation; moreover, the 3An state was observed for 9-An-NDI, whereas the final state is 3NDI for both 9-An-Ph-NDI and 2-An-Ph-NDI, which have an intervening phenyl linker between the An and NDI units. Nanosecond transient absorption (ns-TA) spectra indicate that the lowest triplet state of all the dyads is 3An, with triplet lifetimes of 139-354 μs. An unusually slow intramolecular triplet-triplet energy transfer (TTET) was observed for 9-An-Ph-NDI and 2-An-Ph-NDI (32-85 ns). Time-resolved electron paramagnetic resonance (TREPR) spectroscopy confirms that the intersystem crossing (ISC) mechanism is spin orbit charge transfer ISC (SOCT-ISC) for all the dyads; for 9-An-NDI, only the 3An state was observed, while for the other two dyads, both 3NDI and 3An states were observed, with their relative population changing with increasing delay time, which supports TTET.
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Affiliation(s)
- Xi Chen
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, School of Chemical Engineering, Dalian University of Technology, E-208 West Campus, 2 Ling Gong Road, Dalian 116024, P. R. China
| | - Andrey A Sukhanov
- Zavoisky Physical-Technical Institute, FRC Kazan Scientific Center of RAS, Kazan 420029, Russia
| | - Maria Taddei
- LENS (European Laboratory for Non-Linear Spectroscopy), Via N. Carrara 1, 50019 Sesto Fiorentino (FI), Italy
| | - Bernhard Dick
- Lehrstuhl für Physikalische Chemie, Institut für Physikalische und Theoretische Chemie, Universität Regensburg, Regensburg 93053, Germany
| | - Jianzhang Zhao
- State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, School of Chemical Engineering, Dalian University of Technology, E-208 West Campus, 2 Ling Gong Road, Dalian 116024, P. R. China
- State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi 830046, P. R. China
| | - Violeta K Voronkova
- Zavoisky Physical-Technical Institute, FRC Kazan Scientific Center of RAS, Kazan 420029, Russia
| | - Mariangela Di Donato
- LENS (European Laboratory for Non-Linear Spectroscopy), Via N. Carrara 1, 50019 Sesto Fiorentino (FI), Italy
- ICCOM-CNR, via Madonna del Piano 10-12, 50019 Sesto Fiorentino, Italy
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12
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Małecka M, Szlapa-Kula A, Maroń AM, Ledwon P, Siwy M, Schab-Balcerzak E, Sulowska K, Maćkowski S, Erfurt K, Machura B. Impact of the Anthryl Linking Mode on the Photophysics and Excited-State Dynamics of Re(I) Complexes [ReCl(CO) 3(4′-An-terpy-κ 2N)]. Inorg Chem 2022; 61:15070-15084. [PMID: 36101987 PMCID: PMC9516691 DOI: 10.1021/acs.inorgchem.2c02160] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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Rhenium(I) complexes with 2,2′:6′,2″-terpyridines
(terpy) substituted with 9-anthryl (1) and 2-anthryl
(2) were synthesized, and the impact of the anthryl linking
mode on the ground- and excited-state properties of resulting complexes
[ReCl(CO)3(4′-An-terpy-κ2N)] (An—anthryl)
was investigated using a combination of steady-state and time-resolved
optical techniques accompanied by theoretical calculations. Different
attachment positions of anthracene modify the overlap between the
molecular orbitals and thus the electronic coupling of the anthracene
and {ReCl(CO)3(terpy-κ2N)} chromophores.
Following the femtosecond transient absorption, the lowest triplet
excited state of both complexes was found to be localized on the anthracene
chromophore. The striking difference between 1 and 2 concerns the triplet-state formation dynamics. A more planar
geometry of 2-anthryl-terpy (2), and thus better electronic
communication between the anthracene and {ReCl(CO)3(terpy-κ2N)} chromophores, facilitates the formation of the 3An triplet state. In steady-state photoluminescence spectra, the
population ratio of 3MLCT and 3An was found
to be dependent not only on the anthryl linking mode but also on solvent
polarity and excitation wavelengths. In dimethyl sulfoxide (DMSO),
compounds 1 and 2 excited with λexc > 410 nm show both 3MLCT and 3An
emissions, which are rarely observed. Additionally, the abilities
of the designed complexes for 1O2 generation
and light emission under the external voltage were preliminary examined. The impact of the anthryl linking mode
on the ground- and
excited-state properties of [ReCl(CO)3(4′-An-terpy-κ2N)] with 2,2′:6′,2″-terpyridines (terpy)
substituted with 9-anthryl (1) and 2-anthryl (2) was thoroughly investigated. Different attachment positions of
anthracene were evidenced to modify the overlap between the molecular
orbitals and electronic coupling of the anthracene and {ReCl(CO)3(terpy-κ2N)} chromophores and thus the optical
properties of the resulting complexes. The striking difference between 1 and 2 was demonstrated in the triplet-state
formation dynamics.
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Affiliation(s)
- Magdalena Małecka
- Institute of Chemistry, University of Silesia, 9th Szkolna Street, 40-006 Katowice, Poland
| | - Agata Szlapa-Kula
- Institute of Chemistry, University of Silesia, 9th Szkolna Street, 40-006 Katowice, Poland
| | - Anna M. Maroń
- Institute of Chemistry, University of Silesia, 9th Szkolna Street, 40-006 Katowice, Poland
| | - Przemyslaw Ledwon
- Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, Strzody 9, 44-100 Gliwice, Poland
| | - Mariola Siwy
- Centre of Polymer and Carbon Materials, Polish Academy of Sciences, 34 M. Curie-Sklodowska Street, 41-819 Zabrze, Poland
| | - Ewa Schab-Balcerzak
- Institute of Chemistry, University of Silesia, 9th Szkolna Street, 40-006 Katowice, Poland
- Centre of Polymer and Carbon Materials, Polish Academy of Sciences, 34 M. Curie-Sklodowska Street, 41-819 Zabrze, Poland
| | - Karolina Sulowska
- Nanophotonics Group, Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, 5 Grudziadzka Street, 87-100 Torun, Poland
| | - Sebastian Maćkowski
- Nanophotonics Group, Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, 5 Grudziadzka Street, 87-100 Torun, Poland
| | - Karol Erfurt
- Department of Chemical Organic Technology and Petrochemistry, Silesian University of Technology, Krzywoustego 4, 44-100 Gliwice, Poland
| | - Barbara Machura
- Institute of Chemistry, University of Silesia, 9th Szkolna Street, 40-006 Katowice, Poland
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13
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Liang H, Tang L, He J, Li J, Chen Z, Cai S, Pang J, Mahmood Z, Chen W, Li MD, Zhao Z, Huo Y, Ji S. Modulating the intersystem crossing mechanism of anthracene carboxyimide-based photosensitizers via structural adjustments and application as a potent photodynamic therapeutic reagent. Phys Chem Chem Phys 2022; 24:20901-20912. [PMID: 36047252 DOI: 10.1039/d2cp02897b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein, a series of compact anthracene carboxyimide (ACI) based donor-acceptor dyads were prepared by substituting bulky aryl moieties with various electron-donating ability to study the triplet-excited state properties. The ISC mechanism and triplet yield of the dyads were successfully tuned via structural manipulation. Efficient ISC (ΦΔ ≈ 99%) and long-lived triplet state (τT ≈ 122 μs) was observed for the orthogonal anthracene-labeled ACI derivative compared to the Ph-ACI and NP-ACI dyads, which showed fast triplet state decay (τT ≈ 7.7 μs). Femtosecond transient absorption study demonstrated the ultrafast charge separation (CS) and efficient charge recombination (CR) in the orthogonal dyads and ISC occurring via spin-orbit charge transfer (SOCT) mechanism (AN-ACI: τCS = 355 fs, τCR = 2.41 ns; PY-ACI: τCS = 321 fs, τCR = 1.61 ns), while in Ph-ACI and NP-ACI dyads triplet populate following the normal ISC channel (nπ* → ππ* transition), no CS was observed. We found that the attachment of suitable aryl donor moiety (AN- or PY-) to the ACI core can ensure the insertion of the intermediate triplet state, resulting in a small energy gap among charge separated state (CSS) and triplet state, which leads to efficient ISC in these derivatives. The SOCT-ISC-based AN-ACI dyad was confirmed to be a potent photodynamic therapeutic reagent; an ultra-low IC50 value (0.27 nM) that was nearly 214 times lower than that of the commercial Rose Bengal photosensitizer (57.8 nM) was observed.
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Affiliation(s)
- Hui Liang
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China.
| | - Liting Tang
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China.
| | - Jiaxing He
- Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province, Shantou University, Shantou, 515063, P. R. China.
| | - Jianqing Li
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou 510640, P. R. China.
| | - Zeduan Chen
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China.
| | - Shuqing Cai
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China.
| | - Junhong Pang
- Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province, Shantou University, Shantou, 515063, P. R. China.
| | - Zafar Mahmood
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China.
| | - Wencheng Chen
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China.
| | - Ming-De Li
- Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province, Shantou University, Shantou, 515063, P. R. China.
| | - Zujin Zhao
- State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou 510640, P. R. China.
| | - Yanping Huo
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China.
| | - Shaomin Ji
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China.
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14
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Understanding electrooxidation mechanism of anticancer drugs utilizing ultrafast pump probe spectroscopy. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.133071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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15
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Ahmed R, Manna AK. Understanding High Fluorescence Quantum Yield and Simultaneous Large Stokes Shift in Phenyl Bridged Donor-π-Acceptor Dyads with Varied Bridge Lengths in Polar Solvents. J Phys Chem A 2022; 126:4221-4229. [PMID: 35737581 DOI: 10.1021/acs.jpca.2c02950] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Photophysical properties of electron donor-π-acceptor (D-π-A) dyads for a given pair of D and A highly depend on the π-bridge type and length and also on the solvent polarity. In this work, first-principles calculations with optimally tuned range-separated hybrids are implemented to explore and understand the optical absorption and emission properties of recently synthesized novel D-π-A dyads with 1,2-diphenylphenanthroimidazole (PPI) as D and 1,2,4-triazolopyridine (TP) as A with varied phenyl π-bridge lengths (denoted as PPI-Pn-TP, n = 0-2 considered here) in solvents of different dielectrics. All three D-π-A dyads display almost an unaltered low-lying optical peak position and a red-shifted emission with increasing solvent polarity, corroborating well with the reported experimental observations. The observed emission shift was attributed to the stabilization of an intramolecular charge-transfer (ICT) state by the polar solvent. Contrastingly, our calculations reveal no ICT; rather the shift is essentially originated from the substantial excited-state relaxation involving primarily rotation of the PPI phenyl ring directly linked to the π-bridge, leading to an almost planarized emissive state. Further, the greater frontier molecular orbital delocalization-driven high fluorescence rate together with increased structural rigidity of the emissive state rationalize the observed high fluorescence quantum yield. The present research findings not only are helpful to better understand the reported experimental observations but also show routes to molecularly design functional D-π-A molecules for advanced optoelectronic, sensing, and biomedical applications.
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Affiliation(s)
- Raka Ahmed
- Department of Chemistry and Center for Atomic, Molecular and Optical Sciences & Technologies, Indian Institute of Technology Tirupati, Tirupati, Andhra Pradesh 517506, India
| | - Arun K Manna
- Department of Chemistry and Center for Atomic, Molecular and Optical Sciences & Technologies, Indian Institute of Technology Tirupati, Tirupati, Andhra Pradesh 517506, India
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16
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Tang G, Yang W, Zhao J. Naphthalimide-Carbazole Compact Electron Donor-Acceptor Dyads: Effect of Molecular Geometry and Electron-Donating Capacity on the Spin-Orbit Charge Transfer Intersystem Crossing. J Phys Chem A 2022; 126:3653-3668. [PMID: 35647872 DOI: 10.1021/acs.jpca.2c01046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We prepared a series of naphthalimide (NI)-carbazole (Cz) compact electron donor-acceptor dyads showing different substitution positions, C-N/C-C linkers, and conformation restriction magnitudes to study the spin-orbit charge transfer intersystem crossing (SOCT-ISC). The varied conformation restrictions lead to different dihedral angles between the donor and acceptor (37°-81°) and electronic coupling magnitude (matrix elements V: 1290-3070 cm-1). Based on the comparison between the dyads containing C-N and C-C linkers, we found that a large dihedral angle between the donor and acceptor is favorable to efficient SOCT-ISC. For one dyad, the singlet oxygen quantum yield (ΦΔ) is up to 84.4% (in dichloromethane), which is much higher than that of the previously reported NI-phenothiazine (PTZ) analogue dyad (ΦΔ = 16.0% in n-hexane). The intrinsic triplet state lifetime (τT) is 270 μs, longer than that accessed by the heavy atom effect (75.2 μs). As compared with the NI-PTZ analogue dyad, the Cz unit in the current dyads is a weaker electron donor than PTZ. Thus, a higher CT state energy in NI-Cz dyads was observed, which makes the SOCT-ISC efficient in solvents with a wide range of polarities. Meanwhile, the localized triplet state (3LE) becomes the lowest-lying state in the NI-Cz dyads, which is different from the triplet charge transfer (3CT) state observed in the analogue NI-PTZ dyad. Moreover, the large energy gap between the CT and 3LE states inhibits the reverse ISC; as a result, no thermally activated delayed fluorescence was observed for the current NI-Cz dyads.
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Affiliation(s)
- Geliang Tang
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, P. R. China
| | - Wenbo Yang
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, P. R. China
| | - Jianzhang Zhao
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, P. R. China
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17
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Karatay A, Yılmaz H, Yildiz EA, Sevinç G, Hayvali M, Boyacioglu B, Unver H, Elmali A. Two-photon absorption and triplet excited state quenching of near-IR region aza-BODIPY photosensitizers via a triphenylamine moiety despite heavy bromine atoms. Phys Chem Chem Phys 2022; 24:25495-25505. [DOI: 10.1039/d2cp02960j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Aza-BODIPY compounds with methoxy groups at -3 and -5 positons and triphenylamine moieties at -1, -7 positions with and without heavy bromine atoms at -2, -6 positions have been designed and synthesized.
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Affiliation(s)
- Ahmet Karatay
- Department of Engineering Physics, Faculty of Engineering, Ankara University, 06100 Beşevler, Ankara, Turkey
| | - Halil Yılmaz
- Department of Chemistry, Faculty of Science, Ankara University, Beşevler, 06100 Ankara, Turkey
| | - Elif Akhuseyin Yildiz
- Department of Engineering Physics, Faculty of Engineering, Ankara University, 06100 Beşevler, Ankara, Turkey
| | - Gökhan Sevinç
- Department of Chemistry, Faculty of Science and Literature, Bilecik Şeyh Edebali University, 11230, Bilecik, Turkey
| | - Mustafa Hayvali
- Department of Chemistry, Faculty of Science, Ankara University, Beşevler, 06100 Ankara, Turkey
| | - Bahadir Boyacioglu
- Vocational School of Health Services, Ankara University, 06290 Kecioren-Ankara, Turkey
| | - Huseyin Unver
- Department of Physics, Faculty of Science, Ankara University, 06100 Besevler-Ankara, Turkey
| | - Ayhan Elmali
- Department of Engineering Physics, Faculty of Engineering, Ankara University, 06100 Beşevler, Ankara, Turkey
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Imran M, Zhang X, Wang Z, Chen X, Zhao J, Barbon A, Voronkova VK. Electron spin dynamics in excited state photochemistry: recent development in the study of intersystem crossing and charge transfer in organic compounds. Phys Chem Chem Phys 2021; 23:15835-15868. [PMID: 34318823 DOI: 10.1039/d1cp01937f] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Electron spin dynamics are crucial to photochemical and photophysical processes. However, to a large extent, they are neglected in routine photochemistry studies. Herein, we summarized the recent developments of electron spin dynamics in organic molecular systems. The electron-spin selective intersystem crossing (ISC) as well as charge separation (CS) and charge recombination (CR) of the organic molecular system are discussed, including ISC of the compounds with twisted π-conjugation frameworks and CR-induced ISC in compact orthogonal electron donor-acceptor dyads. We found that the electron spin polarization (ESP) of the triplet state formed in these systems is highly dependent on the molecular structure and geometry. The zero-field-splitting (ZFS) D and E parameters of the triplet state of series chromophores determined with time-resolved electron paramagnetic resonance (TREPR) spectroscopy are presented. Some unanswered questions in related areas are raised, which may inspire further theoretical investigations. The examples demonstrate that the study of electron spin dynamics is not only important in fundamental photochemistry to attain in-depth understanding of the ISC and the charge transfer processes, but is also useful for designing new efficient organic molecular materials for applications including photodynamic therapy, organic light-emitting diodes, and photon upconversion.
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Affiliation(s)
- Muhammad Imran
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, 2 Ling-Gong Road, Dalian, 116024, P. R. China.
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