1
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Zhang W, Ma Y, Song H, Miao R, Kong J, Zhou M. Deciphering the photophysical properties of naphthalimide derivatives using ultrafast spectroscopy. Phys Chem Chem Phys 2024; 26:4607-4613. [PMID: 38251277 DOI: 10.1039/d3cp05654f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
Naphthalimide derivatives composed of donor-acceptor type structures hold significant promise across a wide range of applications. Here, the solvent polarity and viscosity controlled excited-state dynamics of a naphthalimide derivative with a donor-acceptor structure were studied using multiple spectroscopic techniques. From the stationary spectroscopic investigations, large Stokes shift and low fluorescence quantum yield were observed with increasing the solvent polarity, suggesting a more polar excited state relative to the ground state, which is evidenced by the Lippert-Mataga relationship. We also observe an enhanced fluorescence with a prolonged lifetime in a more viscous solution due to the restriction of excited-state molecular rearrangement. These observations result from the emerged twisted intramolecular charge transfer (TICT) state. The ultrafast spectroscopy studies further unravel a solvent polarity dependent excited state evolution from the intramolecular charge transfer state to the TICT state, revealing that the TICT state can be populated only in strong polar solvents. Control experiments by tuning the solvent viscosity in ultrafast experiments were employed to verify the excited state molecular rearrangement subsequently. These observations collectively emphasize how fine-tuning the photophysical properties of naphthalimide derivatives can be achieved through strategic manipulation of solvent polarity and viscosity.
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Affiliation(s)
- Wei Zhang
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Anhui 230026, China.
| | - Yalei Ma
- Laboratory of Applied Surface and Colloids Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, P. R. China.
| | - Hongwei Song
- Department of Chemistry-Angstrom Laboratory, Uppsala University, Box 523, Uppsala 75120, Sweden
| | - Rong Miao
- Laboratory of Applied Surface and Colloids Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, P. R. China.
| | - Jie Kong
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Anhui 230026, China.
| | - Meng Zhou
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Anhui 230026, China.
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2
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Herbert JM. Visualizing and characterizing excited states from time-dependent density functional theory. Phys Chem Chem Phys 2024; 26:3755-3794. [PMID: 38226636 DOI: 10.1039/d3cp04226j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2024]
Abstract
Time-dependent density functional theory (TD-DFT) is the most widely-used electronic structure method for excited states, due to a favorable combination of low cost and semi-quantitative accuracy in many contexts, even if there are well recognized limitations. This Perspective describes various ways in which excited states from TD-DFT calculations can be visualized and analyzed, both qualitatively and quantitatively. This includes not just orbitals and densities but also well-defined statistical measures of electron-hole separation and of Frenkel-type exciton delocalization. Emphasis is placed on mathematical connections between methods that have often been discussed separately. Particular attention is paid to charge-transfer diagnostics, which provide indicators of when TD-DFT may not be trustworthy due to its categorical failure to describe long-range electron transfer. Measures of exciton size and charge separation that are directly connected to the underlying transition density are recommended over more ad hoc metrics for quantifying charge-transfer character.
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Affiliation(s)
- John M Herbert
- Department of Chemistry & Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA.
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3
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Sun G, Fang H. Fluorescent deactivation behaviors based on ESIPT and TICT of novel double target fluorescent probe and its sensing mechanism for Al 3+/Mg 2+: A TD-DFT study. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 297:122718. [PMID: 37054565 DOI: 10.1016/j.saa.2023.122718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 03/14/2023] [Accepted: 04/04/2023] [Indexed: 05/14/2023]
Abstract
Based on density functional theory (DFT) and time-dependent DFT (TD-DFT) methods with integral equation formula polarized continuum model (IEFPCM), the fluorescent behavior and recognizing mechanism of probe N'-((1-hydroxynaphthalen-2-yl)methylene)isoquinoline-3-carbohydrazide (NHMI) for Al3+/Mg2+ ion were investigated in more detail. Excited state intramolecular proton transfer (ESIPT) process in probe NHMI occurs in the stepwise pattern. The proton H5 of enol structure (E1) firstly moves from O4 to N6 to form single proton-transfer (SPT2) structure, and then the proton H2 of SPT2 transfers from N1 to N3 to form the stable double proton-transfer (DPT) structure. Subsequently, the transformation from DPT to its isomer (DPT1) induces the twisted intramolecular charge transfer (TICT) process. Two non-emissive TICT states (TICT1 and TICT2) were obtained, and TICT2 state quenches the fluorescence observed in the experiment. With the addition of aluminum (Al3+) or magnesium (Mg2+) ion, TICT process is prohibited by the coordination interaction between NHMI and Al3+/Mg2+, and the strong fluorescent signal is turned on. For probe NHMI, the twisted C-N single bond of acylhydrazone part leads to the TICT state. This sensing mechanism may inspire researchers to develop new probes from a different direction.
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Affiliation(s)
- Guotao Sun
- Department of Chemistry and Material Science, College of Science, Nanjing Forestry University, Nanjing 210037, People's Republic of China
| | - Hua Fang
- Department of Chemistry and Material Science, College of Science, Nanjing Forestry University, Nanjing 210037, People's Republic of China.
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4
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Photophysical investigation of a donor-acceptor based Schiff base in solvents of varying polarities. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.132435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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5
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The suppression of intramolecular charge transfer emission by tautomerism in 2-(4′-amino-2′-hydroxyphenyl)-1H-imidazo-[4,5-c]pyridine: Intramolecular proton transfer versus intermolecular proton transfer. J Photochem Photobiol A Chem 2021. [DOI: 10.1016/j.jphotochem.2021.113199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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6
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Liu L, Sun B, Ding R, Mao Y. Theoretical Investigations on the Excited-State Dynamics of an Al 3+ Fluorescence Sensor. J Phys Chem A 2020; 124:11093-11101. [PMID: 33325702 DOI: 10.1021/acs.jpca.0c09977] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Twisted internal charge transfer (TICT) states are of fundamental importance during the photo-physical processes of dyes and sensors. In this contribution, excited-state dynamics of an Al3+ fluorescence sensor 1-{[(2-hydroxyphenyl)-imino]methyl}naphthalen-2-ol based on the turn-on signal is clarified. Two different dark TICT states are observed by exploring the excited-state potential energy surface. With the twist of the C2-N bond, the two dark states can be reached facilely, which induce the experimentally observed weak fluorescence of the sensor. The sensing mechanism is then uncovered by investigating the electronic coupling between the sensor and analyte. Al3+ is proved to form strong coordination bonds with the sensor, which restricts the motion of the C2-N bond. Consequently, the TICT states are eliminated, which generate the turn-on signal. This sensing mechanism is trustworthy and intrinsically different from the previously proposed one, which would shed some light on the design of turn-on sensors.
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Affiliation(s)
- Lei Liu
- College of Chemical and Materials Engineering, Anhui Science and Technology University, Fengyang 233100, P. R. China.,State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Bingqing Sun
- College of Resource and Environment, Anhui Science and Technology University, Fengyang 233100, P. R. China
| | - Ran Ding
- College of Chemical and Materials Engineering, Anhui Science and Technology University, Fengyang 233100, P. R. China
| | - Yueyuan Mao
- College of Chemical and Materials Engineering, Anhui Science and Technology University, Fengyang 233100, P. R. China
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7
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Combined Picosecond Time-Resolved UV-Vis and NMR Techniques Used for Investigation of the Excited State Intramolecular Triplet-Triplet Energy Transfer. J Phys Chem A 2019; 123:6978-6985. [PMID: 31329436 DOI: 10.1021/acs.jpca.9b03414] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The phenomenon of the intramolecular triplet-triplet (T-T) energy transfer observed for spiro[9,10-dihydro-9-oxoanthracene-10,2'-5',6'-benzindan] (AN) molecule was investigated using stationary and time-resolved techniques in the UV/vis spectral region. The rate constant for energy transfer from anthrone chromophore to the triplet state localized on the naphthalene subunit of AN molecule is 2.8 × 1010 s-1. NMR spectroscopy is rarely used for investigation of molecules in the electronically excited states. Here, we propose 1H NMR combined with UV laser irradiation as a useful method for the recognition of an electron spin densities distribution in the excited triplet state that exists for tens of microseconds in the liquid phase. The direct registration of the 1H NMR signals from molecules in the excited triplet state was not possible due to its short lifetime. However, even the short interaction between unpaired electrons and nuclear spins leads to the changes in the NMR spectrum. The analysis of difference NMR spectra delivers information about the electron spin densities distribution over the skeleton of the molecule in the excited triplet state. In order to understand the nature of the excited states involved in the triplet-triplet energy transfer process, quantum chemical calculations were performed.
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8
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Matsumoto S, Fuchi Y, Usui K, Hirai G, Karasawa S. Development of Turn-On Probes for Acids Triggered by Aromaticity Enhancement Using Tricyclic Amidine Derivatives. J Org Chem 2019; 84:6612-6622. [DOI: 10.1021/acs.joc.9b00023] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Shota Matsumoto
- Faculty of Pharmaceutical Sciences, Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo 194-8543, Japan
| | - Yasufumi Fuchi
- Faculty of Pharmaceutical Sciences, Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo 194-8543, Japan
| | - Kazuteru Usui
- Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Go Hirai
- Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Satoru Karasawa
- Faculty of Pharmaceutical Sciences, Showa Pharmaceutical University, 3-3165 Higashi-Tamagawagakuen, Machida, Tokyo 194-8543, Japan
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9
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On the Nature of Interplay among Major Flexibility Channels in Molecular Rotors. J CHEM-NY 2019. [DOI: 10.1155/2019/8359527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
As a part of our interest in the excited-state dynamics of flexible materials, we have undertaken a theoretical investigation to the photo-induced reactions of 2-[4-(dimethylamino)benzylidene]malononitrile (BMN) by a combination of the density functional theory, its extended time-dependent (TD-DFT) single reference, and ab initio molecular dynamic (MD) simulations. The results showed that double-bond twisting and the neighbor single-bond twisting togetherness in the excited singlet state is the most important nonradiative deactivation channel to the ground state. Double- and single-bond twisting insert clear intersections among the potential energy surfaces of the singlet states (especially S1/S0) leading to fluorescence quenching. Furthermore, effects of molecular dynamic simulations on molecular properties in the femtosecond to picosecond time domain are studied to validate the results. In agreement with the experimental results, the findings conclude the existence of a flexible geometry-dependent single emission band. Such a study may give information on how the molecule could be externally modified/fixed to yield a desired effect, i.e., more fluorescence or more nonradiative decay.
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10
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Larsen MAB, Stephansen AB, Alarousu E, Pittelkow M, Mohammed OF, Sølling TI. Solvent-dependent dual fluorescence of the push-pull system 2-diethylamino-7-nitrofluorene. Phys Chem Chem Phys 2018; 20:5942-5951. [PMID: 29423491 DOI: 10.1039/c8cp00235e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The solvent-dependent excited state behavior of the molecular push-pull system 2-diethylamino-7-nitrofluorene has been explored using femtosecond transient absorption spectroscopy in combination with density functional theory calculations. Several excited state minima have been identified computationally, all possessing significant intramolecular charge transfer character. The experimentally observed dual fluorescence is suggested to arise from a planar excited state minimum and another minimum reached by twisting of the aryl-nitrogen bond of the amino group. The majority of the excited state population, however, undergo non-radiative transitions and potential excited state deactivation pathways are assessed in the computational investigation. A third excited state conformer, characterized by twisting around the aryl-nitrogen bond of the nitro group, is reasoned to be responsible for the majority of the non-radiative decays and a crossing between the excited state and ground state is localized. Additionally, ultrafast intersystem crossing is observed in the apolar solvent cyclohexane and rationalized to occur via an El-Sayed assisted transition from one of the identified excited state minima. The solvent thus determines more than just the fluorescence lifetime and shapes the potential energy landscape, thereby dictating the available excited state pathways.
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Affiliation(s)
- M A B Larsen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark.
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11
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Babailov SP, Purtov PA, Fomin ES. Dynamic NMR under nonstationary conditions: Theoretical model, numerical calculation, and potential of application. J Chem Phys 2016; 145:054201. [DOI: 10.1063/1.4959592] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- S. P. Babailov
- A. V. Nikolaevs Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russian Federation
- National Research Tomsk Polytechnic University, Lenin Avenue 30, Tomsk 634050, Russia
| | - P. A. Purtov
- Voevodsky Institute of Chemical Kinetics and Combustion, Siberian Branch of the Russian Academy of Sciences, Insitutskaya 3, 630090 Novosibirsk, Russian Federation
| | - E. S. Fomin
- Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences, Av. Lavrentyev 10, 630090 Novosibirsk, Russia
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12
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Yang D, Zheng R, Wang Y, Lv J. Time-dependent density functional theory study on excited-state spectral and dynamic properties of hydrogen-bonded complexes formed by DMACA and water. RSC Adv 2016. [DOI: 10.1039/c6ra17132j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Excited-state spectral and dynamic properties of hydrogen-bonded complexes formed by 4-(dimethylamino)cinnamic acid with water molecules were studied using the TDDFT method.
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Affiliation(s)
- Dapeng Yang
- College of Mathematics and Information Science
- North China University of Water Resources and Electric Power
- Zhengzhou 450045
- China
| | - Rui Zheng
- College of Mathematics and Information Science
- North China University of Water Resources and Electric Power
- Zhengzhou 450045
- China
| | - Yusheng Wang
- College of Mathematics and Information Science
- North China University of Water Resources and Electric Power
- Zhengzhou 450045
- China
| | - Jian Lv
- College of Mathematics and Information Science
- North China University of Water Resources and Electric Power
- Zhengzhou 450045
- China
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13
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Mishra A, Sahu S, Tripathi S, Krishnamoorthy G. Photoinduced intramolecular charge transfer in trans-2-[4'-(N,N-dimethylamino)styryl]imidazo[4,5-b]pyridine: effect of introducing a C[double bond, length as m-dash]C double bond. Photochem Photobiol Sci 2015; 13:1476-86. [PMID: 25103414 DOI: 10.1039/c4pp00237g] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The spectral characteristics of trans-2-[4'-(N,N-dimethylamino)styryl]imidazo[4,5-b]pyridine (t-DMASIP-b) have been investigated using absorption and fluorescence techniques, and compared with 2-(4'-N,N-dimethylamino)imidazo[4,5-b]pyridine (DMAPIP-b). The study reveals that introduction of a C[double bond, length as m-dash]C double bond strongly perturbs the photophysics of the system. Unlike DMAPIP-b, t-DMASIP-b emits a single emission in aprotic and protic solvents. The emission occurs from the locally excited state in nonpolar solvents and from a planar intramolecular charge transfer (PICT) state in polar solvents. Multiple linear regression analysis suggests that among the different solvent parameters, the dipolar interaction contributes more to the stabilization of the system in both the ground and excited states. Theoretical calculations suggest that, unlike in DMAPIP-b, proton coupled twisted intramolecular charge transfer (TICT) emission does not occur in t-DMASIP-b. The higher quantum yield obtained in the viscous solvent glycerol is attributed to the restriction of the twisting of the olefinic bond. The photoirradiation of t-DMASIP-b shows that isomerization takes place in all solvents, including viscous glycerol. The theoretically simulated potential energy surface shows that isomerization occurs via a phantom state, which is a nonradiative process. The rise in temperature favors the photoisomerization, thus, the fluorescence quantum yield decreases. The prototropic study indicates that, unlike in DMAPIP-b, the protonation takes place at different places to form the monocations.
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Affiliation(s)
- Anasuya Mishra
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, India.
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14
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Pietrzak M, Dobkowski J, Gorski A, Gawinkowski S, Kijak M, Luboradzki R, Hansen PE, Waluk J. Arresting consecutive steps of a photochromic reaction: studies of β-thioxoketones combining laser photolysis with NMR detection. Phys Chem Chem Phys 2014; 16:9128-37. [DOI: 10.1039/c4cp00530a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Laser photolysis coupled with NMR detection was used for the identification of photoproducts and the photoreaction pathway of monothiodibenzoylmethane.
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Affiliation(s)
- Mariusz Pietrzak
- Institute of Physical Chemistry
- Polish Academy of Sciences
- 01-224 Warsaw, Poland
| | - Jacek Dobkowski
- Institute of Physical Chemistry
- Polish Academy of Sciences
- 01-224 Warsaw, Poland
| | - Alexandr Gorski
- Institute of Physical Chemistry
- Polish Academy of Sciences
- 01-224 Warsaw, Poland
| | | | - Michał Kijak
- Institute of Physical Chemistry
- Polish Academy of Sciences
- 01-224 Warsaw, Poland
| | - Roman Luboradzki
- Institute of Physical Chemistry
- Polish Academy of Sciences
- 01-224 Warsaw, Poland
| | - Poul Erik Hansen
- Department of Science
- Systems and Models
- Roskilde University
- DK-4000 Roskilde, Denmark
| | - Jacek Waluk
- Institute of Physical Chemistry
- Polish Academy of Sciences
- 01-224 Warsaw, Poland
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15
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Mohamed RK, Peterson PW, Alabugin IV. Concerted Reactions That Produce Diradicals and Zwitterions: Electronic, Steric, Conformational, and Kinetic Control of Cycloaromatization Processes. Chem Rev 2013; 113:7089-129. [DOI: 10.1021/cr4000682] [Citation(s) in RCA: 166] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Rana K. Mohamed
- Department of Chemistry
and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390,
United States
| | - Paul W. Peterson
- Department of Chemistry
and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390,
United States
| | - Igor V. Alabugin
- Department of Chemistry
and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390,
United States
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16
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Johnson JC, Akdag A, Zamadar M, Chen X, Schwerin AF, Paci I, Smith MB, Havlas Z, Miller JR, Ratner MA, Nozik AJ, Michl J. Toward designed singlet fission: solution photophysics of two indirectly coupled covalent dimers of 1,3-diphenylisobenzofuran. J Phys Chem B 2013; 117:4680-95. [PMID: 23383860 DOI: 10.1021/jp310979q] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In order to identify optimal conditions for singlet fission, we are examining the photophysics of 1,3-diphenylisobenzofuran (1) dimers covalently coupled in various ways. In the two dimers studied presently, the coupling is weak. The subunits are linked via the para position of one of the phenyl substituents, in one case (2) through a CH2 linker and in the other (3) directly, but with methyl substituents in ortho positions forcing a nearly perpendicular twist between the two joint phenyl rings. The measurements are accompanied with density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. Although in neat solid state, 1 undergoes singlet fission with a rate constant higher than 10(11) s(-1); in nonpolar solutions of 2 and 3, the triplet formation rate constant is less than 10(6) s(-1) and fluorescence is the only significant event following electronic excitation. In polar solvents, fluorescence is weaker because the initial excited singlet state S1 equilibrates by sub-nanosecond charge transfer with a nonemissive dipolar species in which a radical cation of 1 is attached to a radical anion of 1. Most of this charge transfer species decays to S0, and some is converted into triplet T1 with a rate constant near 10(8) s(-1). Experimental uncertainties prevent an accurate determination of the number of T1 excitations that result when a single S1 excitation changes into triplet excitation. It would be one if the charge-transfer species undergoes ordinary intersystem crossing and two if it undergoes the second step of two-step singlet fission. The triplet yield maximizes below room temperature to a value of roughly 9% for 3 and 4% for 2. Above ∼360 K, some of the S1 molecules of 3 are converted into an isomeric charge-transfer species with a shorter lifetime, possibly with a twisted intramolecular charge transfer (TICT) structure. This is not observed in 2.
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Affiliation(s)
- Justin C Johnson
- National Renewable Energy Laboratory, Golden, Colorado 80401, USA
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17
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How to Lose a Bond in Two Ways ― The Diradical/Zwitterion Dichotomy in Cycloaromatization Reactions. European J Org Chem 2013. [DOI: 10.1002/ejoc.201201656] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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18
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Zhu L, Zhong C, Liu C, Liu Z, Qin J, Yang C. Spiroconjugated Intramolecular Charge-Transfer Emission in Non-Typical Spiroconjugated Molecules: The Effect of Molecular Structure upon the Excited-State Configuration. Chemphyschem 2013; 14:982-9. [DOI: 10.1002/cphc.201201095] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Revised: 01/22/2013] [Indexed: 11/08/2022]
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19
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Jang CK, Song CJ, Park JH, Yao W, Jaung JY. Red-emitting Materials Derived from 2,3-dicyanopyrazine for Organic Light Emitting Devices. JOURNAL OF CHEMICAL RESEARCH 2013. [DOI: 10.3184/174751912x13554011072941] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Styryl-substituted derivatives of 2,3-dicyanopyrazine were designed and synthesised by the Knoevenagel condensation of 2,3-dicyano-5-methylpyrazines with 4-(diphenylamino)benzaldehyde for use as red-emitting fluorescent dyes in organic light-emitting devices. Structural analysis of the red-emitting styryl fluorescent dyes was carried out using 1H NMR, FT-IR, and elemental analysis. The electroluminescent performance of multi-layered organic light-emitting devices fabricated with the triphenylamine-substituted dicyanopyrazine compound as the emitting layer achieved a current efficiency of 1.57 cd A-1 in the green region with CIE coordinates of (0.37, 0.51). However, the green emission (525 nm) observed from the tris-(8-hydroxyquinolinato)aluminum(III) (Alq3) electron-transport layer indicated the action of a recombination phenomenon between the emitting layer and the Alq3 electron-transport layer. The device fabricated with the tert-butylphenyl-substituted compound achieved a current efficiency of 0.238 cd A-1 in the red region with CIE coordinates of (0.54, 0.42) and showed no recombination phenomenon.
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Affiliation(s)
- Chun Keun Jang
- Department of Organic and Nano Engineering, Hanyang University, Aengdang-dong, Seongdong-gu, Seoul, 133791, Korea
| | - Cheol Jun Song
- Department of Organic and Nano Engineering, Hanyang University, Aengdang-dong, Seongdong-gu, Seoul, 133791, Korea
| | - Ji Hyun Park
- Department of Organic and Nano Engineering, Hanyang University, Aengdang-dong, Seongdong-gu, Seoul, 133791, Korea
| | - Wang Yao
- Department of Organic and Nano Engineering, Hanyang University, Aengdang-dong, Seongdong-gu, Seoul, 133791, Korea
| | - Jae Yun Jaung
- Department of Organic and Nano Engineering, Hanyang University, Aengdang-dong, Seongdong-gu, Seoul, 133791, Korea
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20
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Younes AH, Zhu L. Tunable dual fluorescence of 3-(2,2'-bipyridyl)-substituted iminocoumarin. Chemphyschem 2012; 13:3827-35. [PMID: 22969014 DOI: 10.1002/cphc.201200583] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Indexed: 12/29/2022]
Abstract
3-(2,2'-Bipyridyl)-substituted iminocoumarin molecules (compounds 1 and 2) exhibit dual fluorescence. Each molecule has one electron donor and two electron acceptors that are in conjugation, which leads to fluorescence from two independent charge transfer (CT) states. To account for the dual fluorescence, we subscribe to a kinetic model in which both CT states form after rapid decays from the directly accessed S(1) and S(2) excited states. Due to the slow internal conversion from S(2) to S(1), or more likely the slow interconversion between the two subsequently formed CT states, dual emission is allowed to occur. This hypothesis is supported by the following evidence: 1) the emission at short and long ends of the spectrum originates from two different excitation spectra, which eliminates the possibility that dual emission occurs after an adiabatic reaction at the S(1) level. 2) The fluorescence quantum yield of compound 2 grows with increasing excitation wavelength, which indicates that the high-energy excitation elevates the molecule to a weakly emissive state that does not internally convert to the low-energy, highly emissive state. The intensity of the two emission bands of 1 is tunable through the specific interactions between either of the two electron acceptors with another species, such as Zn(2+) in the current demonstration. Therefore, the development of ratiometric fluorescent indicators based on the dual-emitting iminocoumarin system is conceivable. Further fundamental studies on this series of compounds using time-resolved spectroscopic techniques, and explorations of their applications will be carried out in the near future.
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Affiliation(s)
- Ali H Younes
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, USA
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Chipem FAS, Mishra A, Krishnamoorthy G. The role of hydrogen bonding in excited state intramolecular charge transfer. Phys Chem Chem Phys 2012; 14:8775-90. [DOI: 10.1039/c2cp23879a] [Citation(s) in RCA: 142] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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22
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LI JUANQIN, LI XIANGYUAN, WANG FENG. A THEORETICAL STUDY ON DUAL FLUORESCENCE OF 4-DIMETHYLAMINOPYRIDINE BY POLARIZABLE CONTINUUM MODEL. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2011. [DOI: 10.1142/s0219633608004143] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Dual fluorescence spectra of 4-dimethylaminopyridine (DMAP) is investigated using time-dependent density functional theory and complete active space self-consistent field methods. Electronic absorption and emission spectra of DMAP have been investigated in three solvents, that is, cyclohexane, chloroform, and acetonitrile. The present study reveals that the dual fluorescence phenomena of DMAP appear in the cases of acetonitrile and chloroform, but not in cyclohexane. The electronic structures of the ground state and the intramolecular charge transfer states are, therefore, studied in order to reveal the insight of dual fluorescence. Our theoretical results suggest that the twisting of dimethylamino moiety in DMAP is necessary for the intramolecular charge transfer. The mechanism of the dual fluorescence of DMAP is discussed based on the twisted intramolecular charge transfer model and the dual fluorescence phenomenon is explained theoretically.
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Affiliation(s)
- JUAN-QIN LI
- College of Chemical Engineering and State Key Laboratory of Biotherapy, Sichuan University, Chengdu 610065, P. R. China
| | - XIANG-YUAN LI
- College of Chemical Engineering and State Key Laboratory of Biotherapy, Sichuan University, Chengdu 610065, P. R. China
| | - FENG WANG
- Center for Molecular Simulation, Swinburne University of Technology, Hawthorn, Melbourne, Vic. 3122, Australia
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Solvent Polarity and Excitation Wavelength Dependence of the Dual Fluorescence in N,N-Diethyl-4-Nitrosoaniline. J Fluoresc 2011; 22:451-6. [DOI: 10.1007/s10895-011-0978-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 09/13/2011] [Indexed: 10/17/2022]
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Coto PB, Serrano-Andrés L, Gustavsson T, Fujiwara T, Lim EC. Intramolecular charge transfer and dual fluorescence of 4-(dimethylamino)benzonitrile: ultrafast branching followed by a two-fold decay mechanism. Phys Chem Chem Phys 2011; 13:15182-8. [PMID: 21769358 DOI: 10.1039/c1cp21089k] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this contribution we present new experimental and theoretical results for the intramolecular charge transfer (ICT) reaction underlying the dual fluorescence of 4-(dimethylamino)benzonitrile (DMABN), which indicate that the fully twisted ICT (TICT) state is responsible for the time-resolved transient absorption spectrum while a distinct partially twisted ICT (pTICT) structure is suggested for the fluorescent ICT state.
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Affiliation(s)
- Pedro B Coto
- Interdisziplinäres Zentrum für Molekulare Materialien (ICMM), Friedrich-Alexander-Universität Erlangen-Nürnberg Staudtstrasse 7/B2, D-91058 Erlangen, Germany.
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25
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Yan ZQ, Yang ZY, Wang H, Li AW, Wang LP, Yang H, Gao BR. Study of aggregation induced emission of cyano-substituted oligo (p-phenylenevinylene) by femtosecond time resolved fluorescence. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2011; 78:1640-1645. [PMID: 21388863 DOI: 10.1016/j.saa.2011.01.056] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Revised: 01/25/2011] [Accepted: 01/28/2011] [Indexed: 05/30/2023]
Abstract
The aggregation induced emission (AIE) mechanism of the cyano-substituted oligo (p-phenylenevinylene)1,4-bis [1-cyano-2-(4-(diphenylamino) phenyl) vinyl] benzene (TPCNDSB) is investigated by time resolved fluorescence technique. By reconstructing the time resolved emission spectra (TRES), it is found that in solvent of low polarity, the emission is mainly from the local emission (LE) state with high quantum yield, but in high polarity solvent, the emission is mainly from the intramolecular charge transfer (ICT) state, which is a relatively dark state, with low quantum yield. In crystal form, the restriction of transfer from LE state to ICT state results in efficient AIE.
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Affiliation(s)
- Zi-Qi Yan
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun, China
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26
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Ghosh D, Sarkar D, Chattopadhyay N. Intramolecular charge transfer promoted fluorescence transfer: A demonstration of re-absorption of the donor fluorescence by the acceptor. J Mol Liq 2010. [DOI: 10.1016/j.molliq.2010.06.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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27
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Excitation Wavelength Dependence of Dual Fluorescence of DMABN in Polar Solvents. J Fluoresc 2010; 20:1241-8. [DOI: 10.1007/s10895-010-0675-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Accepted: 05/05/2010] [Indexed: 10/19/2022]
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Gao BR, Wang HY, Hao YW, Fu LM, Fang HH, Jiang Y, Wang L, Chen QD, Xia H, Pan LY, Ma YG, Sun HB. Time-Resolved Fluorescence Study of Aggregation-Induced Emission Enhancement by Restriction of Intramolecular Charge Transfer State. J Phys Chem B 2009; 114:128-34. [DOI: 10.1021/jp909063d] [Citation(s) in RCA: 173] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Bing-Rong Gao
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China, College of Physics, Jilin University, 119 Jiefang Road, Changchun 130023, China, Department of Chemistry, Renmin University of China, Beijing 100872, China, and State Key Laboratory on Supramolecular Structures and Materials, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Hai-Yu Wang
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China, College of Physics, Jilin University, 119 Jiefang Road, Changchun 130023, China, Department of Chemistry, Renmin University of China, Beijing 100872, China, and State Key Laboratory on Supramolecular Structures and Materials, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Ya-Wei Hao
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China, College of Physics, Jilin University, 119 Jiefang Road, Changchun 130023, China, Department of Chemistry, Renmin University of China, Beijing 100872, China, and State Key Laboratory on Supramolecular Structures and Materials, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Li-Min Fu
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China, College of Physics, Jilin University, 119 Jiefang Road, Changchun 130023, China, Department of Chemistry, Renmin University of China, Beijing 100872, China, and State Key Laboratory on Supramolecular Structures and Materials, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Hong-Hua Fang
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China, College of Physics, Jilin University, 119 Jiefang Road, Changchun 130023, China, Department of Chemistry, Renmin University of China, Beijing 100872, China, and State Key Laboratory on Supramolecular Structures and Materials, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Ying Jiang
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China, College of Physics, Jilin University, 119 Jiefang Road, Changchun 130023, China, Department of Chemistry, Renmin University of China, Beijing 100872, China, and State Key Laboratory on Supramolecular Structures and Materials, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Lei Wang
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China, College of Physics, Jilin University, 119 Jiefang Road, Changchun 130023, China, Department of Chemistry, Renmin University of China, Beijing 100872, China, and State Key Laboratory on Supramolecular Structures and Materials, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Qi-Dai Chen
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China, College of Physics, Jilin University, 119 Jiefang Road, Changchun 130023, China, Department of Chemistry, Renmin University of China, Beijing 100872, China, and State Key Laboratory on Supramolecular Structures and Materials, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Hong Xia
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China, College of Physics, Jilin University, 119 Jiefang Road, Changchun 130023, China, Department of Chemistry, Renmin University of China, Beijing 100872, China, and State Key Laboratory on Supramolecular Structures and Materials, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Ling-Yun Pan
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China, College of Physics, Jilin University, 119 Jiefang Road, Changchun 130023, China, Department of Chemistry, Renmin University of China, Beijing 100872, China, and State Key Laboratory on Supramolecular Structures and Materials, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Yu-Guang Ma
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China, College of Physics, Jilin University, 119 Jiefang Road, Changchun 130023, China, Department of Chemistry, Renmin University of China, Beijing 100872, China, and State Key Laboratory on Supramolecular Structures and Materials, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Hong-Bo Sun
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China, College of Physics, Jilin University, 119 Jiefang Road, Changchun 130023, China, Department of Chemistry, Renmin University of China, Beijing 100872, China, and State Key Laboratory on Supramolecular Structures and Materials, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, China
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Song P, Sun SG, Liu JY, Xu YQ, Han KL, Peng XJ. Theoretical and experimental study on the intramolecular charge transfer excited state of the new highly fluorescent terpyridine compound. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2009; 74:753-757. [PMID: 19720560 DOI: 10.1016/j.saa.2009.08.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Revised: 07/08/2009] [Accepted: 08/07/2009] [Indexed: 05/28/2023]
Abstract
Experimental and theoretical methods have been used to investigate the relaxation dynamics and photophysical properties of the donor-acceptor compound 4'-(4-N,N-diphenylaminophenyl)-2,2':6',2''-terpyridine (DPAPT), a compound which is found to exhibit efficient intramolecular charge transfer emission in polar solvents with relatively large Stokes shifts and strong solvatochromism. The difference between the ground and excited state dipole moments (Deltamu) is estimated to be 13.7D on the basis of Lippert-Mataga models. To gain insight into the relaxation dynamics of DPAPT in the excited state, the potential energy curves for conformational relaxation are calculated. From the frontier molecular orbital (MO) pictures at the geometry of the twisted ICT excited state, the intramolecular charger transfer mainly takes place from HOMO (triphenylamine) to LUMO (terpyridine) in this donor-acceptor system.
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Affiliation(s)
- Peng Song
- State Key Lab of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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30
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Do J, Huh J, Kim E. Solvatochromic fluorescence of piperazine-modified bipyridazines for an organic solvent-sensitive film. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:9405-9412. [PMID: 19601612 DOI: 10.1021/la901476q] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Bipyridazines were modified with heterocyclic amines such as piperazine to give symmetric quadrupolar (SPBP) and asymmetric dipolar (APBP) bipyridazine. The fluorescence of SPBP and APBP was highly sensitive to solvent polarity, giving a synthetic rainbow of emission in different organic solvents. The solvent-induced changes in the Stokes shift of the bipyridazines resulted in positive solvatochromism. The symmetric bipyridazine showed higher solvatochromic sensitivity than that of the asymmetric bipyridazine and diazines. The positive solvatochromic fluorescence properties were reproduced in a binary system of toluene/dimethyl sulfoxide (DMSO) mixture, which showed a synthetic rainbow of emission by varying the DMSO content in toluene. An organic sensitive poly(methyl methacrylate) film containing SPBP exhibited a visible sensitivity for the detection of solvents by their polarity upon exposure to organic solvent molecules.
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Affiliation(s)
- Jaekwon Do
- Department of Chemical and Biomolecular Engineering, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul 120-749, Korea
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31
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Kucheryavy P, Li G, Vyas S, Hadad C, Glusac KD. Electronic Properties of 4-Substituted Naphthalimides. J Phys Chem A 2009; 113:6453-61. [PMID: 19445525 DOI: 10.1021/jp901982r] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Pavel Kucheryavy
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, and Department of Chemistry, Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210
| | - Guifeng Li
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, and Department of Chemistry, Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210
| | - Shubham Vyas
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, and Department of Chemistry, Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210
| | - Christopher Hadad
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, and Department of Chemistry, Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210
| | - Ksenija D. Glusac
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, and Department of Chemistry, Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210
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Kowalski K, Long NJ, Kuimova MK, Kornyshev AA, Taylor AG, White AJP. Synthesis and characterisation of substituted diphenylamines—charge-transfer, donor–acceptor systems localised at water–oil interfaces. NEW J CHEM 2009. [DOI: 10.1039/b818110a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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33
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Zgierski MZ, Fujiwara T, Lim EC. Conical intersections and ultrafast intramolecular excited-state dynamics in nucleic acid bases and electron donor–acceptor molecules. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.06.024] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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34
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Zhao GJ, Chen RK, Sun MT, Liu JY, Li GY, Gao YL, Han KL, Yang XC, Sun L. Photoinduced Intramolecular Charge Transfer and S2Fluorescence in Thiophene-π-Conjugated Donor-Acceptor Systems: Experimental and TDDFT Studies. Chemistry 2008; 14:6935-47. [DOI: 10.1002/chem.200701868] [Citation(s) in RCA: 191] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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35
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Dash N, Chipem F, Swaminathan R, Krishnamoorthy G. Hydrogen bond induced twisted intramolecular charge transfer in 2-(4′-N,N-dimethylaminophenyl)imidazo[4,5-b]pyridine. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.05.092] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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36
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A combined experimental and theoretical study on photoinduced intramolecular charge transfer in trans-ethyl p-(dimethylamino)cinamate. J Photochem Photobiol A Chem 2008. [DOI: 10.1016/j.jphotochem.2008.01.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Tan W, Zhang D, Wu H, Zhu D. A new 4-(N,N-dimethylamino)benzonitrile (DMABN) derivative with tetrathiafulvalene unit: modulation of the dual fluorescence of DMABN by redox reaction of tetrathiafulvalene unit. Tetrahedron Lett 2008. [DOI: 10.1016/j.tetlet.2007.12.087] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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38
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Demeter A, Mile V, Bérces T. Hydrogen Bond Formation between 4-(Dimethylamino)pyridine and Aliphatic Alcohols. J Phys Chem A 2007; 111:8942-9. [PMID: 17718545 DOI: 10.1021/jp072989i] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The photophysics of 4-(dimethylamino)pyridine (DMAP) has been investigated in different solvents in the presence of aliphatic and fluorinated aliphatic alcohols, respectively. For most systems, consecutive two-step hydrogen-bonded complex formation is observed in the presence of alcohols. Equilibrium constants are determined from UV spectroscopic results for the formation of singly and doubly complexed species. The resolved absorption and fluorescence spectra for the singly and doubly complexed DMAP are derived by means of the equilibrium constants. Exceptionally large hydrogen bond basicity values are found for the ground and singlet excited DMAP molecules. In n-hexane, as a consequence of complex formation, the intramolecular charge transfer (ICT) emission becomes dominant over of the locally excited fluorescence; the fluorescence and triplet yields increase considerably with complexation. In polar solvents, both the fluorescence and triplet yields of the complex are much smaller than that of the uncomplexed DMAP. The dipole moments derived for the singly complexed species from the Lippert-Mataga analysis are much larger than those of the uncomplexed molecules. However, for the relaxed ICT excited-state one obtains different dipole moments in apolar and polar solvents. This may be explained by a conformational change of the molecule in the ICT excited state from planar geometry in apolar solvent to the perpendicular structure (characterized with bigger dipole moment) in polar solvent.
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Affiliation(s)
- Attila Demeter
- Institute of Materials and Environmental Chemistry, Chemical Research Center, Hungarian Academy of Sciences, 1025 Budapest, Pusztaszeri u. 59-67, Hungary.
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Abramov S, Schweke D, Zilberg S, Haas Y. The fluorescence of 5-cyano-2-(1-pyrrolyl)-pyridine (CPP) in different solvents and in solid argon: An experimental and theoretical study. Chem Phys 2007. [DOI: 10.1016/j.chemphys.2007.03.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Fuss W, Schmid WE, Kuttan Pushpa K, Trushin SA, Yatsuhashi T. Ultrafast relaxation and coherent oscillations in aminobenzonitriles in the gas phase probed by intense-field ionization. Phys Chem Chem Phys 2007; 9:1151-69. [PMID: 17325762 DOI: 10.1039/b611877a] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
4-Aminobenzonitrile derivatives have two excited states of similar energy: besides the benzene-like L(b) state (also termed "locally excited" or LE state) one with charge-transfer (CT) character that is slightly higher in the isolated molecules. The CT state can be lowered by solvents of suitable polarity, so that dual fluorescence can be observed in them. It is controversial along which coordinate this state is displaced, although the amino-group twist is a wide-spread assumption. We investigated a number of such compounds by transient ionization in the gas phase, initially exciting the higher-lying L(a) state (S(2)). Here we briefly review the previous results on 4-(dimethylamino)benzonitrile (the prototype of this class of molecules), 4-piperidino-, pyrrolidino- and pyrrolyl-benzonitrile and compare them with new results on 4-aminobenzonitrile and on the bridged derivative N-methyl-6-cyano-1,2,3,4-tetrahydroquinoline (NMC6). Although in the latter two molecules the CT state has never been detected before, we find the same relaxation path for all compounds: From S(2), the wave packet passes through a conical intersection (CI); from there part of it reaches the S(1) (L(b)) state directly, whereas another part temporarily populates the CT state (also in NMC6), from where it goes around the CI also to the L(b) well. The wave packet directly reaching the L(b) well oscillates there along coordinates involving amino-group twist and wagging or molecular arching and a quinoidal distortion. These coordinates must be components of the CI displacement vector. A vibration involving bond-length alternation of the benzene ring is ascribed to a momentum caused by the electronic symmetry change in the CI, i.e., to the nonadiabatic coupling vector. Also the CT state involves amino-group twist, as to conclude from the anisotropy of the corresponding signal. The six-membered aliphatic ring in NMC6 hinders the twist and raises the CT state to an energy that is, however, still below the L(a) state, so that it can be temporarily populated in a barrierless process. Also in aminobenzonitrile the CT state is between L(a) and L(b) and is reached from L(a) without a barrier. The twist is rationalized by vibronic interaction with a higher state that is pi-antibonding between the amino group and the aromatic ring.
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Affiliation(s)
- Werner Fuss
- Max-Planck-Institut für Quantenoptik, D-85741 Garching, Germany
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Tan W, Zhang D, Wang Z, Liu C, Zhu D. 4-(N,N-Dimethylamine)benzonitrile (DMABN) derivatives with boronic acid and boronate groups: new fluorescent sensors for saccharides and fluoride ion. ACTA ACUST UNITED AC 2007. [DOI: 10.1039/b618183j] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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43
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Kwok WM, Ma C, George MW, Grills DC, Matousek P, Parker AW, Phillips D, Toner WT, Towrie M. Solvent effects on the charge transfer excited states of 4-dimethylaminobenzonitrile (DMABN) and 4-dimethylamino-3,5-dimethylbenzonitrile (TMABN) studied by time-resolved infrared spectroscopy: a direct observation of hydrogen bonding interactions. Photochem Photobiol Sci 2007; 6:987-94. [PMID: 17721598 DOI: 10.1039/b708414e] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Time-resolved infrared absorption spectra of the C[triple bond]N bands of photoexcited TMABN and DMABN have been measured in non-polar hexane, polar aprotic THF and polar protic butanol with high temporal and spectral resolution (<0.5 ps and 5 cm(-1), respectively). In butanol, the intramolecular charge transfer (ICT) state C[triple bond]N infrared absorption bands of DMABN and TMABN both develop from an initial singlet into a doublet, demonstrating the co-existence of two charge transfer excited states, one of which is hydrogen-bonded and the other similar to the state formed in aprotic solvents. The ICT C[triple bond]N absorption band of TMABN is already strong at the earliest measurement time of 2 ps in THF, hexane, and butanol, indicating prompt population of ICT by a barrierless process, as expected from the pre-twisted structure of this molecule. There are little or no subsequent fast kinetics in hexane and THF but the signal observed in butanol continues to grow substantially at later times, prior to decay, indicating population transfer from a second state excited at 267 nm. No CN absorption band attributable to this state is observed, consistent with it being similar to the LE state of DMABN. The kinetics of the later stages of the hydrogen-bonding of both DMABN and TMABN in butanol takes place on timescales consistent with known values for dipolar solvation relaxation and result in a ratio of the hydrogen-bonded to non-bonded species of approximately 3 : 1 at equilibrium for both molecules. The contrast between the prompt population of the charge transfer state of TMABN in all three solvents and charge transfer rates in DMABN limited to 13 ps(-1) in THF and 9 ps(-1) in butanol is fully consistent with the TICT description for the ICT state structure.
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Affiliation(s)
- W M Kwok
- Department of Chemistry, Imperial College, Exhibition Road, London, UK
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Cogan S, Zilberg S, Haas Y. The Electronic Origin of the Dual Fluorescence in Donor−Acceptor Substituted Benzene Derivatives. J Am Chem Soc 2006; 128:3335-45. [PMID: 16522115 DOI: 10.1021/ja0548945] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The origin of the dual fluorescence of DMABN (dimethylaminobenzonitrile) and other benzene derivatives is explained by a charge transfer model based on the properties of the benzene anion radical. It is shown that, in general, three low-lying electronically excited states are expected for these molecules, two of which are of charge transfer (CT) character, whereas the third is a locally excited (LE) state. Dual fluorescence may arise from any two of these states, as each has a different geometry at which it attains a minimum. The Jahn-Teller induced distortion of the benzene anion radical ground state helps to classify the CT states as having quinoid (Q) and antiquinoid (AQ) forms. The intramolecular charge transfer (ICT) state is formed by the transfer of an electron from a covalently linked donor group to an anti-bonding orbital of the pi-electron system of benzene. The change in charge distribution of the molecule in the CT states leads to the most significant geometry change undergone by the molecule which is the distortion of the benzene ring to a Q or AQ structure. As the dipole moment is larger in the perpendicular geometry than in the planar one, this geometry is preferred in polar solvents, supporting the twisted intramolecular charge transfer (TICT) model. However, in many cases the planar conformation of CT excited states is lower in energy than that of the LE state, and dual fluorescence can be observed also from planar structures.
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Affiliation(s)
- Semyon Cogan
- Department of Physical Chemistry and the Farkas Center for Light Induced Processes, The Hebrew University of Jerusalem, Jerusalem, Israel
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Ishikawa H, Sugiyama M, Baba I, Setaka W, Kira M, Mikami N. Determination of the Equilibrium Structure of the Charge-transfer State of (p-Cyanophenyl)pentamethyldisilane by Means of Transient Infrared Spectroscopy. J Phys Chem A 2005; 109:8959-61. [PMID: 16331997 DOI: 10.1021/jp054117r] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An equilibrium structure of the charge-transfer (CT) state of (p-cyanophenyl)pentamethyldisilane was determined by transient infrared absorption spectroscopy of its CH stretching vibration region, and by the spectral simulation with quantum chemical calculations. It was found that a pattern of the CH stretching vibration bands of the CT state is substantially different from that of the S0 state. This band feature of the CT state was well reproduced assuming the planar sigma(Si-Si)pi* state, where the disilanyl group and the phenyl ring lie in the same plane. Considering that the disilanyl group in the S0 and the locally excited pipi* states lie in the plane perpendicular to the phenyl ring, an occurrence of a twisting-type structural change during the ICT process was experimentally identified in the present study.
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Affiliation(s)
- Haruki Ishikawa
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578 Japan.
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46
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Szydłowska I, Kubicki J, Herbich J. Picosecond kinetics of excited-state charge separation in 4-(dimethylamino)pyridine. Photochem Photobiol Sci 2005; 4:106-12. [PMID: 15616700 DOI: 10.1039/b411627e] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
4-(Dimethylamino)pyridine (DMAP) shows solvent-dependent dual fluorescence from the initially excited state B* and a highly polar TICT state A*. Room-temperature time-resolved picosecond fluorescence investigations prove the bimodal kinetics of the excited-state electron transfer reaction B*-->A* in polar aprotic media. In medium polarity solvents (such as ethyl acetate) two emitting states of DMAP are shown to reach equilibrium within 50 ps. Both emitting states originate from the same ground state. The rate of excited-state charge separation depends on polarity and proton donating ability of the surrounding medium. The effects of temperature on the quantum yields of both fluorescences of DMAP in polar aprotic media indicate the transition from the kinetic regime (at low temperatures) to the equilibrium regime (at high temperatures). The kinetic behaviour of the dual luminescence of DMAP in protic solvents is more complex than in aprotic ones. In alcohols an efficient nonradiative channel competes with excited-state charge separation.
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Affiliation(s)
- Izabela Szydłowska
- Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland
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47
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Fang A, Mello J, Finney N. Structural studies of biarylpyridines fluorophores lead to the identification of promising long wavelength emitters for use in fluorescent chemosensors. Tetrahedron 2004. [DOI: 10.1016/j.tet.2004.08.049] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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48
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Yang JS, Liau KL, Wang CM, Hwang CY. Substituent-Dependent Photoinduced Intramolecular Charge Transfer in N-Aryl-Substituted trans-4-Aminostilbenes. J Am Chem Soc 2004; 126:12325-35. [PMID: 15453766 DOI: 10.1021/ja047604d] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The photochemical behavior of trans-4-(N-arylamino)stilbene (1, aryl = 4-substituted phenyl) in solvents more polar than THF is strongly dependent on the substituent in the N-aryl group. This is attributed to the formation of a twisted intramolecular charge transfer (TICT) state for those with a methoxy (1OM), methoxycarbonyl (1CO), or cyano (1CN) substituent but not for those with a methyl (1Me), hydrogen (1H), chloro (1Cl), or trifluoromethyl (1CF) substituent. On the basis of the ring-bridged model compounds 3-6, the TICT states for 1CN and 1CO result from the twisting of the anilino-benzonitrilo C-N bond, but for 1OM it is from the twisting of the stilbenyl-anilino C-N bond, both of which are distinct from the TICT states previously proposed for N,N-dimethylaminostilbenes.
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Affiliation(s)
- Jye-Shane Yang
- Department of Chemistry and Center for Nano Science and Technology, National Central University/UST, Chung-Li, Taiwan 32054.
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49
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Yoshihara T, Druzhinin SI, Zachariasse KA. Fast Intramolecular Charge Transfer with a Planar Rigidized Electron Donor/Acceptor Molecule. J Am Chem Soc 2004; 126:8535-9. [PMID: 15238011 DOI: 10.1021/ja049809s] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The planar rigidized molecule fluorazene (FPP) undergoes fast reversible intramolecular charge transfer (ICT) in the excited state, with a reaction time of 12 ps in the polar solvent ethyl cyanide at -45 degrees C. The ICT state of FPP has a dipole moment mu(e)(ICT) of 13 D, much larger than that of the locally excited state LE (1 D). The ICT behavior of FPP is similar to that of its flexible counterpart N-phenylpyrrole (PP), for which mu(e)(ICT) = 12 D. These results show that intramolecular charge transfer to a planar ICT state can occur efficiently. In designing ICT systems capable of rapid switching, it is therefore important to realize that large amplitude motions such as those necessary for the formation of a twisted intramolecular charge transfer (TICT) state are not required.
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Affiliation(s)
- Toshitada Yoshihara
- Max-Planck-Institut für biophysikalische Chemie, Spektroskopie und Photochemische Kinetik, 37070 Göttingen, Germany
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50
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Techert S, Zachariasse KA. Structure Determination of the Intramolecular Charge Transfer State in Crystalline 4-(Diisopropylamino)benzonitrile from Picosecond X-ray Diffraction. J Am Chem Soc 2004; 126:5593-600. [PMID: 15113231 DOI: 10.1021/ja0379518] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The molecular structure of photoexcited crystalline 4-(diisopropylamino)benzonitrile (DIABN) is determined by time-resolved X-ray diffraction with a time resolution of 70 ps. Spectroscopic results suggest that an ICT state with a lifetime of 3 ns is produced after photoexcitation. According to structural refinement of the X-ray data (powder diffraction), the torsional angle of the diisopropylamino group with respect to the plane of the phenyl ring of DIABN decreases from 14 degrees in the electronic ground state to 10 degrees in the equilibrated ICT state.
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Affiliation(s)
- Simone Techert
- Max-Planck-Institut für biophysikalische Chemie, Spektroskopie und Photochemische Kinetik, 37070 Goettingen, Germany.
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