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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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2
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Sekaran B, Guragain M, Misra R, D'Souza F. β-Pyrrole Functionalized Push or Pull Porphyrins: Excited Charge Transfer Promoted Singlet Oxygen Generation. J Phys Chem A 2023; 127:7964-7975. [PMID: 37707534 DOI: 10.1021/acs.jpca.3c05292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/15/2023]
Abstract
Singlet oxygen (1O2) producing photosensitizers are highly sought for developing new photodynamic therapy agents and facilitating 1O2-involved chemical reactions. Often singlet oxygen is produced by the reaction of triplet-excited photosensitizers with dioxygen via an energy transfer mechanism. In the present study, we demonstrate a charge transfer mechanism to produce singlet oxygen involving push or pull functionalized porphyrins. For this, 20 β-pyrrole functionalized porphyrins carrying either an electron-rich push or electron-deficient pull group have been newly synthesized. Photoexcitation of these push-pull porphyrins has been shown to produce high-energy MPδ+-Aδ- or MPδ--Dδ+ charge transfer states. Subsequent charge recombination results in populating the triplet excited states of extended lifetimes in the case of the push group containing porphyrins that eventually react with dioxygen to produce the reactive singlet oxygen of relatively higher quantum yields. The effect of the push and pull groups on the porphyrin periphery in governing initial charge transfer, the population of triplet excited states and their lifetimes, and resulting in improved singlet oxygen quantum yields are systematically probed. The improved performance of 1O2 generation by porphyrins carrying push groups is borne out from this study.
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Affiliation(s)
- Bijesh Sekaran
- Department of Chemistry, Indian Institute of Technology, Indore 453552, India
| | - Manan Guragain
- Department of Chemistry, University of North Texas, 1155 Union Circle, #305070, Denton, Texas 76203-5017, United States
| | - Rajneesh Misra
- Department of Chemistry, Indian Institute of Technology, Indore 453552, India
| | - Francis D'Souza
- Department of Chemistry, University of North Texas, 1155 Union Circle, #305070, Denton, Texas 76203-5017, United States
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3
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Hernández-Segura LI, Köster AM. Efficient implementation of time-dependent auxiliary density functional theory. J Chem Phys 2023; 158:024108. [PMID: 36641386 DOI: 10.1063/5.0135263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The random phase approximation of time-dependent auxiliary density functional theory (TDADFT) is rederived from auxiliary density perturbation theory. Our exhaustive validation of TDADFT reveals an upshift of the excitation energies by ∼0.1 eV with respect to standard time-dependent density functional theory. For the computationally efficient implementation of TDADFT, floating point operation optimized three-center electron repulsion integral recurrence relations and their double asymptotic expansions are implemented into the Davidson solver. The computational efficiency of TDADFT is benchmarked with four sets of molecules comprising alkanes, fullerenes, DNA fragments, and zeolites. The results show that TDADFT has a computational scaling between 1.3 and 1.9 with respect to the number of basis functions, which is lower than the scaling of standard time-dependent density functional theory. Due to its computational simplifications, TDADFT is particularly well suited for Born-Oppenheimer molecular dynamics simulations. As illustrative examples, we present the temperature effects on the gas-phase absorption spectra of benzene, naphthalene, and anthracene.
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Affiliation(s)
- Luis I Hernández-Segura
- Departamento de Química, Cinvestav, Avenida Instituto Politécnico Nacional 2508, A.P. 14-740, CDMX C.P. 07360, Mexico
| | - Andreas M Köster
- Departamento de Química, Cinvestav, Avenida Instituto Politécnico Nacional 2508, A.P. 14-740, CDMX C.P. 07360, Mexico
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4
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Ma J, Miao TJ, Tang J. Charge carrier dynamics and reaction intermediates in heterogeneous photocatalysis by time-resolved spectroscopies. Chem Soc Rev 2022; 51:5777-5794. [PMID: 35770623 DOI: 10.1039/d1cs01164b] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sunlight as the most abundant renewable energy holds the promise to make our society sustainable. However, due to its low power density and intermittence, efficient conversion and storage of solar energy as a clean fuel are crucial. Apart from solar fuel synthesis, sunlight can also be used to drive other reactions including organic conversion and air/water purification. Given such potential of photocatalysis, the past few decades have seen a surge in the discovery of photocatalysts. However, the current photocatalytic efficiency is still very moderate. To address this challenge, it is important to understand fundamental factors that dominate the efficiency of a photocatalytic process to enable the rational design and development of photocatalytic systems. Many recent studies highlighted transient absorption spectroscopy (TAS) and time-resolved infrared (TRIR) spectroscopy as powerful approaches to characterise charge carrier dynamics and reaction pathways to elucidate the reasons behind low photocatalytic efficiencies, and to rationalise photocatalytic activities exhibited by closely related materials. Accordingly, as a fast-moving area, the past decade has witnessed an explosion in reports on charge carrier dynamics and reaction mechanisms on a wide range of photocatalytic materials. This critical review will discuss the application of TAS and TRIR in a wide range of heterogeneous photocatalytic systems, demonstrating the variety of ways in which these techniques can be used to understand the correlation between materials design, charge carrier behaviour, and photocatalytic activity. Finally, it provides a comprehensive outlook for potential developments in the area of time-resolved spectroscopies with an aim to provide design strategies for photocatalysts.
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Affiliation(s)
- Jiani Ma
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, and the Energy and Catalysis Hub, College of Chemistry and Materials Science, Northwest University, Xi'an, P. R. China
| | - Tina Jingyan Miao
- Department of Chemical Engineering, University College London (UCL), WC1E 7JE, London, UK.,Department of Chemistry, University College London (UCL), WC1H 0AJ, London, UK.
| | - Junwang Tang
- Department of Chemical Engineering, University College London (UCL), WC1E 7JE, London, UK
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5
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Pal A, Karmakar M, Bhatta SR, Thakur A. A detailed insight into anion sensing based on intramolecular charge transfer (ICT) mechanism: A comprehensive review of the years 2016 to 2021. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.214167] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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6
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Branched Electron-Donor Core Effect in D-π-A Star-Shaped Small Molecules on Their Properties and Performance in Single-Component and Bulk-Heterojunction Organic Solar Cells †. ENERGIES 2021. [DOI: 10.3390/en14123596] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Star-shaped donor-acceptor molecules are full of promise for organic photovoltaics and electronics. However, the effect of the branching core on physicochemical properties, charge transport and photovoltaic performance of such donor-acceptor materials in single-component (SC) and bulk heterojunction (BHJ) organic solar cells has not been thoroughly addressed. This work shows the comprehensive investigation of six star-shaped donor-acceptor molecules with terminal hexyldicyanovinyl blocks linked through 2,2′-bithiophene π-conjugated bridge to different electron-donating cores such as the pristine and fused triphenylamine, tris(2-methoxyphenyl)amine, carbazole- and benzotriindole-based units. Variation of the branching core strongly impacts on such important properties as the solubility, highest occupied molecular orbital energy, optical absorption, phase behavior, molecular packing and also on the charge-carrier mobility. The performance of SC or BHJ organic solar cells are comprehensively studied and compared. The results obtained provide insight on how to predict and fine-tune photovoltaic performance as well as properties of donor-acceptor star-shaped molecules for organic solar cells.
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7
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Marcelli A, Patrizi B, Bonamore A, Boffi A, Becucci M, Foggi P. Exciplex Formation in Lipid-bound Escherichia coli Flavohemoglobin. Chemphyschem 2021; 22:1134-1140. [PMID: 33794073 DOI: 10.1002/cphc.202100019] [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: 01/14/2021] [Revised: 03/30/2021] [Indexed: 11/10/2022]
Abstract
Flavohemoglobins have the particular capability of binding unsaturated and cyclopropanated fatty acids as free acids or phospholipids. Fatty acid binding to the ferric heme results in a weak but direct bonding interaction. Ferrous and ferric protein, in presence or absence of a bound lipid molecule, have been characterized by transient absorption spectroscopy. Measurements have been also carried out both on the ferrous deoxygenated and on the CO bound protein to investigate possible long-range interaction between the lipid acyl chain moiety and the ferrous heme. After excitation of the deoxygenated derivatives the relaxation process reveals a slow dynamics (350 ps) in lipid-bound protein but is not observed in the lipid-free protein. The latter feature and the presence of an extra contribution in the absorption spectrum, indicates that the interaction of iron heme with the acyl chain moiety occurs only in the excited electronic state and not in the ground electronic state. Data analysis highlights the formation of a charge-transfer complex in which the iron ion of the lipid-bound protein in the expanded electronic excited state, possibly represented by a high spin Fe III intermediate, is able to bind to the sixth coordination ligand placed at a distance of at 3.5 Å from the iron. A very small nanosecond geminate rebinding is observed for CO adduct in lipid-free but not in the lipid-bound protein. The presence of the lipid thus appears to inhibit the mobility of CO in the heme pocket.
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Affiliation(s)
- Agnese Marcelli
- European Laboratory for Non-Linear Spectroscopy (LENS), Via Nello Carrara, 1, 50019 Sesto Fiorentino, Florence), Italy
| | - Barbara Patrizi
- European Laboratory for Non-Linear Spectroscopy (LENS), Via Nello Carrara, 1, 50019 Sesto Fiorentino, Florence), Italy.,National Institute of Optics-National Research Council (INO-CNR), Via Madonna del Piano 10, 50019, Sesto Fiorentino (Florence), Italy
| | - Alessandra Bonamore
- Istituto Pasteur-Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche, Università "Sapienza" di Roma, P. Aldo Moro 5, 00185, Rome, Italy
| | - Alberto Boffi
- Istituto Pasteur-Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche, Università "Sapienza" di Roma, P. Aldo Moro 5, 00185, Rome, Italy
| | - Maurizio Becucci
- European Laboratory for Non-Linear Spectroscopy (LENS), Via Nello Carrara, 1, 50019 Sesto Fiorentino, Florence), Italy.,Department of Chemistry Ugo Schiff, University of Florence, Via Della Lastruccia 3-13, 50019 Sesto Fiorentino, Florence), Italy
| | - Paolo Foggi
- European Laboratory for Non-Linear Spectroscopy (LENS), Via Nello Carrara, 1, 50019 Sesto Fiorentino, Florence), Italy.,National Institute of Optics-National Research Council (INO-CNR), Via Madonna del Piano 10, 50019, Sesto Fiorentino (Florence), Italy.,Department of Chemistry, University of Perugia, Via Elce di sotto 8, 06100, Perugia, Italy
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8
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Novel D-A-D Fluorescent Dyes Based on 9-( p-Tolyl)-2,3,4,4a,9,9a-hexahydro-1 H-carbazole as a Donor Unit for Solution-Processed Organic Light-Emitting-Diodes. Molecules 2021; 26:molecules26102872. [PMID: 34066150 PMCID: PMC8151704 DOI: 10.3390/molecules26102872] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/26/2021] [Accepted: 05/08/2021] [Indexed: 12/01/2022] Open
Abstract
New fluorescent D-A-D dyes containing 9-(p-tolyl)-2,3,4,4a,9,9a-hexahydro-1H-carbazole as a donor unit and 2,1,3-benzochalcogenadiazoles as an electron-withdrawing group were synthesized. The photoluminescent and electroluminescent properties of novel dyes for fluorescent OLED application were investigated. It was demonstrated that the replacement of lightweight heteroatoms by heavier ones enables the fine tuning of the maximum emission without significantly reducing the luminescence quantum yield. The maximum quantum yield value of 62.6% for derivatives based on 2,1,3-benzoxadiazole (1a) in cyclohexane was achieved. Two devices with the architecture of glass/ITO/PEDOT-PSS/poly-TPD/EML/TPBi/LiF/Al (EML = emitting layer) were fabricated to check the suitability of the synthesized compounds as a single active emission layer in OLED. These OLEDs exhibited clear red electroluminescence of the dyes with the maximum current efficiency of 0.85 Cd/A.
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9
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Chahal MK, Liyanage A, Alsaleh AZ, Karr PA, Hill JP, D'Souza F. Anion-enhanced excited state charge separation in a spiro-locked N-heterocycle-fused push-pull zinc porphyrin. Chem Sci 2021; 12:4925-4930. [PMID: 34168764 PMCID: PMC8179616 DOI: 10.1039/d1sc00038a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A new type of push–pull charge transfer complex, viz., a spiro-locked N-heterocycle-fused zinc porphyrin, ZnP-SQ, is shown to undergo excited state charge separation, which is enhanced by axial F− binding to the Zn center. In this push–pull design, the spiro-quinone group acts as a ‘lock’ promoting charge transfer interactions by constraining mutual coplanarity of the meso-phenol-substituted electron-rich Zn(ii) porphyrin and an electron deficient N-heterocycle, as revealed by electrochemical and computational studies. Spectroelectrochemical studies have been used to identify the spectra of charge separated states, and charge separation upon photoexcitation of ZnP has been unequivocally established by using transient absorption spectroscopic techniques covering wide spatial and temporal regions. Further, global target analysis of the transient data using GloTarAn software is used to obtain the lifetimes of different photochemical events and reveal that fluoride anion complexation stabilizes the charge separated state to an appreciable extent. A new type of push–pull charge transfer complex, viz., a spiro-locked N-heterocycle-fused zinc porphyrin, ZnP-SQ, is shown to undergo excited state charge separation, which is enhanced by axial F− binding to the Zn center.![]()
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Affiliation(s)
- Mandeep K Chahal
- International Centre for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS) Namiki 1-1, Tsukuba Ibaraki 305-0044 Japan
| | - Anuradha Liyanage
- Department of Chemistry, University of North Texas 1155 Union Circle, #305070 Denton TX 76203-5017 USA
| | - Ajyal Z Alsaleh
- Department of Chemistry, University of North Texas 1155 Union Circle, #305070 Denton TX 76203-5017 USA
| | - Paul A Karr
- Department of Physical Sciences and Mathematics, Wayne State College 111 Main Street Wayne Nebraska 68787 USA
| | - Jonathan P Hill
- International Centre for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS) Namiki 1-1, Tsukuba Ibaraki 305-0044 Japan
| | - Francis D'Souza
- Department of Chemistry, University of North Texas 1155 Union Circle, #305070 Denton TX 76203-5017 USA
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10
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Ye JT, Qiu YQ. The inspiration and challenge for through-space charge transfer architecture: from thermally activated delayed fluorescence to non-linear optical properties. Phys Chem Chem Phys 2021; 23:15881-15898. [PMID: 34296718 DOI: 10.1039/d1cp02565a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Organic molecules consisting of electron donor (D) and electron acceptor (A) subunits linked by π-conjugated bridges are promising building blocks for thermally activated delayed fluorescence (TADF) and non-linear optics (NLO) materials due to their intramolecular charge transfer (CT) processes in response to external stimuli. According to the electron interaction pattern, the CT process in D-π-A architectures can be divided into two categories, through-bond/-space charge transfer (TB/TSCT). To date, research into the TADF properties of TSCT characteristic molecules has since seen significant growth. In fact, TSCT characteristic materials show great advantages in such NLO responses. In this perspective, we first briefly introduced the basic principles of NLO and TADF effects. Successively, we discuss the influence of TBCT and TSCT patterns on NLO and TADF properties, especially for TSCT characteristic. In the final part, we address the diversity and potential advantages of TSCT characteristic molecules as high-performance NLO materials. With these, it is expected that the greater structural flexibility of spatial conjugation can bring more functionality to NLO materials in the future.
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Affiliation(s)
- Jin-Ting Ye
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun, 130024, China.
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11
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Gayathri P, Kanagajothi K, Nag P, Anand N, Reddy VS, Moon D, Anthony SP, Madhu V. Symmetrical and unsymmetrical thiazole-based ESIPT derivatives: the highly selective fluorescence sensing of Cu 2+ and structure-controlled reversible mechanofluorochromism. CrystEngComm 2021. [DOI: 10.1039/d1ce00927c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Excited state intramolecular proton transfer (ESIPT) process-based organic fluorophores provide an opportunity to develop large Stokes-shifted multifunctional fluorescence systems for light emitting, chemosensing and bioimaging applications.
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Affiliation(s)
- Parthasarathy Gayathri
- School of Chemical & Biotechnology, SASTRA Deemed University, Thanjavur-613401, Tamil Nadu, India
| | - Karuppaiah Kanagajothi
- Department of Applied Chemistry, Karunya Institute of Technology and Sciences, Coimbatore-641 114, Tamil Nadu, India
| | - Probal Nag
- Indian Institute of Science Education and Research Thiruvananthapuram, Kerala 695551, India
| | - Neethu Anand
- Indian Institute of Science Education and Research Thiruvananthapuram, Kerala 695551, India
| | | | - Dohyun Moon
- Beamline Department, Pohang Accelerator Laboratory, 80 Jigokro-127 beongil, Nam-gu, Pohang, Gyeongbuk, Korea
| | | | - Vedichi Madhu
- Department of Applied Chemistry, Karunya Institute of Technology and Sciences, Coimbatore-641 114, Tamil Nadu, India
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12
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Pinjari D, Alsaleh AZ, Patil Y, Misra R, D'Souza F. Interfacing High‐Energy Charge‐Transfer States to a Near‐IR Sensitizer for Efficient Electron Transfer upon Near‐IR Irradiation. Angew Chem Int Ed Engl 2020; 59:23697-23705. [DOI: 10.1002/anie.202013036] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Indexed: 12/11/2022]
Affiliation(s)
- Dilip Pinjari
- Department of Chemistry Indian Institute of Technology Indore 453552 India
| | - Ajyal Z. Alsaleh
- Department of Chemistry University of North Texas 1155 Union Circle, #305070 Denton TX 76203-5017 USA
| | - Yuvraj Patil
- Department of Chemistry Indian Institute of Technology Indore 453552 India
| | - Rajneesh Misra
- Department of Chemistry Indian Institute of Technology Indore 453552 India
| | - Francis D'Souza
- Department of Chemistry University of North Texas 1155 Union Circle, #305070 Denton TX 76203-5017 USA
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13
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Pinjari D, Alsaleh AZ, Patil Y, Misra R, D'Souza F. Interfacing High‐Energy Charge‐Transfer States to a Near‐IR Sensitizer for Efficient Electron Transfer upon Near‐IR Irradiation. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202013036] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Dilip Pinjari
- Department of Chemistry Indian Institute of Technology Indore 453552 India
| | - Ajyal Z. Alsaleh
- Department of Chemistry University of North Texas 1155 Union Circle, #305070 Denton TX 76203-5017 USA
| | - Yuvraj Patil
- Department of Chemistry Indian Institute of Technology Indore 453552 India
| | - Rajneesh Misra
- Department of Chemistry Indian Institute of Technology Indore 453552 India
| | - Francis D'Souza
- Department of Chemistry University of North Texas 1155 Union Circle, #305070 Denton TX 76203-5017 USA
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14
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Vishnumurthy KA, Girish KH, Adhikari AV. Synthesis, physicochemical properties and computational study of donor–acceptor polymer for optical limiting application. SN APPLIED SCIENCES 2020. [DOI: 10.1007/s42452-020-03523-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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15
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Lin CY, Boxer SG. Mechanism of Color and Photoacidity Tuning for the Protonated Green Fluorescent Protein Chromophore. J Am Chem Soc 2020; 142:11032-11041. [PMID: 32453950 DOI: 10.1021/jacs.0c02796] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The neutral or A state of the green fluorescent protein (GFP) chromophore is a remarkable example of a photoacid naturally embedded in the protein environment and accounts for the large Stokes shift of GFP in response to near UV excitation. Its color tuning mechanism has been largely overlooked, as it is less preferred for imaging applications than the redder anionic or B state. Past studies, based on site-directed mutagenesis or solvatochromism of the isolated chromophore, have concluded that its color tuning range is much narrower than its anionic counterpart. However, as we performed extensive investigation on more GFP mutants, we found that the color of the neutral chromophore can be more sensitive to protein electrostatics than can the anionic counterpart. Electronic Stark spectroscopy reveals a fundamentally different electrostatic color tuning mechanism for the neutral state of the chromophore that demands a three-form model as compared to that of the anionic state, which requires only two forms ( J. Am. Chem. Soc. 2019, 141, 15250-15265). Specifically, an underlying zwitterionic charge-transfer state is required to explain its sensitivity to electrostatics. As the Stokes shift is tightly linked to excited-state proton transfer (ESPT) of the protonated chromophore, we infer design principles of the GFP chromophore as a photoacid through the color tuning mechanisms of both protonation states. The three-form model could also be applied to similar biological and nonbiological dyes and complements the failure of the two-form model for donor-acceptor systems with localized ground-state electronic distributions.
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Affiliation(s)
- Chi-Yun Lin
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Steven G Boxer
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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16
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Pietropaolo A, Nakano T. Learning how planarization can affect dichroic patterns in polyfluorenes. Chirality 2020; 32:661-666. [PMID: 32160652 DOI: 10.1002/chir.23219] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 03/02/2020] [Accepted: 03/03/2020] [Indexed: 01/03/2023]
Abstract
The circular dichroism spectra of a single chain of polyfluorene was predicted for a p-twisted helix conformation and local planarized polymer sections in the presence and in the absence of thermal vibrations. Under thermal vibrations at 300 K, the planarized section of polyfluorene affords a red-shifted positive dichroic band between 446 and 456 nm, preserving a degree of chirality. The S1 ← S0 excitation energy decreases from 3.29 eV, for the p-twisted helix to 2.77 or 2.71 eV, for planarized sections with one or two coplanar twists, respectively. Thermal vibrations and intramolecular rotations eventually affect the circular dichroism spectrum patterns, where planarized bent conformers induce a positive band towards 450 nm.
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Affiliation(s)
- Adriana Pietropaolo
- Dipartimento di Scienze della Salute, Università di Catanzaro, Catanzaro, Italy
| | - Tamaki Nakano
- Institute for Catalysis (ICAT), Hokkaido University, Sapporo, Japan
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