1
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Petropoulos V, Rukin PS, Quintela F, Russo M, Moretti L, Moore A, Moore T, Gust D, Prezzi D, Scholes GD, Molinari E, Cerullo G, Troiani F, Rozzi CA, Maiuri M. Vibronic Coupling Drives the Ultrafast Internal Conversion in a Functionalized Free-Base Porphyrin. J Phys Chem Lett 2024; 15:4461-4467. [PMID: 38630018 DOI: 10.1021/acs.jpclett.4c00372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Internal conversion (IC) is a common radiationless transition in polyatomic molecules. Theory predicts that molecular vibrations assist IC between excited states, and ultrafast experiments can provide insight into their structure-function relationship. Here we elucidate the dynamics of the vibrational modes driving the IC process within the Q band of a functionalized porphyrin molecule. Through a combination of ultrafast multidimensional spectroscopies and theoretical modeling, we observe a 60 fs Qy-Qx IC and demonstrate that it is driven by the interplay among multiple high-frequency modes. Notably, we identify 1510 cm-1 as the leading tuning mode that brings the porphyrin to an optimal geometry for energy surface crossing. By employing coherent wave packet analysis, we highlight a set of short-lived vibrations (1200-1400 cm-1), promoting the IC within ≈60 fs. Furthermore, we identify one coupling mode (1350 cm-1) that is responsible for vibronic mixing within the Q states. Our findings indicate that porphyrin-core functionalization modulates IC effectively, offering new opportunities in photocatalysis and optoelectronics.
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Affiliation(s)
- Vasilis Petropoulos
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Pavel S Rukin
- CNR - Istituto Nanoscienze, Via Campi 213A, I-41125 Modena, Italy
| | - Frank Quintela
- Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Università degli Studi di Modena e Reggio Emilia, via G. Campi 213A, I-41125 Modena, Italy
| | - Mattia Russo
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Luca Moretti
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Ana Moore
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
| | - Thomas Moore
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
| | - Devens Gust
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
| | - Deborah Prezzi
- CNR - Istituto Nanoscienze, Via Campi 213A, I-41125 Modena, Italy
| | - Gregory D Scholes
- Department of Chemistry, Princeton University, Princeton, New Jersey 08540, United States
| | - Elisa Molinari
- CNR - Istituto Nanoscienze, Via Campi 213A, I-41125 Modena, Italy
- Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Università degli Studi di Modena e Reggio Emilia, via G. Campi 213A, I-41125 Modena, Italy
| | - Giulio Cerullo
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Filippo Troiani
- CNR - Istituto Nanoscienze, Via Campi 213A, I-41125 Modena, Italy
| | - Carlo A Rozzi
- CNR - Istituto Nanoscienze, Via Campi 213A, I-41125 Modena, Italy
| | - Margherita Maiuri
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
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2
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Li Y, Castillo HD, Dobscha JR, Morgan AR, Tait SL, Flood AH. Breaking Radial Dipole Symmetry in Planar Macrocycles Modulates Edge-to-Edge Packing and Disrupts Cofacial Stacking. Chemistry 2024; 30:e202302946. [PMID: 37950681 DOI: 10.1002/chem.202302946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 11/07/2023] [Accepted: 11/08/2023] [Indexed: 11/13/2023]
Abstract
Dipolar interactions are ever-present in supramolecular architectures, though their impact is typically revealed by making dipoles stronger. While it is also possible to assess the role of dipoles by altering their orientations by using synthetic design, doing so without altering the molecular shape is not straightforward. We have now done this by flipping one triazole unit in a rigid macrocycle, tricarb. The macrocycle is composed of three carbazoles (2 Debye) and three triazoles (5 Debye) defining an array of dipoles aligned radially but organized alternately in and out. These dipoles are believed to dictate edge-to-edge tiling and face-to-face stacking. We modified our synthesis to prepare isosteric macrocycles with the orientation of one triazole dipole rotated 40°. The new dipole orientation guides edge-to-edge contacts to reorder the stability of two surface-bound 2D polymorphs. The impact on dipole-enhanced π stacking, however, was unexpected. Our stacking model identified an unchanged set of short-range (3.4 Å) anti-parallel dipole contacts. Despite this situation, the reduction in self-association was attributed to long-range (~6.4 Å) dipolar repulsions between π-stacked macrocycles. This work highlights our ability to control the build-up and symmetry of macrocyclic skeletons by synthetic design, and the work needed to further our understanding of how dipoles control self-assembly.
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Affiliation(s)
- Yan Li
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, IN, 47405, USA
| | - Henry D Castillo
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, IN, 47405, USA
| | - James R Dobscha
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, IN, 47405, USA
| | - Amanda R Morgan
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, IN, 47405, USA
| | - Steven L Tait
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, IN, 47405, USA
| | - Amar H Flood
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, IN, 47405, USA
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3
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Han F, Abbas Abedi SA, He S, Zhang H, Long S, Zhou X, Chanmungkalakul S, Ma H, Sun W, Liu X, Du J, Fan J, Peng X. Aryl-Modified Pentamethyl Cyanine Dyes at the C2' Position: A Tunable Platform for Activatable Photosensitizers. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2305761. [PMID: 38063803 PMCID: PMC10870032 DOI: 10.1002/advs.202305761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 11/03/2023] [Indexed: 12/24/2023]
Abstract
Pentamethyl cyanine dyes are promising fluorophores for fluorescence sensing and imaging. However, advanced biomedical applications require enhanced control of their excited-state properties. Herein, a synthetic approach for attaching aryl substituents at the C2' position of the thio-pentamethine cyanine (TCy5) dye structure is reported for the first time. C2'-aryl substitution enables the regulation of both the twisted intramolecular charge transfer (TICT) and photoinduced electron transfer (PET) mechanisms to be regulated in the excited state. Modulation of these mechanisms allows the design of a nitroreductase-activatable TCy5 fluorophore for hypoxic tumor photodynamic therapy and fluorescence imaging. These C2'-aryl TCy5 dyes provide a tunable platform for engineering cyanine dyes tailored to sophisticated biological applications, such as photodynamic therapy.
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Affiliation(s)
- Fuping Han
- State Key Laboratory of Fine ChemicalsFrontiers Science Center for Smart MaterialsDalian University of TechnologyDalian116024China
| | - Syed Ali Abbas Abedi
- Fluorescence Research GroupSingapore University of Technology and DesignSingapore487372Singapore
| | - Shan He
- Department of ChemistryHong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction and Institute for Advanced StudyThe Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina
| | - Han Zhang
- State Key Laboratory of Fine ChemicalsFrontiers Science Center for Smart MaterialsDalian University of TechnologyDalian116024China
| | - Saran Long
- State Key Laboratory of Fine ChemicalsFrontiers Science Center for Smart MaterialsDalian University of TechnologyDalian116024China
| | - Xiao Zhou
- State Key Laboratory of Fine ChemicalsFrontiers Science Center for Smart MaterialsDalian University of TechnologyDalian116024China
| | | | - He Ma
- State Key Laboratory of Fine ChemicalsFrontiers Science Center for Smart MaterialsDalian University of TechnologyDalian116024China
| | - Wen Sun
- State Key Laboratory of Fine ChemicalsFrontiers Science Center for Smart MaterialsDalian University of TechnologyDalian116024China
- Ningbo Institute of Dalian University of TechnologyDalian University of Technology26 Yucai Road, Jiangbei DistrictNingbo315016China
| | - Xiaogang Liu
- Fluorescence Research GroupSingapore University of Technology and DesignSingapore487372Singapore
| | - Jianjun Du
- State Key Laboratory of Fine ChemicalsFrontiers Science Center for Smart MaterialsDalian University of TechnologyDalian116024China
- Ningbo Institute of Dalian University of TechnologyDalian University of Technology26 Yucai Road, Jiangbei DistrictNingbo315016China
| | - Jiangli Fan
- State Key Laboratory of Fine ChemicalsFrontiers Science Center for Smart MaterialsDalian University of TechnologyDalian116024China
- Ningbo Institute of Dalian University of TechnologyDalian University of Technology26 Yucai Road, Jiangbei DistrictNingbo315016China
| | - Xiaojun Peng
- State Key Laboratory of Fine ChemicalsFrontiers Science Center for Smart MaterialsDalian University of TechnologyDalian116024China
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4
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Kim T, Feng Y, O'Connor JP, Stoddart JF, Young RM, Wasielewski MR. Coherent Vibronic Wavepackets Show Structure-Directed Charge Flow in Host-Guest Donor-Acceptor Complexes. J Am Chem Soc 2023. [PMID: 37018535 DOI: 10.1021/jacs.2c13576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
Abstract
Designing and controlling charge transfer (CT) pathways in organic semiconductors are important for solar energy applications. To be useful, a photogenerated, Coulombically bound CT exciton must further separate into free charge carriers; direct observations of the detailed CT relaxation pathways, however, are lacking. Here, photoinduced CT and relaxation dynamics in three host-guest complexes, where a perylene (Per) electron donor guest is incorporated into two symmetric and one asymmetric extended viologen cyclophane acceptor hosts, are presented. The central ring in the extended viologen is either p-phenylene (ExV2+) or electron-rich 2,5-dimethoxy-p-phenylene (ExMeOV2+), resulting in two symmetric cyclophanes with unsubstituted or methoxy-substituted central rings, ExBox4+ and ExMeOBox4+, respectively, and an asymmetric cyclophane with one of the central viologen rings being methoxylated ExMeOVBox4+. Upon photoexcitation, the asymmetric host-guest ExMeOVBox4+ ⊃ Per complex exhibits directional CT toward the energetically unfavorable methoxylated side due to structural restrictions that facilitate strong interactions between the Per donor and the ExMeOV2+ side. The CT state relaxation pathways are probed using ultrafast optical spectroscopy by focusing on coherent vibronic wavepackets, which are used to identify CT relaxations along charge localization and vibronic decoherence coordinates. Specific low- and high-frequency nuclear motions are direct indicators of a delocalized CT state and the degree of CT character. Our results show that the CT pathway can be controlled by subtle chemical modifications of the acceptor host in addition to illustrating how coherent vibronic wavepackets can be used to probe the nature and time evolution of the CT states.
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Affiliation(s)
- Taeyeon Kim
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Yuanning Feng
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - James P O'Connor
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - J Fraser Stoddart
- Stoddart Institute of Molecular Science, Department of Chemistry, Zhejiang University, Hangzhou 310027, China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou 311215, China
- School of Chemistry, University of New South Wales, Sydney, New South Wales 2052, Australia
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Ryan M Young
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Michael R Wasielewski
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
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5
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Kim T, Kim Y, Park S, Park K, Wang Z, Oh SH, Jeong S, Kim D. Shape-Tuned Multiphoton-Emitting InP Nanotetrapods. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2110665. [PMID: 35285555 DOI: 10.1002/adma.202110665] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/19/2022] [Indexed: 06/14/2023]
Abstract
As the properties of a semiconductor material depend on the fate of the excitons, manipulating exciton behavior is the primary objective of nanomaterials. Although nanocrystals exhibit unusual excitonic characteristics owing to strong spatial confinement, studying the interactions between excitons in a single nanoparticle remains challenging due to the rapidly vanishing multiexciton species. Here, a platform for exciton tailoring using a straightforward strategy of shape-tuning of single-crystalline nanocrystals is presented. Spectroscopic and theoretical studies reveal a systematic transition of exciton confinement orientation from 3D to 2D, which is solely tuned by the geometric shape of material. Such a precise shape-effect triggers a multiphoton emission in single nanotetrapods with arms longer than the exciton Bohr radius of material. In consequence, the unique interplay between the multiple quantum states allows a geometric modulation of the quantum-confined Stark effect and nanocrystal memory effect in single nanotetrapods. These results provide a useful metric in designing nanomaterials for future photonic applications.
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Affiliation(s)
- Taehee Kim
- Department of Chemistry, Yonsei University, Seoul, 03722, Republic of Korea
| | - Youngsik Kim
- Department of Energy Science and Center for Artificial Atoms, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Seongmin Park
- Department of Energy Science and Center for Artificial Atoms, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Kyoungwon Park
- Display Research Center, Korea Electronics Technology Institute (KETI), Seongnam, 13509, Republic of Korea
| | - Zhen Wang
- Department of Energy Science and Center for Artificial Atoms, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Sang Ho Oh
- Department of Energy Science and Center for Artificial Atoms, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Sohee Jeong
- Department of Energy Science and Center for Artificial Atoms, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Dongho Kim
- Department of Chemistry, Yonsei University, Seoul, 03722, Republic of Korea
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6
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Accelerating symmetry-breaking charge separation in a perylenediimide trimer through a vibronically coherent dimer intermediate. Nat Chem 2022; 14:786-793. [PMID: 35469005 DOI: 10.1038/s41557-022-00927-y] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 03/10/2022] [Indexed: 11/08/2022]
Abstract
Understanding the photophysics and photochemistry of molecular π-stacked chromophores is important for utilizing them as functional photonic materials. However, these investigations have been mostly limited to covalent molecular dimers, which can only approximate the electronic and vibronic interactions present in the higher oligomers typical of functional organic materials. Here we show that a comparison of the excited-state dynamics of a covalent slip-stacked perylenediimide dimer (2) and trimer (3) provides fundamental insights into electronic state mixing and symmetry-breaking charge separation (SB-CS) beyond the dimer limit. We find that coherent vibronic coupling to high-frequency modes facilitates ultrafast state mixing between the Frenkel exciton (FE) and charge-transfer (CT) states. Subsequently, solvent fluctuations and interchromophore low-frequency vibrations promote CT character in the coherent FE/CT mixed state. The coherent FE/CT mixed state persists in 2, but, in 3, low-frequency vibronic coupling collapses the coherence, resulting in ultrafast SB-CS between the distal perylenediimide units.
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7
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Gole B, Kauffmann B, Tron A, Maurizot V, McClenaghan N, Huc I, Ferrand Y. Selective and Cooperative Photocycloadditions within Multistranded Aromatic Sheets. J Am Chem Soc 2022; 144:6894-6906. [PMID: 35380826 DOI: 10.1021/jacs.2c01269] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
A series of aromatic helix-sheet-helix oligoamide foldamers composed of several different photosensitive diazaanthracene units have been designed and synthesized. Molecular objects up to 7 kDa were straightforwardly produced on a 100 mg scale. Nuclear magnetic resonance and crystallographic investigations revealed that helix-sheet-helix architectures can adopt one or two distinct conformations. Sequences composed of an even number of turn units were found to fold in a canonical symmetrical conformation with two helices of identical handedness stacked above and below the sheet segment. Sequences composed of an odd number of turns revealed a coexistence between a canonical fold with helices of opposite handedness and an alternate fold with a twist within the sheet and two helices of identical handedness. The proportions between these species could be manipulated, in some cases quantitatively, being dependent on solvent, temperature, and absolute control of helix handedness. Diazaanthracene units were shown to display distinct reactivity toward [4 + 4] photocycloadditions according to the substituent in position 9. Their organization within the sequences was programmed to allow photoreactions to take place in a specific order. Reaction pathways and kinetics were deciphered and product characterized, demonstrating the possibility to orchestrate successive photoreactions so as to avoid orphan units or to deliberately produce orphan units at precise locations. Strong cooperative effects were observed in which the photoreaction rate was influenced by the presence (or absence) of photoadducts in the structure. Multiple photoreactions within the aromatic sheet eventually lead to structure lengthening and stiffening, locking conformational equilibria. Photoproducts could be thermally reverted.
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Affiliation(s)
- Bappaditya Gole
- Univ. Bordeaux, CNRS, Bordeaux Institut National Polytechnique, CBMN (UMR 5248), 2 rue Escarpit, 33600 Pessac, France
| | - Brice Kauffmann
- Univ. Bordeaux, CNRS, INSERM, Institut Européen de Chimie Biologie (UMS3033/US001), 2 rue Escarpit, 33600 Pessac, France
| | - Arnaud Tron
- Univ. Bordeaux, CNRS, Institut des Sciences Moléculaires (UMR5255), 351 cours de la Libération, 33405 Talence cedex, France
| | - Victor Maurizot
- Univ. Bordeaux, CNRS, Bordeaux Institut National Polytechnique, CBMN (UMR 5248), 2 rue Escarpit, 33600 Pessac, France
| | - Nathan McClenaghan
- Univ. Bordeaux, CNRS, Institut des Sciences Moléculaires (UMR5255), 351 cours de la Libération, 33405 Talence cedex, France
| | - Ivan Huc
- Department of Pharmacy, Ludwig-Maximilians-University, Butenandtstr. 5-13, 81377 Munich, Germany.,Cluster of Excellence e-Conversion, 85748 Garching, Germany
| | - Yann Ferrand
- Univ. Bordeaux, CNRS, Bordeaux Institut National Polytechnique, CBMN (UMR 5248), 2 rue Escarpit, 33600 Pessac, France
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8
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Hong Y, Kim W, Kim T, Kaufmann C, Kim H, Würthner F, Kim D. Real-time Observation of Structural Dynamics Triggering Excimer Formation in a Perylene Bisimide Folda-dimer by Ultrafast Time-Domain Raman Spectroscopy. Angew Chem Int Ed Engl 2022; 61:e202114474. [PMID: 35075813 PMCID: PMC9306572 DOI: 10.1002/anie.202114474] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Indexed: 01/31/2023]
Abstract
In π‐conjugated organic photovoltaic materials, an excimer state has been generally regarded as a trap state which hinders efficient excitation energy transport. But despite wide investigations of the excimer for overcoming the undesirable energy loss, the understanding of the relationship between the structure of the excimer in stacked organic compounds and its properties remains elusive. Here, we present the landscape of structural dynamics from the excimer formation to its relaxation in a co‐facially stacked archetypical perylene bisimide folda‐dimer using ultrafast time‐domain Raman spectroscopy. We directly captured vibrational snapshots illustrating the ultrafast structural evolution triggering the excimer formation along the interchromophore coordinate on the complex excited‐state potential surfaces and following evolution into a relaxed excimer state. Not only does this work showcase the ultrafast structural dynamics necessary for the excimer formation and control of excimer characteristics but also provides important criteria for designing the π‐conjugated organic molecules.
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Affiliation(s)
- Yongseok Hong
- Department of Chemistry, Spectroscopy Laboratory for Functional π-Electronic Systems, Yonsei University, 03722, Seoul, Republic of Korea
| | - Woojae Kim
- Department of Chemistry, Spectroscopy Laboratory for Functional π-Electronic Systems, Yonsei University, 03722, Seoul, Republic of Korea.,Department of Chemistry and Chemical Biology, Cornell University, Ithaca, 14853, New York, USA
| | - Taeyeon Kim
- Department of Chemistry, Spectroscopy Laboratory for Functional π-Electronic Systems, Yonsei University, 03722, Seoul, Republic of Korea.,The Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, 60208, Illinois, USA
| | - Christina Kaufmann
- Institut für Organische Chemie & Center for Nanosystems Chemistry, Universitat Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Hyungjun Kim
- Department of Chemistry, Incheon National University, 119 Academy-ro, Yeonsu-gu, 22012, Incheon, Republic of Korea
| | - Frank Würthner
- Institut für Organische Chemie & Center for Nanosystems Chemistry, Universitat Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Dongho Kim
- Department of Chemistry, Spectroscopy Laboratory for Functional π-Electronic Systems, Yonsei University, 03722, Seoul, Republic of Korea
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9
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Hong Y, Kim W, Kim T, Kaufmann C, Kim H, Würthner F, Kim D. Real‐time Observation of Structural Dynamics Triggering Excimer Formation in a Perylene Bisimide Folda‐dimer by Ultrafast Time‐Domain Raman Spectroscopy. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202114474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Yongseok Hong
- Department of Chemistry Spectroscopy Laboratory for Functional π-Electronic Systems Yonsei University 03722 Seoul Republic of Korea
| | - Woojae Kim
- Department of Chemistry Spectroscopy Laboratory for Functional π-Electronic Systems Yonsei University 03722 Seoul Republic of Korea
- Department of Chemistry and Chemical Biology Cornell University Ithaca 14853 New York USA
| | - Taeyeon Kim
- Department of Chemistry Spectroscopy Laboratory for Functional π-Electronic Systems Yonsei University 03722 Seoul Republic of Korea
- The Institute for Sustainability and Energy at Northwestern Northwestern University Evanston 60208 Illinois USA
| | - Christina Kaufmann
- Institut für Organische Chemie & Center for Nanosystems Chemistry Universitat Würzburg Am Hubland 97074 Würzburg Germany
| | - Hyungjun Kim
- Department of Chemistry Incheon National University 119 Academy-ro, Yeonsu-gu 22012 Incheon Republic of Korea
| | - Frank Würthner
- Institut für Organische Chemie & Center for Nanosystems Chemistry Universitat Würzburg Am Hubland 97074 Würzburg Germany
| | - Dongho Kim
- Department of Chemistry Spectroscopy Laboratory for Functional π-Electronic Systems Yonsei University 03722 Seoul Republic of Korea
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10
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Folding‐induced Fluorescence Enhancement in a Series of Merocyanine Hetero‐Folda‐Trimers. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202114667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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11
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Schulz A, Würthner F. Folding-induced Fluorescence Enhancement in a Series of Merocyanine Hetero-Folda-Trimers. Angew Chem Int Ed Engl 2021; 61:e202114667. [PMID: 34784435 PMCID: PMC9299730 DOI: 10.1002/anie.202114667] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Indexed: 12/12/2022]
Abstract
Many dyes suffer from fast non-radiative decay pathways, thereby showing only short-lived excited states and weak photoluminescence. Here we show a pronounced fluorescence enhancement for a weakly fluorescent merocyanine (MC) dye by being co-facially stacked to other dyes in hetero-folda-trimer architectures. By means of fluorescence spectroscopy (lifetime, quantum yield) the fluorescence enhancement was explained by the rigidification of the emitting chromophore in the defined foldamer architecture and the presence of a non-forbidden lowest exciton state in H-coupled hetero-aggregates. This folding-induced fluorescence enhancement (FIFE) for specific sequences of π-stacked dyes points at a viable strategy toward improved fluorophores that relates to the approach used by nature in the green fluorescent protein (GFP).
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Affiliation(s)
- Alexander Schulz
- Institut für Organische Chemie and Center for Nanosystems Chemistry, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Frank Würthner
- Institut für Organische Chemie and Center for Nanosystems Chemistry, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
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12
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Vonhausen Y, Lohr A, Stolte M, Würthner F. Two-step anti-cooperative self-assembly process into defined π-stacked dye oligomers: insights into aggregation-induced enhanced emission. Chem Sci 2021; 12:12302-12314. [PMID: 34603660 PMCID: PMC8480337 DOI: 10.1039/d1sc03813c] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 08/17/2021] [Indexed: 12/24/2022] Open
Abstract
Aggregation-induced emission enhancement (AIEE) phenomena received great popularity during the last decade but in most cases insights into the packing structure – fluorescence properties remained scarce. Here, an almost non-fluorescent merocyanine dye was equipped with large solubilizing substituents, which allowed the investigation of it's aggregation behaviour in unpolar solvents over a large concentration range (10−2 to 10−7 M). In depth analysis of the self-assembly process by concentration-dependent UV/Vis spectroscopy at different temperatures revealed a two-step anti-cooperative aggregation mechanism. In the first step a co-facially stacked dimer is formed driven by dipole–dipole interactions. In a second step these dimers self-assemble to give an oligomer stack consisting of about ten dyes. Concentration- and temperature-dependent UV/Vis spectroscopy provided insight into the thermodynamic parameters and allowed to identify conditions where either the monomer, the dimer or the decamer prevails. The centrosymmetric dimer structure could be proven by 2D NMR spectroscopy. For the larger decamer atomic force microscopy (AFM), diffusion ordered spectroscopy (DOSY) and vapour pressure osmometric (VPO) measurements consistently indicated that it is of small and defined size. Fluorescence, circular dichroism (CD) and circularly polarized luminescence (CPL) spectroscopy provided insights into the photofunctional properties of the dye aggregates. Starting from an essentially non-fluorescent monomer (ΦFl = 0.23%) a strong AIEE effect with excimer-type fluorescence (large Stokes shift, increased fluorescence lifetime) is observed upon formation of the dimer (ΦFl = 2.3%) and decamer (ΦFl = 4.5%) stack. This increase in fluorescence is accompanied for both aggregates by an aggregation-induced CPL enhancement with a strong increase of the glum from ∼0.001 for the dimer up to ∼0.011 for the higher aggregate. Analysis of the radiative and non-radiative decay rates corroborates the interpretation that the AIEE effect originates from a pronounced decrease of the non-radiative rate due to π–π-stacking induced rigidification that outmatches the effect of the reduced radiative rate that originates from the H-type exciton coupling in the co-facially stacked dyes. The self-assembly of a dipolar merocyanine into preferred dimers and small-sized chiral aggregates leads to enhanced emission due to a reduced non-radiative rate as well as amplified circular polarized luminescence.![]()
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Affiliation(s)
- Yvonne Vonhausen
- Institut für Organische Chemie, Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Andreas Lohr
- Institut für Organische Chemie, Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Matthias Stolte
- Institut für Organische Chemie, Universität Würzburg Am Hubland 97074 Würzburg Germany .,Center for Nanosystems Chemistry (CNC), Bavarian Polymer Institute (BPI), Universität Würzburg Theodor-Boveri-Weg 97074 Würzburg Germany
| | - Frank Würthner
- Institut für Organische Chemie, Universität Würzburg Am Hubland 97074 Würzburg Germany .,Center for Nanosystems Chemistry (CNC), Bavarian Polymer Institute (BPI), Universität Würzburg Theodor-Boveri-Weg 97074 Würzburg Germany
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13
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Kang S, Kim T, Hong Y, Würthner F, Kim D. Charge-Delocalized State and Coherent Vibrational Dynamics in Rigid PBI H-Aggregates. J Am Chem Soc 2021; 143:9825-9833. [PMID: 34165972 DOI: 10.1021/jacs.1c03276] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Herein, the ultrafast photoinduced dynamics and vibrational coherences for two perylenebisimide (PBI) H-aggregates showcase the formation of the excimer state and the delocalized radical anion state in the excited state, respectively. Using femtosecond transient absorption (fs-TA) and time-resolved impulsive stimulated Raman scattering (TR-ISRS) measurements, we unveiled excited-state dynamics of PBI H-aggregates in two aspects: (1) the intermolecular interactions between PBI units in H-aggregates induce the formation of new excited states, excimer and delocalized radical anion states, and (2) the intermolecular out-of-plane along the aggregate axis and the PBI core C═C stretch Raman modes can be a crucial indicator to understand the coherent exciton dynamics in H-aggregates. Notably, those excited-state Raman modes showed stationary peak positions during the excited-state dynamics. TR-ISRS analysis provides insights into the excited-state vibrational coherences concerning the formation of the excimer and charge-delocalized state in each aggregate system.
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Affiliation(s)
- Seongsoo Kang
- Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University, Seoul 03722, South Korea
| | - Taeyeon Kim
- Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University, Seoul 03722, South Korea
| | - Yongseok Hong
- Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University, Seoul 03722, South Korea
| | - Frank Würthner
- Institut for Organische Chemie and Center for Nanosystems Chemistry, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Dongho Kim
- Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University, Seoul 03722, South Korea
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14
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Hu X, Schulz A, Lindner JO, Grüne M, Bialas D, Würthner F. Folding and fluorescence enhancement with strong odd-even effect for a series of merocyanine dye oligomers. Chem Sci 2021; 12:8342-8352. [PMID: 34221315 PMCID: PMC8221066 DOI: 10.1039/d1sc01678d] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
A series of merocyanine (MC) oligomers with a varying number of chromophores from two to six has been synthesized via a peptide synthesis strategy. Solvent-dependent UV/vis spectroscopic studies reveal folding processes for the MC oligomers driven by strong dipole–dipole interactions resulting in well-defined π-stacks with antiparallel orientation of the dyes. Whilst even-numbered tetramer 4 and hexamer 6 only show partial folding into dimeric units, odd-numbered trimer 3 and pentamer 5 fold into π-stacks of three and five MC units upon decreasing solvent polarity. In-depth 2D NMR studies provided insight into the supramolecular structure. For trimer 3, an NMR structure could be generated revealing the presence of a well-defined triple π-stack in the folded state. Concomitant with folding, the fluorescence quantum yield is increased for all MC oligomers in comparison to the single chromophore. Based on radiative and non-radiative decay rates, this fluorescence enhancement can be attributed to the rigidification of the chromophores within the π-stacks that affords a pronounced decrease of the non-radiative decay rates. Theoretical investigations for the double and triple dye stacks based on time-dependent density functional theory (TD-DFT) calculations indicate for trimer 3 a pronounced mixing of Frenkel and charge transfer (CT) states. This leads to significant deviations from the predictions obtained by the molecular exciton theory which only accounts for the Coulomb interaction between the transition dipole moments of the chromophores. A series of merocyanine (MC) oligomers with a varying number of chromophores from two to six has been synthesized via a peptide synthesis strategy.![]()
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Affiliation(s)
- Xiaobo Hu
- Institut für Organische Chemie, Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Alexander Schulz
- Institut für Organische Chemie, Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Joachim O Lindner
- Center for Nanosystems Chemistry (CNC), Universität Würzburg Theodor-Boveri-Weg 97074 Würzburg Germany
| | - Matthias Grüne
- Institut für Organische Chemie, Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - David Bialas
- Center for Nanosystems Chemistry (CNC), Universität Würzburg Theodor-Boveri-Weg 97074 Würzburg Germany
| | - Frank Würthner
- Institut für Organische Chemie, Universität Würzburg Am Hubland 97074 Würzburg Germany.,Center for Nanosystems Chemistry (CNC), Universität Würzburg Theodor-Boveri-Weg 97074 Würzburg Germany
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15
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Bialas D, Kirchner E, Röhr MIS, Würthner F. Perspectives in Dye Chemistry: A Rational Approach toward Functional Materials by Understanding the Aggregate State. J Am Chem Soc 2021; 143:4500-4518. [DOI: 10.1021/jacs.0c13245] [Citation(s) in RCA: 87] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- David Bialas
- Center for Nanosystems Chemistry, Universität Würzburg, Theodor-Boveri-Weg, 97074 Würzburg, Germany
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Eva Kirchner
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Merle I. S. Röhr
- Center for Nanosystems Chemistry, Universität Würzburg, Theodor-Boveri-Weg, 97074 Würzburg, Germany
| | - Frank Würthner
- Center for Nanosystems Chemistry, Universität Würzburg, Theodor-Boveri-Weg, 97074 Würzburg, Germany
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
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