1
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Balanikas E, Reymond-Joubin M, Vauthey E. Excited-State Symmetry Breaking in Solvent Mixtures. J Phys Chem Lett 2024; 15:2447-2452. [PMID: 38407054 DOI: 10.1021/acs.jpclett.4c00213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
A large number of multipolar dyes undergo excited-state symmetry breaking (ESSB) in polar media. During this process, electronic excitation, initially distributed evenly over the molecule, localizes, at least partially, on one donor-acceptor branch. To resolve its initial stage, ESSB is investigated with a donor-acceptor-donor dye in binary mixtures of nonpolar and polar solvents using time-resolved infrared absorption spectroscopy. The presence of a few polar molecules around the dye is sufficient to initiate ESSB. Although the extent of asymmetry in a mixture is close to that in a pure solvent of similar polarity, the dynamics are slower and involve translational diffusion. However, preferential solvation in the mixtures leads to a larger local polarity. Furthermore, inhomogeneous broadening of the S1 ← S0 absorption band of the dye is observed in the mixtures, allowing for a photoselection of solutes with different local environments and ESSB dynamics.
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Affiliation(s)
- Evangelos Balanikas
- Department of Physical Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Maric Reymond-Joubin
- Department of Physical Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Eric Vauthey
- Department of Physical Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
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2
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Clark JA, Kusy D, Vakuliuk O, Krzeszewski M, Kochanowski KJ, Koszarna B, O'Mari O, Jacquemin D, Gryko DT, Vullev VI. The magic of biaryl linkers: the electronic coupling through them defines the propensity for excited-state symmetry breaking in quadrupolar acceptor-donor-acceptor fluorophores. Chem Sci 2023; 14:13537-13550. [PMID: 38033901 PMCID: PMC10685337 DOI: 10.1039/d3sc03812b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Accepted: 11/04/2023] [Indexed: 12/02/2023] Open
Abstract
Charge transfer (CT) is key for molecular photonics, governing the optical properties of chromophores comprising electron-rich and electron-deficient components. In photoexcited dyes with an acceptor-donor-acceptor or donor-acceptor-donor architecture, CT breaks their quadrupolar symmetry and yields dipolar structures manifesting pronounced solvatochromism. Herein, we explore the effects of electronic coupling through biaryl linkers on the excited-state symmetry breaking of such hybrid dyes composed of an electron-rich core, i.e., 1,4-dihydropyrrolo[3,2-b]pyrrole (DHPP), and pyrene substituents that can act as electron acceptors. Experimental and theoretical studies reveal that strengthening the donor-acceptor electronic coupling decreases the CT rates and the propensity for symmetry breaking. We ascribe this unexpected result to effects of electronic coupling on the CT thermodynamics, which in its turn affects the CT kinetics. In cases of intermediate electronic coupling, the pyrene-DHPP conjugates produce fluorescence spectra, spreading over the whole visible range, that in addition to the broad CT emission, show bands from the radiative deactivation of the locally excited states of the donor and the acceptors. Because the radiative deactivation of the low-lying CT states is distinctly slow, fluorescence from upper locally excited states emerge leading to the observed anti-Kasha behaviour. As a result, these dyes exhibit white fluorescence. In addition to demonstrating the multifaceted nature of the effects of electronic coupling on CT dynamics, these chromophores can act as broad-band light sources with practical importance for imaging and photonics.
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Affiliation(s)
- John A Clark
- Department of Bioengineering, University of California Riverside, 900 University Ave. Riverside CA 92521 USA
| | - Damian Kusy
- Institute of Organic Chemistry, Polish Academy of Sciences Kasprzaka 44-52 01-224 Warsaw Poland
| | - Olena Vakuliuk
- Institute of Organic Chemistry, Polish Academy of Sciences Kasprzaka 44-52 01-224 Warsaw Poland
| | - Maciej Krzeszewski
- Institute of Organic Chemistry, Polish Academy of Sciences Kasprzaka 44-52 01-224 Warsaw Poland
| | - Krzysztof J Kochanowski
- Institute of Organic Chemistry, Polish Academy of Sciences Kasprzaka 44-52 01-224 Warsaw Poland
| | - Beata Koszarna
- Institute of Organic Chemistry, Polish Academy of Sciences Kasprzaka 44-52 01-224 Warsaw Poland
| | - Omar O'Mari
- Department of Bioengineering, University of California Riverside, 900 University Ave. Riverside CA 92521 USA
| | - Denis Jacquemin
- Nantes Université, CNRS CEISAM UMR 6230 F-44000 Nantes France
- Institut Universitaire de France (IUF) F-75005 Paris France
| | - Daniel T Gryko
- Institute of Organic Chemistry, Polish Academy of Sciences Kasprzaka 44-52 01-224 Warsaw Poland
| | - Valentine I Vullev
- Department of Bioengineering, University of California Riverside, 900 University Ave. Riverside CA 92521 USA
- Department of Chemistry, University of California Riverside CA 92521 USA
- Department of Biochemistry, University of California Riverside CA 92521 USA
- Materials Science and Engineering Program, University of California Riverside CA 92521 USA
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3
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Verma P, Tasior M, Roy P, Meech SR, Gryko DT, Vauthey E. Excited-state symmetry breaking in quadrupolar pull-push-pull molecules: dicyanovinyl vs. cyanophenyl acceptors. Phys Chem Chem Phys 2023; 25:22689-22699. [PMID: 37602791 PMCID: PMC10467566 DOI: 10.1039/d3cp02810k] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 08/02/2023] [Indexed: 08/22/2023]
Abstract
A significant number of quadrupolar dyes behave as their dipolar analogues when photoexcited in polar environments. This is due to the occurrence of excited-state symmetry breaking (ES-SB), upon which the electronic excitation, initially distributed over the whole molecule, localises preferentially on one side. Here, we investigate the ES-SB properties of two A-D-A dyes, consisting of a pyrrolo-pyrrole donor (D) and either cyanophenyl or dicyanovinyl acceptors (A). For this, we use time-resolved vibrational spectroscopy, comparing IR absorption and femtosecond stimulated Raman spectroscopies. Although dicyanovinyl is a stronger electron-withdrawing group, ES-SB is not observed with the dicyanovinyl-based dye even in highly polar media, whereas it already takes place in weakly polar solvents with dyes containing cyanophenyl accepting groups. This difference is attributed to the large electronic coupling between the D-A branches in the former dye, whose loss upon symmetry breaking cannot be counterbalanced by a gain in solvation energy. Comparison with analogues of the cyanophenyl-based dye containing different spacers reveals that interbranch coupling does not so much depend on the distance between the D-A subunits than on the nature of the spacer. We show that transient Raman spectra probe different modes of these centrosymmetric molecules but are consistent with the transient IR data. However, lifetime broadening of the Raman bands, probably due to the resonance enhancement, may limit the application of this technique for monitoring ES-SB.
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Affiliation(s)
- Pragya Verma
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, CH-1211, Geneva 4, Switzerland.
| | - Mariusz Tasior
- Institute of Organic Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Poland
| | - Palas Roy
- School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Stephen R Meech
- School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Daniel T Gryko
- Institute of Organic Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Poland
| | - Eric Vauthey
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, CH-1211, Geneva 4, Switzerland.
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4
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Stark CW, Rammo M, Trummal A, Uudsemaa M, Pahapill J, Sildoja MM, Tshepelevitsh S, Leito I, Young DC, Szymański B, Vakuliuk O, Gryko DT, Rebane A. On-off-on Control of Molecular Inversion Symmetry via Multi-stage Protonation: Elucidating Vibronic Laporte Rule. Angew Chem Int Ed Engl 2022; 61:e202212581. [PMID: 36286343 DOI: 10.1002/anie.202212581] [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: 08/25/2022] [Indexed: 11/07/2022]
Abstract
The Laporte rule dictates that one- and two-photon absorption spectra of inversion-symmetric molecules should display alternatively forbidden electronic transitions; however, for organic fluorophores, drawing clear distinction between the symmetric- and non-inversion symmetric two-photon spectra is often obscured due to prevalent vibronic interactions. We take advantage of consecutive single- and double-protonation to break and then reconstitute inversion symmetry in a nominally symmetric diketopyrrolopyrrole, causing large changes in two-photon absorption. By performing detailed one- and two-photon titration experiments, with supporting quantum-chemical model calculations, we explain how certain low-frequency vibrational modes may lead to apparent deviations from the strict Laporte rule. As a result, the system may be indeed considered as an on-off-on inversion symmetry switch, opening new avenues for two-photon sensing applications.
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Affiliation(s)
- Charles W Stark
- Laboratory of Chemical Physics, Keemilise ja Bioloogilise Füüsika Instituut, Akadeemia tee 23, 12618, Tallinn, Estonia
| | - Matt Rammo
- Laboratory of Chemical Physics, Keemilise ja Bioloogilise Füüsika Instituut, Akadeemia tee 23, 12618, Tallinn, Estonia
| | - Aleksander Trummal
- Laboratory of Chemical Physics, Keemilise ja Bioloogilise Füüsika Instituut, Akadeemia tee 23, 12618, Tallinn, Estonia
| | - Merle Uudsemaa
- Laboratory of Chemical Physics, Keemilise ja Bioloogilise Füüsika Instituut, Akadeemia tee 23, 12618, Tallinn, Estonia
| | - Juri Pahapill
- Laboratory of Chemical Physics, Keemilise ja Bioloogilise Füüsika Instituut, Akadeemia tee 23, 12618, Tallinn, Estonia
| | - Meelis-Mait Sildoja
- Laboratory of Chemical Physics, Keemilise ja Bioloogilise Füüsika Instituut, Akadeemia tee 23, 12618, Tallinn, Estonia
| | - Sofja Tshepelevitsh
- Institute of Chemistry, Tartu Ülikool, 14a Ravila Str, 50411, Tartu, Estonia
| | - Ivo Leito
- Institute of Chemistry, Tartu Ülikool, 14a Ravila Str, 50411, Tartu, Estonia
| | - David C Young
- Instytut Chemii Organicznej, Polska Akademia Nauk, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Bartosz Szymański
- Instytut Chemii Organicznej, Polska Akademia Nauk, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Olena Vakuliuk
- Instytut Chemii Organicznej, Polska Akademia Nauk, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Daniel T Gryko
- Instytut Chemii Organicznej, Polska Akademia Nauk, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Aleksander Rebane
- Laboratory of Chemical Physics, Keemilise ja Bioloogilise Füüsika Instituut, Akadeemia tee 23, 12618, Tallinn, Estonia.,Department of Physics, Montana State University, 264 EPS, Bozeman, MT, 59717, USA
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5
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Fakis M, Petropoulos V, Hrobárik P, Nociarová J, Osuský P, Maiuri M, Cerullo G. Exploring Solvent and Substituent Effects on the Excited State Dynamics and Symmetry Breaking of Quadrupolar Triarylamine End-Capped Benzothiazole Chromophores by Femtosecond Spectroscopy. J Phys Chem B 2022; 126:8532-8543. [PMID: 36256786 DOI: 10.1021/acs.jpcb.2c03103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We investigate herein the excited state dynamics and symmetry breaking processes in three benzothiazole-derived two-photon absorbing chromophores by femtosecond fluorescence and transient absorption (fs-TA) spectroscopies in solvents of various polarity. The chromophores feature a quasi-quadrupolar D-π-A-π-D architecture comprised of an electron-withdrawing benzothiazole core and lateral triphenylamine donors (Qbtz-H), while the acceptor strength of the central unit is enforced by attached cyano groups (Qbtz-CN) and the electron-donating strength of the arylamine moieties by introduction of peripheral methoxy groups (Qbtz'-CN). Steady state spectroscopy reveals positive solvatochromism, which is mostly pronounced for Qbtz'-CN. Femtosecond spectroscopy of Qbtz-H reveals the coexistence of the Franck-Condon (FC) state and states populated after symmetry breaking (SB) in low-polarity solvents such as toluene and tetrahydrofuran, while the SB state becomes favorable in polar acetonitrile. For the other two molecules possessing a stronger electron-accepting unit and thus more polar excited state, SB takes place even in low-polarity solvents, as shown by fs-TA spectroscopy. Global fitting of the fs-TA spectra together with investigation of the evolution associated spectra (EAS) reveals the existence of an initial FC state in Qbtz-H, in all studied solvents, which relaxes toward Intermediate Charge Transfer (I-CT) and SB states. On the other hand, for Qbtz-CN and Qbtz'-CN in more polar solvents, the FC state undergoes ultrafast relaxation toward symmetry-broken charge transfer (SB-CT) states which in turn show very fast recombination to the ground state. Our measurements confirm that the extent of symmetry breaking is larger for D-π-A-π-D systems with the stronger acceptor core and increases further by increasing electron-donating strength of triarylamine moieties, giving rise to symmetry breaking in these nonionic quadrupolar molecules with ethynylene (triple bond) π-spacers also in less polar solvents.
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Affiliation(s)
- Mihalis Fakis
- Department of Physics, University of Patras, PatrasGR-26500, Greece
| | - Vasilis Petropoulos
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133Milan, Italy
| | - Peter Hrobárik
- Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, Ilkovičova 6, SK-84215Bratislava, Slovakia
| | - Jela Nociarová
- Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, Ilkovičova 6, SK-84215Bratislava, Slovakia
| | - Patrik Osuský
- Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, Ilkovičova 6, SK-84215Bratislava, Slovakia
| | - Margherita Maiuri
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133Milan, Italy
| | - Giulio Cerullo
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133Milan, Italy
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6
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Kowalczyk P, Tasior M, Ozaki S, Kamada K, Gryko DT. From 2,5-Diformyl-1,4-dihydropyrrolo[3,2- b]pyrroles to Quadrupolar, Centrosymmetric Two-Photon-Absorbing A-D-A Dyes. Org Lett 2022; 24:2551-2555. [PMID: 35343707 PMCID: PMC9003575 DOI: 10.1021/acs.orglett.2c00718] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
![]()
An original approach
has been developed for the insertion of formyl
substituents at positions 2 and 5 of 1,4-dihydropyrrolo[3,2-b]pyrroles by conversion of thiazol-2-yl substituents. The
synthetic utility of these formyl groups was investigated, and a series
of centrosymmetric A−π–D−π–A
frameworks were constructed. The two-photon absorption of the quadrupolar
pyrrolo[3,2-b]pyrrole possessing two dicyanovinylidene
flanking groups is attributed to an S0 → (S1) → S4 transition which has a large TPA
cross-section (1300 GM) for a molecule of this size.
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Affiliation(s)
- Paweł Kowalczyk
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Mariusz Tasior
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Shuhei Ozaki
- NMRI, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka 563-8577, Japan.,Department of Chemistry, Graduate School of Science and Technology, Kwansei Gakuin University, Sanda 669-1337, Japan
| | - Kenji Kamada
- NMRI, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka 563-8577, Japan.,Department of Chemistry, Graduate School of Science and Technology, Kwansei Gakuin University, Sanda 669-1337, Japan
| | - Daniel T Gryko
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
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7
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Vauthey E. Watching Excited-State Symmetry Breaking in Multibranched Push-Pull Molecules. J Phys Chem Lett 2022; 13:2064-2071. [PMID: 35212550 DOI: 10.1021/acs.jpclett.2c00259] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The emissive properties of symmetric molecules containing several donor-acceptor branches are often similar to those of the single-branched analogues. This is due to the at least partial localization of the excitation on one branch. Detailed understanding of this excited-state symmetry breaking (ES-SB) requires the ability to monitor this process in real time. Over the past few years, several spectroscopic approaches were shown to enable visualization of ES-SB and of its dynamics. They include the detection of new vibrational or electronic absorption bands associated with transitions that are forbidden in the symmetric excited state. Alternatively, ES-SB can be detected by observing transitions that become weaker or vanish upon localization of the excitation. Herein, we discuss these different approaches as well as their merits and weaknesses.
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Affiliation(s)
- Eric Vauthey
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, CH-1211 Geneva, Switzerland
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8
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Cesaretti A, Spalletti A, Elisei F, Foggi P, Germani R, Fortuna CG, Carlotti B. The role of twisting in driving excited-state symmetry breaking and enhanced two-photon absorption in quadrupolar cationic pyridinium derivatives. Phys Chem Chem Phys 2021; 23:16739-16753. [PMID: 34318828 DOI: 10.1039/d1cp01888d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Two symmetric quadrupolar cationic push-pull compounds with a central electron-acceptor (N+-methylpyrydinium, A+) and different lateral electron-donors, (N,N-dimethylamino and N,N-diphenylamino, D) in a D-π-A+-π-D arrangement, were investigated together with their dipolar counterparts (D-π-A+) for their excited-state dynamics and NLO properties. As for the quadrupolar compounds, attention was focused on excited-state symmetry breaking (ESSB), which leads to a relaxed dipolar excited state. Both electron charge displacements and structural rearrangements were recognized in the excited-state dynamics of these molecules by resorting to femtosecond-resolved broadband fluorescence up-conversion experiments and advanced data analysis, used as a valuable alternative approach for fluorescent molecules compared to time-resolved IR spectroscopy, only suitable for compounds bearing IR markers. Specifically, intramolecular charge transfer (ICT) was found to be guided by ultrafast inertial solvation, while diffusive solvation can drive the twisting of lateral groups to originate twisted-ICT (TICT) states on a picosecond time scale. Yet still, only the bis-N,N-diphenylamino-substituted compound undergoes ESSB, in both highly and sparingly polar solvents, provided that it can experience large amplitude motions to a fully symmetry-broken TICT state. Besides well-known solvation effects, this structural requirement proved to be a necessary condition for these quadrupolar cations to undergo ESSB. In fact, a more efficient uncoupling between the out-of-plane D and A+ groups in the TICT state allows a greater stabilization gained through solvation, relative to the bis-N,N-dimethylamino-substituted derivative, which instead maintains its symmetry. This different behavior parallels the two-photon absorption (TPA) ability, which is greatly enhanced in the case of the bis-N,N-diphenylamino-substituted compound, paving the way for cutting-edge bio-imaging applications.
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Affiliation(s)
- Alessio Cesaretti
- Department of Chemistry, Biology and Biotechnology and Centro di Eccellenza sui Materiali Innovativi Nanostrutturati (CEMIN) University of Perugia, via Elce di Sotto 8, 06123 Perugia, Italy.
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9
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Abstract
Excited-state symmetry breaking (ES-SB) is common to a large number of multibranched electron donor-acceptor (DA) molecules in polar environments. During this process, the electronic excitation, originally evenly distributed over the molecule, localizes, at least partially, on one branch. Due to the absence of an unambiguous spectroscopic signature in the UV-vis region, electronic transient absorption (TA) has not been the method of choice for real-time observation of this phenomenon. Herein, we demonstrate that the Laporte rule, which states that one-photon transitions conserving parity are forbidden in centrosymmetric molecules, provides such clear signature of ES-SB in electronic TA spectroscopy. Using a dicyanoanthracene-based D-A-D dye, we show that transitions from the S1 state of this molecule, which are initially Laporte forbidden, become allowed upon ES-SB. This leads to the rise of new TA bands, whose intensity provides a direct measure of the extent of asymmetry in the excited state.
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Affiliation(s)
- Zoltán Szakács
- Department of Physical Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Eric Vauthey
- Department of Physical Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
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10
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Szakács Z, Glöcklhofer F, Plasser F, Vauthey E. Excited-state symmetry breaking in 9,10-dicyanoanthracene-based quadrupolar molecules: the effect of donor-acceptor branch length. Phys Chem Chem Phys 2021; 23:15150-15158. [PMID: 34259270 PMCID: PMC8294646 DOI: 10.1039/d1cp02376d] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Excited-state symmetry breaking is investigated in a series of symmetric 9,10-dicyanoanthracenes linked to electron-donating groups on the 2 and 6 positions via different spacers, allowing for a tuning of the length of the donor–acceptor branches. The excited-state properties of these compounds are compared with their dipolar single-branch analogues. The changes in electronic structure upon their optical excitation are monitored by transient electronic spectroscopy in the visible and near-infrared regions as well as by transient vibrational spectroscopy in the mid-infrared. Our results reveal that, with the shortest branches, electronic excitation remains distributed almost symmetrically over the molecule even in polar environments. Upon increasing the donor–acceptor distance, excitation becomes unevenly distributed and, with the longest one, it fully localises on one branch in polar solvents. The influence of the branch length on the propensity of quadrupolar dyes to undergo excited-state symmetry breaking is rationalised in terms of the balance between interbranch coupling and solvation energy. Excited-state symmetry breaking in quadrupolar molecules depends on the balance between inter-branch coupling and polar solvation energy.![]()
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Affiliation(s)
- Zoltán Szakács
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest Ansermet, Geneva, Switzerland.
| | - Florian Glöcklhofer
- Department of Chemistry and Centre for Processable Electronics, Imperial College London, Molecular Sciences Research Hub, 80 Wood Lane, London, W12 0BZ, UK
| | - Felix Plasser
- Department of Chemistry, Loughborough University, Loughborough, LE11 3TU, UK
| | - Eric Vauthey
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest Ansermet, Geneva, Switzerland.
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11
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Poronik YM, Baryshnikov GV, Deperasińska I, Espinoza EM, Clark JA, Ågren H, Gryko DT, Vullev VI. Deciphering the unusual fluorescence in weakly coupled bis-nitro-pyrrolo[3,2-b]pyrroles. Commun Chem 2020; 3:190. [PMID: 36703353 PMCID: PMC9814504 DOI: 10.1038/s42004-020-00434-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 11/13/2020] [Indexed: 01/29/2023] Open
Abstract
Electron-deficient π-conjugated functional dyes lie at the heart of organic optoelectronics. Adding nitro groups to aromatic compounds usually quenches their fluorescence via inter-system crossing (ISC) or internal conversion (IC). While strong electronic coupling of the nitro groups with the dyes ensures the benefits from these electron-withdrawing substituents, it also leads to fluorescence quenching. Here, we demonstrate how such electronic coupling affects the photophysics of acceptor-donor-acceptor fluorescent dyes, with nitrophenyl acceptors and a pyrrolo[3,2-b]pyrrole donor. The position of the nitro groups and the donor-acceptor distance strongly affect the fluorescence properties of the bis-nitrotetraphenylpyrrolopyrroles. Concurrently, increasing solvent polarity quenches the emission that recovers upon solidifying the media. Intramolecular charge transfer (CT) and molecular dynamics, therefore, govern the fluorescence of these nitro-aromatics. While balanced donor-acceptor coupling ensures fast radiative deactivation and slow ISC essential for large fluorescence quantum yields, vibronic borrowing accounts for medium dependent IC via back CT. These mechanistic paradigms set important design principles for molecular photonics and electronics.
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Affiliation(s)
- Yevgen M. Poronik
- grid.413454.30000 0001 1958 0162Institute of Organic Chemistry, Polish Academy of Sciences, Warsaw, Poland
| | - Glib V. Baryshnikov
- grid.8993.b0000 0004 1936 9457Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
| | - Irena Deperasińska
- grid.413454.30000 0001 1958 0162Institute of Physics, Polish Academy of Sciences, Warsaw, Poland
| | - Eli M. Espinoza
- grid.266097.c0000 0001 2222 1582Department of Chemistry, University of California, Riverside, CA USA ,grid.47840.3f0000 0001 2181 7878Present Address: College of Bioengineering, University of California, Berkeley, CA 94720 USA
| | - John A. Clark
- grid.266097.c0000 0001 2222 1582Department of Bioengineering, University of California, Riverside, CA USA
| | - Hans Ågren
- grid.8993.b0000 0004 1936 9457Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden ,grid.77602.340000 0001 1088 3909Department of Physics, Tomsk State University, 36 Lenin Avenue, Tomsk, 634050 Russian Federation
| | - Daniel T. Gryko
- grid.413454.30000 0001 1958 0162Institute of Organic Chemistry, Polish Academy of Sciences, Warsaw, Poland
| | - Valentine I. Vullev
- grid.266097.c0000 0001 2222 1582Department of Chemistry, University of California, Riverside, CA USA ,grid.266097.c0000 0001 2222 1582Department of Bioengineering, University of California, Riverside, CA USA ,grid.266097.c0000 0001 2222 1582Department of Biochemistry, University of California, Riverside, CA USA ,grid.266097.c0000 0001 2222 1582Materials Science and Engineering Program, University of California, Riverside, CA USA
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12
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Chen MC, Chen DG, Chou PT. Fluorescent Chromophores Containing the Nitro Group: Relatively Unexplored Emissive Properties. Chempluschem 2020; 86:11-27. [PMID: 33094565 DOI: 10.1002/cplu.202000592] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/05/2020] [Indexed: 12/13/2022]
Abstract
Apart from numerous applications, for example in azo dye precursors, explosives, and industrial processes, the nitro group (-NO2 ) appears on countless molecules in photochemical research owing to its unique characteristics such as a strong electron-withdrawing ability and facile conversion to the reduced substituent. Although it is well known as a fluorescence quencher, fluorescent chromophores that contain the nitro group have also emerged, with 3-nitrophenothiazine being recently reported to have 100 % emission quantum yield in nonpolar solvents. The diverse characters of nitro-containing chromophores motivated us to systematically review those chromophores with nitro substituents, their associated photophysical properties, and applications. In this Review, we succinctly elaborate the advance of the fluorescent nitro chromophores in fields of intramolecular charge transfer, fluorescent probes and nonlinear properties. Special attention is paid to the rationalization of the associated emission spectroscopy, so that the readers can gain insights into the structure-photophysics relationship and hence gain insights for the strategic design of nitro chromophores.
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Affiliation(s)
- Meng-Chi Chen
- Department of Chemistry, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei, 10617, Taiwan
| | - Deng-Gao Chen
- Department of Chemistry, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei, 10617, Taiwan
| | - Pi-Tai Chou
- Department of Chemistry, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei, 10617, Taiwan
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Szakács Z, Tasior M, Gryko DT, Vauthey E. Change of Quadrupole Moment upon Excitation and Symmetry Breaking in Multibranched Donor-Acceptor Dyes. Chemphyschem 2020; 21:1718-1730. [PMID: 32415748 DOI: 10.1002/cphc.202000253] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 05/11/2020] [Indexed: 02/04/2023]
Abstract
Upon photoexcitation, a majority of quadrupolar dyes, developed for large two-photon absorption, undergo excited-state symmetry breaking (ES-SB) and behave as dipolar molecules. We investigate how the change of quadrupole moment upon S1 ←S0 excitation, ΔQ, influences the propensity of a dye to undergo ES-SB using a series of molecules with a A-π-D-π-A motif where D is the exceptionally electron-rich pyrrolo[3,2-b]pyrrole and A are accepting groups. Tuning of ΔQ is achieved by appending a secondary acceptor group, A', on both sides of the D core and ES-SB is monitored using a combination of time-resolved IR and broadband fluorescence spectroscopy. The results reveal a clear correlation between ΔQ and the tendency to undergo ES-SB. When A is a stronger acceptor than A', ES-SB occurs already in non-dipolar but quadrupolar solvents. When A and A' are identical, ES-SB is only partial even in highly dipolar solvents. When A is a weaker acceptor than A', the orientation of ΔQ changes, ES-SB is observed in dipolar solvents only and involves major redistribution of the excitation over the D-π-A and D-A' branches of the dye.
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Affiliation(s)
- Zoltán Szakács
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, 1211, Genève 4, Switzerland
| | - Mariusz Tasior
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Daniel T Gryko
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Eric Vauthey
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, 1211, Genève 4, Switzerland
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14
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Phan Huu DKA, Sissa C, Terenziani F, Painelli A. Optical spectra of organic dyes in condensed phases: the role of the medium polarizability. Phys Chem Chem Phys 2020; 22:25483-25491. [DOI: 10.1039/d0cp04496b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
An effective model is presented to account for the effects of the medium electronic polarizability on spectral properties and on symmetry-breaking phenomena in charge-transfer dyes.
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Affiliation(s)
- D. K. Andrea Phan Huu
- Department of Chemistry
- Life Science and Environmental Sustainability
- Parma University
- 43124 Parma
- Italy
| | - Cristina Sissa
- Department of Chemistry
- Life Science and Environmental Sustainability
- Parma University
- 43124 Parma
- Italy
| | - Francesca Terenziani
- Department of Chemistry
- Life Science and Environmental Sustainability
- Parma University
- 43124 Parma
- Italy
| | - Anna Painelli
- Department of Chemistry
- Life Science and Environmental Sustainability
- Parma University
- 43124 Parma
- Italy
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