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Mendis KC, Li X, Valdiviezo J, Banziger SD, Zhang P, Ren T, Beratan DN, Rubtsov IV. Electron transfer rate modulation with mid-IR in butadiyne-bridged donor-bridge-acceptor compounds. Phys Chem Chem Phys 2024; 26:1819-1828. [PMID: 38168814 DOI: 10.1039/d3cp03175f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Controlling electron transfer (ET) processes in donor-bridge-acceptor (DBA) compounds by mid-IR excitation can enhance our understanding of the ET dynamics and may find practical applications in molecular sensing and molecular-scale electronics. Alkyne moieties are attractive to serve as ET bridges, as they offer the possibility of fast ET and present convenient vibrational modes to perturb the ET dynamics. Yet, these bridges introduce complexity because of the strong torsion angle dependence of the ET rates and transition dipoles among electronic states and a shallow torsion barrier. In this study, we implemented ultrafast 3-pulse laser spectroscopy to investigate how the ET from the dimethyl aniline (D) electron donor to the N-isopropyl-1,8-napthalimide (NAP) electron acceptor can be altered by exciting the CC stretching mode (νCC) of the butadiyne bridge linking the donor and acceptor. The electron transfer was initiated by electronically exciting the acceptor moiety at 400 nm, followed by vibrational excitation of the alkyne, νCC, and detecting the changes in the absorption spectrum in the visible spectral region. The experiments were performed at different delay times t1 and t2, which are the delays between UV-mid-IR and mid-IR-Vis pulses, respectively. Two sets of torsion-angle conformers were identified, one featuring a very fast mean ET time of 0.63 ps (group A) and another featuring a slower mean ET time of 4.3 ps (group B), in the absence of the mid-IR excitation. TD-DFT calculations were performed to determine key torsion angle dependent molecular parameters, including the electronic and vibrational transition dipoles, transition frequencies, and electronic couplings. To describe the 3-pulse data, we developed a kinetic model that includes a locally excited, acceptor-based S2 state, a charge separated S1 state, and their vibrationally excited counterparts, with either excited νCC (denoted as S1Atr, S1Btr, S2Atr, and S2Btr, where tr stands for the excited triplet bond, νCC) or excited daughter modes of the νCC relaxation (S1Ah, S1Bh, S2Ah, and S2Bh, where h stands for vibrationally hot species). The kinetic model was solved analytically, and the species-associated spectra (SAS) were determined numerically using a matrix approach, treating first the experiments with longer t1 delays and then using the already determined SAS for modeling the experiments with shorter t1 delays. Strong vibronic coupling of νCC and of vibrationally hot states makes the analysis complicated. Nevertheless, the SAS were identified and the ET rates of the vibrationally excited species, S2Atr, S2Btr and S2Bh, were determined. The results show that the ET rate for the S2A species is ca. 1.2-fold slower when the νCC mode is excited. The ET rate for species S2B is slower by ca. 1.3-fold if the compound is vibrationally hot and is essentially unchanged when the νCC mode is excited. The SAS determined for the tr and h species resemble the SAS for their respective precursor species in the 2-pulse transient absorption experiments, which validates the procedure used and the results.
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Affiliation(s)
- Kasun C Mendis
- Department of Chemistry, Tulane University, New Orleans, LA 70118, USA.
| | - Xiao Li
- Department of Chemistry, Tulane University, New Orleans, LA 70118, USA.
| | - Jesús Valdiviezo
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
| | - Susannah D Banziger
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - Peng Zhang
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
| | - Tong Ren
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - David N Beratan
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
- Department of Biochemistry, Duke University, Durham, North Carolina 27710, USA
| | - Igor V Rubtsov
- Department of Chemistry, Tulane University, New Orleans, LA 70118, USA.
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Yu L, Shi M, Wang Z, Xing X, Umair Ali M, He Y, Meng H. Tuning the UV/Vis Absorption Spectra of Electrochromic Small Molecular Radicals Through Bridge Modulation. Chemphyschem 2021; 22:1684-1691. [PMID: 34164904 DOI: 10.1002/cphc.202100369] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/19/2021] [Indexed: 02/02/2023]
Abstract
Studies on the optical properties of donor-bridge-acceptor (DBA) materials in their radical anion state are rare but important. Such investigations can help to extend the application of DBA materials to opto-electrochemical devices and no longer limit them to optical physics research. In this work, a series of new DBA materials, TACzs, for overcoming this limitation are reported. All TACzs show strong intramolecular charge transfer (ICT) in their photoexcited states, leading to noticeable solvatochromism. Besides, the electronic structures of their radical anions show great variability, displaying different absorption spectra and diverse colors. Moreover, the potential application of TACzs as electrochromic and electro-fluorochromic materials are discussed. This work demonstrates that manipulating the π bridge between the donor and acceptor in the DBA system is an effective pathway not only to tailor the ICT properties of materials in their neutral state, but also to tune the absorption characteristics of their radical anion state, which makes them very promising for applications in electroluminescent and electrochemical devices.
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Affiliation(s)
- Lirong Yu
- School of Advanced Materials, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Ming Shi
- School of Advanced Materials, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Zikuan Wang
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, Mülheim an der Ruhr, 45470, Germany
| | - Xing Xing
- Research & Development Institute of Northwestern Polytechnical University (Shenzhen), Northwestern Polytechnical University, Shenzhen, 518057, China
| | - Muhammad Umair Ali
- Tsinghua-Berkeley Shenzhen Institute (TBSI), Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China
| | - Yaowu He
- School of Advanced Materials, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Hong Meng
- School of Advanced Materials, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
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Li X, Valdiviezo J, Banziger SD, Zhang P, Ren T, Beratan DN, Rubtsov IV. Symmetry controlled photo-selection and charge separation in butadiyne-bridged donor–bridge–acceptor compounds. Phys Chem Chem Phys 2020; 22:9664-9676. [DOI: 10.1039/d0cp01235a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electron transfer (ET) in donor–bridge–acceptor (DBA) compounds featuring alkyne bridges depends strongly on the torsion angle between the donor and acceptor.
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Affiliation(s)
- Xiao Li
- Department of Chemistry
- Tulane University
- New Orleans
- USA
| | | | | | - Peng Zhang
- Department of Chemistry
- Duke University
- Durham
- USA
| | - Tong Ren
- Department of Chemistry
- Purdue University
- West Lafayette
- USA
| | - David N. Beratan
- Department of Chemistry
- Duke University
- Durham
- USA
- Department of Physics, Duke University
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Lei H, Langlois A, Fortin D, Karsenti PL, Aly SM, Harvey PD. Rendering cross-conjugated azophenine derivatives emissive to probe the silent photophysical properties of emeraldine. Phys Chem Chem Phys 2018; 19:21532-21539. [PMID: 28762412 DOI: 10.1039/c7cp04102k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An azophenine derivative was synthesized by coupling truxene and azophenine via the copper-free Sonagashira reaction using Pd2(dba)3 and As(PPh)3 as catalysts. The crystal structure of this heavy azophenine model (∼4000) was made and the identity of the structure was confirmed. By introducing truxene groups into this cross-conjugated structure, the deactivating rotations around the NH-C6H4 bonds were slowed down, which rendered this derivative near-IR emissive at 298 K. This species provided then the appropriate spectral and kinetic signatures for knowing where and what to look for in emeraldine, which was called non-emissive. Besides, two other compounds were also synthesized as models for this azophenine derivative for comparison and interpretation purposes.
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Affiliation(s)
- Hu Lei
- Département de Chimie, Université de Sherbrooke, Sherbrooke, PQ J1K 2R1, Canada.
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Pati AK, Gharpure SJ, Mishra AK. On the photophysics of butadiyne bridged pyrene–phenyl molecular conjugates: multiple emissive pathways through locally excited, intramolecular charge transfer and excimer states. Faraday Discuss 2015; 177:213-35. [DOI: 10.1039/c4fd00170b] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The present work describes the photophysical properties of a group of butadiyne bridged pyrene–phenyl molecular hybrids having different substitutions with varying donor and acceptor abilities. In addition to emission from the locally excited (LE) state originating from the pyrene moiety, intramolecular charge transfer (ICT) emissions were observed in molecules with donor–acceptor character. The positions of the ICT emission maxima varied over a wide range of wavelengths (475–600 nm). Pyrene behaved as a donor when a strong acceptor group (–CN) was attached to the phenyl ring and it behaved as an acceptor when the phenyl group contained a strong donor group (–NMe2). In mixed aqueous solvents at higher percentages of water (80–99%), the derivatives showed emissions from the aggregate state in addition to the LE and ICT states. Emissions from the aggregate states of the derivatives were centred in the range 510–560 nm. The aggregate state emissions were found to originate from static excimers involving pyrene moieties. A detailed structure–property relationship of the butadiynyl derivatives was revealed in this study.
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Affiliation(s)
- Avik Kumar Pati
- Department of Chemistry
- Indian Institute of Technology Madras
- Chennai 600036
- India
| | - Santosh J. Gharpure
- Department of Chemistry
- Indian Institute of Technology Bombay
- Mumbai 400076
- India
| | - Ashok K. Mishra
- Department of Chemistry
- Indian Institute of Technology Madras
- Chennai 600036
- India
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Ramsaywack S, Karaca S, Gholami M, Murray AH, Hampel F, McDonald R, Elmaci N, Lüthi HP, Tykwinski RR. Donor- and/or Acceptor-Substituted Expanded Radialenes: Theory, Synthesis, and Properties. J Org Chem 2014; 79:10013-29. [DOI: 10.1021/jo5016085] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Sharwatie Ramsaywack
- Department
of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Sila Karaca
- Department
of Chemistry, İzmir Institute of Technology, Urla, 35430 İzmir, Turkey
| | - Mojtaba Gholami
- Department
of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Adrian H. Murray
- Department
of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Frank Hampel
- Department of Chemistry and Pharmacy & Interdisciplinary Center of Molecular Materials (ICMM), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Henkestrasse 42, 91054 Erlangen, Germany
| | - Robert McDonald
- Department
of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Nuran Elmaci
- Department
of Chemistry, İzmir Institute of Technology, Urla, 35430 İzmir, Turkey
| | - Hans Peter Lüthi
- Department
of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg
2, 8093 Zürich, Switzerland
| | - Rik R. Tykwinski
- Department of Chemistry and Pharmacy & Interdisciplinary Center of Molecular Materials (ICMM), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Henkestrasse 42, 91054 Erlangen, Germany
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