DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Probing Intermolecular Electron Delocalization in Dimer Radical Anions by Vibrational Spectroscopy

Abstract

Delocalization of charges is one of the factors controlling charge transport in conjugated molecules. It is considered to play an important role in the performance of a wide range of molecular technologies, including organic solar cells and organic electronics. Dimerization reactions are well-suited as a model to investigate intermolecular spatial delocalization of charges. And while dimerization reactions of radical cations are well investigated, studies on radical anions are still scarce. Upon dimerization of radical anions with neutral counterparts, an electron is considered to delocalize over the two molecules. By using time-resolved infrared (TRIR) detection coupled with pulse radiolysis, we show that radical anions of 4-n-hexyl-4'-cyanobiphenyl (6CB) undergo such dimerization reactions, with an electron equally delocalized over the two molecules. We have recently demonstrated that nitrile ν(C≡N) vibrations respond to the degree of electron localization of nitrile-substituted anions: we can quantify the changes in the electronic charges from the neutral to the anion states in the nitriles by monitoring the ν(C≡N) IR shifts. In the first part of this article, we show that the sensitivity of the ν(C≡N) IR shifts does not depend on solvent polarity. In the second part, we describe how probing the shifts of the nitrile IR vibrationalmore » band unambiguously confirms the formation of dimer radical anions, with Kdim = 3 × 104 M–1. IR findings are corroborated by electronic absorption spectroscopy and electronic structure calculations. We find that the presence of a hexyl chain and the formation of π–π interactions are both crucial for dimerization of radical anions of 6CB with neutral 6CB. Our study provides clear evidence of spatial delocalization of electrons over two molecular fragments.« less

Authors:
ORCiD logo [1]; ORCiD logo [2]
  1. Univ. of Connecticut, Storrs, CT (United States). Dept. of Chemistry; Brookhaven National Lab. (BNL), Upton, NY (United States). Chemistry Division
  2. Brookhaven National Lab. (BNL), Upton, NY (United States). Chemistry Division
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1399684
Report Number(s):
BNL-114408-2017-JA
Journal ID: ISSN 1520-6106; R&D Project: CO026; KC0304030; TRN: US1703088
Grant/Contract Number:  
SC0012704
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry
Additional Journal Information:
Journal Volume: 121; Journal Issue: 30; Journal ID: ISSN 1520-6106
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Mani, Tomoyasu, and Grills, David C. Probing Intermolecular Electron Delocalization in Dimer Radical Anions by Vibrational Spectroscopy. United States: N. p., 2017. Web. doi:10.1021/acs.jpcb.7b02559.
Mani, Tomoyasu, & Grills, David C. Probing Intermolecular Electron Delocalization in Dimer Radical Anions by Vibrational Spectroscopy. United States. https://doi.org/10.1021/acs.jpcb.7b02559
Mani, Tomoyasu, and Grills, David C. Wed . "Probing Intermolecular Electron Delocalization in Dimer Radical Anions by Vibrational Spectroscopy". United States. https://doi.org/10.1021/acs.jpcb.7b02559. https://www.osti.gov/servlets/purl/1399684.
@article{osti_1399684,
title = {Probing Intermolecular Electron Delocalization in Dimer Radical Anions by Vibrational Spectroscopy},
author = {Mani, Tomoyasu and Grills, David C.},
abstractNote = {Delocalization of charges is one of the factors controlling charge transport in conjugated molecules. It is considered to play an important role in the performance of a wide range of molecular technologies, including organic solar cells and organic electronics. Dimerization reactions are well-suited as a model to investigate intermolecular spatial delocalization of charges. And while dimerization reactions of radical cations are well investigated, studies on radical anions are still scarce. Upon dimerization of radical anions with neutral counterparts, an electron is considered to delocalize over the two molecules. By using time-resolved infrared (TRIR) detection coupled with pulse radiolysis, we show that radical anions of 4-n-hexyl-4'-cyanobiphenyl (6CB) undergo such dimerization reactions, with an electron equally delocalized over the two molecules. We have recently demonstrated that nitrile ν(C≡N) vibrations respond to the degree of electron localization of nitrile-substituted anions: we can quantify the changes in the electronic charges from the neutral to the anion states in the nitriles by monitoring the ν(C≡N) IR shifts. In the first part of this article, we show that the sensitivity of the ν(C≡N) IR shifts does not depend on solvent polarity. In the second part, we describe how probing the shifts of the nitrile IR vibrational band unambiguously confirms the formation of dimer radical anions, with Kdim = 3 × 104 M–1. IR findings are corroborated by electronic absorption spectroscopy and electronic structure calculations. We find that the presence of a hexyl chain and the formation of π–π interactions are both crucial for dimerization of radical anions of 6CB with neutral 6CB. Our study provides clear evidence of spatial delocalization of electrons over two molecular fragments.},
doi = {10.1021/acs.jpcb.7b02559},
journal = {Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry},
number = 30,
volume = 121,
place = {United States},
year = {Wed Jul 05 00:00:00 EDT 2017},
month = {Wed Jul 05 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 14 works
Citation information provided by
Web of Science

Save / Share:

Works referenced in this record:

Charge Photogeneration in Organic Solar Cells
journal, November 2010

  • Clarke, Tracey M.; Durrant, James R.
  • Chemical Reviews, Vol. 110, Issue 11, p. 6736-6767
  • DOI: 10.1021/cr900271s

Formation of Dimer Cations of Aromatic Hydrocarbons
journal, July 1968

  • Badger, B.; Brocklehurst, B.
  • Nature, Vol. 219, Issue 5151
  • DOI: 10.1038/219263a0

Radical cations in condensed phases
journal, January 1984


Conformations of naphthalene dimer cation radicals studies by laser photolysis
journal, February 1989

  • Tsuchida, Akira; Tsujii, Yoshinobu; Ito, Shinzaburo
  • The Journal of Physical Chemistry, Vol. 93, Issue 4
  • DOI: 10.1021/j100341a015

Photodissociation Spectrum of Naphthalene Dimer Cation
journal, March 1995

  • Inokuchi, Yoshiya; Ohashi, Kazuhiko; Matsumoto, Masaki
  • The Journal of Physical Chemistry, Vol. 99, Issue 11
  • DOI: 10.1021/j100011a002

Photophysical and theoretical investigations of the [8]cycloparaphenylene radical cation and its charge-resonance dimer
journal, January 2013

  • Golder, Matthew R.; Wong, Bryan M.; Jasti, Ramesh
  • Chemical Science, Vol. 4, Issue 11
  • DOI: 10.1039/c3sc51861b

What Is the Structure of the Naphthalene–Benzene Heterodimer Radical Cation? Binding Energy, Charge Delocalization, and Unexpected Charge-Transfer Interaction in Stacked Dimer and Trimer Radical Cations
journal, March 2015

  • Attah, Isaac K.; Platt, Sean P.; Meot-Ner (Mautner), Michael
  • The Journal of Physical Chemistry Letters, Vol. 6, Issue 7
  • DOI: 10.1021/jz502438x

Formation of Dimer Radical Anions of Aromatic Acetylenes during Pulse Radiolysis and γ-Radiolysis
journal, February 1997

  • Majima, Tetsuro; Tojo, Sachiko; Takamuku, Setsuo
  • The Journal of Physical Chemistry A, Vol. 101, Issue 6
  • DOI: 10.1021/jp962999b

Observation of intramolecular dimer radical anion of 1,1-diarylmethanols bearing electron withdrawing groups at room temperature
journal, November 2000


Dimerization Reaction of Regioisomeric Bis(phenylethynyl)benzene Radical Anions during Pulse Radiolysis
journal, July 2012


Reactions of radical anions. Part IV. The dimerisation of the tolan radical anion
journal, January 1967

  • Dadley, D.; Evans, Alwyn G.
  • Journal of the Chemical Society B: Physical Organic
  • DOI: 10.1039/j29670000418

Electronic absorption and E.S.R. spectra of the benzene and paracyclophane anions
journal, January 1967


Absorption Spectra of Dianthracene Anion Radical and Anthracene Dimer Anion
journal, March 1972

  • Shida, Tadamasa; Iwata, Suehiro
  • The Journal of Chemical Physics, Vol. 56, Issue 6
  • DOI: 10.1063/1.1677618

Low-temperature pulse radiolysis and .gamma.-irradiated matrix studies of dimer anions of olefin derivatives
journal, January 1977

  • Arai, Shigeyoshi; Kira, Akira; Imamura, Masashi
  • The Journal of Physical Chemistry, Vol. 81, Issue 2
  • DOI: 10.1021/j100517a004

Absorption spectra of acrylonitrile monomer and dimer anions as studied by a rigid-matrix method
journal, January 1980

  • Kira, Akira; Ishiwata, Masatoshi; Imamura, Masashi
  • Radiation Physics and Chemistry (1977), Vol. 15, Issue 6
  • DOI: 10.1016/0146-5724(80)90038-2

Isolation of the Latent Precursor Complex in Electron-Transfer Dynamics. Intermolecular Association and Self-Exchange with Acceptor Anion Radicals
journal, March 2003

  • Ganesan, Vellaichamy; Rosokha, Sergiy V.; Kochi, Jay K.
  • Journal of the American Chemical Society, Vol. 125, Issue 9
  • DOI: 10.1021/ja0211611

Intramolecular dimer radical anions of [3n] cyclophanes: transannular distance dependent stabilization energy
journal, January 2009

  • Fujitsuka, Mamoru; Tojo, Sachiko; Shinmyozu, Teruo
  • Chemical Communications, Issue 12
  • DOI: 10.1039/b810122a

Intramolecular Charge Resonance in Dimer Radical Anions of Di-, Tri-, Tetra-, and Pentaphenylalkanes
journal, May 2012

  • Tojo, Sachiko; Fujitsuka, Mamoru; Majima, Tetsuro
  • The Journal of Organic Chemistry, Vol. 77, Issue 11
  • DOI: 10.1021/jo300144r

Measuring Electric Fields and Noncovalent Interactions Using the Vibrational Stark Effect
journal, March 2015

  • Fried, Stephen D.; Boxer, Steven G.
  • Accounts of Chemical Research, Vol. 48, Issue 4
  • DOI: 10.1021/ar500464j

Electron-Transfer Acceleration Investigated by Time Resolved Infrared Spectroscopy
journal, February 2015

  • Vlček, Antonín; Kvapilová, Hana; Towrie, Michael
  • Accounts of Chemical Research, Vol. 48, Issue 3
  • DOI: 10.1021/ar5004048

Looking at Photoinduced Charge Transfer Processes in the IR: Answers to Several Long-Standing Questions
journal, January 2017


Development of nanosecond time-resolved infrared detection at the LEAF pulse radiolysis facility
journal, April 2015

  • Grills, David C.; Farrington, Jaime A.; Layne, Bobby H.
  • Review of Scientific Instruments, Vol. 86, Issue 4
  • DOI: 10.1063/1.4918728

Electron Localization of Anions Probed by Nitrile Vibrations
journal, August 2015

  • Mani, Tomoyasu; Grills, David C.; Newton, Marshall D.
  • Journal of the American Chemical Society, Vol. 137, Issue 34
  • DOI: 10.1021/jacs.5b04648

The LEAF picosecond pulse radiolysis facility at Brookhaven National Laboratory
journal, November 2004

  • Wishart, James F.; Cook, Andrew R.; Miller, John R.
  • Review of Scientific Instruments, Vol. 75, Issue 11
  • DOI: 10.1063/1.1807004

Nature and Energies of Electrons and Holes in a Conjugated Polymer, Polyfluorene
journal, December 2006

  • Takeda, Norihiko; Asaoka, Sadayuki; Miller, John R.
  • Journal of the American Chemical Society, Vol. 128, Issue 50
  • DOI: 10.1021/ja062596h

Polarons, Bipolarons, and Side-By-Side Polarons in Reduction of Oligofluorenes
journal, June 2012

  • Zaikowski, Lori; Kaur, Parmeet; Gelfond, Claudia
  • Journal of the American Chemical Society, Vol. 134, Issue 26
  • DOI: 10.1021/ja301494n

Density‐functional thermochemistry. III. The role of exact exchange
journal, April 1993

  • Becke, Axel D.
  • The Journal of Chemical Physics, Vol. 98, Issue 7, p. 5648-5652
  • DOI: 10.1063/1.464913

Ab Initio Calculation of Vibrational Absorption and Circular Dichroism Spectra Using Density Functional Force Fields
journal, November 1994

  • Stephens, P. J.; Devlin, F. J.; Chabalowski, C. F.
  • The Journal of Physical Chemistry, Vol. 98, Issue 45, p. 11623-11627
  • DOI: 10.1021/j100096a001

Importance of short-range versus long-range Hartree-Fock exchange for the performance of hybrid density functionals
journal, August 2006

  • Vydrov, Oleg A.; Heyd, Jochen; Krukau, Aliaksandr V.
  • The Journal of Chemical Physics, Vol. 125, Issue 7
  • DOI: 10.1063/1.2244560

Assessment of a long-range corrected hybrid functional
journal, December 2006

  • Vydrov, Oleg A.; Scuseria, Gustavo E.
  • The Journal of Chemical Physics, Vol. 125, Issue 23
  • DOI: 10.1063/1.2409292

Tests of functionals for systems with fractional electron number
journal, April 2007

  • Vydrov, Oleg A.; Scuseria, Gustavo E.; Perdew, John P.
  • The Journal of Chemical Physics, Vol. 126, Issue 15
  • DOI: 10.1063/1.2723119

Long-range corrected hybrid density functionals with damped atom–atom dispersion corrections
journal, January 2008

  • Chai, Jeng-Da; Head-Gordon, Martin
  • Physical Chemistry Chemical Physics, Vol. 10, Issue 44
  • DOI: 10.1039/b810189b

Effect of the damping function in dispersion corrected density functional theory
journal, March 2011

  • Grimme, Stefan; Ehrlich, Stephan; Goerigk, Lars
  • Journal of Computational Chemistry, Vol. 32, Issue 7
  • DOI: 10.1002/jcc.21759

Quantum Mechanical Continuum Solvation Models
journal, August 2005

  • Tomasi, Jacopo; Mennucci, Benedetta; Cammi, Roberto
  • Chemical Reviews, Vol. 105, Issue 8
  • DOI: 10.1021/cr9904009

A state-specific polarizable continuum model time dependent density functional theory method for excited state calculations in solution
journal, August 2006

  • Improta, Roberto; Barone, Vincenzo; Scalmani, Giovanni
  • The Journal of Chemical Physics, Vol. 125, Issue 5
  • DOI: 10.1063/1.2222364

Toward effective and reliable fluorescence energies in solution by a new state specific polarizable continuum model time dependent density functional theory approach
journal, August 2007

  • Improta, Roberto; Scalmani, Giovanni; Frisch, Michael J.
  • The Journal of Chemical Physics, Vol. 127, Issue 7
  • DOI: 10.1063/1.2757168

Dimer cations of polycyclic aromatics. Experimental bonding energies and resonance stabilization
journal, October 1980

  • Meot-Ner, Michael
  • The Journal of Physical Chemistry, Vol. 84, Issue 21
  • DOI: 10.1021/j100458a012

Mass-Selected Ion Mobility Studies of the Isomerization of the Benzene Radical Cation and Binding Energy of the Benzene Dimer Cation. Separation of Isomeric Ions by Dimer Formation
journal, September 2003

  • Rusyniak, Mark; Ibrahim, Yehia; Alsharaeh, Edreese
  • The Journal of Physical Chemistry A, Vol. 107, Issue 38
  • DOI: 10.1021/jp034850n

Determining atom-centered monopoles from molecular electrostatic potentials. The need for high sampling density in formamide conformational analysis
journal, April 1990

  • Breneman, Curt M.; Wiberg, Kenneth B.
  • Journal of Computational Chemistry, Vol. 11, Issue 3
  • DOI: 10.1002/jcc.540110311

Solvent-Induced Nitrile Frequency Shifts: Acetonitrile and Benzonitrile
journal, September 1990


Vibrational Stark Effects of Nitriles I. Methods and Experimental Results
journal, December 2000

  • Andrews, Steven S.; Boxer, Steven G.
  • The Journal of Physical Chemistry A, Vol. 104, Issue 51
  • DOI: 10.1021/jp002242r

Charge Transfer Fluorescence and 34 nm Exciton Diffusion Length in Polymers with Electron Acceptor End Traps
journal, December 2014

  • Zaikowski, Lori; Mauro, Gina; Bird, Matthew
  • The Journal of Physical Chemistry B, Vol. 119, Issue 24
  • DOI: 10.1021/jp510095p

Identification of Ion-Pair Structures in Solution by Vibrational Stark Effects
journal, February 2016

  • Hack, John; Grills, David C.; Miller, John R.
  • The Journal of Physical Chemistry B, Vol. 120, Issue 6
  • DOI: 10.1021/acs.jpcb.5b11893

Vibrational Stark Effects To Identify Ion Pairing and Determine Reduction Potentials in Electrolyte-Free Environments
journal, January 2015

  • Mani, Tomoyasu; Grills, David C.; Miller, John R.
  • Journal of the American Chemical Society, Vol. 137, Issue 3
  • DOI: 10.1021/ja512302c

Four-Center Carbon−Carbon Bonding
journal, March 2007

  • Miller, Joel S.
  • Accounts of Chemical Research, Vol. 40, Issue 3
  • DOI: 10.1021/ar068175m

Crystal structures of 4-cyano-4-hexylbiphenyl (6CB) and 4-cyano-4-heptylbiphenyl (7CB) in relation to odd-even effects
journal, June 1999


Structure, Energetics, and Electronic Coupling in the (TCNE 2 ) - • Encounter Complex in Solution:  A Polarizable Continuum Study
journal, October 2007

  • Wang, Qian; Newton, Marshall D.
  • The Journal of Physical Chemistry B, Vol. 112, Issue 2
  • DOI: 10.1021/jp0753528

Electronic structure of the benzene dimer cation
journal, July 2007

  • Pieniazek, Piotr A.; Krylov, Anna I.; Bradforth, Stephen E.
  • The Journal of Chemical Physics, Vol. 127, Issue 4
  • DOI: 10.1063/1.2749506

Electronic Structure and Optical Properties of Charged Oligofluorenes Studied by VIS/NIR Spectroscopy and Time-Dependent Density Functional Theory
journal, March 2006

  • Fratiloiu, Silvia; Grozema, Ferdinand C.; Koizumi, Yoshiko
  • The Journal of Physical Chemistry B, Vol. 110, Issue 12
  • DOI: 10.1021/jp055785f

Role of Bad Dihedral Angles: Methylfluorenes Act as Energy Barriers for Excitons and Polarons of Oligofluorenes
journal, September 2014

  • Mani, Tomoyasu; Miller, John R.
  • The Journal of Physical Chemistry A, Vol. 118, Issue 40
  • DOI: 10.1021/jp5080626

Using Nitrile-Derivatized Amino Acids as Infrared Probes of Local Environment
journal, January 2003

  • Getahun, Zelleka; Huang, Cheng-Yen; Wang, Ting
  • Journal of the American Chemical Society, Vol. 125, Issue 2
  • DOI: 10.1021/ja0285262

Solvent-Induced Infrared Frequency Shifts in Aromatic Nitriles Are Quantitatively Described by the Vibrational Stark Effect
journal, April 2012

  • Levinson, Nicholas M.; Fried, Stephen D.; Boxer, Steven G.
  • The Journal of Physical Chemistry B, Vol. 116, Issue 35
  • DOI: 10.1021/jp301054e

The CN Stretching Band of Aliphatic Thiocyanate is Sensitive to Solvent Dynamics and Specific Solvation
journal, October 2007

  • Maienschein-Cline, Mark G.; Londergan, Casey H.
  • The Journal of Physical Chemistry A, Vol. 111, Issue 40
  • DOI: 10.1021/jp0761158

Role of solvent on vibrational energy transfer in solution
journal, October 1990

  • Bakker, H. J.; Planken, P. C. M.; Lagendijk, A.
  • Nature, Vol. 347, Issue 6295
  • DOI: 10.1038/347745a0

Infrared Probes Based on Nitrile-Derivatized Prolines: Thermal Insulation Effect and Enhanced Dynamic Range
journal, June 2013

  • Park, Kwang-Hee; Jeon, Jonggu; Park, Yumi
  • The Journal of Physical Chemistry Letters, Vol. 4, Issue 13
  • DOI: 10.1021/jz400954r

Density functional theory with London dispersion corrections: Density functional theory with London dispersion corrections
journal, March 2011

  • Grimme, Stefan
  • Wiley Interdisciplinary Reviews: Computational Molecular Science, Vol. 1, Issue 2
  • DOI: 10.1002/wcms.30

Exploring the Limits of Density Functional Approximations for Interaction Energies of Molecular Precursors to Organic Electronics
journal, October 2012

  • Steinmann, Stephan N.; Corminboeuf, Clemence
  • Journal of Chemical Theory and Computation, Vol. 8, Issue 11
  • DOI: 10.1021/ct300657h

Why are the Interaction Energies of Charge-Transfer Complexes Challenging for DFT?
journal, April 2012

  • Steinmann, Stephan N.; Piemontesi, Cyril; Delachat, Aurore
  • Journal of Chemical Theory and Computation, Vol. 8, Issue 5
  • DOI: 10.1021/ct200930x

Minimizing Density Functional Failures for Non-Covalent Interactions Beyond van der Waals Complexes
journal, March 2014

  • Corminboeuf, Clemence
  • Accounts of Chemical Research, Vol. 47, Issue 11
  • DOI: 10.1021/ar400303a

Evidence for Multicenter Bonding in Dianionic Tetracyanoethylene Dimers by Raman Spectroscopy
journal, April 2013

  • Casado, Juan; Burrezo, Paula Mayorga; Ramírez, Francisco J.
  • Angewandte Chemie International Edition, Vol. 52, Issue 25
  • DOI: 10.1002/anie.201207813

Calculation of the intermolecular energy of large molecules by a fragmentation scheme: Application to the 4- n -pentyl-4 - cyanobiphenyl (5CB) dimer
journal, August 2002

  • Amovilli, Claudio; Cacelli, Ivo; Campanile, Silvio
  • The Journal of Chemical Physics, Vol. 117, Issue 7
  • DOI: 10.1063/1.1494799

Transferability of Coarse-Grained Force Field for n CB Liquid Crystal Systems
journal, April 2014

  • Zhang, Jianguo; Guo, Hongxia
  • The Journal of Physical Chemistry B, Vol. 118, Issue 17
  • DOI: 10.1021/jp411615f

Works referencing / citing this record:

Aromatic Charge Resonance Interaction Probed by Infrared Spectroscopy
journal, March 2019

  • Chatterjee, Kuntal; Matsumoto, Yoshiteru; Dopfer, Otto
  • Angewandte Chemie International Edition, Vol. 58, Issue 11
  • DOI: 10.1002/anie.201811432

Structural origins of the electronic properties of materials via time-resolved infrared spectroscopy
journal, January 2019

  • Munson, Kyle T.; Kennehan, Eric R.; Asbury, John B.
  • Journal of Materials Chemistry C, Vol. 7, Issue 20
  • DOI: 10.1039/c9tc01348b

Aromatic Charge Resonance Interaction Probed by Infrared Spectroscopy
journal, December 2018