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Ahmed J, Mandal SK. Phenalenyl Radical: Smallest Polycyclic Odd Alternant Hydrocarbon Present in the Graphene Sheet. Chem Rev 2022; 122:11369-11431. [PMID: 35561295 DOI: 10.1021/acs.chemrev.1c00963] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Phenalenyl, a zigzag-edged odd alternant hydrocarbon unit can be found in the graphene nanosheet. Hückel molecular orbital calculations indicate the presence of a nonbonding molecular orbital (NBMO), which originates from the linear combination of atomic orbitals (LCAO) arising from 13 carbon atoms of the phenalenyl molecule. Three redox states (cationic, neutral radical, and anionic) of the phenalenyl-based molecules were attributed to the presence of this NBMO. The cationic state can undergo two consecutive reductions to result in neutral radical and anionic states, stepwise, respectively. The phenalenyl-based radicals were found as crucial building blocks and attracted the attention of various research fields such as organic synthesis, material science, computation, and device physics. From 2012 onward, a strategy was devised using the cationic state of phenalenyl-based molecules and in situ generated phenalenyl radicals, which created a new domain of catalysis. The in situ generated phenalenyl radicals were utilized for the single electron transfer (SET) process resulting in redox catalysis. This emerging range of applications rejuvenates the more than six decades-old phenalenyl chemistry. This review captures such developments ranging from fundamental understanding to multidirectional applications of phenalenyl-based radicals.
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Affiliation(s)
- Jasimuddin Ahmed
- Department of Chemical Sciences, Indian Institute of Science Education and Research-Kolkata, Mohanpur 741246, India
| | - Swadhin K Mandal
- Department of Chemical Sciences, Indian Institute of Science Education and Research-Kolkata, Mohanpur 741246, India
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2
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Lebert J, Kratzer EM, Bourdick A, Coric M, Gekle S, Herzig EM. Directing the Aggregation of Native Polythiophene during in Situ Polymerization. ACS OMEGA 2018; 3:6388-6394. [PMID: 31458821 PMCID: PMC6644340 DOI: 10.1021/acsomega.8b00684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 05/22/2018] [Indexed: 05/10/2023]
Abstract
The performance of semiconducting polymers strongly depends on their intra- and intermolecular electronic interactions. Therefore, the morphology and particularly crystallinity and crystal structure play a crucial role in enabling a sufficient overlap between the orbitals of neighboring polymers. A new solution-based in situ polymerization for the fabrication of native polythiophene thin films is presented, which exploits the film formation process to influence the polymer crystal structure in the resulting thin films. The synthesis of the insoluble polythiophene is based on an oxidative reaction in which the oxidizing agent, iron(III) p-toluenesulfonate (FeTos), initially oxidizes the monomers to enable the polymer chain growth and secondly the final polymers, thereby chemically doping the polythiophene. To exploit the fact that the doped polythiophene has a different crystal packing structure compared to the undoped polythiophene, we investigate the structural effect of this inherent doping process by varying the amounts of FeTos in the reaction mixture, creating polythiophene thin films with different degrees of doping. The structural investigation performed by means of grazing incidence wide-angle X-ray scattering (GIWAXS) suggests that the strongly doped polymer chains aggregate in a π-stacked manner in the film formation process. Moreover, this π-stacking can be maintained after the removal of the dopant molecules. GIWAXS measurements, molecular dynamics simulations, and spectroscopic analysis suggest the presence of polythiophene in a novel and stable crystal structure with an enhanced intermolecular interaction.
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Affiliation(s)
- Jenny Lebert
- Herzig
Group, Munich School of Engineering, Technische
Universität München, Lichtenbergtstraße 4a, 85748 Garching, Germany
| | - Eva M. Kratzer
- Herzig
Group, Munich School of Engineering, Technische
Universität München, Lichtenbergtstraße 4a, 85748 Garching, Germany
| | - Axel Bourdick
- Biofluid
Simulation and Modeling, Theoretische Physik, Universität Bayreuth, Universitätsstraße 30, 95440 Bayreuth, Germany
| | - Mihael Coric
- Herzig
Group, Munich School of Engineering, Technische
Universität München, Lichtenbergtstraße 4a, 85748 Garching, Germany
| | - Stephan Gekle
- Biofluid
Simulation and Modeling, Theoretische Physik, Universität Bayreuth, Universitätsstraße 30, 95440 Bayreuth, Germany
| | - Eva M. Herzig
- Herzig
Group, Munich School of Engineering, Technische
Universität München, Lichtenbergtstraße 4a, 85748 Garching, Germany
- Dynamics
and Structure Formation - Herzig Group, Experimentalphysik, Universität Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
- E-mail:
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3
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Structural and electronic properties of doped oligothiophenes in the presence of p-toluenesulfonate acids. Theor Chem Acc 2015. [DOI: 10.1007/s00214-015-1663-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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4
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Salzner U. Electronic structure of conducting organic polymers: insights from time-dependent density functional theory. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2014. [DOI: 10.1002/wcms.1194] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Ulrike Salzner
- Department of Chemistry; Bilkent University; Ankara Turkey
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Tateno M, Takase M, Iyoda M, Komatsu K, Nishinaga T. Steric control in the π-dimerization of oligothiophene radical cations annelated with bicyclo[2.2.2]octene units. Chemistry 2013; 19:5457-67. [PMID: 23450728 DOI: 10.1002/chem.201204332] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Indexed: 11/08/2022]
Abstract
A Two series of oligothiophenes 2(nT) (n=4,5), annelated with bicyclo[2.2.2]octene (BCO) units at both ends, and quaterthiophenes 3 a-c, annelated with various numbers of BCO units at different positions, were newly synthesized to investigate the driving forces of π-dimerization and the structure-property relationships of the π-dimers of oligothiophene radical cations. Their radical-cation salts were prepared through chemical one-electron oxidation by using nitrosonium hexafluoroantimonate. From variable-temperature electron spin resonance and electronic absorption measurements, the π-dimerization capability was found to vary among the members of the 2(nT)(+)(·)SbF6(-) series and 3(+)(·)SbF6(-) series of compounds. To examine these results, density functional theory (DFT) calculations at the M06-2X/6-31G(d) level were conducted for the π-dimers. This level of theory was found to successfully reproduce the previously reported X-ray structure of (2(3T))2(2+) having a bent π-dimer structure with cis-cis conformations. The absorption bands obtained by time-dependent DFT calculations for the π-dimers were in reasonable agreement with the experimental spectra. The attractive and repulsive forces for the π-dimerization were divided into four factors: 1) SOMO-SOMO interactions, 2) van der Waals forces, 3) solvation, and 4) Coulomb repulsion, and the effects of each factor on the structural differences and chain-length dependence are discussed in detail.
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Affiliation(s)
- Masaki Tateno
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
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Malavé Osuna R, Ruiz Delgado M, Hernández V, López Navarrete J, Vercelli B, Zotti G, Novoa J, Suzuki Y, Yamaguchi S, Henssler J, Matzger A. Oxidation of End-Capped Pentathienoacenes and Characterization of Their Radical Cations. Chemistry 2009; 15:12346-61. [DOI: 10.1002/chem.200900246] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Okur S, Salzner U. Theoretical Modeling of the Doping Process in Polypyrrole by Calculating UV/Vis Absorption Spectra of Neutral and Charged Oligomers. J Phys Chem A 2008; 112:11842-53. [DOI: 10.1021/jp8063257] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Serife Okur
- Department of Chemistry, Bilkent University, Bilkent, 06800 Ankara, Turkey
| | - Ulrike Salzner
- Department of Chemistry, Bilkent University, Bilkent, 06800 Ankara, Turkey
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10
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Takita R, Song C, Swager TM. π-Dimer Formation in an Oligothiophene Tweezer Molecule. Org Lett 2008; 10:5003-5. [DOI: 10.1021/ol8020995] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ryo Takita
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Changsik Song
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Timothy M. Swager
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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Huang J, Kingsbury S, Kertesz M. Crystal packing of TCNQ anion π-radicals governed by intermolecular covalent π–π bonding: DFT calculations and statistical analysis of crystal structures. Phys Chem Chem Phys 2008; 10:2625-35. [DOI: 10.1039/b717752f] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Kurata T, Mohri T, Takimiya K, Otsubo T. Conductive, Magnetic, and Optical Properties of Sterically Hindered Dodecithiophenes. Evidence for the Coexistence of Bipolaron and π-Dimer. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2007. [DOI: 10.1246/bcsj.80.1799] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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13
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Sun M, Liu L, Ding Y, Xu H. Do coupling exciton and oscillation of electron-hole pair exist in neutral and charged π-dimeric quinquethiophenes? J Chem Phys 2007; 127:084706. [PMID: 17764283 DOI: 10.1063/1.2757175] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Optical physical properties of neutral and charged quinquethiophene monomer, and neutral and cationic pi-dimeric quinquethiophenes were investigated with density functional theory as well as the two dimensional (2D) site (transition density matrix) and three dimensional (3D) cube (transition density and charge difference density) representations, stimulated by the recent experimental report [T. Sakai et al., J. Am. Chem. Soc. 127, 8082 (2005)]. Transition density shows the orientation and strength of the transition dipole moment of neutral and charged quinquethiophene monomer, and charge difference density reveals the orientation and result of the charge transfer in neutral and charged quinquethiophene monomer. To study if coupling exciton and oscillation of electron-hole pair exist in neutral and cationic pi-dimeric quinquethiophenes, the coupling constants J (coupling exciton of electron-hole pair) and K (coupling oscillation of electron-hole pair) were introduced to the exciton coordinate and momentum operators, respectively, and the 2D and 3D analysis methods were further developed by extending our previous theoretical methods [M. T. Sun, J. Chem. Phys. 124, 054903 (2006)]. With the new developed 2D and 3D analysis methods, we investigated the excited state properties of neutral and cationic pi-dimeric quinquethiophenes, especially on the coupling exciton and oscillation of electron-hole pair between monomers. The 2D results show that there is neither coupling exciton (J=0) nor oscillation (K=0) of electron-hole pair in neutral pi-dimeric quinquethiophenes. For some excited states of cationic pi-dimeric quinquethiophenes, there is no coupling exciton (J=0), but there is coupling oscillation (K not equal0); while for some excited states, there are both coupling exciton and coupling oscillator simultaneously (J not equal0 and K not equal0). The strength of transition dipole moments of pi-dimeric quinquethiophenes were interpreted with 3D transition density, which reveals the orientations of their two subtransition dipole moments. The 3D charge transition density reveals the orientation and result of intermonomer and/or intramonomer charge transfer. The calculated results reveal that excited state properties of neutral pi-dimeric quinquethiophene are significantly different from those of the cationic pi-dimeric quinquethiophenes.
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Affiliation(s)
- Mengtao Sun
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603-146, Beijing 100080, China.
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Lüer L, Manzoni C, Cerullo G, Lanzani G, Meneghetti M. Ultrafast dynamics of a charge-transfer dimer as a model for the photoinduced phase transition of charge-transfer compounds. PHYSICAL REVIEW LETTERS 2007; 99:027401. [PMID: 17678257 DOI: 10.1103/physrevlett.99.027401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2006] [Indexed: 05/16/2023]
Abstract
By applying ultrafast pump-probe spectroscopy with 15 fs temporal resolution to (TMTTF(+))(2) dimers we provide a full picture of the structural relaxation following photoexcitation of their CT transition. Both population and coherent phonon dynamics allow tracking wave packet motion onto the multidimensional excited state potential energy surface, as obtained by density functional theory calculations. We show that the vibrations that are strongly coupled to the charge-transfer transition of the dimer correspond to those driving the photoinduced phase transition occurring in charge-transfer crystalline solids.
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Affiliation(s)
- Larry Lüer
- National Laboratory for Ultrafast and Ultraintense Optical Science, INFM-CNR, Dipartimento di Fisica, Politecnico di Milano, 20133 Milano, Italy
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Huang J, Kertesz M. Theoretical Analysis of Intermolecular Covalent π−π Bonding and Magnetic Properties of Phenalenyl and spiro-Biphenalenyl Radical π-Dimers. J Phys Chem A 2007; 111:6304-15. [PMID: 17591758 DOI: 10.1021/jp072086p] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Singlet-triplet splittings DeltaEST and intermolecular covalent pi-pi bonding characteristics of the prototypical phenalenyl pi-dimer and eight spiro-biphenalenyl radical pi-dimer structures are analyzed with the aid of restricted and unrestricted density functional theory calculations and paramagnetic susceptibility data fitted using the Bleaney-Bowers dimer model and the Curie-Weiss model. Single determinant approximations for DeltaEST as a function of transfer integrals and on-site Coulomb repulsion energy are presented for the two-electron two-site pi-dimers of phenalenyls and the two-electron four-site pi-dimers of spiro-biphenalenyl radicals. Within the range of intermolecular separation of 3.12<D<3.51 A, for the shorter separations, restricted theory works quite well and indicates the presence of a relatively strong intermolecular covalent pi-pi bonding interaction. For the longer separations, the singlet-triplet splittings are small; electron correlation plays a significant role, and only the unrestricted theory provides results that are in qualitative agreement with experiments. The bonding interactions in the pi-dimers are gradually weakened with increasing D, showing a transition from low D values with significant intermolecular pi-pi bonding and electron delocalization to high D values with localized spins and a biradicaloid character.
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Affiliation(s)
- Jingsong Huang
- Department of Chemistry, Georgetown University, 37th and O Street, Washington, DC 20057-1227, USA.
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17
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Huang J, Kertesz M. Intermolecular Covalent π−π Bonding Interaction Indicated by Bond Distances, Energy Bands, and Magnetism in Biphenalenyl Biradicaloid Molecular Crystal. J Am Chem Soc 2007; 129:1634-43. [PMID: 17284004 DOI: 10.1021/ja066426g] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Density-functional theory (DFT) calculations were performed for energy band structure and geometry optimizations on the stepped pi-chain, the isolated molecule and (di)cations of the chain, and various related molecules of a neutral biphenalenyl biradicaloid (BPBR) organic semiconductor 2. The dependence of the geometries on crystal packing provides indirect evidence for the intermolecular covalent pi-pi bonding interaction through space between neighboring pi-stacked phenalenyl units along the chain. The two phenalenyl electrons on each molecule, occupying the singly occupied molecular orbitals (SOMOs), are participating in the intermolecular covalent pi-pi bonding making them partially localized on the phenalenyl units and less available for intramolecular delocalization. The band structure shows a relatively large bandwidth and small band gap indicative of good pi-pi overlap and delocalization between neighboring pi-stacked phenalenyl units. A new interpretation is presented for the magnetism of the stepped pi-chain of 2 using an alternating Heisenberg chain model, which is consistent with DFT total energy calculations for 2 and prevails against the previous interpretation using a Bleaney-Bowers dimer model. The obtained transfer integrals and the magnetic exchange parameters fit well into the framework of a Hubbard model. All presented analyses on molecular geometries, energy bands, and magnetism provide a coherent picture for 2 pointing toward an alternating chain with significant intermolecular through-space covalent pi-pi bonding interactions in the molecular crystal. Surprisingly, both the intermolecular transfer integrals and exchange parameters are larger than the intramolecular through-bond values indicating the effectiveness of the intermolecular overlap of the phenalenyl SOMO electrons.
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Affiliation(s)
- Jingsong Huang
- Department of Chemistry, Georgetown University, 37th & O Street, Washington, D.C. 20057-1227, USA.
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Salzner U. Theoretical Investigation of Excited States of Large Polyene Cations as Model Systems for Lightly Doped Polyacetylene. J Chem Theory Comput 2006; 3:219-31. [DOI: 10.1021/ct600223f] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ulrike Salzner
- Department of Chemistry, Bilkent University, 06800 Bilkent, Ankara, Turkey
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Singh-Miller NE, Scherlis DA, Marzari N. Effect of Counterions on the Interactions of Charged Oligothiophenes. J Phys Chem B 2006; 110:24822-6. [PMID: 17149900 DOI: 10.1021/jp063478j] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The functionality of conjugated polymer systems often relies on oxidations or reductions, in most cases mediated by the presence of counterions. The effect that the common counterion hexafluorophosphate (PF6-) has on the intermolecular interactions between charged oligothiophenes is investigated here using ab initio quantum chemistry methods. Counterions are explicitly included in the simulations of oxidized oligothiophenes and in the dimerization process. Our calculations provide quantitative and qualitative insight into the intermolecular interactions in oligothiophene-counterion systems and show that the intermolecular pi-stacking of oligothiophenes is not adversely affected by the presence of counterions and that in fact oligothiophene dimerization is further stabilized by their presence.
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Affiliation(s)
- Nicholas E Singh-Miller
- Department of Materials Science and Engineering and Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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Koh SE, Delley B, Medvedeva JE, Facchetti A, Freeman AJ, Marks TJ, Ratner MA. Quantum Chemical Analysis of Electronic Structure and n- and p-Type Charge Transport in Perfluoroarene-Modified Oligothiophene Semiconductors. J Phys Chem B 2006; 110:24361-70. [PMID: 17134188 DOI: 10.1021/jp064840x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Density-functional theory (DFT) is employed to investigate the structural, electronic, and transport properties of several isomeric fluoroarene-oligothiophene-based semiconductors. Three oligothiophene systems varying in the perfluoroarene group positions within the molecule are studied to understand the electronic structure leading to the observed mobility values and to the n- or p-type behavior in these structures. Analyses of both intermolecular interactions in dimers and extended interactions in crystalline structures afford considerable insight into the electronic properties and carrier mobilities of these materials, as well as the polarity of the charge carriers. From the calculated carrier effective masses, we find that sterically governed molecular planarity plays a crucial role in the transport properties of these semiconductors. Our calculations correlate well with experimentally obtained geometries, highest-occupied molecular orbital (HOMO)/lowest-unoccupied molecular orbital (LUMO) energies, and the experimental carrier mobility trends among the systems investigated.
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Affiliation(s)
- Sharon E Koh
- Department of Chemistry and Materials Research Center, Northwestern University, Evanston, Illinois 60208, USA
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Yamazaki D, Nishinaga T, Tanino N, Komatsu K. Terthiophene Radical Cations End-Capped by Bicyclo[2.2.2]octene Units: Formation of Bent π-Dimers Mutually Attracted at the Central Position. J Am Chem Soc 2006; 128:14470-1. [PMID: 17090025 DOI: 10.1021/ja065995l] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A terthiophene fused with bicyclo[2.2.2]octene units only at both ends was newly synthesized. Since there is no steric hindrance at the central position, this terthiophene has a possibility to interact only at the central position. One-electron oxidation of this terthiophene afforded a highly stable radical-cation salt as deep blue crystals. The result of X-ray crystal structural analysis demonstrated a characteristically bent pi-dimereric structure, which is formed by mutual attraction of single radical-cation species at the central position to minimize the steric repulsion. Remarkably short intermolecular distances between the central thiophene rings of each unit of the dimeric pair, that is, 2.976(10) A for Cbeta-Cbeta, 3.091(10) A for Calpha-Calpha, and 3.779(3) A for S-S, are good indication of the existence of attracting interaction, which was confirmed by theoretical calculations. This interaction was experimentally demonstrated by the reversible formation of the pi-dimer in CH2Cl2 solution using ESR and UV-vis-NIR spectroscopy. The crystal of the pi-dimer is in its singlet state and ESR silent in the solid state at 300 K, but the signal of a triplet state of the pi-dimer was observed by heating the solid at 400 K. This indicates that this pi-dimer has a quite small triplet-singlet enegy gap and the triplet state is thermally accessible.
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Affiliation(s)
- Daisuke Yamazaki
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
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Zade SS, Bendikov M. Theoretical Study of Long Oligothiophene Dications: Bipolaron vs Polaron Pair vs Triplet State. J Phys Chem B 2006; 110:15839-46. [PMID: 16898734 DOI: 10.1021/jp062748v] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A series of oligothiophene dications (from the sexithiophene dication to the 50-mer oligothiophene dication, nT2+, n = 6-50) were studied. Density functional theory (DFT) at the B3LYP/6-31G(d) level and, in some cases, also at BLYP/6-31Gd, was applied to study the singlet and triplet states of the whole series. We found that the singlet state is the ground state for all oligothiophene dications up to the 20-mer, and that the singlet and triplet states are degenerate for longer oligomers. Thus, the triplet state is never a pure ground state for these dications. We found that, for short oligothiophenes dication (e.g., 6T2+), the bipolaron state is the more important state, with only a small contribution made by the polaron pair state. For medium size oligothiophene dications (e.g., 14T2+), both the bipolaron state and the polaron-pair state contribute to the electronic structure. Finally, in long oligothiophene dications, such as 30T2+ and 50T2+, the contribution from the polaron pair state becomes dominant, and these molecules can be considered as consisting of two independent cation radicals or a polaron pair. Results from isodesmic reactions show that the stability of oligothiophene cation radicals over dications is inversely proportional to chain length. Small oligothiophene dications (n = 6-12) were studied at the CASSCF(m,m)/6-31G(d) (m = 4, 6, and 10) level. The major conclusions of this paper regarding the relative energy of the singlet state versus the triplet state and regarding the relative stability of the bipolaron versus the polaron pair were also supported by CASSCF calculations.
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Affiliation(s)
- Sanjio S Zade
- Department of Organic Chemistry, Weizmann Institute of Science, 76100 Rehovot, Israel
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Scherlis DA, Fattebert JL, Marzari N. Stacking of oligo- and polythiophene cations in solution: Surface tension and dielectric saturation. J Chem Phys 2006; 124:194902. [PMID: 16729839 DOI: 10.1063/1.2198811] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The stacking of positively charged (or doped) terthiophene oligomers and quaterthiophene polymers in solution is investigated applying a recently developed unified electrostatic and cavitation model for first-principles calculations in a continuum solvent. The thermodynamic and structural patterns of the dimerization are explored in different solvents, and the distinctive roles of polarity and surface tension are characterized and analyzed. Interestingly, we discover a saturation in the stabilization effect of the dielectric screening that takes place at rather small values of epsilon(0). Moreover, we address the interactions in trimers of terthiophene cations, with the aim of generalizing the results obtained for the dimers to the case of higher-order stacks and nanoaggregates.
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Affiliation(s)
- Damián A Scherlis
- Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón II, Buenos Aires C1428EHA, Argentina.
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State of partial oxidation of the regioregular sexi (3-octyl thiophene) oligomer in solid phase on electrode surface. J Solid State Electrochem 2005. [DOI: 10.1007/s10008-005-0055-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Ni Z, Ren X, Ma J, Xie J, Ni C, Chen Z, Meng Q. Theoretical Studies on the Magnetic Switching Controlled by Stacking Patterns of Bis(maleonitriledithiolato) Nickelate(III) Dimers. J Am Chem Soc 2005; 127:14330-8. [PMID: 16218627 DOI: 10.1021/ja050631z] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Magnetic switchable maleonitriledithiolate (mnt) complexes were studied by density functional theory. The calculations were performed for anion dimers of [RBzPyR'][Ni(mnt)(2)] (RBzPyR' = derivatives of benzylpyridinium) to elucidate magnetostructural correlations and the nature of the weak intermolecular chemical bonding. The calculated results showed that the spin delocalization, favored by the eclipsed stacking and the shorter interlayer distance, was responsible for the diamagnetic character of [1-benzyl-4-aminopyridinium][Ni(mnt)(2)] at low temperature. The weak antiferromagnetic and ferromagnetic interactions were also reproduced for [1-benzyl-4-aminopyridinium][Ni(mnt)(2)] and [1-(4'-fluorobenzyl)pyridinium][Ni(mnt)(2)] at high temperature, respectively. The natural bond orbital analysis suggested that the cooperative effect of the weak intermolecular bondings may be the intrinsic driving force resulting in the switchable property, which is essentially similar to those in organic radicals exhibiting magnetic bistability. Further investigations with varying interlayer distance d, the extent of slippage (slipping distance r and deviation angle alpha), and rotational angle theta suggested that the extent of slippage played an important role in magnetic interactions. Therefore, the abrupt modulation of the extent of slippage in the [Ni(mnt)(2)](-) complexes by external perturbations provided new possibilities for the design of molecular magnetic switching devices.
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Affiliation(s)
- Zhaoping Ni
- Coordination Chemistry Institute, State Key Laboratory of Coordination Chemistry, and Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry of MOE, Nanjing University, Nanjing 210093, P. R. China
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Sakai T, Satou T, Kaikawa T, Takimiya K, Otsubo T, Aso Y. Syntheses, Structures, Spectroscopic Properties, and π-Dimeric Interactions of [n.n]Quinquethiophenophanes. J Am Chem Soc 2005; 127:8082-9. [PMID: 15926834 DOI: 10.1021/ja050783u] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A cyclophane-type of dimeric quinquethiophenes (4a-e) with the bridge chains consecutively varying from two to six methylenes has been synthesized and studied as ideal pi-dimer models. The double-decker structures of these compounds are verified by upfield shifts for the proton NMR signals of the inside thiophenes, as compared to those of monomeric dimethylquinquethiophene (3). The electronic absorption and emission spectra of 4a-e are perturbed by through-space pi-electronic interactions involving exciton-exciton coupling between the two overlapped quinquethiophenes, which become marked with shortening of the bridged alkylene chains. One-electron oxidation of 4a-e with FeCl(3) in dichloromethane results in the appearance of specific polaronic bands in the near-infrared region of the electronic absorption spectra, due to the generation of a radical cation species (polaron) on one of the quinquethiophenes, which electronically interacts with the remaining neutral species. Two-electron oxidation of 4a-e introduces spectral changes, revealing that the resulting two quinquethiophene radical cations readily form an intramolecular pi-dimer, thanks to their close stacking, in contrast to the difficult formation of an intermolecular pi-dimer from 3. The pi-dimeric spectra of 4b-e are comprised of two strong absorption bands, similar to that of 3, the low-energy band of which is considerably red-shifted by an effective pi-dimeric interaction depending on the lengths of the bridged alkylene chains. Quite different is the spectrum of 4a with three absorption bands inherent in pi-dimer, presumably because the two short bridging chains of 4a force the pi-dimer to take a constrained, strongly interactive structure.
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Affiliation(s)
- Toyofumi Sakai
- Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan
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Scherlis DA, Marzari N. π-Stacking in Thiophene Oligomers as the Driving Force for Electroactive Materials and Devices. J Am Chem Soc 2005; 127:3207-12. [PMID: 15740161 DOI: 10.1021/ja043557d] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The pi-stacking between aromatic oligomers has been extensively studied for many years, although the notion of exploiting this phenomenon as the driving force for molecular actuation has only recently emerged. In this work we examine with MP2 and Car-Parrinello ab initio calculations the actuation properties of a novel class of thiophene-based materials introduced by Swager et al. (Adv. Mater. 2002, 14, 368; J. Am. Chem. Soc. 2003, 125, 1142). The chemical ingredients of the assembly, calix[4]arenes and oligothiophenes, are screened separately to characterize the actuation mechanisms and design optimal architectures. In particular, ab initio methods are used to study pi-stacking in mixed-valence oligothiophene dimers, revealing strong interactions that can be turned on and off as a function of the electrochemical potential. We show how these interactions could be harnessed to achieve molecular actuation and investigate the response of an active unit in real time with first-principles molecular dynamics simulations.
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Affiliation(s)
- Damian A Scherlis
- Department of Materials Science and Engineering and Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Affiliation(s)
- Damián A. Scherlis
- Department of Materials Science and Engineering and Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Nicola Marzari
- Department of Materials Science and Engineering and Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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Brocks G, van den Brink J, Morpurgo AF. Electronic correlations in oligo-acene and -thiopene organic molecular crystals. PHYSICAL REVIEW LETTERS 2004; 93:146405. [PMID: 15524821 DOI: 10.1103/physrevlett.93.146405] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2003] [Indexed: 05/24/2023]
Abstract
From first-principles calculations we determine the Coulomb interaction between two holes on oligo-acene and -thiophene molecules in a crystal, as a function of the oligomer length. The electronic polarization of the molecules that surround the charged oligomer reduces the bare Coulomb repulsion between the holes by approximately a factor of 2. The effects of relaxing the molecular geometry in the presence of holes is found to be significantly smaller. In all cases the effective hole-hole repulsion is much larger than the valence bandwidth, which implies that at high doping levels the properties of these organic semiconductors are determined by electron-electron correlations.
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Affiliation(s)
- Geert Brocks
- Faculty of Science and Technology and MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
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Satou T, Sakai T, Kaikawa T, Takimiya K, Otsubo T, Aso Y. α,ω-Bis(quinquethienyl)alkanes as a π-Dimer Model of Polythiophene. Org Lett 2004; 6:997-1000. [PMID: 15012084 DOI: 10.1021/ol0499396] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[structure: see text] A series of the title dimeric quinquethiophenes linked with a di- to hexamethylene spacer was synthesized and examined as a pi-dimer model of polythiophene. Upon two-electron oxidation with iron(III) chloride in dichloromethane, they readily form intramolecular pi-dimer species, except for the dimethylene-linked dimer that cannot be bent into a pi-stacked structure.
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Affiliation(s)
- Teizi Satou
- Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan
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Huang J, Kertesz M. Spin Crossover of Spiro-Biphenalenyl Neutral Radical Molecular Conductors. J Am Chem Soc 2003; 125:13334-5. [PMID: 14583010 DOI: 10.1021/ja038038+] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present ab initio molecular and solid-state calculations at the level of density functional theory (DFT) for the ethyl-substituted spiro-biphenalenyl neutral radical organic conductor. We find that the phase transition of this material is accompanied by a spin crossover (low-spin, LS, to high-spin, HS), and consequently a different band becomes the conduction band. The energy gap (Eg) increases from 0.12 eV of the low-temperature polymorph to 0.23 eV of the high-temperature polymorph corresponding to a different occupancy causing a change in the number of the available charge carriers, explaining the change of conductivity by 2 orders of magnitude at the phase transition. These gap values are also consistent with structural, IR, electrical conductivity, and magnetic susceptibility data of Itkis et al. The proximity of the monomers in the stacking dimers is closely related to the spin crossover in this material.
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Affiliation(s)
- Jingsong Huang
- Chemistry Department, Georgetown University, 37th & O Street, Washington, DC 20057, USA
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Geskin VM, Brédas JL. Polaron pair versus bipolaron on oligothiophene chains: a theoretical study of the singlet and triplet states. Chemphyschem 2003; 4:498-505. [PMID: 12785266 DOI: 10.1002/cphc.200200446] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Victor M Geskin
- Service de Chimie des Matériaux Nouveaux Centre de Recherche en Electronique et Photonique Moléculaires Université de Mons-Hainaut Place du Parc 20, 7000 Mons, Belgium
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Ivanova A, Baumgarten M, Karabunarliev S, Tyutyulkov N. Design of ferromagnetic alternating stacks of neutral and ion-radical hydrocarbons. Phys Chem Chem Phys 2003. [DOI: 10.1039/b309328j] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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SAMs functionalised by α-quaterthiophene as model for polythiophene grafting. Colloids Surf A Physicochem Eng Asp 2002. [DOI: 10.1016/s0927-7757(01)00965-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Otsubo T, Aso Y, Takimiya K. Synthesis, Optical, and Conductive Properties of Long Oligothiophenes and Their Utilization as Molecular Wires. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2001. [DOI: 10.1246/bcsj.74.1789] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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