1
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Li X, Anderson JSM, Jobst KJ. Bioaccumulative chemicals are either too hard or too soft: Conceptual density functional theory as a screening tool for emerging pollutants. ENVIRONMENT INTERNATIONAL 2024; 183:108388. [PMID: 38159370 DOI: 10.1016/j.envint.2023.108388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 11/29/2023] [Accepted: 12/12/2023] [Indexed: 01/03/2024]
Abstract
Conceptual density functional theory (CDFT) descriptors were computed to predict the environmental fate of approximately 6,000 widely used industrial chemicals. CDFT descriptors aligned with a molecule's possible bioaccumulation mechanism, i.e., soft chemicals are lipophilic, whereas hard chemicals may bioaccumulate by other mechanisms such as protein binding. The results have provided us with a new "rule of thumb" to guide risk assessment of chemical hazards: suspected persistent organic pollutants are either too hard (η > 0.40 hartree) or too soft (α > 200 Å3). This offers a novel approach to environmental risk assessment using two fundamental properties of a molecule.
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Affiliation(s)
- Xiaolei Li
- Department of Chemistry, Memorial University of Newfoundland, 45 Arctic Ave., St. John's, Canada A1C 5S7
| | - James S M Anderson
- Institute of Chemistry, National Autonomous University of Mexico, Mexico City, Mexico 04510.
| | - Karl J Jobst
- Department of Chemistry, Memorial University of Newfoundland, 45 Arctic Ave., St. John's, Canada A1C 5S7.
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2
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Sitha S. Planar in Brooker's mode and twisted in Reichardt's mode: defying the steric forces in biphenyl types of zwitterionic systems through metameric resonance stabilizations. Phys Chem Chem Phys 2022; 24:13110-13118. [PMID: 35588239 DOI: 10.1039/d1cp05372h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
To be planar or to be twisted at the bridge junctions in biphenyls or biaryl types of molecular systems depends on two conflicting forces: (1) steric repulsions (destabilizations) and (2) conjugation assisted electron delocalizations (resonance stabilizations). This work reports an unfamiliar kind of behaviour shown by metamers of a zwitterionic biphenyl type of system, where the Reichardt's metamer was found to be in an usual twisted conformation (delicate balance of conflicting forces), but the Brooker's metamer was found to be in a fully planar conformation. Interestingly, at the ωB97xD/aug-cc-pVDZ level, energetically (ΔE) the planar Brooker's metamer was found to be 16.7 kcal mol-1 lower (22.9 kcal mol-1 lower in the CASSCF method) in energy (more stable) than the isoelectronic twisted Reichardt's metamer, and also thermodynamic ΔG values were found to be close to ΔE values for various methods (for example, 15.6 kcal mol-1 in the above case using the ωB97xD method). When the steric repulsions are in their full potentials at the ring junction site, attainment of a conformational planarity by any biaryl type of system has not been reported previously. Without reducing the steric constraints or even without inducing any attractive forces, determining what other factors were responsible for defying the steric forces is the main focus of this investigation. Using the results of quantum mechanical computations of NBO, rotational barriers, and other saddle points (metastable conformations in singlet and triplet surfaces) in the potential energy surfaces, the dominant contribution of the resonance stabilized quinonoid form to the ground state was delineated as the possible reason for this unusual behaviour.
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Affiliation(s)
- Sanyasi Sitha
- Department of Chemical Sciences, University of Johannesburg, PO Box 524, Auckland Park, Johannesburg, 2006, South Africa.
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3
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Sun X, Neidlinger LR, Bossert LR, Kolling DR. Inner-Sphere and Outer-Sphere Charge-Transfer Quenching of the Uranyl UO22+(VI) Luminescence, and Kinetics for the Tertiary and Secondary Alcohols Activated Uranyl Emission. Inorganica Chim Acta 2022. [DOI: 10.1016/j.ica.2022.121009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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4
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Patera LL, Queck F, Repp J. Imaging Charge Localization in a Conjugated Oligophenylene. PHYSICAL REVIEW LETTERS 2020; 125:176803. [PMID: 33156651 DOI: 10.1103/physrevlett.125.176803] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/23/2020] [Accepted: 09/08/2020] [Indexed: 06/11/2023]
Abstract
Polaron formation in conjugated polymers has a major impact on their optical and electronic properties. In polyphenylene, the molecular conformation is determined by a delicate interplay between electron delocalization and steric effects. Injection of excess charges is expected to increase the degree of conjugation, leading to structural distortions of the chain. Here we investigated at the single-molecule level the role of an excess charge in an individual oligophenylene deposited on sodium chloride films. By combining sub-molecular-resolved atomic force microscopy with redox-state-selective orbital imaging, we characterize both structural and electronical changes occurring upon hole injection. While the neutral molecule exhibits a delocalized frontier orbital, for the cationic radical the excess charge is observed to localize, inducing a partial planarization of the molecule. These results provide direct evidence for self-trapping of the excess charge in oligophenylenes, shedding light on the interplay of charge localization and structural distortion.
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Affiliation(s)
- Laerte L Patera
- Institute of Experimental and Applied Physics, University of Regensburg, 93053 Regensburg, Germany
| | - Fabian Queck
- Institute of Experimental and Applied Physics, University of Regensburg, 93053 Regensburg, Germany
| | - Jascha Repp
- Institute of Experimental and Applied Physics, University of Regensburg, 93053 Regensburg, Germany
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5
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Role of π-electron conjugation in determining the electrical responsive properties of polychlorinated biphenyls: a DFT based computational study. SN APPLIED SCIENCES 2020. [DOI: 10.1007/s42452-020-2068-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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6
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Srishailam K, Reddy BV, Rao GR. Investigation of torsional potentials, hindered rotation, molecular structure and vibrational properties of some biphenyl carboxaldehydes using spectroscopic techniques and density functional formalism. J Mol Struct 2019. [DOI: 10.1016/j.molstruc.2019.06.064] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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7
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Vergura S, Scafato P, Belviso S, Superchi S. Absolute Configuration Assignment from Optical Rotation Data by Means of Biphenyl Chiroptical Probes. Chemistry 2019; 25:5682-5690. [PMID: 30730078 DOI: 10.1002/chem.201806435] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 02/06/2019] [Indexed: 11/10/2022]
Abstract
A non-empirical approach for the assignment of the absolute configuration of chiral 2-alkyl-substituted carboxylic acids and primary amines by [α]D measurements has been developed. The method requires the conversion of the chiral acids or amines into the corresponding 4,4'-disubstituted biphenylamides or biphenylazepines, respectively. In these derivatives a central-to-axial chirality transfer induces a preferred torsion in the biphenyl moiety revealed by the sign of the biphenyl A band in the ECD spectrum. By 4,4'-substitution on the biphenyl moiety a redshift of the A band is obtained, leading to an increase of its relative contribution to optical rotation. This allows to reliably establish a direct correlation between the [α]D sign, the biphenyl twist and, then, the substrate absolute configuration. This approach thus constitutes a really practical and reliable method to assign the absolute configuration of chiral carboxylic acids and primary amines by simple and straightforward [α]D measurement, readily obtainable by a routine instrumentation like the polarimeter.
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Affiliation(s)
- Stefania Vergura
- Department of Science, Università degli Studi della Basilicata, Via dell'Ateneo Lucano, 10, 85100, Potenza, Italy
| | - Patrizia Scafato
- Department of Science, Università degli Studi della Basilicata, Via dell'Ateneo Lucano, 10, 85100, Potenza, Italy
| | - Sandra Belviso
- Department of Science, Università degli Studi della Basilicata, Via dell'Ateneo Lucano, 10, 85100, Potenza, Italy
| | - Stefano Superchi
- Department of Science, Università degli Studi della Basilicata, Via dell'Ateneo Lucano, 10, 85100, Potenza, Italy
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8
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Popelier PLA, Maxwell PI, Thacker JCR, Alkorta I. A relative energy gradient (REG) study of the planar and perpendicular torsional energy barriers in biphenyl. Theor Chem Acc 2018; 138:12. [PMID: 30872951 PMCID: PMC6383956 DOI: 10.1007/s00214-018-2383-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 11/14/2018] [Indexed: 11/24/2022]
Abstract
Biphenyl is a prototype molecule, the study of which is important for a proper understanding of stereo-electronic effects. In the gas phase it has an equilibrium central torsion angle of ~ 45° and shows both a planar (0°) and a perpendicular (90°) torsional energy barrier. The latter is analysed for the first time. We use the newly proposed REG method, which is an exhaustive procedure that automatically ranks atomic energy contributions according to their importance in explaining the energy profile of a total system. Here, the REG method operates on energy contributions computed by the interacting quantum atoms method. This method is minimal in architecture and provides a crisp picture of well-defined and well-separated electrostatic, steric and exchange (covalent) energies at atomistic level. It is shown that the bond critical point occurring between the ortho-hydrogens in the planar geometry has been wrongly interpreted as a sign of repulsive interaction. A convenient metaphor of analysing football matches is introduced to clarify the role of a REG analysis.
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Affiliation(s)
- Paul L. A. Popelier
- Manchester Institute of Biotechnology (MIB), 131 Princess Street, Manchester, M1 7DN UK
- School of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL UK
| | - Peter I. Maxwell
- Manchester Institute of Biotechnology (MIB), 131 Princess Street, Manchester, M1 7DN UK
- School of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL UK
| | - Joseph C. R. Thacker
- Manchester Institute of Biotechnology (MIB), 131 Princess Street, Manchester, M1 7DN UK
- School of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL UK
| | - Ibon Alkorta
- Instituto de Química Médica (IQM-CSIC), Juan de la Cierva, 3, 28006 Madrid, Spain
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9
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Tahchieva DN, Bakowies D, Ramakrishnan R, von Lilienfeld OA. Torsional Potentials of Glyoxal, Oxalyl Halides, and Their Thiocarbonyl Derivatives: Challenges for Popular Density Functional Approximations. J Chem Theory Comput 2018; 14:4806-4817. [PMID: 30011363 DOI: 10.1021/acs.jctc.8b00174] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reliability of popular density functionals was studied for the description of torsional profiles of 36 molecules: glyoxal, oxalyl halides, and their thiocarbonyl derivatives. HF and 18 functionals of varying complexity, from local density to range-separated hybrid approximations and double-hybrid, have been considered and benchmarked against CCSD(T)-level rotational profiles. For molecules containing heavy halogens, most functionals fail to reproduce barrier heights accurately and a number of functionals introduce spurious minima. Dispersion corrections show no improvement. Calibrated torsion-corrected atom-centered potentials rectify the shortcomings of PBE and also improve on σ-hole based intermolecular binding in dimers and crystals.
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Affiliation(s)
- Diana N Tahchieva
- Institute of Physical Chemistry and National Center for Computational Design and Discovery of Novel Materials (MARVEL), Department of Chemistry , University of Basel , Klingelbergstrasse 80 , CH-4056 Basel , Switzerland
| | - Dirk Bakowies
- Institute of Physical Chemistry and National Center for Computational Design and Discovery of Novel Materials (MARVEL), Department of Chemistry , University of Basel , Klingelbergstrasse 80 , CH-4056 Basel , Switzerland
| | - Raghunathan Ramakrishnan
- Institute of Physical Chemistry and National Center for Computational Design and Discovery of Novel Materials (MARVEL), Department of Chemistry , University of Basel , Klingelbergstrasse 80 , CH-4056 Basel , Switzerland
| | - O Anatole von Lilienfeld
- Institute of Physical Chemistry and National Center for Computational Design and Discovery of Novel Materials (MARVEL), Department of Chemistry , University of Basel , Klingelbergstrasse 80 , CH-4056 Basel , Switzerland
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10
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Tachikawa H. Effects of micro-solvation on the reaction dynamics of biphenyl cations following hole capture. Chem Phys 2017. [DOI: 10.1016/j.chemphys.2017.03.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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11
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Xin N, Wang J, Jia C, Liu Z, Zhang X, Yu C, Li M, Wang S, Gong Y, Sun H, Zhang G, Liu Z, Zhang G, Liao J, Zhang D, Guo X. Stereoelectronic Effect-Induced Conductance Switching in Aromatic Chain Single-Molecule Junctions. NANO LETTERS 2017; 17:856-861. [PMID: 28071918 DOI: 10.1021/acs.nanolett.6b04139] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Biphenyl, as the elementary unit of organic functional materials, has been widely used in electronic and optoelectronic devices. However, over decades little has been fundamentally understood regarding how the intramolecular conformation of biphenyl dynamically affects its transport properties at the single-molecule level. Here, we establish the stereoelectronic effect of biphenyl on its electrical conductance based on the platform of graphene-molecule single-molecule junctions, where a specifically designed hexaphenyl aromatic chain molecule is covalently sandwiched between nanogapped graphene point contacts to create stable single-molecule junctions. Both theoretical and temperature-dependent experimental results consistently demonstrate that phenyl twisting in the aromatic chain molecule produces different microstates with different degrees of conjugation, thus leading to stochastic switching between high- and low-conductance states. These investigations offer new molecular design insights into building functional single-molecule electrical devices.
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Affiliation(s)
- Na Xin
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, China
| | - Jinying Wang
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, China
- Department of Applied Physics, University of Tokyo , Hongo, Tokyo 113-8656, Japan
| | - Chuancheng Jia
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, China
| | - Zitong Liu
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China
| | - Xisha Zhang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China
| | - Chenmin Yu
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China
| | - Mingliang Li
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, China
| | - Shuopei Wang
- Institute of Physics, Chinese Academy of Sciences , Beijing 100190, People's Republic of China
| | - Yao Gong
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, China
| | - Hantao Sun
- Key Laboratory for the Physics and Chemistry of Nanodevices, Department of Electronics, Peking University , Beijing 100871, China
| | - Guanxin Zhang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China
| | - Zhirong Liu
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, China
| | - Guangyu Zhang
- Institute of Physics, Chinese Academy of Sciences , Beijing 100190, People's Republic of China
| | - Jianhui Liao
- Key Laboratory for the Physics and Chemistry of Nanodevices, Department of Electronics, Peking University , Beijing 100871, China
| | - Deqing Zhang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China
| | - Xuefeng Guo
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, China
- Department of Materials Science and Engineering, College of Engineering, Peking University , Beijing 100871, China
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12
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Buevich AV. Atropisomerization of 8-Membered Dibenzolactam: Experimental NMR and Theoretical DFT Study. J Org Chem 2015; 81:485-501. [DOI: 10.1021/acs.joc.5b02321] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Alexei V. Buevich
- Merck Research Laboratories,
Discovery and Preclinical Sciences, Process and Analytical Chemistry, NMR Structure Elucidation, Kenilworth, New Jersey 07033, United States
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13
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Theoretical study of conformational effect on electronic structure and charge transfer in silabiphenyl system. COMPUT THEOR CHEM 2015. [DOI: 10.1016/j.comptc.2014.11.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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14
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Zhang X, Vieker H, Beyer A, Gölzhäuser A. Fabrication of carbon nanomembranes by helium ion beam lithography. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2014; 5:188-94. [PMID: 24605285 PMCID: PMC3943867 DOI: 10.3762/bjnano.5.20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 01/22/2014] [Indexed: 06/01/2023]
Abstract
The irradiation-induced cross-linking of aromatic self-assembled monolayers (SAMs) is a universal method for the fabrication of ultrathin carbon nanomembranes (CNMs). Here we demonstrate the cross-linking of aromatic SAMs due to exposure to helium ions. The distinction of cross-linked from non-cross-linked regions in the SAM was facilitated by transferring the irradiated SAM to a new substrate, which allowed for an ex situ observation of the cross-linking process by helium ion microscopy (HIM). In this way, three growth regimes of cross-linked areas were identified: formation of nuclei, one-dimensional (1D) and two-dimensional (2D) growth. The evaluation of the corresponding HIM images revealed the dose-dependent coverage, i.e., the relative monolayer area, whose density of cross-links surpassed a certain threshold value, as a function of the exposure dose. A complete cross-linking of aromatic SAMs by He(+) ion irradiation requires an exposure dose of about 850 µC/cm(2), which is roughly 60 times smaller than the corresponding electron irradiation dose. Most likely, this is due to the energy distribution of secondary electrons shifted to lower energies, which results in a more efficient dissociative electron attachment (DEA) process.
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Affiliation(s)
- Xianghui Zhang
- Department of Physics, Physics of Supramolecular Systems and Surfaces, Bielefeld University, 33615 Bielefeld, Germany
| | - Henning Vieker
- Department of Physics, Physics of Supramolecular Systems and Surfaces, Bielefeld University, 33615 Bielefeld, Germany
| | - André Beyer
- Department of Physics, Physics of Supramolecular Systems and Surfaces, Bielefeld University, 33615 Bielefeld, Germany
| | - Armin Gölzhäuser
- Department of Physics, Physics of Supramolecular Systems and Surfaces, Bielefeld University, 33615 Bielefeld, Germany
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15
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Park K, Lee TW, Yoon MJ, Choe JI. Calculated and Experimental UV and IR Spectra of Oligo-para-phenylenes. B KOREAN CHEM SOC 2014. [DOI: 10.5012/bkcs.2014.35.2.531] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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16
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Dolg M. Approaching the complete basis set limit of CCSD(T) for large systems by the third-order incremental dual-basis set zero-buffer F12 method. J Chem Phys 2014; 140:044114. [DOI: 10.1063/1.4862826] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
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17
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Samori S, Tojo S, Fujitsuka M, Lin JH, Ho TI, Yang JS, Majima T. Emission from Charge Recombination between Radical Cations and Radical Anions of 9-Cyano-10-(p-Substituted Phenyl)Anthracene Generated during Pulse Radiolysis. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.200600164] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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18
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Campanelli AR, Domenicano A. A computational study of 4-substituted biphenyls in their minimum energy conformation: twist angles, structural variation, and substituent effects. Struct Chem 2013. [DOI: 10.1007/s11224-013-0242-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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19
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Esteruelas MA, Fernández I, Gómez-Gallego M, Martín-Ortíz M, Molina P, Oliván M, Otón F, Sierra MA, Valencia M. Mono- and dinuclear osmium N,N'-di- and tetraphenylbipyridyls and extended bipyridyls. Synthesis, structure and electrochemistry. Dalton Trans 2013; 42:3597-608. [PMID: 23292252 DOI: 10.1039/c2dt32548a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The efficient synthesis of mono- and dinuclear Os(IV) bipyridyl complexes is reported. These compounds show a two-step oxidation process leading to notable structural changes, which are reflected in their emission properties. During the second oxidation process a tetracation with a hydride-dihydrogen structure (instead of a trihydride) is formed. This results in a significant bathochromic shift of the emission band, accompanied by a moderate increase in intensity.
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Affiliation(s)
- Miguel A Esteruelas
- Departamento de Quíımica Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea, Universidad de Zaragoza-CSIC, 50009, Zaragoza, Spain.
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20
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Fukuda R, Ehara M. Electronic excited states and electronic spectra of biphenyl: a study using many-body wavefunction methods and density functional theories. Phys Chem Chem Phys 2013; 15:17426-34. [DOI: 10.1039/c3cp52636d] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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Potzel O, Taubmann G. The pressure dependence of the solid state structure of biphenyl from DFT calculations. Phys Chem Chem Phys 2013; 15:20288-93. [DOI: 10.1039/c3cp53680g] [Citation(s) in RCA: 3] [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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22
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Jia J, Wu HS, Chen Z, Mo Y. Elucidation of the Forces Governing the Stereochemistry of Biphenyl. European J Org Chem 2012. [DOI: 10.1002/ejoc.201201273] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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23
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Lee NK, Park S, Yoon MH, Kim ZH, Kim SK. Effect of ring torsion on intramolecular vibrational redistribution dynamics of 1,1'-binaphthyl and 2,2'-binaphthyl. Phys Chem Chem Phys 2012; 14:840-8. [PMID: 22124335 DOI: 10.1039/c1cp22854d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The role of ring torsion in the enhancement of intramolecular vibrational energy redistribution (IVR) in aromatic molecules was investigated by conducting excitation and dispersed fluorescence spectroscopy of 1,1'-binaphthyl (1,1'-BN) and 2,2'-BN. The dispersed fluorescence spectra of 1,1'-BN in the origin region of S(1)-S(0) were well resolved, which presented 25-27 cm(-1) gaps of torsional mode in the ground state. The overall profile of the dispersed spectra of 1,1'-BN is similar to that of naphthalene. In contrast, the spectra of 2,2'-BN were not resolved due to the multitude of the active torsional modes. In both cases, dissipative IVR was observed to take place with a relatively small excess vibrational energy: 237.5 cm(-1) for 1,1'-BN and 658 cm(-1) for 2,2'-BN, which clearly shows that ring torsion efficiently enhances the IVR rate. Ab initio and density functional theory calculations with medium-sized basis sets showed that the torsional potential of 1,1'-BN has a very flat minimum over the range of torsional angles from ca. 60° to 120°, whereas that of 2,2'-BN showed two well-defined potential minima at ca. 40° and 140°, in resemblance to the case of biphenyl. In this work, we propose that aromatic molecules be classified into "strong" and "weak" torsional hindrance cases: molecules with strong hindrance case show shorter torsional progressions and more effective IVR dynamics than do those with weak hindrance.
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Affiliation(s)
- Nam Ki Lee
- Department of Physics and School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang, Korea.
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24
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Torsional potential and nonlinear optical properties of phenyldiazines and phenyltetrazines. COMPUT THEOR CHEM 2011. [DOI: 10.1016/j.comptc.2011.09.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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25
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Gómez-Gallego M, Martín-Ortiz M, Sierra MA. Concerning the Electronic Control of Torsion Angles in Biphenyls. European J Org Chem 2011. [DOI: 10.1002/ejoc.201100874] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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26
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Lee C, Maeng G, Kim HW, Sohlberg K. Quantum mechanical modeling of a tripodal [2]rotaxane and its binding to TiO2. COMPUT THEOR CHEM 2011. [DOI: 10.1016/j.comptc.2011.02.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Abstract
A new model for graphene epitaxially grown on silicon carbide is proposed. Density functional theory modeling of epitaxial graphene functionalization by hydrogen, fluorine, methyl and phenyl groups has been performed, with hydrogen and fluorine showing a high probability of cluster formation in high adatom concentration. It has also been shown that the clusterization of fluorine adatoms provides midgap states in formation, due to significant flat distortion of graphene. The functionalization of epitaxial graphene using larger species (methyl and phenyl groups) renders cluster formation impossible, due to the steric effect, and results in uniform coverage with the energy gap opening.
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Affiliation(s)
- D W Boukhvalov
- Computational Materials Science Center, National Institute for Materials Science, Tsukuba, Ibaraki, Japan.
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Brabec CJ, Heeney M, McCulloch I, Nelson J. Influence of blend microstructure on bulk heterojunction organic photovoltaic performance. Chem Soc Rev 2011; 40:1185-99. [DOI: 10.1039/c0cs00045k] [Citation(s) in RCA: 476] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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Min W, Sun L. Internal Reorganization Energy Contributed by Torsional Motion in Electron Transfer Reaction between Biphenyl and Biphenyl Anion Radical. CHINESE J CHEM 2010. [DOI: 10.1002/cjoc.20020201008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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30
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Ferro N, Bredow T. Assessment of quantum-chemical methods for electronic properties and geometry of signaling biomolecules. J Comput Chem 2010; 31:1063-79. [PMID: 19899146 DOI: 10.1002/jcc.21393] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A reasonable balance between accuracy and feasibility of quantum-chemical methods depends on the complexity of the molecular system and the scientific goals. Six series of indole-, naphthalene-, phenol-, benzoic-, phenoxy-, other auxin-derivatives, and a test set of similar organic molecules have been chosen for an assessment of 13 density functional and semi-empirical molecular orbital methods with respect to electronic and structural properties. The accuracy and precision of HOMO/LUMO calculations are determined by comparison with experimental ionization potentials and electron affinities. Further comparison was performed at atomic level by covariance analysis. The methods KMLYP, MSINDO, and PM3 are precise and accurate for the whole set of molecules. The method AM1 offers comparable accuracy with the exception of electron affinities of indole derivatives, where significant deviations from experiment were observed. Geometrical properties were best reproduced with the semi-empirical method MSINDO.
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Affiliation(s)
- Noel Ferro
- Institute of Plant Genetic, University of Hannover, Hannover, Germany.
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31
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Pacios LF, Campos VM, Merino I, Gómez L. Structures and thermodynamics of biphenyl dihydrodiol stereoisomers and their metabolites in the enzymatic degradation of arene xenobiotics. J Comput Chem 2009; 30:2420-32. [PMID: 19360792 DOI: 10.1002/jcc.21248] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A key step in the metabolic degradation of biphenyl xenobiotics is catechol formation upon dehydrogenation of cis- and trans-dihydrodiols in prokaryotic and eukaryotic pathways, respectively. Structure and thermodynamics of stereoisomers of cis-, trans-2,3-biphenyl-dihydrodiols (I) and their dehydrogenation products (hydroxyketones, II), as well as final catechol (2,3-biphenyldiol, III) are studied by means of ab initio MP2/6-311++G(2df,2p)//MP2/6-311G(d,p) calculations. Formation of stereoisomers I and II is exothermic and endergonic, whereas III is enthalpically and entropically driven. Dehydrogenations are endothermic (DeltaHR0 approximately 1.5-4 kcal mol(-1)) and exergonic (DeltaGR0 approximately -5 to -7.5 kcal mol(-1)) without noticeable differences between cis and trans pathways, although the same keto stereoisomer II-(2S) is found to be the more favored product from both cis- and trans-I. The final II --> III tautomerization is thermodynamically enhanced (DeltaHR0 approximately -27, DeltaGR0 approximately -28 kcal mol(-1)) but the process is shown to have a large activation energy if it had to occur via unimolecular path. Although this tautomerization is generally assumed to be a nonenzymatic process as it involves rearomatization of an oxygenated ring, proton transfer with an anionic intermediate might be a more probable process.
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Affiliation(s)
- Luis F Pacios
- Unidad de Química y Bioquímica, Departamento de Biotecnología, E. T. S. Ingenieros de Montes, Universidad Politécnica de Madrid, 28040 Madrid, Spain.
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32
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XUE C, ZHONG C. Molecular Simulation Study of Hexane Diffusion in Dynamic Metal-Organic Frameworks. CHINESE J CHEM 2009. [DOI: 10.1002/cjoc.200990077] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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33
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André P, Cheng G, Ruseckas A, van Mourik T, Früchtl H, Crayston JA, Morris RE, Cole-Hamilton D, Samuel IDW. Hybrid Dendritic Molecules with Confined Chromophore Architecture to Tune Fluorescence Efficiency. J Phys Chem B 2008; 112:16382-92. [DOI: 10.1021/jp806031q] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Pascal André
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews, Fife, UK KY16 9SS; EaStCHEM, School of Chemistry, University of St. Andrews, St. Andrews, Fife, UK KY16 9ST; and Organic Semiconductor Centre, University of St. Andrews, St. Andrews, Fife, UK KY16 9SS
| | - Ge Cheng
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews, Fife, UK KY16 9SS; EaStCHEM, School of Chemistry, University of St. Andrews, St. Andrews, Fife, UK KY16 9ST; and Organic Semiconductor Centre, University of St. Andrews, St. Andrews, Fife, UK KY16 9SS
| | - Arvydas Ruseckas
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews, Fife, UK KY16 9SS; EaStCHEM, School of Chemistry, University of St. Andrews, St. Andrews, Fife, UK KY16 9ST; and Organic Semiconductor Centre, University of St. Andrews, St. Andrews, Fife, UK KY16 9SS
| | - Tanja van Mourik
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews, Fife, UK KY16 9SS; EaStCHEM, School of Chemistry, University of St. Andrews, St. Andrews, Fife, UK KY16 9ST; and Organic Semiconductor Centre, University of St. Andrews, St. Andrews, Fife, UK KY16 9SS
| | - Herbert Früchtl
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews, Fife, UK KY16 9SS; EaStCHEM, School of Chemistry, University of St. Andrews, St. Andrews, Fife, UK KY16 9ST; and Organic Semiconductor Centre, University of St. Andrews, St. Andrews, Fife, UK KY16 9SS
| | - Joe A. Crayston
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews, Fife, UK KY16 9SS; EaStCHEM, School of Chemistry, University of St. Andrews, St. Andrews, Fife, UK KY16 9ST; and Organic Semiconductor Centre, University of St. Andrews, St. Andrews, Fife, UK KY16 9SS
| | - Russell E. Morris
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews, Fife, UK KY16 9SS; EaStCHEM, School of Chemistry, University of St. Andrews, St. Andrews, Fife, UK KY16 9ST; and Organic Semiconductor Centre, University of St. Andrews, St. Andrews, Fife, UK KY16 9SS
| | - David Cole-Hamilton
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews, Fife, UK KY16 9SS; EaStCHEM, School of Chemistry, University of St. Andrews, St. Andrews, Fife, UK KY16 9ST; and Organic Semiconductor Centre, University of St. Andrews, St. Andrews, Fife, UK KY16 9SS
| | - Ifor D. W. Samuel
- SUPA, School of Physics and Astronomy, University of St. Andrews, St. Andrews, Fife, UK KY16 9SS; EaStCHEM, School of Chemistry, University of St. Andrews, St. Andrews, Fife, UK KY16 9ST; and Organic Semiconductor Centre, University of St. Andrews, St. Andrews, Fife, UK KY16 9SS
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Johansson MP, Olsen J. Torsional Barriers and Equilibrium Angle of Biphenyl: Reconciling Theory with Experiment. J Chem Theory Comput 2008; 4:1460-71. [DOI: 10.1021/ct800182e] [Citation(s) in RCA: 172] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Mikael P. Johansson
- Lundbeck Foundation Center for Theoretical Chemistry, Aarhus University, DK-8000 Århus C, Denmark, and Department of Chemistry, University of Helsinki, Helsinki, Finland
| | - Jeppe Olsen
- Lundbeck Foundation Center for Theoretical Chemistry, Aarhus University, DK-8000 Århus C, Denmark, and Department of Chemistry, University of Helsinki, Helsinki, Finland
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Hmadeh M, Traboulsi H, Elhabiri M, Braunstein P, Albrecht-Gary AM, Siri O. Synthesis, characterization and photophysical properties of benzidine-based compounds. Tetrahedron 2008. [DOI: 10.1016/j.tet.2008.04.058] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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36
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Alonso M, Casado S, Miranda C, Tarazona JV, Navas JM, Herradón B. Decabromobiphenyl (PBB-209) activates the aryl hydrocarbon receptor while decachlorobiphenyl (PCB-209) is inactive: experimental evidence and computational rationalization of the different behavior of some halogenated biphenyls. Chem Res Toxicol 2008; 21:643-58. [PMID: 18311929 DOI: 10.1021/tx700362u] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In rat H4IIE cells permanently transfected with a luciferase gene under the control of AhR, incubation with PBB-209 led to a statistically significant increase of luminescence. In this system, PCB-209 only caused a small induction of luciferase activity. In a fish cell line, only PBB-209 was able to provoke an induction of ethoxyresorufin- O-deethylase activity. Ligand binding to the AhR was studied by means of a cell-free in vitro system in which the activation of AhR is very unlikely to occur without ligand binding. None of the biphenyls studied provoked any activation of AhR in this system. To rationalize the results and to get insight into the molecular mechanism of activation of AhR by PBB-209 as compared with PCB-209, a comprehensive computational study was carried out on these congeners as well as on PCB-126 and PCB-169, two potent AhR activators through ligand binding. The calculations include (i) conformational analysis and dipole moments of each conformer, (ii) aromaticity indices, (iii) molecular electrostatic potentials, (iv) quadrupole moments, (v) electronic and reactivity descriptors, and (vi) dissociation energies of C-Cl and C-Br bonds in model aromatic compounds. It was found that some molecular features of PBB-209, such as the electrostatic potential (EP) and EP-derived descriptors (Politzer's parameters), indicate that PBB-209 is more similar to PCB-126 and PCB-169 than to PCB-209, which share quite similar geometries based on the substitution pattern. The similarity between PBB-209, PCB-126, and PCB-169 seems to hint that these three compounds can share, at least partially, similar mechanisms of activation of AhR. It is unquestionable that PCB-126 and PCB-169 directly bind AhR and PBB-209 does not. We hypothesize that there are several simultaneous mechanisms for activation of AhR, and the most active compounds act for more than one mechanism.
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Affiliation(s)
- Mercedes Alonso
- Instituto de Química Orgánica General, CSIC, Juan de la Cierva 3, E-28006 Madrid, Spain
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37
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Owen G, Stahl J, Hampel F, Gladysz J. Coordination-Driven Self-Assembly, Structures, and Dynamic Properties of Diplatinum Hexatriynediyl and Butadiynediyl Complexes in which the sp Carbon Chains are Shielded by sp3Carbon Chains: Towards Endgroup-Endgroup Interactions. Chemistry 2007; 14:73-87. [DOI: 10.1002/chem.200701268] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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38
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Pacios LF. A theoretical study of the intramolecular interaction between proximal atoms in planar conformations of biphenyl and related systems. Struct Chem 2007. [DOI: 10.1007/s11224-007-9230-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Lukes V, Aquino AJA, Lischka H, Kauffmann HF. Dependence of Optical Properties of Oligo-para-phenylenes on Torsional Modes and Chain Length. J Phys Chem B 2007; 111:7954-62. [PMID: 17592865 DOI: 10.1021/jp068496f] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A systematic characterization of excited-state properties of para-phenylene oligomers constructed from two to eight aromatic rings is presented using density functional theory (DFT) and the coupled-cluster singles and doubles (CC2) method. Geometry optimizations have been performed for the ground state and for the electronically excited state. Vertical excitations and the fluorescence transitions have been calculated. Time-dependent DFT (TDDFT) method underestimates excitation and fluorescence energies systematically in comparison with experimental results. The computed TDDFT lifetime for the polymer limit (0.43 ns) is in agreement with the experimental value of 0.55 ns. The TDDFT torsional potential curves were investigated for biphenyl, terphenyl, and quarterphenyl oligomers in their electronic ground and excited states. Our calculations show an increase in the separation of the lowest excited state (S1) to the next higher one with increasing molecular size. No indication is found for state crossings of the S1 state with higher ones from planar structures up to torsional angles of 60 degrees to 70 degrees. Thus, an adiabatic description of the dynamics of the S1 state might significantly simplify any dynamics simulations of torsional broadenings.
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Affiliation(s)
- Vladimír Lukes
- Department of Chemical Physics, Slovak University of Technology, Radlinského 9, SK-81 237 Bratislava, Slovakia.
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40
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41
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Müller C, Pidko EA, Totev D, Lutz M, Spek AL, van Santen RA, Vogt D. Atropisomeric phosphinines: design and synthesis. Dalton Trans 2007:5372-5. [DOI: 10.1039/b715197g] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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42
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Pacios LF, Gómez L. Conformational changes of the electrostatic potential of biphenyl: A theoretical study. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.10.119] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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43
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Affiliation(s)
- Kerwin D. Dobbs
- DuPont Central Research & Development, Experimental Station, P.O. Box 80320, Wilmington, Delaware 19880-0320, and Department of Chemistry, Drexel University, 3141 Chestnut Street, Philadelphia, Pennsylvania 19104
| | - Karl Sohlberg
- DuPont Central Research & Development, Experimental Station, P.O. Box 80320, Wilmington, Delaware 19880-0320, and Department of Chemistry, Drexel University, 3141 Chestnut Street, Philadelphia, Pennsylvania 19104
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Sancho-García JC. Assessing a new nonempirical density functional: Difficulties in treating π-conjugation effects. J Chem Phys 2006; 124:124112. [PMID: 16599667 DOI: 10.1063/1.2180774] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The reliability of the Tao-Perdew-Staroverov-Scuseria (TPSS) exchange-correlation functional for the description of conjugation effects in model pi-conjugated systems has been thoroughly assessed through the calculation of torsion energy profiles. The functional reproduces qualitatively the shape of torsional potentials but, interestingly, the mixing of TPSS and exact exchange governs the quantitative results: thus, well-defined hybrid extensions of the functional are consistently employed to improve the results. The hybrid approaches led to more accurate descriptions of conjugation effects but, however, the finest performance along the whole range of dihedral angles was obtained by a customized mixing of pure or hybrid TPSS functionals and wave function methods in a multicoefficient fashion. Despite the successful construction of this nonempirical functional, higher rungs of the ladder of methods in which TPSS is based are hoped to reduce the errors with respect to reference data for pi-conjugated systems.
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Affiliation(s)
- J C Sancho-García
- Departamento de Química Física, Universidad de Alicante, E-03080 Alicante, Spain.
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45
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Theoretical study of building blocks for molecular switches based on electrically induced conformational changes. Chem Phys 2006. [DOI: 10.1016/j.chemphys.2005.06.033] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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46
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Wang J, Cooper G, Tulumello D, Hitchcock AP. Inner Shell Excitation Spectroscopy of Biphenyl and Substituted Biphenyls: Probing Ring−Ring Delocalization. J Phys Chem A 2005; 109:10886-96. [PMID: 16331932 DOI: 10.1021/jp054693n] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Quantitative optical oscillator strength spectra for C 1s excitation and ionization of gas-phase biphenyl, decafluorobiphenyl, and 2,2'-bis(bromomethyl)-1,1'-biphenyl have been derived from electron energy loss spectroscopy recorded under electric dipole dominated conditions. The C 1s X-ray absorption spectrum of hexaphenylbenzene has been recorded in the solid state. The C 1s spectral features are interpreted with the aid of ab initio calculations for core excitation of benzene, biphenyl, hexafluorobenzene, and decafluorobiphenyl. A weak feature at 287.7 eV in biphenyl is identified as a C 1s --> pi(deloc) transition, characteristic of ring-ring delocalization. Its intensity and position are shown to be related to the average torsion angle and thus the extent of pi-pi-interaction between adjacent aromatic rings. The effects of perfluoro substitution on core excitation spectra are also characterized and discussed.
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Affiliation(s)
- Jian Wang
- Department of Chemistry, McMaster University, Hamilton, Ontario, Canada L8S 4M1
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47
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Deleuze MS, Francois JP, Kryachko ES. The Fate of Dicationic States in Molecular Clusters of Benzene and Related Compounds. J Am Chem Soc 2005; 127:16824-34. [PMID: 16316229 DOI: 10.1021/ja042238j] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Calculations employing density functional theory indicate that, rather than undergoing fragmentation, dicationic clusters of benzene, hexafluorobenzene, and naphthalene produced by sequential one-electron or sudden double-ionization experiments on the neutrals can relax via the formation of inter-ring covalent C-C bonds, along with a series of proton transfers that enable a substantial reduction of inter- and intramolecular Coulomb repulsions. The theoretically predicted chemically bound structures correspond to deep local energy minima on the potential energy surface pertaining to the lowest electronic state of the dications and can therefore be regarded as metastable (kinetically long-lived) species. This discovery invalidates on theoretical grounds the liquid-droplet model of multiply charged clusters and sheds very unexpected light on possible consequences in chemistry of the intermolecular Coulombic decay (ICD) mechanism [Cederbaum, L. S.; et al. Phys. Rev. Lett. 1997, 79, 4778; Jahnke, T.; et al. Phys. Rev. Lett. 2004, 93, 163401] for deep inner-valence ionized states. Propagation of charge rearrangement reactions and proton transfers to several monomers may eventually lead to the formation of rather extended dicationic assemblies.
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Affiliation(s)
- Michael S Deleuze
- Theoretische Chemie Onderzoeksgroep, Departement SBG, Universiteit Hasselt, Gebouw D, Diepenbeek, Belgium.
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Kishimoto N, Hagihara Y, Ohno K, Knippenberg S, François JP, Deleuze MS. Probing the Shape and Stereochemistry of Molecular Orbitals in Locally Flexible Aromatic Chains: A Penning Ionization Electron Spectroscopy and Green's Function Study of the Electronic Structure of Biphenyl. J Phys Chem A 2005; 109:10535-46. [PMID: 16834309 DOI: 10.1021/jp053678f] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We report on the results of an exhaustive study of the interplay between the valence electronic structure, the topology and reactivity of orbitals, and the molecular structure of biphenyl by means of Penning ionization electron spectroscopy in the gas phase upon collision with metastable He*(2(3)S) atoms. The measurements are compared with one-particle Green's function calculations of one-electron and shake-up valence ionization spectra employing the third-order algebraic diagrammatic construction scheme [ADC(3)]. Penning ionization intensities are also analyzed by means of the exterior electron-density model and comparison with photoelectron spectra: in contrast with the lines originating from sigma orbitals, ionization lines belonging to the pi-band system have large Penning ionization cross sections due to their greater extent outside the molecular van der Waals surface. The involved chemi-ionization processes are further experimentally investigated using collision-energy-resolved Penning ionization electron spectroscopy. The cross sections of pi-ionization bands exhibit a markedly negative collision-energy dependence and indicate that the interaction potential that prevails between the molecule and the He*(2(3)S) atom is strongly attractive in the pi-orbital region. On the other hand, the partial ionization cross sections pertaining to sigma-ionization channels are characterized by more limited collision-energy dependencies, as a consequence of rather repulsive interactions within the sigma-orbital region. A comparison of ADC(3) simulations with the Penning ionization electron spectra and UV photoelectron spectra measured by Kubota et al. [Chem. Phys. Lett. 1980, 74, 409] on thin films of biphenyl deposited at 170 and 109 K on copper demonstrates that biphenyl molecules lying at the surface of polycrystalline layers adopt predominantly a planar configuration, whereas within an amorphous sample most molecules have twisted structures similar to those prevailing in the gas phase.
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Affiliation(s)
- Naoki Kishimoto
- Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan
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49
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Beenken WJD, Lischka H. Spectral broadening and diffusion by torsional motion in biphenyl. J Chem Phys 2005; 123:144311. [PMID: 16238395 DOI: 10.1063/1.2049269] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have studied biphenyl by time-dependent density-functional theory. In particular, we have analyzed the dependence of singlet excitation energies and transition dipoles on the torsional angle between the phenyl groups. The torsional spectrum has been computed quantum mechanically as well as semiclassically in order to understand how this influences the broadening of absorption and luminescence spectra. Our results are in best agreement with supersonic jet spectroscopy data, but also fit astonishingly well to spectra of biphenyl in condensed phase. Furthermore, we compare the torsional and vibrational relaxation and discuss qualitatively the general consequences for poly-para-phenylenes and related conjugated polymers as poly-thiophenes, considering, in particular, how side chains and solvents may affect the optical spectra.
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Affiliation(s)
- Wichard J D Beenken
- Department of Theoretical Physics I, Technische Universität Ilmenau, Postfach 100565, 98684 Ilmenau, Germany.
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50
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Holman MW, Yan P, Ching KC, Liu R, Ishak FI, Adams DM. A conformational switch of intramolecular electron transfer. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.06.128] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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