1
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Zhao D, Zhao Y, Xu T, He X, Hu S, Ayers PW, Liu S. Chiral Jahn-Teller Distortion in Quasi-Planar Boron Clusters. Molecules 2024; 29:1624. [PMID: 38611903 PMCID: PMC11013085 DOI: 10.3390/molecules29071624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 04/03/2024] [Accepted: 04/03/2024] [Indexed: 04/14/2024] Open
Abstract
In this work, we have observed that some chiral boron clusters (B16-, B20-, B24-, and B28-) can simultaneously have helical molecular orbitals and helical spin densities; these seem to be the first compounds discovered to have this intriguing property. We show that chiral Jahn-Teller distortion of quasi-planar boron clusters drives the formation of the helical molecular spin densities in these clusters and show that elongation/enhancement in helical molecular orbitals can be achieved by simply adding more building blocks via a linker. Aromaticity of these boron clusters is discussed. Chiral boron clusters may find potential applications in spintronics, such as molecular magnets.
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Affiliation(s)
- Dongbo Zhao
- Institute of Biomedical Research, Yunnan University, Kunming 650500, China
| | - Yilin Zhao
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON L8S 4M1, Canada
| | - Tianlv Xu
- College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, China
| | - Xin He
- Qingdao Institute for Theoretical and Computational Sciences, Shandong University, Qingdao 266237, China
| | - Shankai Hu
- Institute of Biomedical Research, Yunnan University, Kunming 650500, China
| | - Paul W. Ayers
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON L8S 4M1, Canada
| | - Shubin Liu
- Research Computing Center, University of North Carolina, Chapel Hill, NC 27599-3420, USA
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599-3290, USA
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2
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Portela-Pino J, Talavera M, Chiussi S, Bolaño S, Peña-Gallego Á, Alonso-Gómez JL. Development of robust chiroptical systems through spirobifluorenes. Chirality 2024; 36:e23624. [PMID: 37823399 DOI: 10.1002/chir.23624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 09/26/2023] [Accepted: 09/26/2023] [Indexed: 10/13/2023]
Abstract
Chiroptical responses are valuable for the structural determination of dissymmetric molecules. However, the development of everyday applications based on chiroptical systems is yet to come. We have been earlier using axially chiral allenes for the construction of linear, cyclic, and cage-shaped molecules that present remarkable chiroptical responses. Additionally, we have developed chiral surfaces through upstanding chiral architectures. Since the goal is to obtain robust chiroptical materials, more recently we have been studying spirobifluorenes (SBFs), a well-established building block in optoelectronic applications. After theoretical and experimental demonstration, the suitability of chiral SBFs for the development of robust chiroptical systems was certified by the construction all-carbon double helices, flexible shape-persistent macrocycles, chiral frameworks for surface functionalization, and structures featuring helical or spiroconjugated molecular orbitals. Here, we give an overview of our contribution to these matters.
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Affiliation(s)
| | - María Talavera
- University of Vigo, Inorganic Chemistry Department, Vigo, Spain
| | - Stefano Chiussi
- CINTECX, University of Vigo, Applied Physic Department, Vigo, Spain
| | - Sandra Bolaño
- University of Vigo, Inorganic Chemistry Department, Vigo, Spain
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3
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Sburlati S, Gustafson A, Kahr B. Comparative rotatory power of bent and twisted polyynes. Chirality 2023; 35:838-845. [PMID: 37226985 DOI: 10.1002/chir.23579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 04/29/2023] [Accepted: 05/03/2023] [Indexed: 05/26/2023]
Abstract
Linear polyynes of the formula C18 H2 (symmetry D∞h ) were bent in silico by progressively introducing CCC angles less than 180°. The bent structures (symmetry C2v ) were then twisted by introducing torsion angles across the CCCC segments by as much as 60°. The gyration tensors of these 19 structures (linear, bent, and twisted) were computed by linear response methods. Bending is massively generative of optical activity in oriented structures, even achiral structures, whereas twisting in conjunction with bending, serves to linearize the molecules and diminish maximally observable optical activity. This computational exercise is intended to unbind the infelicitous linkage of optical activity and chirality, which is only meaningful in isotropic media. Although bent structures are not optically active in solution-the spatial average of the optical activity is necessarily zero-solution measurements that deliver the spatial averages are a special class of measurements, albeit the overwhelmingly most common chiroptical measurements, that prejudice our common understanding of how π-conjugated structures generate gyration. Bending is far more effective than twisting at generating optical activity along some directions for oriented structures. The respective contributions from the transition electric dipole-magnetic dipole polarizability and the transition electric dipole-electric quadrupole polarizability are compared.
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Affiliation(s)
- Sophia Sburlati
- Department of Chemistry and Molecular Design Institute, New York University, New York City, New York, USA
| | - Afton Gustafson
- Department of Chemistry and Molecular Design Institute, New York University, New York City, New York, USA
| | - Bart Kahr
- Department of Chemistry and Molecular Design Institute, New York University, New York City, New York, USA
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4
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Ozcelik A, Aranda D, Pereira-Cameselle R, Talavera M, Covelo B, Santoro F, Peña-Gallego Á, Alonso-Gómez JL. ON/OFF Spiroconjugation through Peripheral Functionalization: Impact on the Reactivity and Chiroptical Properties of Spirobifluorenes. Chempluschem 2022; 87:e202100554. [PMID: 35415974 DOI: 10.1002/cplu.202100554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 03/16/2022] [Indexed: 02/03/2023]
Abstract
Spirobifluorenes are an important class of spiro compounds frequently used in the field of organic electronics. However, harnessing spiroconjugation to obtain high-performance in such structural motifs remains unexplored. We herein propose that peripheral functionalization may serve as a useful tool to control spiroconjugation in an ON/OFF manner on both chemical reactivity and photophysical properties. In particular, the ratio of mono- and di-functionalized spirobifluorenes found experimentally during their synthesis were found to be 3/2, 7/2, and 12/2 for phenyl, nitro-phenyl and amino-phenyl analogues, respectively. These remarkable reactivity differences correlate with the spiroconjugation character evaluated theoretically at the CAM-B3LYP/6-31G(d,p) level of theory. Additionally, comparison of experimental and predicted optical and chiroptical responses shows that spiroconjugated molecular orbitals have a significant or negligible involvement on the main electronic transitions depending on the peripheral functionality of the spirobifluorene.
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Affiliation(s)
- Ani Ozcelik
- Departamento de Química Orgánica, Universidad de Vigo, Campus Universitario, 36310, Vigo, Spain
| | - Daniel Aranda
- Istituto di Chimica dei Composti Organometallici, Consiglio Nazionale delle Ricerche, Via Madonna del Piano 10, 50019, Sesto Fiorentino, Pisa, Italy
| | | | - María Talavera
- Department of Chemistry, Humboldt Universität zu Berlin, Brook-Taylor-Strasse 2, 12489, Berlin, Germany
| | - Berta Covelo
- CACTI (Centro de Apoyo Científico-Tecnológico a la Investigación), Universidad de Vigo, Campus Universitario, 36310, Vigo, Spain
| | - Fabrizio Santoro
- Istituto di Chimica dei Composti Organometallici, Consiglio Nazionale delle Ricerche, Via Madonna del Piano 10, 50019, Sesto Fiorentino, Pisa, Italy
| | - Ángeles Peña-Gallego
- Departamento de Química Física, Universidad de Vigo, Campus Universitario, 36310, Vigo, Spain
| | - J Lorenzo Alonso-Gómez
- Departamento de Química Orgánica, Universidad de Vigo, Campus Universitario, 36310, Vigo, Spain
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5
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Ozcelik A, Pereira R, Peña-Gallego Á, Alonso Gómez JL. A Tetracyanobutadiene Spirobifluorene: Synthesis, Enantiomeric Resolution and Chiroptical Properties. European J Org Chem 2022. [DOI: 10.1002/ejoc.202101333] [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]
Affiliation(s)
- Ani Ozcelik
- University of Vigo - Lagoas Marcosende Campus: Universidade de Vigo Organic Chemistry SPAIN
| | - Raquel Pereira
- University of Vigo - Lagoas Marcosende Campus: Universidade de Vigo Organic Chemistry SPAIN
| | - Ángeles Peña-Gallego
- University of Vigo - Lagoas Marcosende Campus: Universidade de Vigo Physical Chemistry SPAIN
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6
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Garner MH, Laplaza R, Corminboeuf C. Helical versus linear Jahn–Teller distortions in allene and spiropentadiene radical cations. Phys Chem Chem Phys 2022; 24:26134-26143. [DOI: 10.1039/d2cp03544h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
The allene radical cation can be stabilized both by Jahn–Teller distortion of the bond lengths and by torsion of the end-groups.
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Affiliation(s)
- Marc H. Garner
- Laboratory for Computational Molecular Design, Institute of Chemical Sciences and Engineering, Ecole Polytechnique federale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Ruben Laplaza
- Laboratory for Computational Molecular Design, Institute of Chemical Sciences and Engineering, Ecole Polytechnique federale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Clemence Corminboeuf
- Laboratory for Computational Molecular Design, Institute of Chemical Sciences and Engineering, Ecole Polytechnique federale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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7
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Wei Y, Yan Y, Li X, Xie L, Huang W. Covalent nanosynthesis of fluorene-based macrocycles and organic nanogrids. Org Biomol Chem 2021; 20:73-97. [PMID: 34859249 DOI: 10.1039/d1ob01558c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Gridization is an alternative way to create macromolecules of various sizes in addition to linear and dendritic polymerization as well as cyclization. Organic nanogrids are an expanding family of macrocycle-like closed structures at the nanoscale, but with a series of well-defined extension edges and vertices. Cyclic nanogrids can be used as nanoscale building blocks for the fabrication of not only rotaxanes, catenanes, knots, 3D cages, but also nanopolymers, covalent organic frameworks (COFs), metal-organic frameworks (MOFs), and complex molecular cross-scale architectures. In this review, the history of fluorene-based macrocycles has first been explored, followed by the development of the synthetic methodologies; in particular, fluorene-based nanogrids are highlighted owing to their features and applications. Typically, fluorenes are fused arenes with a hybrid entity between tetrahedral Csp3 and Csp2. Four ingenious connection modes of fluorene-based macrocycles, including 2,7-, 3,6-, 9,9-, and 2,9-linkages, fully demonstrate the geometric possibilities of the macrocycles and nanogrids. Such fluorene-based nanogrids will give birth to organic intelligence.
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Affiliation(s)
- Ying Wei
- Centre for Molecular Systems and Organic Devices (CMSOD), State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, China.
| | - Yongxia Yan
- Centre for Molecular Systems and Organic Devices (CMSOD), State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, China.
| | - Xiaoyan Li
- Centre for Molecular Systems and Organic Devices (CMSOD), State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, China.
| | - Linghai Xie
- Centre for Molecular Systems and Organic Devices (CMSOD), State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, China.
| | - Wei Huang
- Centre for Molecular Systems and Organic Devices (CMSOD), State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, China. .,Frontiers Science Center for Flexible Electronics (FSCFE), MIIT Key Laboratory of Flexible Electronics (KLoFE), Northwestern Polytechnical University, Xi'an 710072, China
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8
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Bro-Jørgensen W, Garner MH, Solomon GC. Quantification of the Helicality of Helical Molecular Orbitals. J Phys Chem A 2021; 125:8107-8115. [PMID: 34491758 PMCID: PMC8450904 DOI: 10.1021/acs.jpca.1c05799] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The frontier molecular orbital (MO) topology of linear carbon molecules, such as polyynes, can be visually identified as helices. However, there is no clear way to quantify the helical curvature of these π-MOs, and it is thus challenging to quantify correlations between the helical curvature and molecular properties. In this paper, we develop a method that enables us to compute the helical curvature of MOs based on their nodal planes. Using this method, we define a robust way of quantifying the helical nature of MOs (helicality) by their deviation from a perfect helix. We explore several limiting cases, including polyynes, metallacumulenes, cyclic allenes, and spiroconjugated systems, where the change in helical curvature is subtle yet clearly highlighted with this method. For example, we show that strain only has a minor effect on the helicality of the frontier orbitals of cycloallenes and that the MOs of spiroconjugated systems are close to perfect helices around the spiro-carbon. Our work provides a well-defined method for assessing orbital helicality beyond visual inspection of MO isosurfaces, thus paving the way for future studies of how the helicality of π-MOs affects molecular properties.
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Affiliation(s)
- William Bro-Jørgensen
- Department of Chemistry and Nano-Science Center, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | - Marc H Garner
- Department of Chemistry and Nano-Science Center, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | - Gemma C Solomon
- Department of Chemistry and Nano-Science Center, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
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9
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Baronas P, Komskis R, Tankelevičiu Tė E, Adomėnas P, Adomėnienė O, Juršėnas S. Helical Molecular Orbitals to Induce Spin-Orbit Coupling in Oligoyne-Bridged Bifluorenes. J Phys Chem Lett 2021; 12:6827-6833. [PMID: 34270894 DOI: 10.1021/acs.jpclett.1c01569] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Singlet-Triplet energy exchange is an area of active research due to its role in optoelectronic devices and photodynamic therapy. Large spin-orbit coupling (SOC) is difficult to achieve in simple hydrocarbon structures limiting the intersystem crossing (ISC) rates. A new approach to enhance the spin-orbit coupling via helical molecular orbitals is investigated in oligoyne-bridged bifluorenes. Transient absorption studies showed a singlet-to-triplet ISC rate of up to 6 ns-1 resulting in 0.84 triplet yield. Density functional calculations revealed a direct relation between high ISC and large SOC values mediated by helical molecular orbitals. Calculations and spectroscopic data also suggested that El-Sayed forbidden ISC occurs as a direct transition between 1ππ* and 3ππ*, which becomes allowed due to a symmetry-breaking interaction leading to mixing between orthogonal π-systems in the oligoyne fragment.
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Affiliation(s)
- P Baronas
- Institute of Photonics and Nanotechnology, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania
| | - R Komskis
- Institute of Photonics and Nanotechnology, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania
| | - E Tankelevičiu Tė
- Institute of Photonics and Nanotechnology, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania
| | - P Adomėnas
- Fine Synthesis, Ltd., Kalvarijų g. 201E, LT-08311 Vilnius, Lithuania
| | - O Adomėnienė
- Fine Synthesis, Ltd., Kalvarijų g. 201E, LT-08311 Vilnius, Lithuania
| | - S Juršėnas
- Institute of Photonics and Nanotechnology, Vilnius University, Sauletekio 3, LT-10257 Vilnius, Lithuania
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10
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Garner MH, Corminboeuf C. Helical electronic transitions of spiroconjugated molecules. Chem Commun (Camb) 2021; 57:6408-6411. [DOI: 10.1039/d1cc01904j] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The π–π* transitions of disubstituted spiropentadiene become helical due to mixing of its two perpendicular π-systems. The helicity is symmetry-protected and gives rise to experimentally observable effects, such as optical activity.
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Affiliation(s)
- Marc H. Garner
- Laboratory for Computational Molecular Design
- Institute of Chemical Sciences and Engineering
- Ecole Polytechnique Federale de Lausanne (EPFL)
- Lausanne 1015
- Switzerland
| | - Clemence Corminboeuf
- Laboratory for Computational Molecular Design
- Institute of Chemical Sciences and Engineering
- Ecole Polytechnique Federale de Lausanne (EPFL)
- Lausanne 1015
- Switzerland
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11
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Ozcelik A, Pereira-Cameselle R, Alonso-Gómez JL. From Allenes to Spirobifluorenes: On the Way to Device-compatible Chiroptical Systems. CURR ORG CHEM 2020. [DOI: 10.2174/1385272824999201013164534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The last decade has seen a huge growth in the construction of chiral systems to
expand the scope of chiroptical applications. Dependence of chiroptical response on molecular
conformation typically leads to low chiroptical intensities of chiral systems that feature
several conformations in solution. In this respect, allenes were employed for the preparation
of open and cyclic oligomers as well as molecular cages, presenting remarkable chiroptical
responses in solution. Their molecular chirality was also transferred to metal surfaces, yet
photoisomerization of allenes limited their further exploration. In search of a more robust
chiral axis, theoretical and experimental studies confirmed that spirobifluorenes could give
rise to stable systems with tailored optical and chiroptical properties. Additionally, incorporating
a conformational lock into spirobifluorene cyclic architectures served as an efficient
strategy towards the generation of distinct helical molecular orbitals. This review article outlines our results on developing
device-compatible chiroptical systems through axially chiral allenes and spirobifluorenes. The contribution
from other research groups is presented briefly.
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Affiliation(s)
- Ani Ozcelik
- Department of Organic Chemistry, Faculty of Chemistry, University of Vigo, Vigo, Spain
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12
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Garner MH, Corminboeuf C. Correlation between Optical Activity and the Helical Molecular Orbitals of Allene and Cumulenes. Org Lett 2020; 22:8028-8033. [DOI: 10.1021/acs.orglett.0c02980] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Marc H. Garner
- Laboratory for Computational Molecular Design, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Clemence Corminboeuf
- Laboratory for Computational Molecular Design, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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