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Lefrancois-Gagnon KM, Mawhinney RC. Toward Universal Substituent Constants: Relating QTAIM Functional Group Descriptors to Substituent Effect Proxies. J Chem Inf Model 2023; 63:6068-6080. [PMID: 37729015 DOI: 10.1021/acs.jcim.3c00987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Substituents modulate reactions, but their effects are commonly described by using proxies to their functional group properties. Substituent descriptors from the quantum theory of atoms in molecules, which are true functional group properties, are related here to these proxies, which have historically had chemically relevant meaning. Due to the large number of descriptors, multivariate analysis is used to intuit their significance. Multiple linear regression, principal component, and partial least squares regression analyses highlight that these substituent descriptors contain similar information to the proxies while being intrinsic, predictable substituent properties. Sources of error limiting quantitative reproduction of the proxy data include transferability, experimental accuracy, and solvation issues.
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Affiliation(s)
| | - Robert C Mawhinney
- Department of Chemistry, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B 5E1, Canada
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Lefrancois-Gagnon KM, Mawhinney RC. Toward universal substituent constants: Transferability of group descriptors from the quantum theory of atoms in molecules. J Comput Chem 2022; 43:265-278. [PMID: 34842294 DOI: 10.1002/jcc.26787] [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: 06/30/2021] [Revised: 09/29/2021] [Accepted: 11/06/2021] [Indexed: 11/06/2022]
Abstract
Traditionally, substituents are described not by their intrinsic properties, but by their effect elsewhere in a molecule. However, the quantum theory of atoms in molecules (QTAIM) provides a route to intrinsic substituent descriptors. Ideally, these descriptors would exhibit minimal change as the local environment changes, and hence be considered transferable. Whether this is true is an open question. Here, we evaluated the transferability of QTAIM functional group descriptors for 117 functional groups in a series of 17 substrates to determine whether descriptors obtained using hydrogen as substrate are transferable. The functional group volume has a strong, consistent, linear relationship throughout. All other hydrogen-based group descriptors exhibit a relatively strong linear relationship with those in carbon-based substrates and a reasonable linear relationship with those in non-carbon-based substrates. Outliers are readily interpretable in terms of substrate induced functional group geometry changes. As expected, directional descriptors lying along the substituent-substrate axis are the least conserved.
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Lefrancois-Gagnon KM, Mawhinney RC. Toward universal substituent constants: Model chemistry sensitivity of descriptors from the quantum theory of atoms in molecules. J Comput Chem 2020; 41:2485-2503. [PMID: 32864783 DOI: 10.1002/jcc.26404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 08/02/2020] [Indexed: 11/12/2022]
Abstract
The quantum theory of atoms in molecules (QTAIM) provides a theoretical foundation to determine the properties of functional groups through additive atomic contributions. Many studies have used QTAIM in their analyses with a variety of electronic structure methods, but it is unknown if the properties measured using one model chemistry, the combination of the electronic structure method and basis set, can be compared to those measured by another. Here, we evaluate the sensitivity of QTAIM functional group and bond critical point properties using six functionals and seven basis sets. High-level B2PLYPD3-BJ/aug-cc-pV5Z reference values are provided for 116 functional groups and the property sensitivity with respect to these values are evaluated based on absolute deviations and by assessing linear relationships. Functional group properties, including charges, dipoles, quadrupoles and volumes, were found to be mostly insensitive to choice of computational model chemistry. However, due to structural and topological inconsistencies, the 6-31G(d) basis set is not recommended for use. Bond critical point properties varied with choice of model chemistry, but models incorporating hybrid functionals and triple-ζ basis sets provided values suitable for use in regression studies.
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Affiliation(s)
| | - Robert C Mawhinney
- Department of Chemistry, Lakehead University, Thunder Bay, Ontario, Canada
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Mohan N, Suresh CH, Kumar A, Gadre SR. Molecular electrostatics for probing lone pair-π interactions. Phys Chem Chem Phys 2014; 15:18401-9. [PMID: 24085157 DOI: 10.1039/c3cp53379d] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
An electrostatics-based approach has been proposed for probing the weak interactions between lone pair containing molecules and π deficient molecular systems. For electron-rich molecules, the negative minima in molecular electrostatic potential (MESP) topography give the location of electron localization and the MESP value at the minimum (Vmin) quantifies the electron-rich character of that region. Interactive behavior of a lone pair bearing molecule with electron deficient π-systems, such as hexafluorobenzene, 1,3,5-trinitrobenzene, 2,4,6-trifluoro-1,3,5-triazine and 1,2,4,5-tetracyanobenzene explored within DFT brings out good correlation of the lone pair-π interaction energy (E(int)) with the Vmin value of the electron-rich system. Such interaction is found to be portrayed well with the Electrostatic Potential for Intermolecular Complexation (EPIC) model. On the basis of the precise location of MESP minimum, a prediction for the orientation of a lone pair bearing molecule with an electron deficient π-system is possible in the majority of the cases studied.
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Affiliation(s)
- Neetha Mohan
- Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum, 695019, India.
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Mandadapu KK, Templeton JA, Lee JW. Polarization as a field variable from molecular dynamics simulations. J Chem Phys 2013; 139:054115. [DOI: 10.1063/1.4817004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Wheeler SE, Houk KN. Through-Space Effects of Substituents Dominate Molecular Electrostatic Potentials of Substituted Arenes. J Chem Theory Comput 2009; 5:2301-2312. [PMID: 20161573 DOI: 10.1021/ct900344g] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Model systems have been studied using density functional theory to assess the contributions of π-resonance and through-space effects on electrostatic potentials of substituted arenes. The results contradict the widespread assumption that changes in molecular ESPs reflect only local changes in the electron density. Substituent effects on the ESP above the molecular plane are commonly attributed to changes in the aryl π-system. We show that ESP changes for a collection of substituted benzenes and more complex aromatic systems can be accounted for mostly by through-space effects, with no change in the aryl π-electron density. Only when π-resonance effects are substantial do they influence changes in the ESP above the aromatic ring to any extent. Examples of substituted arenes studied here are taken from the fields of drug design, host-guest chemistry, and crystal engineering. These findings emphasize the potential pitfalls of assuming ESP changes reflect changes in the local electron density. Since ESP changes are frequently used to rationalize and predict intermolecular interactions, these findings have profound implications for our understanding of substituent effects in countless areas of chemistry and molecular biology. Specifically, in many non-covalent interactions there are significant, often neglected, through-space interactions with the substituents. Finally, the present results explain the perhaps unexpectedly good performance of many molecular mechanics force-fields applied to supramolecular assembly phenomena and π-π interactions in biological systems despite the neglect of the polarization of the aryl π-system by substituents.
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Affiliation(s)
- Steven E Wheeler
- Department of Chemistry and Biochemistry University of California, Los Angeles, CA 90095
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Matta CF, Bader RFW. An experimentalist's reply to "What is an atom in a molecule?". J Phys Chem A 2007; 110:6365-71. [PMID: 16686473 DOI: 10.1021/jp060761+] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Parr, Ayers and Nalewajski have opined in this Journal that the concept of an atom in a molecule "is an object knowable by the mind or intellect, not by the senses." This view is countered by the two hundred years of experimental chemistry underlying the realization that the properties of some total system are the sum of its atomic contributions. This paper concludes that an experimentalist has no doubt but that he or she is measuring the properties of atoms when performing an experiment.
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Affiliation(s)
- Chérif F Matta
- Department of Chemistry, Dalhousie University, Halifax NS B3H 4J3, Canada
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Bader RFW, Matta CF. Atomic Charges Are Measurable Quantum Expectation Values: A Rebuttal of Criticisms of QTAIM Charges. J Phys Chem A 2004. [DOI: 10.1021/jp0482666] [Citation(s) in RCA: 167] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Richard F. W. Bader
- Department of Chemistry, McMaster University, Hamilton, Ontario L8S 4M1, Canada, and Lash Miller Chemical Laboratories, Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Chérif F. Matta
- Department of Chemistry, McMaster University, Hamilton, Ontario L8S 4M1, Canada, and Lash Miller Chemical Laboratories, Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
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Ponzini F, Zagha R, Hardcastle K, Siegel JS. Phenyl/Pentafluorophenyl Interactions and the Generation of Ordered Mixed Crystals:sym-Triphenethynylbenzene andsym-Tris(perfluorophenethynyl)benzene. Angew Chem Int Ed Engl 2000. [DOI: 10.1002/1521-3757(20000703)112:13<2413::aid-ange2413>3.0.co;2-t] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Ritchie GL, Watson JN. Temperature dependence of electric field-gradient induced birefringence (the Buckingham effect) in C6H6 and C6F6: comparison of electric and magnetic properties of C6H6 and C6F61This Letter is dedicated to Professor A.D. Buckingham, FRS, on the occasion of his retirement as an Editor of Chemical Physics Letters.1. Chem Phys Lett 2000. [DOI: 10.1016/s0009-2614(00)00369-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Alkorta I, Rozas I, Elguero J. An Attractive Interaction between the π-Cloud of C6F6 and Electron-Donor Atoms. J Org Chem 1997. [DOI: 10.1021/jo970125v] [Citation(s) in RCA: 164] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ibon Alkorta
- Instituto de Química Médica (CSIC), Juan de la Cierva, 3, E-28006-Madrid, Spain
| | - Isabel Rozas
- Instituto de Química Médica (CSIC), Juan de la Cierva, 3, E-28006-Madrid, Spain
| | - Jose Elguero
- Instituto de Química Médica (CSIC), Juan de la Cierva, 3, E-28006-Madrid, Spain
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Hernández-Trujillo J, Vela A. Molecular Quadrupole Moments for the Series of Fluoro- and Chlorobenzenes. ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp953576x] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jesús Hernández-Trujillo
- Departamento de Física y Química Teórica, Facultad de Química, Universidad Nacional Autónoma de México, México D.F. 04510, México
| | - Alberto Vela
- Departamento de Química, División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-Iztapalapa, A.P. 55-534, México D.F. 09340, México
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