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Ramasami P, Murray JS. Radial Behavior of Electrostatic Potentials of Atoms and Ions Revisited: Isotropy and Anisotropy. Chemphyschem 2024:e202400450. [PMID: 38775267 DOI: 10.1002/cphc.202400450] [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: 04/19/2024] [Revised: 05/17/2024] [Indexed: 07/12/2024]
Abstract
In this paper we revisit earlier work relating to monoatomic atoms and ions published by pioneers in the area of electrostatic potentials. We include plots of the radial distributions of the electrostatic potentials for spherically symmetric atoms and cations, and for singly, doubly and triply negative anions. For atoms with anisotropy in their densities and electrostatic potentials, such as the halonium cations, it is shown how the molecular surface approach for plotting electrostatic potentials complements that achieved by directional radial distributions.
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Affiliation(s)
- Ponnadurai Ramasami
- Computational Chemistry Group, Department of Chemistry Faculty of Science, University of Mauritius, Reduit, 80837, Mauritius
- Centre of Natural Product Research, Department of Chemical Sciences University of Johannesburg, Doornfontein Campus, Johannesburg, 2028, South Africa
| | - Jane S Murray
- Department of Chemistry, University of New Orleans, New Orleans, LA, 70148, USA
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2
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Sessa F, Rahm M. Electronegativity Equilibration. J Phys Chem A 2022; 126:5472-5482. [PMID: 35939052 PMCID: PMC9393861 DOI: 10.1021/acs.jpca.2c03814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Controlling the distribution of electrons in materials
is the holy
grail of chemistry and material science. Practical attempts at this
feat are common but are often reliant on simplistic arguments based
on electronegativity. One challenge is knowing when such arguments
work, and which other factors may play a role. Ultimately, electrons
move to equalize chemical potentials. In this work, we outline a theory
in which chemical potentials of atoms and molecules are expressed
in terms of reinterpretations of common chemical concepts and some
physical quantities: electronegativity, chemical hardness, and the
sensitivity of electronic repulsion and core levels with respect to
changes in the electron density. At the zero-temperature limit, an
expression of the Fermi level emerges that helps to connect several
of these quantities to a plethora of material properties, theories
and phenomena predominantly explored in condensed matter physics.
Our theory runs counter to Sanderson’s postulate of electronegativity
equalization and allows a perspective in which electronegativities
of bonded atoms need not be equal. As chemical potentials equalize
in this framework, electronegativities equilibrate.
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Affiliation(s)
- Francesco Sessa
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Martin Rahm
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
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3
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Impact of end capped modification on BT-CIC molecule for high-performance photovoltaic attributes: a DFT approach. J Mol Model 2022; 28:218. [PMID: 35821346 DOI: 10.1007/s00894-022-05217-5] [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: 03/01/2022] [Accepted: 07/04/2022] [Indexed: 10/17/2022]
Abstract
With the aim of utilizing structural modeling techniques to design efficient organic solar cells, a quantum chemical density functional theory (DFT) and its time-dependent DFT (TD-DFT) study have been carried out for the examination of the photovoltaic properties of four BT-ClC-based novel non-fullerene acceptor (NFA) molecules. The designed entities (BT1-BT4) have an A-π-D-π-A configuration with seven fused ring-based BDT central core and newly substituted peripheral acceptor moieties. The optical parameters (absorption maxima, light-harvesting efficiency, first excitation energies, and dipole moments), electronic properties (frontier molecular orbitals, density of states, and molecular electrostatic potential), and charge transfer characteristics (open-circuit voltage, transition density matrix, and fill factor) of the investigated molecules were evaluated using the selected B3LYP/6-31G (d,p) level of theory. The systematic computational analysis reveals that under the influence of terminal acceptor groups, there is an augmentation in the absorption range, and reduction in the band gap values. The electron withdrawing effect of acceptor moieties is evident from the electronic density distribution on the HOMO-LUMO orbitals, along with the density of state (DOS) graphs. Transition density matrix (TDM) analyses reveal consistent charge transfer in the newly devised entities. Reorganization energies computed for electron and hole are significantly lower than the reference, making the transfer of charge carriers efficient. Open-circuit voltage (Voc) of reported acceptor entities, theoretically computed with PTB7-Th donor, revealed maximum output. Furthermore, the estimated fill factor (FF) of the investigated molecules predicted an increase in power conversion efficiencies. Consequently, all the computed parameters favor the applicability of our designed molecules in the field of organic photovoltaics by virtue of their excellent charge mobilities, increased absorption maximum values, and reduced band gaps.
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4
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Politzer P, Murray JS. Electronegativity: A continuing enigma. J PHYS ORG CHEM 2022. [DOI: 10.1002/poc.4406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Peter Politzer
- Department of Chemistry University of New Orleans New Orleans Louisiana USA
| | - Jane S. Murray
- Department of Chemistry University of New Orleans New Orleans Louisiana USA
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5
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Mian SA, Khan SU, Hussain A, Rauf A, Ahmed E, Jang J. Molecular Modelling of Optical Biosensor Phosphorene-Thioguanine for Optimal Drug Delivery in Leukemia Treatment. Cancers (Basel) 2022; 14:cancers14030545. [PMID: 35158813 PMCID: PMC8833433 DOI: 10.3390/cancers14030545] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/14/2022] [Accepted: 01/19/2022] [Indexed: 02/04/2023] Open
Abstract
Simple Summary Nanocarriers have been used to solve the problems associated with conventional antitumor drug delivery systems, including no specificity, severe side effects, burst release and damaging the normal cells. It improves the bioavailability and therapeutic efficiency of antitumor drugs, while providing preferential accumulation at the target site. Various 2D nanomaterials such as graphene, MoS2, and WSe2 have been used as nanocarrier. The recent discovery of phosphorene has introduced new possibilities in designing a sensible drug delivery system, due to low cytotoxicity, biocompatibility, high surface to volume ratio, which can increase its drug loading capacity. The biodegradation of phosphorene inside the human body produces non-toxic intermediates, like phosphate. Phosphate is necessary for the formation of bone and teeth. Phosphate is also used by the cell for energy, cell membranes, and DNA (deoxyribonucleic acid). Therefore, phosphorene nanocarrier is not harmful, especially for the treatment of cancer in vivo applications. Abstract Thioguanine is an anti-cancer drug used for the treatment of leukemia. However, thioguanine has weak aqueous solubility and low biocompatibility, which limits its performance in the treatment of cancer. In the present work, these inadequacies were targeted using density functional theory-based simulations. Three stable configurations were obtained for the adsorption of thioguanine molecules on the phosphorene surface, with adsorption energies in the range of −76.99 to −38.69 kJ/mol, indicating physisorption of the drug on the phosphorene surface. The calculated bandgap energies of the individual and combined geometries of phosphorene and thioguanine were 0.97 eV, 2.81 eV and 0.91 eV, respectively. Owing to the physisorption of the drug molecule on the phosphorene surface, the bandgap energy of the material had a direct impact on optical conductivity, which was significantly altered. All parameters that determine the potential ability for drug delivery were calculated, such as the dipole moment, chemical hardness, chemical softness, chemical potential, and electrophilicity index. The higher dipole moment (1.74 D) of the phosphorene–thioguanine complex reflects its higher biodegradability, with no adverse physiological effects.
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Affiliation(s)
- Shabeer Ahmad Mian
- Department of Physics, University of Peshawar, Peshawar 25120, Pakistan; (S.U.K.); (A.H.); (A.R.)
- Correspondence: (S.A.M.); (J.J.)
| | - Shafqat Ullah Khan
- Department of Physics, University of Peshawar, Peshawar 25120, Pakistan; (S.U.K.); (A.H.); (A.R.)
| | - Akbar Hussain
- Department of Physics, University of Peshawar, Peshawar 25120, Pakistan; (S.U.K.); (A.H.); (A.R.)
| | - Abdur Rauf
- Department of Physics, University of Peshawar, Peshawar 25120, Pakistan; (S.U.K.); (A.H.); (A.R.)
| | - Ejaz Ahmed
- Department of Physics, Abdul Wali Khan University Mardan, Mardan 23200, Pakistan;
| | - Joonkyung Jang
- Department of Nano Energy Engineering, Pusan National University, Pusan 46241, Korea
- Correspondence: (S.A.M.); (J.J.)
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Racioppi S, Rahm M. In-Situ Electronegativity and the Bridging of Chemical Bonding Concepts. Chemistry 2021; 27:18156-18167. [PMID: 34668618 PMCID: PMC9299076 DOI: 10.1002/chem.202103477] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Indexed: 12/30/2022]
Abstract
One challenge in chemistry is the plethora of often disparate models for rationalizing the electronic structure of molecules. Chemical concepts abound, but their connections are often frail. This work describes a quantum‐mechanical framework that enables a combination of ideas from three approaches common for the analysis of chemical bonds: energy decomposition analysis (EDA), quantum chemical topology, and molecular orbital (MO) theory. The glue to our theory is the electron energy density, interpretable as one part electrons and one part electronegativity. We present a three‐dimensional analysis of the electron energy density and use it to redefine what constitutes an atom in a molecule. Definitions of atomic partial charge and electronegativity follow in a way that connects these concepts to the total energy of a molecule. The formation of polar bonds is predicted to cause inversion of electronegativity, and a new perspective of bonding in diborane and guanine−cytosine base‐pairing is presented. The electronegativity of atoms inside molecules is shown to be predictive of pKa.
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Affiliation(s)
- Stefano Racioppi
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemigården 4, 41258, Gothenburg, Sweden
| | - Martin Rahm
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemigården 4, 41258, Gothenburg, Sweden
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Bulat FA, Murray JS, Politzer P. Identifying the most energetic electrons in a molecule: The highest occupied molecular orbital and the average local ionization energy. COMPUT THEOR CHEM 2021. [DOI: 10.1016/j.comptc.2021.113192] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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8
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Rahm M, Erhart P, Cammi R. Relating atomic energy, radius and electronegativity through compression. Chem Sci 2021; 12:2397-2403. [PMID: 34164004 PMCID: PMC8179346 DOI: 10.1039/d0sc06675c] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Trends in atomic properties are well-established tools for guiding the analysis and discovery of materials. Here, we show how compression can reveal a long sought-after connection between two central chemical concepts - van-der-Waals (vdW) radii and electronegativity - and how these relate to the driving forces behind chemical and physical transformations.
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Affiliation(s)
- Martin Rahm
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology SE-412 96 Gothenburg Sweden
| | - Paul Erhart
- Department of Physics, Chalmers University of Technology SE-412 96 Gothenburg Sweden
| | - Roberto Cammi
- Department of Chemical Science, Life Science and Environmental Sustainability, University of Parma Parma Italy
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9
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Guo J, Guo C, Chen L, Peng X. Modified mesoporous Y zeolite catalyzed nitration of azobenzene using NO 2 as the nitro source combined with density functional theory studies. NEW J CHEM 2021. [DOI: 10.1039/d1nj04398f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A modified mesoporous Y zeolite (Fe–Y) is developed for high ortho regioselective nitration of azobenzene under a NO2–O2 system.
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Affiliation(s)
- Jiaming Guo
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Chuanzhou Guo
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Lei Chen
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Xinhua Peng
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
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10
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El-Samman AM, Staroverov VN. Asymptotic behavior of the average local ionization energy in finite basis sets. J Chem Phys 2020; 153:134109. [PMID: 33032433 DOI: 10.1063/5.0023459] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The average local ionization energy (ALIE) has important applications in several areas of electronic structure theory. Theoretically, the ALIE should asymptotically approach the first vertical ionization energy (IE) of the system, as implied by the rate of exponential decay of the electron density; for one-determinantal wavefunctions, this IE is the negative of the highest-occupied orbital energy. In practice, finite-basis-set representations of the ALIE exhibit seemingly irregular and sometimes dramatic deviations from the expected asymptotic behavior. We analyze the long-range behavior of the ALIE in finite basis sets and explain the puzzling observations. The findings have implications for practical calculations of the ALIE, the construction of Kohn-Sham potentials from wavefunctions and electron densities, and basis-set development.
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Affiliation(s)
- Amer M El-Samman
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Viktor N Staroverov
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
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11
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Molybdovanadophosphoric Heteropolyacid-Catalyzed Aerobic Oxidation of Methacrolein: The Crucial Role of Ionic Liquid as a Modifier. Catal Letters 2020. [DOI: 10.1007/s10562-019-03063-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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12
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Carniato S. Evolution of Electronegativity of Chlorinated Sulfur‐Containing and Organic Compounds from Neutral to Core‐Excited/Ionized States. ChemistrySelect 2019. [DOI: 10.1002/slct.201903128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Stéphane Carniato
- Sorbonne UniversitéUPMC Université Paris 06, CNRS, LCP-MR (UMR 7614) 4 place Jussieu 75252 Paris Cedex 05 France
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13
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Rahm M, Cammi R, Ashcroft NW, Hoffmann R. Squeezing All Elements in the Periodic Table: Electron Configuration and Electronegativity of the Atoms under Compression. J Am Chem Soc 2019; 141:10253-10271. [PMID: 31144505 DOI: 10.1021/jacs.9b02634] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present a quantum mechanical model capable of describing isotropic compression of single atoms in a non-reactive neon-like environment. Studies of 93 atoms predict drastic changes to ground-state electronic configurations and electronegativity in the pressure range of 0-300 GPa. This extension of atomic reference data assists in the working of chemical intuition at extreme pressure and can act as a guide to both experiments and computational efforts. For example, we can speculate on the existence of pressure-induced polarity (red-ox) inversions in various alloys. Our study confirms that the filling of energy levels in compressed atoms more closely follows the hydrogenic aufbau principle, where the ordering is determined by the principal quantum number. In contrast, the Madelung energy ordering rule is not predictive for atoms under compression. Magnetism may increase or decrease with pressure, depending on which atom is considered. However, Hund's rule is never violated for single atoms in the considered pressure range. Important (and understandable) electron shifts, s→p, s→d, s→f, and d→f are essential chemical and physical consequences of compression. Among the specific intriguing changes predicted are an increase in the range between the most and least electronegative elements with compression; a rearrangement of electronegativities of the alkali metals with pressure, with Na becoming the most electropositive s1 element (while Li becomes a p group element and K and heavier become transition metals); phase transitions in Ca, Sr, and Ba correlating well with s→d transitions; spin-reduction in all d-block atoms for which the valence d-shell occupation is d n (4 ≤ n ≤ 8); d→f transitions in Ce, Dy, and Cm causing Ce to become the most electropositive element of the f-block; f→d transitions in Ho, Dy, and Tb and a s→f transition in Pu. At high pressure Sc and Ti become the most electropositive elements, while Ne, He, and F remain the most electronegative ones.
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Affiliation(s)
- Martin Rahm
- Department of Chemistry and Chemical Engineering , Chalmers University of Technology , SE-412 96 Gothenburg , Sweden
| | - Roberto Cammi
- Department of Chemical Science, Life Science and Environmental Sustainability , University of Parma , 43124 Parma , Italy
| | - N W Ashcroft
- Laboratory of Atomic and Solid State Physics , Cornell University , Ithaca , New York 14853 , United States
| | - Roald Hoffmann
- Department of Chemistry and Chemical Biology, Baker Laboratory , Cornell University , Ithaca , New York 14853 , United States
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14
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Abstract
Our discussion focuses upon three possible features that a bonded halogen atom may exhibit on its outer side, on the extension of the bond. These are (1) a region of lower electronic density (a σ-hole) accompanied by a positive electrostatic potential with a local maximum, (2) a region of lower electronic density (a σ-hole) accompanied by a negative electrostatic potential that also has a local maximum, and (3) a buildup of electronic density accompanied by a negative electrostatic potential that has a local minimum. In the last case, there is no σ-hole. We show that for diatomic halides and halogen-substituted hydrides, the signs and magnitudes of these maxima and minima can be expressed quite well in terms of the differences in the electronegativities of the halogen atoms and their bonding partners, and the polarizabilities of both. We suggest that the buildup of electronic density and absence of a σ-hole on the extension of the bond to the halogen may be an operational indication of ionicity.
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15
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Rahm M, Zeng T, Hoffmann R. Electronegativity Seen as the Ground-State Average Valence Electron Binding Energy. J Am Chem Soc 2018; 141:342-351. [PMID: 30499303 DOI: 10.1021/jacs.8b10246] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
We introduce a new electronegativity scale for atoms, based consistently on ground-state energies of valence electrons. The scale is closely related to (yet different from) L. C. Allen's, which is based on configuration energies. Using a combination of literature experimental values for ground-state energies and ab initio-calculated energies where experimental data are missing, we are able to provide electronegativities for elements 1-96. The values are slightly smaller than Allen's original scale, but correlate well with Allen's and others. Outliers in agreement with other scales are oxygen and fluorine, now somewhat less electronegative, but in better agreement with their chemistry with the noble gas elements. Group 11 and 12 electronegativities emerge as high, although Au less so than in other scales. Our scale also gives relatively high electronegativities for Mn, Co, Ni, Zn, Tc, Cd, Hg (affected by choice of valence state), and Gd. The new electronegativities provide hints for new alloy/compound design, and a framework is in place to analyze those energy changes in reactions in which electronegativity changes may not be controlling.
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Affiliation(s)
- Martin Rahm
- Department of Chemistry and Chemical Engineering , Chalmers University of Technology , SE-412 96 , Gothenburg , Sweden
| | - Tao Zeng
- Department of Chemistry , Carleton University , Ottawa , Ontario K1S 5B6 , Canada
| | - Roald Hoffmann
- Department of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853 , United States
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17
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Brinck T, Stenlid JH. The Molecular Surface Property Approach: A Guide to Chemical Interactions in Chemistry, Medicine, and Material Science. ADVANCED THEORY AND SIMULATIONS 2018. [DOI: 10.1002/adts.201800149] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Tore Brinck
- Applied Physical ChemistryDepartment of ChemistryCBHKTH Royal Institute of Technology SE‐100 44 Stockholm Sweden
| | - Joakim H. Stenlid
- Department of PhysicsAlbaNova University CenterStockholm University SE‐106 91 Stockholm Sweden
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18
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An Occam’s razor approach to chemical hardness: lex parsimoniae. J Mol Model 2018; 24:332. [DOI: 10.1007/s00894-018-3864-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 10/04/2018] [Indexed: 10/27/2022]
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19
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von Szentpály L. Eliminating symmetry problems in electronegativity equalization and correcting self-interaction errors in conceptual DFT. J Comput Chem 2018; 39:1949-1969. [DOI: 10.1002/jcc.25356] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 04/16/2018] [Accepted: 04/16/2018] [Indexed: 11/09/2022]
Affiliation(s)
- László von Szentpály
- Institut für Theoretische Chemie, Universität Stuttgart, Pfaffenwaldring 55; Stuttgart D-70569 Germany
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20
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Abstract
Electronegativity is a very useful concept but it is not a physical observable; it cannot be determined experimentally. Most practicing chemists view it as the electron-attracting power of an atom in a molecule. Various formulations of electronegativity have been proposed on this basis, and predictions made using different formulations generally agree reasonably well with each other and with chemical experience. A quite different approach, loosely linked to density functional theory, is based on a ground-state free atom or molecule, and equates electronegativity to the negative of an electronic chemical potential. A problem that is encountered with this approach is the differentiation of a noncontinuous function. We show that this approach leads to some results that are not chemically valid. A formulation of atomic electronegativity that does prove to be effective is to express it as the average local ionization energy on an outer contour of the atom's electronic density.
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21
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Hashikawa Y, Murata M, Wakamiya A, Murata Y. Water Entrapped inside Fullerene Cages: A Potential Probe for Evaluation of Bond Polarization. Angew Chem Int Ed Engl 2016; 55:13109-13113. [DOI: 10.1002/anie.201607040] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Indexed: 11/10/2022]
Affiliation(s)
| | - Michihisa Murata
- Institute for Chemical Research; Kyoto University; Uji Kyoto 611-0011 Japan
| | - Atsushi Wakamiya
- Institute for Chemical Research; Kyoto University; Uji Kyoto 611-0011 Japan
| | - Yasujiro Murata
- Institute for Chemical Research; Kyoto University; Uji Kyoto 611-0011 Japan
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22
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Hashikawa Y, Murata M, Wakamiya A, Murata Y. Water Entrapped inside Fullerene Cages: A Potential Probe for Evaluation of Bond Polarization. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201607040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
| | - Michihisa Murata
- Institute for Chemical Research; Kyoto University; Uji Kyoto 611-0011 Japan
| | - Atsushi Wakamiya
- Institute for Chemical Research; Kyoto University; Uji Kyoto 611-0011 Japan
| | - Yasujiro Murata
- Institute for Chemical Research; Kyoto University; Uji Kyoto 611-0011 Japan
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Kohut SV, Cuevas-Saavedra R, Staroverov VN. Generalized average local ionization energy and its representations in terms of Dyson and energy orbitals. J Chem Phys 2016; 145:074113. [DOI: 10.1063/1.4961071] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Abstract
The energy change per electron in a chemical or physical transformation, ΔE/n, may be expressed as Δχ̅ + Δ(VNN + ω)/n, where Δχ̅ is the average electron binding energy, a generalized electronegativity, ΔVNN is the change in nuclear repulsions, and Δω is the change in multielectron interactions in the process considered. The last term can be obtained by the difference from experimental or theoretical estimates of the first terms. Previously obtained consequences of this energy partitioning are extended here to a different analysis of bonding in a great variety of diatomics, including more or less polar ones. Arguments are presented for associating the average change in electron binding energy with covalence, and the change in multielectron interactions with electron transfer, either to, out, or within a molecule. A new descriptor Q, essentially the scaled difference between the Δχ̅ and Δ(VNN + ω)/n terms, when plotted versus the bond energy, separates nicely a wide variety of bonding types, covalent, covalent but more correlated, polar and increasingly ionic, metallogenic, electrostatic, charge-shift bonds, and dispersion interactions. Also, Q itself shows a set of interesting relations with the correlation energy of a bond.
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Affiliation(s)
- Martin Rahm
- Chemistry and Chemical Biology, Baker Laboratory, Cornell University , Ithaca, New York 14853, United States
| | - Roald Hoffmann
- Chemistry and Chemical Biology, Baker Laboratory, Cornell University , Ithaca, New York 14853, United States
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Rahm M, Hoffmann R. Toward an Experimental Quantum Chemistry: Exploring a New Energy Partitioning. J Am Chem Soc 2015; 137:10282-91. [PMID: 26193123 DOI: 10.1021/jacs.5b05600] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Following the work of L. C. Allen, this work begins by relating the central chemical concept of electronegativity with the average binding energy of electrons in a system. The average electron binding energy, χ̅, is in principle accessible from experiment, through photoelectron and X-ray spectroscopy. It can also be estimated theoretically. χ̅ has a rigorous and understandable connection to the total energy. That connection defines a new kind of energy decomposition scheme. The changing total energy in a reaction has three primary contributions to it: the average electron binding energy, the nuclear-nuclear repulsion, and multielectron interactions. This partitioning allows one to gain insight into the predominant factors behind a particular energetic preference. We can conclude whether an energy change in a transformation is favored or resisted by collective changes to the binding energy of electrons, the movement of nuclei, or multielectron interactions. For example, in the classical formation of H2 from atoms, orbital interactions dominate nearly canceling nuclear-nuclear repulsion and two-electron interactions. While in electron attachment to an H atom, the multielectron interactions drive the reaction. Looking at the balance of average electron binding energy, multielectron, and nuclear-nuclear contributions one can judge when more traditional electronegativity arguments can be justifiably invoked in the rationalization of a particular chemical event.
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Affiliation(s)
- Martin Rahm
- Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Roald Hoffmann
- Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
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Chamorro E, Duque-Noreña M. Understanding the Highly Varying pKa of Arylamines. A Perspective from the Average Local Ionization Condensed-to-Atom Framework. J Phys Chem A 2015; 119:8156-62. [PMID: 26107310 DOI: 10.1021/acs.jpca.5b03252] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The highly varying experimental pKa values for 36 arylamines spanning 7 orders of magnitude is carefully examined. Within this framework, a valence condensed-to-atom model for the average ionization energy is introduced and tested. The theoretical approach is connected to orbital Fukui functions directly mapped into semilocal or regional site-specific responses. It is revealed that the average local ionization energies associated with the amino nitrogen atom is linearly correlated to the basicity of the substituted arylamines, properly reproducing the experimental ordering of basicity. The condensed-to-atom descriptor exhibits a high predictive power, providing a new direct reactivity evaluation of significant value.
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Affiliation(s)
- Eduardo Chamorro
- Departamento de Ciencias Quimicas. Facultad de Ciencias Exactas. Nucleus Millennium of Chemical Processes and Catalysis, Universidad Andres Bello, Avenida República 275, 8370146 Santiago, Chile
| | - Mario Duque-Noreña
- Departamento de Ciencias Quimicas. Facultad de Ciencias Exactas. Nucleus Millennium of Chemical Processes and Catalysis, Universidad Andres Bello, Avenida República 275, 8370146 Santiago, Chile
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A new equation based on ionization energies and electron affinities of atoms for calculating of group electronegativity. COMPUT THEOR CHEM 2015. [DOI: 10.1016/j.comptc.2014.11.017] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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von Szentpály L. Symmetry laws improve electronegativity equalization by orders of magnitude and call for a paradigm shift in conceptual density functional theory. J Phys Chem A 2014; 119:1715-22. [PMID: 25333372 DOI: 10.1021/jp5084345] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The strict Wigner-Witmer symmetry constraints on chemical bonding are shown to determine the accuracy of electronegativity equalization (ENE) to a high degree. Bonding models employing the electronic chemical potential, μ, as the negative of the ground-state electronegativity, χ(GS), frequently collide with the Wigner-Witmer laws in molecule formation. The violations are presented as the root of the substantially disturbing lack of chemical potential equalization (CPE) in diatomic molecules. For the operational chemical potential, μ(op), the relative deviations from CPE fall between -31% ≤ δμ(op) ≤ +70%. Conceptual density functional theory (cDFT) cannot claim to have operationally (not to mention, rigorously) proven and unified the CPE and ENE principles. The solution to this limitation of cDFT and the symmetry violations is found in substituting μ(op) (i) by Mulliken's valence-state electronegativity, χ(M), for atoms and (ii) its new generalization, the valence-pair-affinity, α(VP), for diatomic molecules. Mulliken's χ(M) is equalized into the α(VP) of the bond, and the accuracy of ENE is orders of magnitude better than that of CPE using μ(op). A paradigm shift replacing the dominance of ground states by emphasizing valence states seems to be in order for conceptual DFT.
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Affiliation(s)
- László von Szentpály
- Institut für Theoretische Chemie, Universität Stuttgart , Pfaffenwaldring 55, D-70569 Stuttgart, Germany
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Ryabinkin IG, Staroverov VN. Average local ionization energy generalized to correlated wavefunctions. J Chem Phys 2014; 141:084107. [DOI: 10.1063/1.4893424] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
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Karen P, McArdle P, Takats J. Toward a comprehensive definition of oxidation state (IUPAC Technical Report). PURE APPL CHEM 2014. [DOI: 10.1515/pac-2013-0505] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractA generic definition of oxidation state (OS) is formulated: “The OS of a bonded atom equals its charge after ionic approximation”. In the ionic approximation, the atom that contributes more to the bonding molecular orbital (MO) becomes negative. This sign can also be estimated by comparing Allen electronegativities of the two bonded atoms, but this simplification carries an exception when the more electronegative atom is bonded as a Lewis acid. Two principal algorithms are outlined for OS determination of an atom in a compound; one based on composition, the other on topology. Both provide the same generic OS because both the ionic approximation and structural formula obey rules of stable electron configurations. A sufficiently simple empirical formula yields OS via the algorithm of direct ionic approximation (DIA) by these rules. The topological algorithm works on a Lewis formula (for a molecule) or a bond graph (for an extended solid) and has two variants. One assigns bonding electrons to more electronegative bond partners, the other sums an atom’s formal charge with bond orders (or bond valences) of sign defined by the ionic approximation of each particular bond at the atom. A glossary of terms and auxiliary rules needed for determination of OS are provided, illustrated with examples, and the origins of ambiguous OS values are pointed out. An electrochemical OS is suggested with a nominal value equal to the average OS for atoms of the same element in a moiety that is charged or otherwise electrochemically relevant.
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Affiliation(s)
- Pavel Karen
- 1Department of Chemistry, University of Oslo, P.O.B. 1033 Blindern, 0315 Oslo, Norway
| | | | - Josef Takats
- 3Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2
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Dral PO. The unrestricted local properties: application in nanoelectronics and for predicting radicals reactivity. J Mol Model 2014; 20:2134. [PMID: 24535109 DOI: 10.1007/s00894-014-2134-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 12/27/2013] [Indexed: 12/12/2022]
Abstract
The local electron affinity (EA(L)) and the local ionization energy (IE(L)) are successfully used for predicting properties of closed-shell species for drug design and for nanoelectronics. Here the respective unrestricted Hartree-Fock variants of EA(L) and IE(L), i.e., the unrestricted local electron affinity (UHF-EA(L)) and ionization energy (UHF-IE(L)), have been shown to be useful for predicting properties of open-shell species. UHF-EA(L) and UHF-IE(L) have been applied for explaining unique electronic properties of an exemplary nanomaterial carbon peapod. It is also demonstrated that UHF-EA(L) is useful for predicting and better understanding reactivity of radicals related to alkanes activation.
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Affiliation(s)
- Pavlo O Dral
- Computer-Chemie-Centrum and Interdisciplinary Center for Molecular Materials, University of Erlangen-Nuremberg, Nägelsbachstr. 25, 91052, Erlangen, Germany,
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Politzer P, Murray JS. Halogen Bonding: An Interim Discussion. Chemphyschem 2013; 14:278-94. [DOI: 10.1002/cphc.201200799] [Citation(s) in RCA: 578] [Impact Index Per Article: 52.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Indexed: 11/10/2022]
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Datta D, Shee NK, von Szentpály L. Chemical potential of molecules contrasted to averaged atomic electronegativities: alarming differences and their theoretical rationalization. J Phys Chem A 2012; 117:200-6. [PMID: 23237321 DOI: 10.1021/jp3103386] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present the first large-scale empirical examination of the relation of molecular chemical potentials, μ(0)(mol) = -½(I(0) + A(0))(mol), to the geometric mean (GM) of atomic electronegativities, <χ(0)(at)>(GM) = <½(I(0) + A(0))(at)>(GM), and demonstrate that μ(0)(mol) ≠ -<χ(0)(at)>(GM). Out of 210 molecular μ(0)(mol)values considered more than 150 are not even in the range min{μ(0)(at)} < μ(0)(mol) < max{μ(0)(at)} spanned by the μ(0)(at) = -χ(0)(at) of the constituent atoms. Thus the chemical potentials of the large majority of our molecules cannot be obtained by any electronegativity equalization scheme, including the "geometric mean equalization principle", ½(I(0) + A(0))(mol) = <½(I(0) + A(0))(at)>(GM). For this equation the root-mean-square of relative errors amounts to SE = 71%. Our results are at strong variance with Sanderson's electronegativity equalization principle and present a challenge to some popular practice in conceptual density functional theory (DFT). The influences of the "external" potential and charge dependent covalent and ionic binding contributions are discussed and provide the theoretical rationalization for the empirical facts. Support is given to the warnings by Hinze, Bader et al., Allen, and Politzer et al. that equating the chemical potential to the negative of electronegativity may lead to misconceptions.
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Affiliation(s)
- Dipankar Datta
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Calcutta 700 032, India.
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The average local ionization energy as a tool for identifying reactive sites on defect-containing model graphene systems. J Mol Model 2012. [DOI: 10.1007/s00894-012-1693-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Carniato S, Journel L, Guillemin R, Piancastelli MN, Stolte WC, Lindle DW, Simon M. A new method to derive electronegativity from resonant inelastic x-ray scattering. J Chem Phys 2012; 137:144303. [DOI: 10.1063/1.4757065] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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Bundhun A, Ramasami P, Murray JS, Politzer P. Trends in σ-hole strengths and interactions of F3MX molecules (M = C, Si, Ge and X = F, Cl, Br, I). J Mol Model 2012; 19:2739-46. [PMID: 22968690 DOI: 10.1007/s00894-012-1571-4] [Citation(s) in RCA: 181] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 08/14/2012] [Indexed: 11/28/2022]
Abstract
It is well-established that many covalently-bonded atoms of Groups IV-VII have directionally-specific regions of positive electrostatic potential (σ-holes) through which they can interact with negative sites. In the case of Group VII, this is called "halogen bonding." We have studied two series of molecules: the F3MX and, for comparison, the H3MX (M = C, Si and Ge; X = F, Cl, Br and I). Our objective was to determine how the interplay between M and X in each molecule affects the σ-holes of both, and consequently their interactions with the nitrogen lone pair of HCN. We find that the relative electronegativities of M and X are not sufficient to explain their effects upon each other's σ-holes; consideration of charge capacity/polarizability (and perhaps other factors) also appears to be necessary. However the results do support the description of normal σ-hole interactions as being largely electrostatically-driven.
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Affiliation(s)
- Ashwini Bundhun
- Computational Chemistry Group, Department of Chemistry, University of Mauritius, Reduit, Mauritius
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Mazurek A, Dobrowolski JC. Heteroatom incorporation effect in σ- and π-electron systems: the sEDA(II) and pEDA(II) descriptors. J Org Chem 2012; 77:2608-18. [PMID: 22329449 DOI: 10.1021/jo202542e] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The effect of heteroatom or heteroatomic group incorporation into unsaturated five- and six-membered cyclic systems was studied by means of DFT/B3LYP/aug-cc-pVDZ calculations. Two descriptors of the incorporation effect, sEDA(II) and pEDA(II), reflecting the influence of the incorporated atom or group on the population of the σ and π valence electrons, were constructed on the basis of natural bond orbital analysis. The sEDA(II) and pEDA(II) descriptors were shown to be linearly independent; the former correlated very well with electronegativity scales, whereas the latter correlated with NICS(1)(ZZ) and HOMA(CC) aromaticity indices. The two descriptors seem to be universal tools for analyzing different chemical and physicochemical effects occurring in unsaturated heterocyclic systems.
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Affiliation(s)
- Andrzej Mazurek
- National Medicines Institute, 30/34 Chełmska Street, 00-725 Warsaw, Poland
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Halogen bonding and beyond: factors influencing the nature of CN–R and SiN–R complexes with F–Cl and Cl2. Theor Chem Acc 2012. [DOI: 10.1007/s00214-012-1114-1] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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von Szentpály L. Reply to “Comment on 'Ruling Out Any Electrophilicity Equalization Principle'”. J Phys Chem A 2011. [DOI: 10.1021/jp210486g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- László von Szentpály
- Institut für Theoretische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D 70569 Stuttgart, Germany
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