Parameterization of the electronegativity equalization method based on the charge model 1

Menegon, Guilherme; Shimizu, Karina; Farah, João Pedro Simon; Dias, Luís Gustavo; Chaimovich, Hernán

doi:10.1039/b206991a

Cited by 32 publications

(43 citation statements)

References 29 publications

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“…Bultinck et al 36 fitted EEM empirical charges to DFT-derived charges and obtained optimized, transferable electronegativity and hardness parameters. As Menegon et al demonstrated, 37 original EEM charges were fitted to reproduce charges of the Charge Model 1, 14 and the quality of fit was as good as 0.977 in terms of the correlation coefficient. A similar approach was employed by Zefirov and coworkers 38 to fit the KCM charges 18,27 to the RESP charges.…”

Section: Introductionmentioning

confidence: 99%

Kirchhoff atomic charges fitted to multipole moments: Implementation for a virtual screening system

et al. 2008

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The Kirchhoff charge model is a viable method of generating inexpensive and electrostatically reasonable atomic charges for molecular mechanical force fields. The charging method uses a computationally fast algorithm based on the principle of electronegativity relaxation. Parameters of the method, orbital electronegativities and hardnesses, are fitted to reproduce reference, ab initio calculated dipole and quadrupole moments of a representative training set of neutral and charged organic molecules covering most medicinal chemistry relevant bonding situations. Transferability and accuracy of the derived parameters are confirmed on an external test set. Comparisons to other charge models are made. Implementation of the new Kirchhoff charges into a virtual screening engine is elucidated.

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Section: Introductionmentioning

confidence: 99%

Kirchhoff atomic charges fitted to multipole moments: Implementation for a virtual screening system

et al. 2008

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“…This fitting is mostly done in a least squares sense by finding the parameters that minimize the quadratic error between the ab initio computed charges and the ones obtained using a set of systematically improved parameters; see, for example, Refs. [11][12][13][14][15][16][17][18]. In practice, such fitting is far from trivial.…”

Section: Introductionmentioning

confidence: 97%

Self-consistent methods constrained to a fixed number of particles in a given fragment and its relation to the electronegativity equalization method

2012

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The variational procedure of the Hartree-Fock and Kohn-Sham methods can be modified by adding one or more constraints that fix the number of electrons in a given number of molecular fragments. The corresponding Euler-Lagrange equations lead to a modified Fock matrix, where the contribution from the constraints only depends on the overlap matrix, when using the Mulliken or Hirshfeld atoms-in-molecules method. For all compounds in the test set, the energy shows a quadratic dependence on the fixed charges. This behavior provides a procedure to obtain the atomic electronegativity and hardness parameters in the electronegativity equalization method

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“…Essentially, the EEM is parameterized for the specified level of theory (e.g., HF, B3LYP), basis set (e.g., STO‐3G, 3‐21G, 6‐31G*) and charge calculation scheme [e.g., Mulliken population analysis (MPA), Merz‐Kollman‐Singh (MK), charges from electrostatic potentials using a grid based method (CHELPG)]7. Nowadays, the EEM is parameterized for different combinations of the theory level, basis set, and the scheme for charge calculation as one can see for example in Yang and Shen8, 9, Menegon et al10 and Bultinck et al11, 12 The EEM is also used in cooperation with other chemical techniques (e.g., Smirnov and van de Graaf13, Heidler et al14, and others). In this article, the process of EEM parameters development was performed according to the methodology described in detail in ref 15,.…”

Section: Introductionmentioning

confidence: 99%

Software news and updates electronegativity equalization method: Parameterization and validation for organic molecules using the Merz‐Kollman‐Singh charge distribution scheme

et al. 2008

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Abstract:The electronegativity equalization method (EEM) was developed by Mortier et al. as a semiempirical method based on the density-functional theory. After parameterization, in which EEM parameters A i , B i , and adjusting factor κ are obtained, this approach can be used for calculation of average electronegativity and charge distribution in a molecule. The aim of this work is to perform the EEM parameterization using the Merz-Kollman-Singh (MK) charge distribution scheme obtained from B3LYP/6-31G* and HF/6-31G* calculations. To achieve this goal, we selected a set of 380 organic molecules from the Cambridge Structural Database (CSD) and used the methodology, which was recently successfully applied to EEM parameterization to calculate the HF/STO-3G Mulliken charges on large sets of molecules. In the case of B3LYP/6-31G* MK charges, we have improved the EEM parameters for already parameterized elements, specifically C, H, N, O, and F. Moreover, EEM parameters for S, Br, Cl, and Zn, which have not as yet been parameterized for this level of theory and basis set, we also developed. In the case of HF/6-31G* MK charges, we have developed the EEM parameters for C, H, N, O, S, Br, Cl, F, and Zn that have not been parameterized for this level of theory and basis set so far. The obtained EEM parameters were verified by a previously developed validation procedure and used for the charge calculation on a different set of 116 organic molecules from the CSD. The calculated EEM charges are in a very good agreement with the quantum mechanically obtained ab initio charges.

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Parameterization of the electronegativity equalization method based on the charge model 1

Cited by 32 publications

References 29 publications

Kirchhoff atomic charges fitted to multipole moments: Implementation for a virtual screening system

Kirchhoff atomic charges fitted to multipole moments: Implementation for a virtual screening system

Self-consistent methods constrained to a fixed number of particles in a given fragment and its relation to the electronegativity equalization method

Software news and updates electronegativity equalization method: Parameterization and validation for organic molecules using the Merz‐Kollman‐Singh charge distribution scheme

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