Molecular electrostatic potentials: A topographical study

Gadre, Shridhar R.; Kulkarni, Sudhir A.; Shrivastava, Indira H.

doi:10.1063/1.462710

Cited by 211 publications

(146 citation statements)

References 28 publications

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“…As previously stated, [4] the positive value implies the presence of an In all cases,t he existence of attractive electrostatic forces in the hydrogen bonding can be observed by the combined analysis of the topologies of the electron density (1(r)) [8, 9, 13a] and of the electrostatic potential( f(r)). [21] The electric field in the plane defined by the carboxylic groups for the neutrala nd protonated glycine dimer (i.e., [ The atomicv olumeo fo ne of the monomers, defined within the AIM methodology,h as been indicated with as haded region. By lookinga tt he electric field lines,calculated from the negative derivative of f(r), it is possible to visualize the direction of the electrostaticf orces acting on ar egion.…”

Section: Computationalmethodsmentioning

confidence: 99%

Charged versus Neutral Hydrogen‐Bonded Complexes: Is There a Difference in the Nature of the Hydrogen Bonds?

Alkorta

Mata

Molins

et al. 2016

Chemistry A European J

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A theoretical study on some carboxylic acid dimers formed by positively or negatively charged molecules has been carried out by using DFT methods. The resulting dimers possess either a charge of +2 or -2. In addition, the corresponding neutral complexes have also been considered. The electron density distribution described by the atoms in molecules and the natural bond orbital methods, as well as the electric field maps of the systems, have been analyzed and compared without finding significant differences between the neutral and ionic complexes. The interaction energy along the dissociation path of the charged dimers shows both a local minimum and a local maximum, defining a stability region between them. When this energetic profile is recalculated by removing the repulsion between the charged groups, it resembles to those of the neutral molecules. Hence, the characteristics of the charged dimers are similar to those of the neutral ones: the addition of a repulsion term for the charged groups permits to retrieve the energetic profiles dependence with the distance in the charged system. The interacting quantum atom (IQA) method has been used to calculate the interaction energy terms, including the classic Coulombic term between the whole molecules and the corresponding of the carboxylic acid groups. The IQA results show repulsive electrostatic interactions when the whole molecules are considered in the ionic complexes, but attractive ones between the carboxylic groups in both neutral and ionic complexes.

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Section: Computationalmethodsmentioning

confidence: 99%

Charged versus Neutral Hydrogen‐Bonded Complexes: Is There a Difference in the Nature of the Hydrogen Bonds?

Alkorta

Mata

Molins

et al. 2016

Chemistry A European J

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“…The MESP minima indicate the concentration sites of electron density and the most favorable sites of electrophilic attack. [45] For nucleophilic attacks, since the maxima of MESP are exclusively located at nuclear positions, it is convenient to use MESP textured on isodensity surfaces for exploring the regions of positive MESP and finding the most electrodeficient sites. Such surfaces have been obtained for BIMINAP, BIMIONAP, and their PdCl 2 complexes ( Figure 6).…”

Section: Molecular Electrostatic Potential Of Bimionapmentioning

confidence: 99%

Imidazoliophosphines are True N‐Heterocyclic Carbene (NHC)–Phosphenium Adducts

Abdellah

Lepetit

Canac

et al. 2010

Chemistry A European J

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Whereas the external nucleophilic reactivity of α-amidiniophosphines has been previously illustrated by their complexation to transition-metal centers, their internal electrophilic reactivity is herein investigated by using BIMIONAP (BIMIONAP=N-methylated BIMINAP cation, BIMINAP=formal contraction of the acronyms BIMIP=2,2'-bis(diphenylphosphino)-1,1'-bibenzimidazole and BINAP=2,2'-bis(diphenylphosphino)-1,1'-binaphthyl). Reaction of tetraethylammonium chloride with free BIMIONAP is found to induce heterolytic cleavage of the N(2)C-P bond to give chlorodiphenylphosphine and a transient phosphine-N-heterocyclic carbene (NHC) species that is trapped in situ by protonation to the corresponding phosphine-benzimidazolium cation. When the chloride anion reacts with the cationic [Pd(η(2)-BIMIONAP)Cl(2)] complex, the same cleavage occurs and the phosphine-NHC moiety is trapped in the corresponding [PdCl(2)(η(2)-phosphine-NHC)] complex. When the chloride anion reacts with the dicationic [Pd(π-allyl)(η(2)-BIMIONAP)](+) complex, allyldiphenylphosphine is produced, and the [PdCl(η(2)-phosphine-NHC)(PPh(2)CH(2)CH=CH(2))](+) complex is obtained. Reaction of free BIMIONAP with the harder n-butyllithium nucleophile also induces heterolytic cleavage of the N(2)C-P bond, from which the phosphine-NHC moiety is trapped by hydrolysis of the benzimidazole ring or by P,C-sulfurization. Cleavage of a C-P bond with the weak Cl(-) nucleophile to release the reactive NHC moiety (according to the unusual scheme C-P+Cl(-)→C:+Cl-P) is a definite experimental indication of the dative nature of the N(2)C-P bond of amidiniophosphines, which are, therefore, better described as NHC→phosphenium adducts. This interpretation is supported by the calculation, at the DFT level, of a heterolytic dissociation mode of the N(2)C-P bond lower in energy than the homolytic one. A mesomeric description of the NHC→phosphenium entity is also proposed on the basis of electron localization function (ELF) and atoms in molecules (AIM) analyses. Finally ELF and AIM-based Fukui indices, molecular orbitals, and MESP analyses show that the initial attack of Cl(-) takes place at the carbenic atom of BIMIONAP.

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“…There are four types of critical points. Starting from the Poisson equation it can be shown analytically that there are no local maxima of the MESP except at the nuclei [12]. Since the nuclei are considered as positive point charges, they are the origin of singularities with infinite positive electrostatic potential.…”

Section: Critical Points Of the Mespmentioning

confidence: 99%

Growth pattern and bonding of copper clusters

Jug

Zimmermann

Köster

2002

Int J of Quantum Chemistry

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Density functional theory calculations of copper cluster Cu n with n = 2-10 are analyzed with respect to their molecular orbitals. It is shown that shell type orbitals of s, p, and d character govern the electronic structure growth and have an influence on the geometric structure. They appear as highest occupied molecular orbital, lowest unoccupied molecular orbital, or as orbitals energetically close to these. Their occurrence can explain the magic numbers of shell models. The bonding in such structures can be explained by an analysis of the critical points of the molecular electrostatic potential. Six types of critical points are observed and related to bonds, rings, cages, lone pairs, and their connections.

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Molecular electrostatic potentials: A topographical study

Cited by 211 publications

References 28 publications

Charged versus Neutral Hydrogen‐Bonded Complexes: Is There a Difference in the Nature of the Hydrogen Bonds?

Charged versus Neutral Hydrogen‐Bonded Complexes: Is There a Difference in the Nature of the Hydrogen Bonds?

Imidazoliophosphines are True N‐Heterocyclic Carbene (NHC)–Phosphenium Adducts

Growth pattern and bonding of copper clusters

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