Lone Pairs: An Electrostatic Viewpoint

Kumar, Anmol; Gadre, Shridhar R.; Mohan, Neetha; Suresh, Cherumuttathu H.

doi:10.1021/jp4117003

Cited by 90 publications

(110 citation statements)

References 36 publications

Supporting

Mentioning

108

Contrasting

Unclassified

Order By: Relevance

“…[65,66] ELF can be understood, in words of D. B. Chesnut, as "a local measure of the Pauli repulsion between electrons due to the exclusion principle" that "allows one to define regions of space that are associated with different electron pairs in a molecule." [67] In this context, and very recently, Gadre et al [68] have addressed questions such as: can a lone pair be defined in terms of physical observables? How can the properties of a lone pair be described?…”

Section: Electron Density Q(r)mentioning

confidence: 99%

Unraveling reaction mechanisms by means of Quantum Chemical Topology Analysis

Andrés

González-Navarrete

Safont

2014

Int J of Quantum Chemistry

View full text Add to dashboard Cite

A chemical reaction can be understood in terms of geometrical changes of the molecular structures and reordering of the electronic densities involved in the process; therefore, identifying structural and electronic density changes taking place along the reaction coordinate renders valuable information on reaction mechanism. Understanding the atomic rearrangements that occur during chemical reactions is of great importance, and this perspective aims to highlight the major developments in quantum chemical topology analysis, based on the combination of electron localization function and catastrophe theory as useful tools in elucidating the bonding and reactivity patterns of molecules. It reveals all the expected, but still ambiguous, elements of electronic structure extensively used by chemists. The chemical bonds determine chemical reactivity, and this technique offers the possibility of their visualization, allowing chemists to understand how atoms bond, how and where bonds are broken/ formed along a given reaction pathway at a most fundamental level, and so, better following and understanding the changes in the bond pattern. Their results clearly herald a new era, in which the atomic imaging of chemical bonds will constitute a new method for examining chemical structures and reaction mechanisms. The important feature of this procedure is that in practice the scope of its values is systemindependent. In addition, from a practical point of view, it is cheap to calculate and implement because wave functions are the required input, which are easily available from standard calculations. To capture these results two reaction mechanisms: isomerization of C(BH) 2 carbene and the thermal cycloheptatriene-norcaradiene isomerizations have been selected, indicating both the generality and utility of this type of analysis.

show abstract

Section: Electron Density Q(r)mentioning

confidence: 99%

Unraveling reaction mechanisms by means of Quantum Chemical Topology Analysis

Andrés

González-Navarrete

Safont

2014

Int J of Quantum Chemistry

View full text Add to dashboard Cite

show abstract

“…33 The use of ELF in studies of molecules and materials is extensive, [34][35][36][37][38][39][40] and the development of the QCT field is rapid. [41][42][43][44][45][46][47] For any density (or function) considered, local "basins" within it can be constructed using zero gradient surfaces, arising around local maxima in the density. 48 Such basins can then, for certain functions like ELF, be formally attributed to chemical concepts such as atoms, bonds and lone pairs ( Figure 1).…”

Section: Journal Of Chemical Theory and Computationmentioning

confidence: 99%

A Chemically Meaningful Measure of Electron Localization

Rahm

2015

J. Chem. Theory Comput.

View full text Add to dashboard Cite

Electron localization and delocalization are commonly invoked in the day-to-day rationalization of chemistry. This work addresses the challenges of quantifying this elusive concept in a chemically useful manner. A general principle, requiring the simultaneous quantification of (1) a limited physical volume (classical criterion) and (2) same-spin loneliness (quantum criterion), is introduced. It is demonstrated how, by beginning with the Electron Localization Function (ELF) scalar field, one can choose to discard all points in space where the same-spin loneliness is lower than a certain value. Such a partitioning approach ensures that both criteria for quantifying localization (1 and 2) are simultaneously met. The most chemically instructive results arise when the dividing boundary condition is set by the local behavior of a homogeneous electron gas. The High Electron Localization domain Population (HELP) is introduced and applied for quantifying the localization of individual domains within molecules, as well as a measure of total electron localization in atoms and molecules. Several striking agreements with chemical intuition, experimental measurable quantities, and quantum chemical constructs are demonstrated along with understandable differences. Studies of diatomic molecules agree with current ideas on chemical bonding. The size-dependence and magnitude of localization in linear hydrocarbons is studied and compared to cyclic systems, such as benzene. The proposed methodology offers a straightforward measure for direct and quantitative comparisons between atoms, molecules, and extended condensed matter.

show abstract

“…Molecular electrostatic potential (MESP) and its topography [56][57][58][59][60][61][62][63][64][65] is a well-established tool for studying molecular reactivity [59,[66][67][68][69][70][71][72][73] (especially weak interactions) and other chemical phenomena such as existence of lone pairs [74,75], aromatic π cloud [76], resonance and inductive effect [77] etc. The research in this area was pioneered by Tomasi and Pullman where the MESP was exploited to understand sites of electrophilic attack [56][57][58]78].…”

Section: Use Of Molecular Electrostatic Potential For Probing Lone Pamentioning

confidence: 99%

“…For instance, in the case of H 2 O, the three eigenvalues of the Hessian matrix of second derivative of MESP are 0.0064, 0.0327 and 0.1304. In a recent work [74], the authors have proposed that the largest among the three eigenvalues enables one to distinguish a CP associated with lone pair from other CPs associated with aromatic ring. Thus, the characterization of lone pairs using MESP topography reveals the location and strength of the lone pairs.…”

Section: Hexafluorobenzenementioning

confidence: 99%

Understanding Lone Pair-π Interactions from Electrostatic Viewpoint

Gadre

Kumar

2015

Challenges and Advances in Computational Chemistry and Physics

Self Cite

View full text Add to dashboard Cite

Over the last two decades, studies on lone pair-π interaction have attracted lot of attention of experimental as well as theoretical chemists due to its intriguing nature and its suspected presence in biological systems. The present Chapter begins with a brief overview of the earlier theoretical and experimental work done in this area. This is followed by exploration of the nuances of bonding in lone pair-π interaction, employing the tool of molecular electrostatic potential (MESP) since such weak interactions are mainly dominated by electrostatic features of host and guest molecules. The critical points associated with the scalar field of MESP are exploited for scrutinizing the directionality and bonding sites involved in the lone pair-π complexes. Furthermore, the electrostatic potential for intermolecular complexation (EPIC) model developed by Gadre et al., has been employed for finding out the electrostatically optimized structures and interaction energies of these complexes. The outcomes of EPIC model are compared with the results obtained from quantum chemical calculations of the complexes employing M06L/6-311++G(d,p) level of theory. The present study details out four different cases of lone pair-π complexes, which are currently in vogue. Hexafluorobenzene, one of the most explored π -deficient host in the present context, is initially taken up to demonstrate various facets of MESP for gaining insights into this interaction. This is followed by the scrutiny of special classes of recently synthesized highly π -deficient molecules, viz. tetraoxacalix [2]arene[2]triazine and naphthalenediimide, which are known to have specificity and large affinity, respectively, towards the electron rich species. The chapter ends with the description of lone pair-π interaction in the case of urate oxidase, an enzyme present in biological systems.

show abstract

Lone Pairs: An Electrostatic Viewpoint

Cited by 90 publications

References 36 publications

Unraveling reaction mechanisms by means of Quantum Chemical Topology Analysis

Unraveling reaction mechanisms by means of Quantum Chemical Topology Analysis

A Chemically Meaningful Measure of Electron Localization

Understanding Lone Pair-π Interactions from Electrostatic Viewpoint

Contact Info

Product

Resources

About