Advancing beyond charge analysis using the electronic localization function: Chemically intuitive distribution of electrostatic moments

Abstract

We propose here an evaluation of chemically intuitive distributed electrostatic moments using the topological analysis of the electron localization function (ELF). As this partition of the total charge density provides an accurate representation of the molecular dipole, the distributed electrostatic moments based on the ELF partition (DEMEP) allows computing of local moments located at non atomic centers such as lone pairs, sigma bonds and pi systems. As the local dipole contribution can be decomposed in polarization and charge transfer components, our results indicate that local dipolar polarization of the lone pairs and chemical reactivity are closely related whereas the charge transfer contribution is the key factor driving the local bond dipole. Results on relevant molecules show that local dipole contributions can be used to rationalize inductive polarization effects in alcohols derivatives and typical hydrogen bond interactions. Moreover, bond quadrupole polarization moments being related to a pi character enable to discuss bond multiplicities, and to sort families of molecules according to their bond order. That way, the nature of the C-O bond has been revisited for several typical systems by means of the DEMEP analysis which appears also helpful to discuss aromaticity. Special attention has been given to the carbon monoxide molecule, to the CuCO complex and to a weak intramolecular N|-CO interaction involved in several biological systems. In this latter case, it is confirmed that the bond formation is mainly linked to the CO bond polarization. Transferability tests show that the approach is suitable for the design of advanced force fields.

A Complete NCI Perspective: From New Bonds to Reactivity

“…[47] The crucial role of weak interactions can also be analyzed in an indirect manner through property computations (from population to electrostatic moments). [48] However, these fluctuations are not easily visualized. In other words, a visual quantum chemical approach was conspicuously missing in this scenario.…”

Unraveling Low‐Barrier Hydrogen Bonds in Complex Systems with a Simple Quantum Topological Criterion

“…Tests performed with the correlated ELF formulation [27] exhibit no topological differences between DFT and post Hartree-Fock levels of computation (see Figure S4 in the Supporting Information) and choice of the basis set (this latter point being well-documented as ELF populations are less sensitive to basis sets than usual Mulliken analyses). [21,28] www.chemeurj.org…”

“…Pseudobonds are essential to obtain a good representation of density/ELF at the boundary between QM and MM systems. All ELF computations and topological analyses were performed with a modified TopMod package, [28,48] which includes the capability of using correlated wave functions. [27] By using TopMod, the ELF topological analysis allows an automatic partition of space within domains related to specific points called attractors (the ELF equivalent of the centroids of the localized orbitals), which can be localized (and associated to xyz coordinates).…”

Pseudobond parameters for QM/MM studies involving nucleosides, nucleotides, and their analogs

“…In addition to the molecules present in the total training set, the testing set also included the monophosphorylated (phosphate dianion) counterparts of each nucleoside (i.e., nucleotides) ( Figure 1(b)). Additional properties included in the assessment were geometries (bond lengths, angles, and dihedrals), ESP and NBO 31, 32 charges, AIM 33,34 charges and AIM first moments 35 (M1). The AIM M1 is the first electrostatic moment of a molecular space (an atom in AIM) and can be compared to the dipole of an atom in a molecule.…”