Abstract This paper reports the application of recently proposed formalism known as generalized population analysis (GPA) a new means for quantitative characterization aromaticity various benzenoid rings in polycyclic aromatic hydrocarbons (PAHs). The quantity which we propose measure is so‐called six‐center bond index. values this index characterize extent delocalized cyclic bonding individual PAHs and it shown that scale represented by closely reflects intuitive idea according to can be...

Molecular aromaticity in the linear polyacenes is investigated using an atoms molecules based six center index (SCI-AIM) which measures electron delocalization. SCI-AIM values for indicate decreasing going from outer to inner rings polyacene series. The approach compared a Mulliken-like approach, and critical comparison PDI made.

Various recently introduced multicenter bond indices were reviewed and their interrelations discussed. In addition to this analysis a simple three-center three-orbital model of bonding was proposed applied several molecules with bonds. The applicability tested by comparing semiempirically ab-initio calculated indices. It shown that the correctly describes phenomenon bonding. Another interesting useful application concerns interpretation as an indicator number electrons involved in (3c-2e vs...

Abstract The local aromaticity of benzenoid rings is examined by means the Polansky index (P) and generalized population analysis (GPA). results are found to agree very well with recently published circuit‐condensed ring currents magnetic‐energetic indices, but no correlation nucleus independent chemical shifts (NICS). This usually seen as a manifestation more general multidimensional nature aromaticity. paper examines sources for observed correlations, showing that some indices give...

The nature of the bonding in above carbonyls was studied using analysis domain averaged Fermi holes (DAFH). results straightforwardly confirm conclusions earlier theoretical studies which existence direct metal-metal bond, anticipated for on basis 18-electron rule, questioned. In addition to indicating lack DAFH also allowed characterize electron pairs involved bridging ligands. has shown that because number available is not sufficient formation ordinary localized 2c-2e bonds between...

Bonding in the hypervalent molecules SF4, BrF5, PF5, and SF6 was studied using multicenter bond order indices examination of eigenvalues eigenvectors Fermi holes constituent atoms. Diagonalization provided quantitative validation Musher's categorization hypervalency with SF4 BrF5 representative type I, PF5 belonging to II. The I distinguished between classic two-center two-electron bonds three-center four-electron bonds, whereas results diagonalization for II demonstrated presence...

Abstract The pairon population analysis based on the geminal expansion of pair densities is introduced and applied. As demonstrated by numerical data calculated for a series simple molecules semiempirical MNDO method, resulting populations provide new means visualizing molecular structure. In addition to reproduction classical structural formula including multiplicity individual bonds, confirm transferability bond energies also interpretation concept quantum chemical valence. © 1994 John...

We demonstrate that domain-average Fermi hole (DAFH) analysis, which has previously been used at the Hartree-Fock level, remains useful after proper introduction of electron correlation. perform a systematic investigation variation picture bonding with increasing bond length in simple diatomic molecules such as N2 and LiH. Alongside values shared-electron distribution index (SEDI), this analysis provides further insight into geometry dependence extent sharing polar non-polar systems. also...

The analysis of domain averaged Fermi holes (DAFH) was applied to the elucidation nature bonding interactions in supported metal carbonyls, where multicenter bridging ligands and direct metal−metal bonds are considered as possible alternatives. main focus is directed on detailed scrutiny impact changes topology electron density induced by systematic variation geometry studied carbonyls picture provided visual description terms DAFH analysis. It has been shown that irrespective dramatic...

The bonding in the ground state of C2 is examined using a combined approach based on analysis domain-averaged Fermi holes and contributions to covalent bond orders that can be associated with individual localised natural orbitals. σ system this molecule turns out particularly sensitive, evolving from description includes fairly traditional shared electron pair bond, for range intermediate nuclear separations, somewhat different situation near equilibrium geometry, where non-classical...

Quantum chemical calculations using ab initio methods at the CCSD(T) level and density functional theory have been carried out for title molecules. The electronic structures of molecules were analyzed with a variety charge energy decomposition methods. equilibrium geometries M2O2 rhombic clusters exhibit very short distances between transannular metal atoms M = Be, Mg, Ca. calculated are close to standard values double triple bonds, but there no M-M bonds. carry large positive partial...

The nature of the Ga−Ga bond in naked dianion PhGaGaPh2- and its Na+-coordinated counterpart is discussed using recently proposed formalism based on analysis domain-averaged Fermi holes. shows clearly that three electron pairs, i.e., two σ one π, contribute to bonding interactions free sodium-complexed species (PhGaGaPh)Na2. eigenvalues eigenvectors hole indicate, however, situation does not correspond classical triple bonds should be interpreted models. reason only pairs involved bonding,...

A new molecular descriptor of hydrophobicity based on quantum similarity measures (MQSM), which can be used to replace the log P parameter in QSAR studies, is proposed. Unlike majority existing approaches for calculation P, present methodology does not rely use fragment additive contributions, but rather it comparison chemically calculated electron density distributions a given molecule water and 1-octanol, using MQSM. The method has been tested broad series 58 molecules including such...

This study reports the use of multicenter bond indices as a new tool for quantitative characterization homoaromaticity. The approach was applied to series bicyclic systems whose homoaromaticity recently discussed in terms traditional aromaticity index, namely, NICS. In this we found that are indeed able quantify degree studied reflected classification these molecules into classes homoaromatic, non-homoaromatic, and anti-homoaromatic suggested on basis NICS values.

Abstract The relative aromaticity of benzenoid rings in the linear polyacenes is investigated using two novel approaches. According to first, individual benzene was gauged by values six‐center bond indices (SCI) calculated within so‐called Generalized Population Analysis (GPA). In second approach, same goal addressed theory Molecular Quantum Similarity (MQS). Both independent approaches are found correlate very well, and both point toward decreasing any upon going from outer inner rings. ©...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTheoretical ab initio SCF investigation of the photochemical behavior three-membered rings. 1. DiazirineB. Bigot, R. Ponec, A. Sevin, and DevaquetCite this: J. Am. Chem. Soc. 1978, 100, 21, 6575–6580Publication Date (Print):October 1, 1978Publication History Published online1 May 2002Published inissue 1 October 1978https://pubs.acs.org/doi/10.1021/ja00489a006https://doi.org/10.1021/ja00489a006research-articleACS PublicationsRequest reuse...

The effect of using different methods to obtain atoms in molecules (AIMs) on the shared-electron distribution indices (SEDIs) and domain-averaged Fermi holes (DAFHs) is examined a test set diatomic molecules. Use Bader's binary AIM model gives significantly SEDIs as function internuclear distances than do self-consistent Hirshfeld-based models. DAFH eigenvectors remain very similar for all among methods. corresponding eigenvalues are found differ significantly, although sums complementary...

Simple analytical models are introduced that significantly enhance the ability to understand and rationalise nature of bonding interactions depicted by domain-averaged Fermi hole (DAFH) analysis. The examples presented show besides shedding new light on role electron-sharing in ordinary two-centre two-electron (2c-2e) chemical bonds well represented classical Lewis model, proposed approach also provides interesting insights into go beyond traditional paradigm. This is, for example, case...