Electron reorganization in allowed and forbidden pericyclic reactions: multicenter bond indices as a measure of aromaticity and/or anti‐aromaticity in transition states of pericyclic electrocyclizations

Mandado, Marcos; Ponec, Robert

doi:10.1002/poc.1589

Cited by 10 publications

(9 citation statements)

References 71 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…proving the validity of this electronic measure for chemical reactivity. 146 In general, electronic-based multicentre indices perform better for this test set than other indices analysed either structural or magnetic.…”

Section: Assessing the Performance Of Aromaticity Indices Using A Tesmentioning

confidence: 85%

Quantifying aromaticity with electron delocalisation measures

et al. 2015

View full text Add to dashboard Cite

Aromaticity cannot be measured directly by any physical or chemical experiment because it is not a well-defined magnitude. Its quantification is done indirectly from the measure of different properties that are usually found in aromatic compounds such as bond length equalisation, energetic stabilisation, and particular magnetic behaviour associated with induced ring currents. These properties have been used to set up the myriad of structural-, energetic-and magnetic-based indices of aromaticity known to date. Cyclic delocalisation of mobile electrons in two or three dimensions is probably one of the key aspects that characterise aromatic compounds. However, it has not been until the last decade that electron delocalisation measures have been widely employed to quantify aromaticity. Some of these new indicators of aromaticity such as the PDI, FLU, ING, and INB were defined in our group. In this paper, we review the different existent descriptors of aromaticity that are based on electron delocalisation properties, we compare their performance with indices based on other properties, and we summarise a number of applications of electronic-based indices for the analysis of aromaticity in interesting chemical problems.2

show abstract

Section: Assessing the Performance Of Aromaticity Indices Using A Tesmentioning

confidence: 85%

Quantifying aromaticity with electron delocalisation measures

et al. 2015

View full text Add to dashboard Cite

show abstract

“…[29][30][31][32][33] The fact that multicenter indices reflect a larger aromaticity for the cyclopropene rings may be related to the nature of the renormalization employed and introduced in ref. 16. This renormalization does not warrant the comparison between multicenter indices of different order and just allows putting the indices in a more or less similar scale.…”

Section: Resultsmentioning

confidence: 99%

“…The reader is referred to ref. 12,[15][16][17][18][19] and 20 for a full description and theoretical backgrounds of multicenter delocalization indices and electron deformation orbitals, respectively. In this work, we have employed the renormalized version of multicenter delocalization indices defined in ref.…”

Section: Computational Detailsmentioning

confidence: 99%

See 1 more Smart Citation

Tunable aromaticity in bicalicenes

Mandado

Ramos‐Berdullas

2015

Phys. Chem. Chem. Phys.

Self Cite

View full text Add to dashboard Cite

The unusual aromatic stability of cyclic bicalicene has been suggested to come from a tetraionic structure, where positive and negative charges are located on the cyclopropene and cyclopentadiene rings, respectively. Energetic, magnetic, geometric and electron delocalization analysis performed on a series of bicalicene derivatives, incorporating different electron donating and withdrawing groups, and electrically perturbed bicalicene structures provide additional proof of the role played by this tetraionic structure in the aromatic stability of bicalicene. In this work the aromatic stabilization is chemically and electrically tuned, enhancing or disrupting the electron delocalization and aromatic stability of the cyclopropene and cyclopentadiene rings by increasing or decreasing their corresponding charges. It is shown how the electron delocalization within these rings is similar to that of cyclopropene cation and cyclopentadiene anion for a perfect polarization of one electron.

show abstract

“…Although the primary goal for the introduction of this approach was a simple alternative reproduction of Woodward‐Hoffmann rules, the methodology of the so‐called overlap determinant method proved to be more general, and its straightforward generalization provided new interesting insights into the details of reorganization of electron density along the concerted reaction path of allowed and forbidden pericyclic reactions . The resulting extension of the original methodology then subsequently found a number of interesting applications, eg, for the quantitative justification of Dewar's concept of aromaticity of transition states . The concise review of the problem of aromaticity of transition states can also be found in the recent study …”

Section: Introductionmentioning

confidence: 99%

Topological aspects of chemical reactivity. Destiny of electron pairs in allowed and forbidden pericyclic reactions

Ponec

2017

J Phys Org Chem

Self Cite

View full text Add to dashboard Cite

The paper represents an attempt to provide a sound theoretical subsidy for the so-called "curved arrow formalism," which proved unprecedented usefulness in shaping our ideas about the mechanisms of organic reactions. The basic idea is to characterize the extent to which the electron pairs are conserved or broken for a given nuclear configuration by the probability of finding the pair of electrons of opposite spin in a given point of space. This probability is quantitatively given by the αβ component of the pair density, with coinciding positions of both electrons. As a function of 3 variables, the quantity Π αβ (r, r) can be displayed in 3D and the monitoring of the snapshots of this quantity for different points along the reaction path thus can bring new interesting insights into the details of bond reorganization in the course of reactions. The paper reports the application of the above approach for the detailed scrutiny of the differences in the electron reorganization of allowed and forbidden pericyclic reactions at the level of simple topological description in terms of overlap determinant method. Despite its simplicity, the approach provided new interesting insights into the factors underlying the different role of electron pairs in allowed and forbidden pericyclic reactions, and we believe that this simple approach could inspire further straightforward extensions that would allow to apply its formalism at the level of contemporary sophisticated computations to real systems of chemical interest. KEYWORDS curved arrow formalism, electron reorganization, overlap determinant method, pericyclic reactions Dedicated to Professor Roald Hoffmann on occasion of his 80th anniversary

show abstract

Electron reorganization in allowed and forbidden pericyclic reactions: multicenter bond indices as a measure of aromaticity and/or anti‐aromaticity in transition states of pericyclic electrocyclizations

Cited by 10 publications

References 71 publications

Quantifying aromaticity with electron delocalisation measures

Quantifying aromaticity with electron delocalisation measures

Tunable aromaticity in bicalicenes

Topological aspects of chemical reactivity. Destiny of electron pairs in allowed and forbidden pericyclic reactions

Contact Info

Product

Resources

About