Ab Initio Topological Analysis of the Electronic Density in<i>n</i>-Butonium Cations and Their van der Waals Complexes

Okulik, Nora Beatriz; Sosa, Laura G.; Esteves, Pierre M.; Mota, Cláudio J. A.; Jubert, Alicia H.; Peruchena, Nélida María

doi:10.1021/jp0130665

Cited by 18 publications

(35 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As it was pointed out in the Introduction, carbonium and butonium organic ions are proposed as systems which possess complex patterns of 2e-3c bonding interactions. 6,7 Our results indicate that these bonding interactions have different characteristics from those well known electron deficient boron hydrids and hence they admit an important new feature which induces a wider interpretation of the rule. To this end, the information obtained may be interpreted as it is not necessary that both views of the rule, i.e., the local and the nonlocal conditions, ought to be satisfied in order to recognize a 2e-3c interaction.…”

Section: Computational Details Results and Discussionmentioning

confidence: 73%

“…Electron deficient compounds like boron hydrids give rise to important complex patterns of bonding which has been associated to two-electron three-center interaction mechanisms. [1][2][3][4][5] These multi-center interactions are known to appear in a wide variety of molecular systems as organic ions, [6][7][8] metallic and non-metallic clusters among others. 9 Nevertheless, the different types of molecular systems, i.e., the boron hydrids and the carbonium ions show different patterns within this type of interactions characterizing the bonding interactions and thus constitute a landmark for comparative detailed studies about them.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Pairing and unpairing electron densities in organic systems: Two-electron three center through space and through bonds interactions

Lobayan

Bochicchio

2014

The Journal of Chemical Physics

View full text Add to dashboard Cite

Two-electron three-center bonding interactions in organic ions like methonium (CH5(+)), ethonium (C2H7(+)), and protonated alkanes n - C4H11(+) isomers (butonium cations) are described and characterized within the theoretical framework of the topological analysis of the electron density decomposition into its effectively paired and unpaired contributions. These interactions manifest in some of this type of systems as a concentration of unpaired electron cloud around the bond paths, in contrast to the well known paradigmatic boron hydrids in which it is not only concentrated close to the atomic nucleus and the bond paths but out of them and over the region defined by the involved atoms as a whole. This result permits to propose an attempt of classification for these interactions based in such manifestations. In the first type, it is called as interactions through bonds and in the second type as interactions through space type.

show abstract

Section: Computational Details Results and Discussionmentioning

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Pairing and unpairing electron densities in organic systems: Two-electron three center through space and through bonds interactions

Lobayan

Bochicchio

2014

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…28 The quantum theory of atoms in molecules (QTAIM) was used to study many carbonium ions, such as proponium and 2-norbornyl cations. [29][30][31][32][33][34][35][36][37][38][39] In this work we show that the QTAIM can be used to evaluate whether a carbocation is classical or not. It is also possible to determine the order of σ or π delocalization within the similar group of cations.…”

Section: Introductionmentioning

confidence: 78%

Identification of carbonium and carbenium ions by QTAIM

Firme¹,

Antunes²,

Esteves³

2009

J. Braz. Chem. Soc.

Self Cite

View full text Add to dashboard Cite

A ferramenta de Gassman-Fentiman da demanda crescente de elétrons foi usada para identificar íons carbênios e íons carbônios. Contudo, devido ao seu entendimento ambíguo, ela foi pivô de uma disputa histórica. Nós aplicamos a metodologia da Teoria Quântica de Átomos em Moléculas -QTAIM -para caracterizar íons carbênios e íons carbônios de uma forma mais eficaz e mais fácil. Essa metodologia pode ser usada para avaliar se um carbocátion é clássico ou não. Além disso, é possível classificar um conjunto de íon carbônio na ordem de magnitude da deslocalização σ, ou π. Há poucas diferenças entre os resultados de nosso modelo baseado na QTAIM e da ferramenta de Gassman-Fentiman. Contudo, diferentemente da ferramenta de Gassman-Fentiman, os cátions 7-anisol-7-norbornenila e 2-anisol-2-norbornila são não-clássicos, embora sejam os menos íons não-clássicos em seus conjuntos correspondentes de cátions estudados.The Gassman-Fentiman tool of increasing electron demand was used to identify carbonium and carbenium ions. Nonetheless, due to its ambiguous understanding, it was pivot of a historical dispute. We applied the Quantum Theory of Atoms in Molecules (QTAIM) metodology to characterize the carbonium and carbenium ions on an easier and more effective way. By comparing selected topological information of reference carbenium ions the QTAIM metodology can be used to evaluate whether a carbocation is classical or not. In addition, it is possible to rank a set of carbonium ions in order of their corresponding σ or π delocalization. There are few differences between our QTAIM-based model and Gassman-Fentiman tool. Unlike Gassman-Fentiman tool results, 7-anisyl-7-norbornenyl and 2-anisyl-2-norbornyl cations are non-classical, although they are the least nonclassical ions in their corresponding set of studied cations.Keywords: norbornyl cation, norbornenyl cation, QTAIM, carbonium ion, carbenium ion IntroductionIn 1949 Winstein and Trifan 1,2 postulated the assistance of σ electron delocalization to account for the large rate differences in acetolysis of exo-and endo-2-norbornyl brosilates. On the other hand, Brown 3,4 attributed these differences to steric effects. Thereafter, heated debates on nature of norbornyl cation, named the nonclassical ion controversy, took place.3-5 Nonetheless, experimental evidences 6-9 indicated that norbornyl cation had no trivalent carbenium center characteristic of a classical ion. Eventually, the nonclassical nature 10 of the hypercoordinate norbornyl cation, characterized by delocalized σ electrons in a threecenter two-electron (3c-2e) bonding, was proved. 11Carbenium and carbonium ions, formerly named classical and nonclassical ions, respectively, can be identified by an index developed by Schleyer and collaborators 12 based on the total 13 C NMR chemical shift difference between a carbocation and the corresponding neutral hydrocarbon. In the classical trivalent carbocations the chemical shift difference, ∆δ, is more than 350 ppm while in nonclassical carbocations ∆δ < 100 ppm.Gassman and Fent...

show abstract

“…These species contain three-center two-electron bonds (3c−2e) and can be generated upon the insertion of a proton or a carbenium ion into the C−H or C−C bonds. The group of Jubert has analyzed the electron distribution of C 3 H 9 + , n -C 4 H 11 + , , and i -C 4 H 11 + . They concluded that the stability of these protonated species depends fundamentally on the way in which the charge of the cation is delocalized around the 3c−2e bonds.…”

Section: 24 Carbocationsmentioning

confidence: 99%