Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

What can we learn from two‐center three‐electron bonding with the topological analysis of ELF?

What can we learn from two‐center three‐electron bonding with the topological analysis of ELF? In this paper, a review is presented of the abundant literature on the two‐center three‐electron (2c‐3e) bonding, which plays a crucial role in electron transfer and radical chemistry. Important questions regarding this peculiar type of interaction are (1) Is a three‐electron bonded complex a molecule or an assembly of molecules?, (2) Since an unpaired electron is involved, where is the spin density located?, and (3) Is there a descriptor of electron fluctuation, which is a central phenomenon in this type of bonding? We demonstrate that the topological analysis of the electron localization function (ELF), which provides a convenient mathematical framework to study chemical bond in molecules and solids, is able to answer these questions. First, examples of potentially 3e‐bonded complexes proposed by Pauling are reinvestigated. Second, the electron attachment process on molecules of the HnXYHm type with X,Y = Cl, S, P, Si and n, m = 0–2 is considered. Finally, the ELF‐based topology of some prototypical radicals containing the SO bond is examined. From these studies, several topological signatures of the 3e bonding have been elaborated. No disynaptic basin, well known as the topological signature of a covalent shared‐electron pair interaction, is found between two 3e‐bonded atoms. Therefore, to distinguish 3e bonds from ionic or hydrogen bonds, a core valence bifurcation (CVB) index has been introduced, similar to the one previously defined by Fuster and Silvi (Theor Chem Acc 2000,104,13) to differentiate weak and medium H‐bonds. Moreover, in 3e‐bonded systems, the spin density is mainly localized within the lone‐pair basins of the heavy atoms. To quantify the electron fluctuation, a topological delocalization index has been defined. An unambiguous characterization of the 3e bonding is thus obtained, which is in agreement with other theoretical approaches, such as the valence bond method. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:135–160, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20325 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Heteroatom Chemistry Wiley

What can we learn from two‐center three‐electron bonding with the topological analysis of ELF?

Fourré, I.; Silvi, B.
Heteroatom Chemistry , Volume 18 (2) – Jan 1, 2007
Download PDF
26 pages

Loading next page...
 
/lp/wiley/what-can-we-learn-from-two-center-three-electron-bonding-with-the-ooGEsHy6K8

References (154)

Publisher
Wiley
Copyright
Copyright © 2007 Wiley Subscription Services
ISSN
1042-7163
eISSN
1098-1071
DOI
10.1002/hc.20325
Publisher site
See Article on Publisher Site

Abstract

In this paper, a review is presented of the abundant literature on the two‐center three‐electron (2c‐3e) bonding, which plays a crucial role in electron transfer and radical chemistry. Important questions regarding this peculiar type of interaction are (1) Is a three‐electron bonded complex a molecule or an assembly of molecules?, (2) Since an unpaired electron is involved, where is the spin density located?, and (3) Is there a descriptor of electron fluctuation, which is a central phenomenon in this type of bonding? We demonstrate that the topological analysis of the electron localization function (ELF), which provides a convenient mathematical framework to study chemical bond in molecules and solids, is able to answer these questions. First, examples of potentially 3e‐bonded complexes proposed by Pauling are reinvestigated. Second, the electron attachment process on molecules of the HnXYHm type with X,Y = Cl, S, P, Si and n, m = 0–2 is considered. Finally, the ELF‐based topology of some prototypical radicals containing the SO bond is examined. From these studies, several topological signatures of the 3e bonding have been elaborated. No disynaptic basin, well known as the topological signature of a covalent shared‐electron pair interaction, is found between two 3e‐bonded atoms. Therefore, to distinguish 3e bonds from ionic or hydrogen bonds, a core valence bifurcation (CVB) index has been introduced, similar to the one previously defined by Fuster and Silvi (Theor Chem Acc 2000,104,13) to differentiate weak and medium H‐bonds. Moreover, in 3e‐bonded systems, the spin density is mainly localized within the lone‐pair basins of the heavy atoms. To quantify the electron fluctuation, a topological delocalization index has been defined. An unambiguous characterization of the 3e bonding is thus obtained, which is in agreement with other theoretical approaches, such as the valence bond method. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:135–160, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20325

Journal

Heteroatom Chemistry – Wiley

Published: Jan 1, 2007

There are no references for this article.