The quadrupole moment of substituted cyclopentadienyl anions.

J Phys Chem A

Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, Saint Louis, Missouri 63103, USA.

Published: November 2010

Previous work in our group on the cation binding of substituted cyclopentadienyl anions (Cp) showed the curious result that Cp traceless electric quadrupole moments (Θ(zz)) are almost all positive. Probing this issue further here we show that substituted Cp Θ(zz) values are always significantly more positive than the analogous substituted benzenes. Given the nature of aromatic Θ(zz) values, this is the opposite of what would be predicted. Furthermore, we show that the quadrupole moments of Cp anions do not behave as one would expect based on Cp substitutions. Unlike the quadrupole moments of substituted benzenes, which generally become more negative with the addition of electron-donating groups and more positive with the addition of electron-withdrawing groups, Cp quadrupole moments become more positive when any substituent is added, regardless of the electron-donating/withdrawing nature of the substituent. To explain these results we propose a model where the anionic Cp π-electron density repels the substituent electron density toward the molecular periphery and AIM calculations support this view.

Download full-text PDF

Source
http://dx.doi.org/10.1021/jp104499yDOI Listing

Publication Analysis

Top Keywords

quadrupole moments
16
substituted cyclopentadienyl
8
cyclopentadienyl anions
8
Θzz values
8
substituted benzenes
8
quadrupole
5
substituted
5
quadrupole moment
4
moment substituted
4
anions previous
4

Similar Publications

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!