Symmetry 2010, 2(3), 1485-1509; doi:10.3390/sym2031485
Article

On the Harmonic Oscillator Model of Electron Delocalization (HOMED) Index and its Application to Heteroatomic π-Electron Systems

Ewa D. Raczyńska 1,* email, Małgorzata Hallman 1 , Katarzyna Kolczyńska 2  and Tomasz M. Stępniewski 2
1 Department of Chemistry, Warsaw University of Life Sciences (SGGW), ul. Nowoursynowska 159c, 02-776 Warszawa, Poland 2 Interdisciplinary Department of Biotechnology, Warsaw University of Life Sciences (SGGW), ul. Nowoursynowska 166, 02-776 Warszawa, Poland
* Author to whom correspondence should be addressed.
Received: 31 December 2009; in revised form: 19 May 2010 / Accepted: 7 July 2010 / Published: 12 July 2010
(This article belongs to the Special Issue Aromaticity and Molecular Symmetry)
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Abstract: The HOMA (Harmonic Oscillator Model of Aromaticity) index, reformulated in 1993, has been very often applied to describe π-electron delocalization for mono- and polycyclic π-electron systems. However, different measures of π-electron delocalization were employed for the CC, CX, and XY bonds, and this index seems to be inappropriate for compounds containing heteroatoms. In order to describe properly various resonance effects (σ-π hyperconjugation, n-π conjugation, π-π conjugation, and aromaticity) possible for heteroatomic π-electron systems, some modifications, based on the original HOMA idea, were proposed and tested for simple DFT structures containing C, N, and O atoms. An abbreviation HOMED was used for the modified index.
Keywords: geometry-based index; π-electron delocalization; σ-π hyperconjugation; n-π conjugation; π-π conjugation; aromaticity; heteroatomic compounds; DFT

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MDPI and ACS Style

Raczyńska, E.D.; Hallman, M.; Kolczyńska, K.; Stępniewski, T.M. On the Harmonic Oscillator Model of Electron Delocalization (HOMED) Index and its Application to Heteroatomic π-Electron Systems. Symmetry 2010, 2, 1485-1509.

AMA Style

Raczyńska ED, Hallman M, Kolczyńska K, Stępniewski TM. On the Harmonic Oscillator Model of Electron Delocalization (HOMED) Index and its Application to Heteroatomic π-Electron Systems. Symmetry. 2010; 2(3):1485-1509.

Chicago/Turabian Style

Raczyńska, Ewa D.; Hallman, Małgorzata; Kolczyńska, Katarzyna; Stępniewski, Tomasz M. 2010. "On the Harmonic Oscillator Model of Electron Delocalization (HOMED) Index and its Application to Heteroatomic π-Electron Systems." Symmetry 2, no. 3: 1485-1509.

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