Next Article in Journal
Under-Reported Aspects of Platinum Drug Pharmacology
Next Article in Special Issue
Discovery of an Octahedral Silicon Complex as a Potent Antifungal Agent
Previous Article in Journal
A Kinetic Approach in the Evaluation of Radical-Scavenging Efficiency of Sinapic Acid and Its Derivatives
Previous Article in Special Issue
Theoretical Study on the Second Hyperpolarizailities of Oligomeric Systems Composed of Carbon and Silicon π-Structures
Article Menu
Issue 3 (March) cover image

Export Article

Open AccessArticle

A Computational Investigation of the Substituent Effects on Geometric, Electronic, and Optical Properties of Siloles and 1,4-Disilacyclohexa-2,5-dienes

Department of Chemistry–Ångström Laboratory, Uppsala University, Box 523, 75120 Uppsala, Sweden
Department of Chemistry–BMC, Uppsala University, Box 576, 75123 Uppsala, Sweden
Nanotechnology and Functional Materials, Department of Engineering Sciences, Uppsala University, Box 534, 75121 Uppsala, Sweden
Author to whom correspondence should be addressed.
Academic Editor: Mitsuo Kira
Molecules 2017, 22(3), 370;
Received: 17 January 2017 / Revised: 16 February 2017 / Accepted: 20 February 2017 / Published: 28 February 2017
(This article belongs to the Special Issue Advances in Silicon Chemistry)
PDF [3351 KB, uploaded 28 February 2017]


Thirty two differently substituted siloles 1a1p and 1,4-disilacyclohexa-2,5-dienes 2a2p were investigated by quantum chemical calculations using the PBE0 hybrid density functional theory (DFT) method. The substituents included σ-electron donating and withdrawing, as well as π-electron donating and withdrawing groups, and their effects when placed at the Si atom(s) or at the C atoms were examined. Focus was placed on geometries, frontier orbital energies and the energies of the first allowed electronic excitations. We analyzed the variation in energies between the orbitals which correspond to HOMO and LUMO for the two parent species, here represented as ΔεHL, motivated by the fact that the first allowed transitions involve excitation between these orbitals. Even though ΔεHL and the excitation energies are lower for siloles than for 1,4-disilacyclohexa-2,5-dienes the latter display significantly larger variations with substitution. The ΔεHL of the siloles vary within 4.57–5.35 eV (ΔΔεHL = 0.78 eV) while for the 1,4-disilacyclohexa-2,5-dienes the range is 5.49–7.15 eV (ΔΔεHL = 1.66 eV). The excitation energy of the first allowed transitions display a moderate variation for siloles (3.60–4.41 eV) whereas the variation for 1,4-disilacyclohexa-2,5-dienes is nearly doubled (4.69–6.21 eV). Cyclobutadisiloles combine the characteristics of siloles and 1,4-disilacyclohexa-2,5-diene by having even lower excitation energies than siloles yet also extensive variation in excitation energies to substitution of 1,4-disilacyclohexa-2,5-dienes (3.47–4.77 eV, variation of 1.30 eV). View Full-Text
Keywords: 1,4-disilacyclohexa-2,5-diene; cyclobutadisilole; silole; substituent effects; cross-hyperconjugation 1,4-disilacyclohexa-2,5-diene; cyclobutadisilole; silole; substituent effects; cross-hyperconjugation

Graphical abstract

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Supplementary material


Share & Cite This Article

MDPI and ACS Style

Denisova, A.V.; Tibbelin, J.; Emanuelsson, R.; Ottosson, H. A Computational Investigation of the Substituent Effects on Geometric, Electronic, and Optical Properties of Siloles and 1,4-Disilacyclohexa-2,5-dienes. Molecules 2017, 22, 370.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Molecules EISSN 1420-3049 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top