A Computational Investigation of the Substituent Effects on Geometric, Electronic, and Optical Properties of Siloles and 1,4-Disilacyclohexa-2,5-dienes
Thirty two differently substituted siloles 1a–1p and 1,4-disilacyclohexa-2,5-dienes 2a–2p 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...
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MDPI AG
2017-02-01
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| Series: | Molecules |
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| Online Access: | http://www.mdpi.com/1420-3049/22/3/370 |
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| author | Aleksandra V. Denisova Julius Tibbelin Rikard Emanuelsson Henrik Ottosson |
| author_facet | Aleksandra V. Denisova Julius Tibbelin Rikard Emanuelsson Henrik Ottosson |
| author_sort | Aleksandra V. Denisova |
| collection | DOAJ |
| description | Thirty two differently substituted siloles 1a–1p and 1,4-disilacyclohexa-2,5-dienes 2a–2p 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). |
| first_indexed | 2024-04-13T06:47:00Z |
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| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-04-13T06:47:00Z |
| publishDate | 2017-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-e0ce4d1435914d0991119298bdbe162e2022-12-22T02:57:33ZengMDPI AGMolecules1420-30492017-02-0122337010.3390/molecules22030370molecules22030370A Computational Investigation of the Substituent Effects on Geometric, Electronic, and Optical Properties of Siloles and 1,4-Disilacyclohexa-2,5-dienesAleksandra V. Denisova0Julius Tibbelin1Rikard Emanuelsson2Henrik Ottosson3Department of Chemistry–Ångström Laboratory, Uppsala University, Box 523, 75120 Uppsala, SwedenDepartment of Chemistry–BMC, Uppsala University, Box 576, 75123 Uppsala, SwedenNanotechnology and Functional Materials, Department of Engineering Sciences, Uppsala University, Box 534, 75121 Uppsala, SwedenDepartment of Chemistry–Ångström Laboratory, Uppsala University, Box 523, 75120 Uppsala, SwedenThirty two differently substituted siloles 1a–1p and 1,4-disilacyclohexa-2,5-dienes 2a–2p 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).http://www.mdpi.com/1420-3049/22/3/3701,4-disilacyclohexa-2,5-dienecyclobutadisilolesilolesubstituent effectscross-hyperconjugation |
| spellingShingle | Aleksandra V. Denisova Julius Tibbelin Rikard Emanuelsson Henrik Ottosson A Computational Investigation of the Substituent Effects on Geometric, Electronic, and Optical Properties of Siloles and 1,4-Disilacyclohexa-2,5-dienes Molecules 1,4-disilacyclohexa-2,5-diene cyclobutadisilole silole substituent effects cross-hyperconjugation |
| title | A Computational Investigation of the Substituent Effects on Geometric, Electronic, and Optical Properties of Siloles and 1,4-Disilacyclohexa-2,5-dienes |
| title_full | A Computational Investigation of the Substituent Effects on Geometric, Electronic, and Optical Properties of Siloles and 1,4-Disilacyclohexa-2,5-dienes |
| title_fullStr | A Computational Investigation of the Substituent Effects on Geometric, Electronic, and Optical Properties of Siloles and 1,4-Disilacyclohexa-2,5-dienes |
| title_full_unstemmed | A Computational Investigation of the Substituent Effects on Geometric, Electronic, and Optical Properties of Siloles and 1,4-Disilacyclohexa-2,5-dienes |
| title_short | A Computational Investigation of the Substituent Effects on Geometric, Electronic, and Optical Properties of Siloles and 1,4-Disilacyclohexa-2,5-dienes |
| title_sort | computational investigation of the substituent effects on geometric electronic and optical properties of siloles and 1 4 disilacyclohexa 2 5 dienes |
| topic | 1,4-disilacyclohexa-2,5-diene cyclobutadisilole silole substituent effects cross-hyperconjugation |
| url | http://www.mdpi.com/1420-3049/22/3/370 |
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