Publication Date:
2011-07-23
Description:
The geometries, energy gap between singlet and triplet states (S–T gap), electronic transitions, and molecular orbitals of the diphenyl derivative of the silole-fused tetramethyleneethane (TME) (3,4-dimethylenesilole) biradical 7 •• were determined by using the density functional theory method at the unrestricted Becke, three-parameter, Lee–Yang–Parr/cc-pVDZ level. In a manner similar to that of the parent TME biradical, the S–T gap of 7 •• is small. The wavelengths of electronic transitions of 3 7 •• ( λ ET = 450 nm) are calculated to be different from that of 1 7 •• ( λ ET = 673 nm). These differences are attributed to interactions between orbitals of the two allyl radical moieties, especially, the existence of double σ*–π* conjugation, that is, π*–σ*–π* conjugation, that takes place in the silole subunit. Copyright © 2011 John Wiley & Sons, Ltd. Density functional theory and time-dependent density functional theory calculations of the silole-fused TME (3,4-dimethylenesilole) biradical ( 7 ) were carried out. The wavelength of the electronic transitions of 3 7 ( λ ET = 450 nm) was shown to be different from that of 1 7 ( λ ET = 673 nm). The difference is attributed to orbital interactions between the two allyl radical moieties, especially, the existence of double σ *– π * conjugation, that is, π *– σ *– π * conjugation, in the silole subunit.
Print ISSN:
0894-3230
Electronic ISSN:
1099-1395
Topics:
Chemistry and Pharmacology
,
Physics
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