Tuning the Electronic Properties of Acetylenic Fluorenes by Phosphaalkene Incorporation
| Autor: | Sascha Ott, Andreas Orthaber, Yurii V. Svyaschenko |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
010405 organic chemistry
Organic Chemistry Sonogashira coupling General Chemistry 010402 general chemistry Photochemistry 01 natural sciences Catalysis Coupling reaction 0104 chemical sciences chemistry.chemical_compound Acetylene chemistry Ab initio quantum chemistry methods Phosphaalkene Cyclic voltammetry Spectroscopy HOMO/LUMO |
| Zdroj: | Chemistry - A European Journal. 22:4247-4255 |
| ISSN: | 0947-6539 |
| DOI: | 10.1002/chem.201503430 |
| Popis: | Versatile synthetic protocols for 2,7- and 3,6-diacetylenic fluorene-9-ylidene phosphanes (F9Ps) were developed. Protodesilylation of trimethylsilyl-protected acetylenic F9Ps affords terminal acetylenes that can be employed in Sonogashira and Glaser-type C-C coupling reactions to give thienyl-decorated and butadiyne-bridged fluorene-9-ylidene phosphanes, respectively. As evidenced by UV/Vis spectroscopy and cyclic voltammetry and corroborated by ab initio calculations, the presence of the P center in the F9Ps induces a significantly reduced HOMO-LUMO splitting that originates from stabilization of the LUMO levels. Variation of the acetylene substitution pattern is an additional tool to influence the optical and electronic properties. Whereas 3,6-disubstituted F9Ps have strong absorptions around 400 nm, mainly due to π-π* transitions, 2,7-diacetylenic F9Ps exhibit longest-wavelength absorptions that have significant charge-transfer character with an onset around 520 nm. |
| Databáze: | OpenAIRE |
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