Expanding the Chemical Structure Space of Opto-Electronic Molecular Materials: Unprecedented Push鈥揚ull Chromophores by Reaction of a Donor-Substituted Tetracyanofulvene with Electron-Rich Alkynes
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- 作者：Govindasamy Jayamurugan ; Oliver Dumele ; Jean-Paul Gisselbrecht ; Corinne Boudon ; W. Bernd Schweizer ; Bruno Bernet ; Fran莽ois Diederich
- 刊名：The Journal of the American Chemical Society
- 出版年：2013
- 出版时间：March 6, 2013
- 年：2013
- 卷：135
- 期：9
- 页码：3599-3606
- 全文大小：436K
- 年卷期：v.135,no.9(March 6, 2013)
- ISSN：1520-5126
文摘
The reaction of a 3,5-bis(N,N-dimethylanilino)-substituted 2,4,6,6-tetracyanopentafulvene (TCPF) with mono- and bis(N,N-dimethylanilino)acetylene provides facile access to push鈥損ull chromophores with diverse new scaffolds. The starting TCPF reacts with bis(N,N-dimethylanilino)acetylene in a formal [2+2] cycloaddition at the exocyclic double bond, followed by retroelectrocyclization, to yield an ethenylene-extended push鈥損ull pentafulvene. The transformation with 4-ethynyl-N,N-dimethylaniline also yields a similar extended pentafulvene as well as two other products that required X-ray analysis for their structure elucidation. One features an 8,8-dicyanoheptafulvene core formed by formal [2+2] cycloaddition, followed by ring opening via fragmentation. The second is a chiral cyclobutenylated tetrahydropentalene, resulting from a cascade of formal [6+2] and [2+2] cycloadditions. All new nonplanar push鈥損ull chromophores display amphoteric redox behavior with both strong electron-donating and -accepting potency. Notably, the N,N-dimethylanilino-substituted extended pentafulvenes show remarkably low oxidation potentials (0.27/0.28 V vs Fc/Fc+ reference) that are lower than those for N,N-dimethylaniline itself. The push鈥損ull-substituted extended pentafulvenes feature intense electronic absorption bands, extending over the entire visible spectral range into the near infrared, and low highest occupied molecular orbital鈥搇owest unoccupied molecular orbital gaps. These properties, together with high thermal stability and good solubility, suggest the potential use of the new chromophores as advanced materials in molecular electronics devices.