,-Diferrocenyl Cumulene Molecular Wires. Synthesis, Spectroscopy
详细信息 查看全文
- 作者：Wolfgang Skibar ; Holger Kopacka ; Klaus Wurst ; Christoph Salzmann ; Karl-Hans Ongania ; Fabrizia Fabrizi de Biani ; Piero Zanello ; and Benno Bildstein
- 刊名：Organometallics
- 出版年：2004
- 出版时间：March 1, 2004
- 年：2004
- 卷：23
- 期：5
- 页码：1024 - 1041
- 全文大小：386K
- 年卷期：v.23,no.5(March 1, 2004)
- ISSN：1520-6041
文摘
Cumulene sp-carbon molecular wires C2 [Fc(Ph)C=C(Ph)Fc] up to C7 [Fc(Ph)C=C=C=C=C=C=C(Ph)Fc] endcapped by two electroactive ferrocenyl groups are presented in thisreport. Synthetically, ferrocenyl cumulenes can be built-up by a modular strategy using C1synthon ferrocenyl(phenyl)ketone as starting material with various acetylenic/propargylic/homopropargylic C2-C5 reagents, taking into account and exploiting the efficient stabilizationof an electron-deficient carbenium center by an adjacent ferrocenyl moiety. With increasingcumulene chain length the reactivity of cumulenes increases considerably, indicating stericprotection as the main requirement for bulk stability. Even cumulenes C2, C4, and C6 areconjugated "molecular wires" effecting electronic communication between the terminalferrocenyl substituents, whereas odd cumulenes C3, C5, and C7 are nonconjugated andelectronically decoupled due to their orthogonal terminal 
-systems. Electrochemically,separate redox waves can be detected up to a C6 cumulene spacer, but the electroniccommunication between the endcapping redox-active ferrocenyl substituents decreases withincreasing cumulene length.
-systems. Electrochemically,separate redox waves can be detected up to a C6 cumulene spacer, but the electroniccommunication between the endcapping redox-active ferrocenyl substituents decreases withincreasing cumulene length.