Multifunctional Ferrocene-Ruthenocene Dyads Linked by Single or Double Aza-Containing Bridges Displaying Metal-Metal Interactions and Cation Recognition Properties

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• 作者：Antonio Caballero ; Rafaela Garcí ; a ; Arturo Espinosa ; Alberto Tá ; rraga ; Pedro Molina
• 刊名：Journal of Organic Chemistry
• 出版年：2007
• 出版时间：February 16, 2007
• 年：2007
• 卷：72
• 期：4
• 页码：1161 - 1173
• 全文大小：588K
• 年卷期：v.72,no.4(February 16, 2007)
• ISSN：1520-6904

文摘

The synthesis, electrochemical, electronic, and cation sensing properties of the ruthenocene-terminated2-aza-1,3-butadiene 2, linear ferrocene-ruthenocene dyads 3 and 5, and the new structural motifs diaza[4.4]ruthenocenophane 7 and mixed ferrocene and ruthenocene metallocenophanes 8 and 10 are presented.The properties of these compounds have been systematically varied by introducing the ferrocene andruthenocene moieties at the 1- or 4-position of the unsymmetrical 2-aza-1,3-butadiene bridge.Spectroelectrochemical studies of compounds 3 and 8, in which the ruthenocene unit appended at the1-position of the bridge exhibits a rather unusual electrochemical behavior, revealed the presence oflow-energy bands in the near-infrared (NIR) region in the partially oxidized forms, at 1070 and 1163nm, respectively, which indicate the existence of intramolecular charge transfer between the iron and theruthenium centers. The electrochemical and intermetallic charge-transfer (MMCT) studies (H_AB, and parameters) indicate that the 3⁺ and 8⁺ systems belong to the Class II classification for a mixed-valencecompound. In addition, the low-energy (LE) band of the absorption spectra of all compounds prepared,except compound 10, are red-shifted by complexation with divalent Mg²⁺, Zn²⁺, Cd²⁺, Hg²⁺, and Ni²⁺metal ions. For open dyads, biruthenocene compound 2 exhibited the higher red-shift by 92 nm, whereasfor closed compounds the [4.4]ruthenocenoferrocenophane 8 displayed a remarkable red-shift by about180 nm for Zn²⁺, Cd²⁺, Hg²⁺, and Ni²⁺ metal ions and by about 146 nm for Mg²⁺ cation. The changesin the absorption spectra are accompanied by dramatic color changes which allow the potential for "nakedeye" detection. The experimental data and conclusions are supported by DFT computations.