Atropisomeric 3,3 ',4,4 ',5,5 '-Hexaferrocenyl-2,2 '-bithiophene: Synthesis, Solid-State Structure, and Electrochemistry

作者：Speck J Matthaeus; Schaarschmidt Dieter; Lang Heinrich^*

来源：Organometallics, 2012, 31(5): 1975-1982.

DOI：10.1021/om201266y

3,3',4,4',5,5'-Hexaferrocenyl-2,2'-bithiophene (4) has been prepared using a straightforward synthesis protocol that follows the palladium-promoted Negishi cross-coupling of 2-Br-3,4,5-Fc(3)-(C4S)-C-c (2) with 3,4,5-FC3-2-ZnCl-(C4S)-C-c (3) (Fc = Fe(eta(5)-C5H4)(eta(5)-C5H5)). The electronic and structural properties of 4 were investigated by UV-vis spectroscopy and single-crystal Xray diffraction studies. Comparison of the appropriate bond distances in the 2,2'-bithiophene moiety shows electron delocalization. Cyclic and square-wave voltammetry and in situ UV-vis/NIR spectroelectrochemistry highlight the electrochemical properties of 4. The ferrocenyls in 4 can be reversibly and separately oxidized in dichloromethane and anisole solutions using [N '' Bu-4][B(C6F5)(4)] as supporting electrolyte. Generally, these studies prove electrostatic interactions among the ferrocenyl termini as oxidation progresses. The atropisomerism of 4 caused by the inner rotation barrier about the 2,2'-bithiophene bond was investigated by dynamic H-1 NMR spectroscopy.

• 出版日期2012-3-12