Substituent Influence on Charge Transfer Interactions in 伪,伪鈥?Diferrocenylthiophenes

详细信息    查看全文

• 作者：J. Matth盲us Speck ; Marcus Korb ; Tobias R眉ffer ; Alexander Hildebrandt ; Heinrich Lang
• 刊名：Organometallics
• 出版年：2014
• 出版时间：September 22, 2014
• 年：2014
• 卷：33
• 期：18
• 页码：4813-4823
• 全文大小：597K
• ISSN：1520-6041

文摘

Within a series of 伪,伪鈥?diferrocenylthiophenes, the influence of electron-withdrawing substituents at the ferrocenyl moieties and electron-donating functionalities at the thiophene bridge on the electronic behavior was studied. The synthesis of the appropriate 2,5-fc₂-^cC₄H₂S and 2,5-fc₂-3,4-(OCH₂CH₂O)-^cC₄S compounds (fc = Fe(畏⁵-C₅H₄)(畏⁵-C₅H₄R); R = H (1, 5), 3,5-(CF₃)₂-^cC₆H₃ (2, 6), CHO (3, 7), C鈮 (4, 8)) was carried out using the Negishi C,C cross-coupling protocol to effect the coupling of the thiophene and the ferrocenyl moieties. The corresponding diferrocenylthiophenes were characterized spectroscopically. Within this context, the structural properties of 2鈥?b>5, [5][B(C₆F₅)₄], 6, and 8 in the solid state were investigated by single-crystal X-ray diffraction studies. Electrochemical investigations of thiophenes 2鈥?b>8 demonstrated an increasing redox separation and hence thermodynamic stability of the corresponding mixed-valent species in the series 1 < 3 < 5 < 4 鈮?2 < 6 < 7 < 8. Moreover, UV/vis/near-IR and infrared spectroelectrochemical studies verify these observations. These studies further reveal a valence trapped situation in corresponding mixed-valent species and allow a class II classification according to Robin and Day.