Synthesis and redox properties of methylbipyridinioalkyl (viologen)-modified β-cyclodextrins at the secondary face

✍ Scribed by Kwanghee Koh Park; Sun Young Han; Youn-Hee Park; Joon Woo Park

• Publisher: Elsevier Science
• Year: 1997
• Tongue: French
• Weight: 236 KB
• Volume: 38
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(97)00851-4

✦ Synopsis

Viologens linked to the secondaD' face of I~-CD via aliphatic chains, which show several desirable properties for an artificial redox enzyme, are prepared. Their redox behaviors and stability are compared with viologens directly bonded to the primary side of 13-CD. © 1997 Elsevier Science Ltd. [3-Cyclodextrin ([3-CD) derivatives have drawn great amount of interest as enzyme mimics and building blocks for supramolecular structures and functional units. 1 Our continued interest in utilization of viologens (l,l'-dialkyl-4,4'-bipyridinium) as electron-transfer catalysts (ETC) in reductive transformation of organic compounds 2~ prompted us to synthesize viologen-appended [3-CDs to combine the recognition properties of ~3-CD with the ETC properties of viologens. AIkyl viologen-modified 13-CDs at the primary side 1 have been prepared by reacting the 6-monoiodo-[3-CD 4 or 6-monotosyl-[3-CD 56 with 1-alkyl-4,4'-bipyridinium ion. Toda et al. 4 showed that ethyl viologen-modified !3-CD undergoes the Rose Bengal-sensitized photochemical