Novel Ferrocenyl Polyene Derivatives and Their Binding to Unmodified Cyclodextrins

• Published in: Journal of organic chemistry Vol. 65; no. 21; pp. 6973 - 6977
• Main Authors: Liu, Jian, Castro, René, Abboud, Khalil A, Kaifer, Angel E
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 20.10.2000; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Organic; Physical Sciences; Science & Technology; BETA-CYCLODEXTRIN; CHEMISTRY; ELECTRON-TRANSFER; OMEGA; COMPLEXATION; MOLECULAR-WIRE
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo000573u

Two new ferrocene derivatives, 7-ferrocenyl-2,4,6-heptatrienal (1) and 7-ferrocenyl-2,4,6-heptatrienol (2), were synthesized and characterized. These two compounds possess a rigid triene chain conjugated to one of the cyclopentadienyl rings of the ferrocene residue, and as a result, they exhibit very stiff structures. The electronic absorption and electrochemical properties of these compounds were utilized to investigate their host−guest binding interactions with the receptors α-cyclodextrin (α-CD) and β-cyclodextrin (β-CD) in aqueous solution. From electronic absorption measurements binding constants in the range 790−12900 M-1 were obtained; β-CD formed more stable complexes than α-CD with both guests. Electrochemical measurements suggest some degree of site selectivity in the complexation processes, with β-CD binding preferentially to the ferrocene moiety while α-CD interacts with the unsaturated chain.