Preparation and properties of surface-active organocobalt complexes having long-chain alkyl groups

✍ Scribed by Shizuyoshi Sakai; Hitoshi Takayanagi; Norifumi Sumimoto; Shin-Ichi Fukuzawa; Tatsuo Fujinami; Hiroshi Saeki

• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: English
• Weight: 538 KB
• Volume: 4
• Category: Article
• ISSN: 0268-2605
• DOI: 10.1002/aoc.590040107

✦ Synopsis

New types of surface-active organocobaltocenium(1) complexes, vC,H,+ IX-CSH&CsHS)2Co+Y -and (r]-CnHzn+,X-C5H4)Co+Y-(n = 6-16; X not present, NHCO or OCO; Y = C1 or PFs) were prepared and their surface character studied. (1) The critical micelle concentrations of the cobaltocenium chlorides were much lower than those of corresponding trimethylammonium-type cationic surfactants. (2) The surface-active character of the cobaltocenium chlorides in aqueous solution (and the redox potentials of the hexafluorophosphates in acetonitrile) were affected by the substituents (X) in the cyclopentadienyl groups. (3) The surface activities of the cobaltocenium salts were lost on reduction with NaBH4 to afford (alkyl-substituted c y c lopen t a diene) c yc lope n t ad i en y Ico bal t (0) complexes which were surface-inactive but could be re-oxidized to afford the surface-active cobaltoceium(1) salts. The cobalt complexes mentioned above may be the first examples of redoxresponsive surfactants.