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Preparation and properties of surface‐active organocobalt complexes having long‐chain alkyl groups
Author(s) -
Sakai Shizuyoshi,
Takayanagi Hitoshi,
Sumimoto Norifumi,
Fukuzawa ShinIchi,
Fujinami Tatsuo,
Saeki Hiroshi
Publication year - 1990
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/aoc.590040107
Subject(s) - chemistry , alkyl , cationic polymerization , acetonitrile , cyclopentadiene , cyclopentadienyl complex , cobalt , medicinal chemistry , aqueous solution , redox , polymer chemistry , micelle , inorganic chemistry , organic chemistry , catalysis
New types of surface‐active organocobaltocenium(I) complexes, η‐C n H 2 n +1 X‐C 5 H 4 (ηC 5 H 5 ) 2 Co + Y − and(η‐C n H 2 n +1 X‐C 5 H 4 )Co + Y − ( n = 6–16; X not present, NHCO or OCO; Y = Cl or PF 6 ) 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 NaBH 4 to afford (alkyl‐substituted cyclopentadiene) cyclopentadienylcobalt (0) complexes which were surface‐inactive but could be re‐oxidized to afford the surface‐active cobaltoceium(I) salts. The cobalt complexes mentioned above may be the first examples of redoxresponsive surfactants.