Redox-responsive surfactants: synthesis of 1,1-diferrocenyl-n-alkanes (1, C5, C7, C19) via reaction of (diferrocenyl)methyl carbocation with carbanions

Article abstract of DOI:10.1016/0022-328X(95)05451-T

Diferrocenylmethylium cation with chloride or tetraphenylborate as counter-ion is prepared from diferrocenylmethanol by dehydration with strong acids.Treatment with trimethylchlorosilane removes residual water to afford anhydrous methylium salts, which are highly reactive electrophiles for alkylation of group 14 (carbanions), group 15 (amines), group 16 (alkoxides), and, remarkably, group 17 (fluoride) nucleophiles.Reaction with long-chain carbanions yields 1,1-diferrocenyl substituted n-alkanes, which are of potential interest as redox-responsive surfactants.Single crystal structure analyses reveal a tendency for ambiphilic behavior to increase with increasing chain length.Medium chain length 1,1-diferrocenyl-n-alkanes show the expected intermolecular stacking, whereas for the longest n-alkane synthesized, 1,1-diferrocenyl-n-nonadecane, intermolecular complexation with n-octadecane is observed. Keywords: Iron, Diferrocenylmethylium carbocation; Surfactants; X-ray diffraction; 1,1-Diferrocenyl-n-alkane; Diferrocenylfluoromethane