Novel silicon- and tin-containing ferrocenophanes and related compounds as Lewis acids

The syntheses of 1 1'-bis(chloromethyldimethylsilyl)ferrocene fe(SiMe2CH2Cl)(2) (2), of the series of open-chain ferrocene- and silicon-containing organotin(IV) compounds (FeMe2-SiCH2)(2)SnPh2 (3), (FeMe2SiCH2SnXPh)(2)CH2 (4, X = Ph; 7, X = I; 8, X = Cl; 9, X = Fl, fe-(SiMe2CH2SnXR2)(2) (5, R = X = Ph; 6, R = X = Me; 10, R = Ph, X = I; 11, R = Me, X = Cl; 12, R = Ph, X = Cl; 13, R = Ph, X = Fl, fe(SiMe2CH2SnPh2CH2SiMe2Fe)(2) (14), and of the ferrocenophanes [fc(SiMe2CH2SnXRCH2SiMe)(2)fe] (15, R = X = Me; 16, R = X = Ph; 17, R = Ph, X = I; 18, R = Ph, X = F; 19, R = Ph, X = Cl; 20, R = Me, X = ct, and two of their chloride complexes {[fe(SiMe2CH2SnClRCH2SiMe2)(2)fc . 2Cl](2)- 2[(Ph3P)(2)N](+)} (22, R = Me; 23, R = Ph) are reported, and the molecular structures of 4, 16, 17, 19, 20, 22, and 23 are described. In solution! the halogen-substituted ferrocenophanes 17-19 undergo cfs-trans isomerization, the rate of which is enhanced by addition of halide ions. Variable-temperature Sn-119 and F-19 NMR studies in solution indicate that the fluoro derivatives 9, 13, and 18 react with different molar equivalents of fluoride ions to give the I:I and 1:2 adducts [(FeMe2SiCH2SnFPh)(2)CH2. nF](n-)[Bu4N](+)(n) (9a,b, n = 1; 9c, n = 2), {[13 . 2F](2)-[(BuN)-N-4](+)(2)}, and {[18 . F](-)[Bu4N](+)} and {[18 . 2F](2)-[Bu4N](+)(2)}, respectively. A more extended electrochemical investigation points out that the species containing halogen-substituted tin groups are more sensitive to anions than their analogues containing diphenyltin groups.