Novel Silicon- and Tin-Containing Ferrocenophanes and Related Compounds as Lewis Acids

Abstract

The syntheses of 1,1′-bis(chloromethyldimethylsilyl)ferrocene, fc(SiMe 2 CH 2 Cl) 2 (2), of the series of open-chain ferrocene-and silicon-containing organotin(IV) compounds 14), and of the ferrocenophanesPh) 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 cis-trans isomerization, the rate of which is enhanced by addition of halide ions. Variable-temperature 119 Sn and 19 F NMR studies in solution indicate that the fluoro derivatives 9, 13, and 18 react with different molar equivalents of fluoride ions to give the 1:1 and 1:2 adductsrespectively. 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.

Bis[di‐n‐alkyl(fluoro)stannyl]methanes, (R2FSn)2CH2 (R = n‐octyl, n‐dodecyl): Stable Fluoride‐Selective Carriers

“…The ESMS spectrum (negative mode) of a solution of 3 and Ph 4 PCl in acetonitrile shows the following mass clusters with the expected isotopic patterns: {[F(noctyl) 2 …”

“…Based on these data, the logarithms of the potentiometric selectivity coefficients log K pot F,J were determined according to the NikolskiiϪEisenman equation (Equation 2) ( Table 1 and 2). (2) E M is the membrane potential in mV, a i the activity (concentration) of the primary ion, a j the activity of the interfering ion and z i and z j the charge of the primary and interfering ions, respectively. Negative potentiometric selectivity coefficients K pot F,J indicate that the ISE is more selective to the …”

“…Moreover 2 , when incorporated into polymeric-membrane ion-selective electrodes, are highly selective carriers for fluoride [8] and phosphate ions, [9] respectively. When these carriers are used to develop chemical sensors, the observed signal is unstable over prolonged periods, while re- peated use influences both the sensitivity (the slope of the calibration curve expressed in mV per Ϫlog[anion] units) and detection limit of the sensor.…”

Molecular Electrochemistry of Cyclophanes

“…Bis(ferrocenes) in which the fc moieties are far removed do only show a single reversible oxidation [79]. On the other hand, ferrocenophanes with a single Ga atom linker [80,81] are oxidized much easier than ferrocene itself with two separate signals for dimeric and three separate signals for trimeric species (Fig.…”

[cyclo-CH2{Sn(Cl2)CH2Si(Me2)}2O]: Synthesis and Complexation Behaviour of a Novel, Cyclic, Bidentate Lewis Acid and Its Conversion into a Tin-Containing Fluorosilane with Intermolecular Si−F⋅⋅⋅Sn Bridges

“…This general concept includes the synthesis of multidentate Lewis acids in which the active sites are part of cyclic8–16 or noncyclic17–38 structures. Elements which serve as the Lewis acidic centres in these host molecules are for instance B,39–42 Al,38, 43, 44 In,30–35 Si,13, 45–47 Ge,14 Sn8–12, 16–29 and Hg 15, 37, 38, 48–53. More recently, bidentate Lewis acids have attracted interest as activators for transition metal based olefin polymerisation catalysts 38, 42, 54.…”