Cryptands ferrocene

Recently, Plenio and co-workers have published a number of papers on ferrocenophanes, ferrocene cryptands and simple ferrocene amines (Plenio et ai, 1993, 1994 Plenio and Diodone, 1995a). They have synthesized 22... 

A large number of ferrocene cryptand-type molecules have been reported in the literature in the last ten years. Hall and co-workers, the initial pioneers of these cryptand systems (Beer etal., 1984 Bell and Hall, 1980 Hammond etal., 1986 Bell etal., 1983 Hall and Sharpe, 1990,1991 Hall etal., 1990a,b, 1991a,b,... 

Interestingly Gokel has demonstrated the existence of a direct coordination coupling pathway between this ferrocene cryptand and a silver cation. Complexation studies were carried out with [24] and [25] (as well as other ferrocene cryptand-type species) by X-ray crystallography, FAB mass spectral analysis, nmr and UV/Vis spectroscopy. 

A number of ferrocene cryptand molecules (66-74) ((29)—(31)) have been reported in the literature and it is only relatively recently that their electrochemical coordination properties have been disclosed. We have synthesized potassium-selective metallocene cryptands (72) (30) and (31) the electrochemistry of the former in the presence of K+ guest cations proved disappointingly irreversible (75). Hall and co-workers (76) have used cyclic voltammetry to investigate the coordination of... 

Ferrocene cryptands have also been studied as cation receptors. Hall ef al. have investigated the coordination of alkaline earth and lanthanide metal cations by cryptand 16 using cyclic voltammetry in CH3GN solution.The cation-induced anodic shift of the Fc/Fc redox couple was found to broadly correlate with the charge density of the cationic guest. Further electrochemical analysis revealed evidence that upon oxidation the 16 Be and 16 Dy complexes readily eject the bound cation from the cryptand cavity, presumably due to electrostatic repulsion. 

The l,l -(OCH2CH20Ts)2-ferrocene derivative was treated with various diaza-[n]-crown-m ethers to give ferrocene cryptands, in which subsequent complexation with Group 1 and 2 metal ions affords large shifts in the redox potentials and consequently to a drastic decrease in the binding strength (up to 10 ) <01CEJ4438>. 

Plenio, H. Yang, J.J. Diodone. R. Heinze. J. Redox-switched bonding of protons to ferrocenophanes, ferrocene cryptands. and simple ferrocene amines—Con elation of x-ray structural data and cyclic voltammetry derived redox potentials. Inorg. Chem. 1994. 33. 4098-4104. 

A host-guest complex, 41, of silver with a bis-ferrocene cryptand has been thoroughly investigated, revealing strong evidence of an interaction between Ag+ and the ferrocene unit, in addition to silver nitrogen (and some silver oxygen) interactions with the macrocycles [85]. 

Miscellaneous macrobicyclic ligands. Numerous other types of macrobicyclic cryptands have been synthesized in recent years, including ferrocene cryptands... 

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