A Decacationic Ferrocene-Based Metallostar

Abstract

Decacationic metallostars have been prepared by the reaction of permercurated ferrocene FeC10(HgO2CCF3)10 with superacidic (C5F5NH)(SbF6) (pKa = −11 estimated in H2O) in multigram scale. In the resulting compound, [FeC10Hg10(NC5F5)n][SbF6]10, the labile pentafluoropyridine ligands are readily displaced by acetonitrile (MeCN) or tetrahydrothiophene (THT). In the X-ray structure of [FeC10Hg10(THT)10][SbF6]10 ‧ 24 MeCN no cation-anion contacts between mercury and fluorine were observed. Moreover, cyclic voltammetry measurements of [FeC10(Hg(MeCN))10]10+ and [FeC10(Hg(THT))10]10+ revealed a (quasi)reversible one-electron oxidation of Fe(II) to Fe(III). From the reaction of [FeC10(Hg(MeCN))10]10+ with MoF6 as oxidant the ferrocenium cation [FeC10(Hg(MeCN))10]11+ was obtained and characterized via single crystal XRD. These electrophilic metallostars are promising potential building blocks for the synthesis of dendritic architectures containing a robust, tenfold functionalized ferrocene core.

A decacationic ferrocene-based metallostar

“…In summary, we investigated the reactivity of permercurated ferrocene derivatives towards neutral ligands in standard organic solvents as well as in superacidic medium. 69 We demonstrated that in the compound FeC 10 (HgTFA) 10 all mercury atoms are accessible to Lewis bases. The Lewis acidity of the {FeC 10 Hg 10 } 10+ framework was tuned by variation of the counter anions.…”