Complexation behavior of 1,1″:1′,1‴-bis(1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diyldimethyl)bisferrocene: structural determination, NMR, 57Fe Mössbauer and electrochemical measurements

The complexing behavior of 1,1″:1′,1‴-bis(1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diyldimethyl)bisferrocene (1) toward KPF6 ion was studied. To gain a better understanding into the factors which determine the extent of this redox-switched bonding in the complexation of KPF6 by 1, we carried out X-ray crystal structural determination, NMR, FAB-MS technique, cyclic voltammetry measurements, and 57Fe Mössbauer analyses. We suggest that the KPF6 salt of 1 is not a kinetically labile system. Our studies also provide direct evidence that ferrocene crown ether displays a drop in complex stability upon oxidation.