Ferrocene-crown ether conjugate

In 1990 we reported the synthesis of new redox-responsive crown ether molecules that contain a conjugated link between the crown ether unit and a ferrocene redox-active centre (Beer et al., 1990a). Examples of some of the species synthesized are shown in Fig. 5. The electrochemical behaviour of these species was investigated and also the electrochemical behaviour of their analogues with a saturated link between the ferrocene unit and the crown ether. The changes in the CVs of [2a] upon addition of magnesium cations are shown in Fig. 6. The metal cation-induced anodic shifts of [2a], [2b] and also their saturated analogue [3] and vinyl derivatives [4a], [4b] are shown in Table 1. 

Beer PD et al (1990) Redox-responsive crown ethers containing a conjugated link between the ferrocene moiety and a benzo crown ether. Inorg Chem 29 378-381... 

In order to elucidate the primary electrostatic through bond mode of electrochemical communication between a ferrocene redox centre and the heteroatoms of the crown ionophore, a variety of conjugated ferrocene benzocrown ether systems such as 60 and 61 [83, 84], 62 and 63 [85, 86], and 64 or 65 [87, 88] were synthesized and their complex formation with mono- and divalent cations studied by multinuclear NMR, X-ray crystallography and cyclic voltammetry. 

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