Synthesis and Properties of the First Ferrocene-Functionalized Ligand in Which All the Donor Atoms Are Cyclopentadienyl-Conjugated

Abstract

The synthesis of a new type of ferrocene-functionalized ligand for transition-metal binding is described. The ligand is the first electroactive ferrocene receptor to possess complete conjugation between all the donor atoms and the cyclopentadienyl moiety to which they are attached. 1H and natural-abundance 15N NMR studies indicate that a complex of 2:1 stoichiometry (ligand:Cu+ ion) is formed, in which the Cu+ ion is surrounded tetrahedrally by a bipyridyl-like pair of donor nitrogen atoms from each of two ligands. Electrochemical data show that the conjugation of each of the donor atoms with the cyclopentadienyl ring results in an enhanced electrochemical response of the ferrocene moiety to Cu+ ion binding relative to a similar ligand in which the donor atoms are not conjugated with the cyclopentadienyl ring.