Properties of some ferrocene macrocyclic dioxotetraamines: the roles of aromatic side-arms

The coordination chemistry and electrochemical behavior of a series of ferr ocene macrocyclic dioxotetraamines 1-4 each of which bears a pendant aromat ic group and a malonic diamide fragment in their framework were investigate d by electronic absorption spectroscopy and cyclic voltammetry. For the pur pose of comparison, their model compounds 5-8 were also synthesized and stu died. The stoichiometry of 1:1 for the complexes has been confirmed by FAB mass spectroscopy and UV-vis titration of Cu(II) ion with ligands 4 and 8. Stability constants for the equilibrium of the above complexes have been ev aluated. The ferrocene ligands 1-4 can electrochemically recognize the tran sition metal ions (Co2+, Ni2+ and Cu2+), while those ligands with a complex ible atom in the side-arm can stabilize selectively the uncommon state of N i(III). (C) 2001 Elsevier Science B.V. All rights reserved.