A mononuclear manganese(III) complex of an asymmetric macrocyclic ligand with a ring contraction [MnHL2(ClO4)](ClO4)center dot 2.5H(2)O

The template reaction of sodium 2,6-diformyl-4-chlorophenolate and N,N-bis( 2-aminoethyl)-hydroxyethylamine followed by in situ transmetallation of Mn( ClO4)(2) results in a mononuclear manganese(III) complex of one 21-membered asymmetric 2:2 Schiff base macrocycle, in which a hydroxyethyl group of th e amine has been eliminated and ring contraction at one chamber of the macr ocycle has occurred to form an imidazolidine ring. An X-ray study indicates that the geometry about the manganese(III) ion is distorted octahedral. Th e electrochemical behavior of this complex in MeCN has been studied by cycl ic voltammetry.