Rational Design of a Covalently Tethered Dinuclear [Mn^II(N₃O₂)Cl(OH₂)]₂²⁺ Macrocyclic Building Block: Synthesis, Structure, and Magnetic Properties

A novel dimeric MnII complex {[Mn(N3O2)]Cl(OH2)}22Cl (2) of a macrocyclic Schiff base ligand derived from the condensation of 2,2‘,6,6‘-tetraacetyl-4,4‘-bipyridine with 3,6-dioxaoctane-1,8-diamine in the presence of a stoichiometric amount of MnII has been prepared and characterized. The X-ray analysis of 2 reveals that the two Mn ions assume a pentagonal-bipyramidal geometry, with the macrocycle occupying the pentagonal plane and the axial positions being filled by a halide ion and a H2O molecule. Magnetic susceptibility data (2−270 K) reveal the occurrence of weak antiferromagnetic interactions between covalently tethered MnII−MnII dimeric units.