Field-dependent anisotropy change in a supramolecular Mn(II)- [3 x 3] grid

The magnetic anisotropy of a novel Mn(II)- 3x3] grid complex was investigated by means of high-field torque magnetometry. Torque vs field curves at low temperatures demonstrates a ground state with S>0 and exhibits a torque step due to a field-induced level crossing at B(*) approximately 7.5 T, accompanied by an abrupt change of magnetic anisotropy from easy-axis to hard-axis types. These observations are discussed in terms of a spin Hamiltonian formalism.