Magnetic Properties of Hexanuclear Manganese Antiferromagnetic Clusters Mn6

Abstract

We report a study of magnetic properties of a series of hexanuclear manganese metallamacrocycles {Mn6}. The magnetic properties are characterized by antiferromagnetic (AFM) coupling constants J(1)/k(B)approximate to-4.0 K, between the nearest neighbors, and J(2)/k(B)approximate to-1.2 K, between the next-nearest neighbors. The temperature dependence of H-1 NMR linewidth is observed to be consistent with the AFM singlet ground state with a total spin S-T=0. H-1 nuclear spin-lattice relaxation rate 1/T-1 shows a strong enhancement at low temperatures with a peak around T approximate to J(1), as commonly observed in AFM molecular rings and clusters. (C) 2006 American Institute of Physics.