A Spin-Frustrated System Composed of Organic Radicals and Magnetic Metal Ions

Despite antiferromagnetic coupling between any two neighboring spins, parallel alignment of the 3d spins of the Mn^II ions and the 2p spins of the organic ligand is observed for the (degenerate) ground state of [{Mn(hfac)₂}₂(bnn)] (shown on the right). The “butterfly”-shaped arrangement of the spins contributes to this noteworthy spin configuration. hfac=hexafluoroacetylacetonate, bnn=2,2′-bis(1-oxyl-3-oxide-4,4,5,5-tetramethylimidazolinyl).