4f-Metal Clusters Exhibiting Slow Relaxation of Magnetization: A Dy 7 Complex with An Hourglass-like Metal Topology - Konstantinos N. Pantelis; Panagiota S. Perlepe; Spyridon Grammatikopoulos; Christos Lampropoulos; Jinkui Tang; Theocharis C. Stamatatos (Molecules, Vol 25, Iss 2191, p 2191 (2020, 2020)