Unveiling the Werner-Type Cluster Chemistry of Heterometallic 4f/Post-Transition Metals: A {Dy₃Bi₈} Complex Exhibiting Quantum Tunneling Steps in the Hysteresis Loops and its 1-D Congener

A new [Dy3Bi8O6Cl3(saph)9] (1) Werner-type cluster has been prepared, which is the first DyIII/BiIII polynuclear compound with no metal–metal bond and one of the very few LnIII–BiIII (Ln = lanthanide) heterometallic complexes reported to date. The molecular compound 1 has been deliberately transformed to its 1-D analogue [Dy3Bi8O6(N3)3(saph)9]n (2) via the replacement of the terminal Cl– ions by end-to-end bridging N3– groups. The overall metallic skeleton of 1 (and 2) can be described as consisting of a diamagnetic {Bi8} unit with an elongated trigonal bipyramidal topology, surrounded by a magnetic {Dy3} equilateral triangle, which does not contain μ3-oxo/hydroxo/alkoxo groups. Detailed magnetic studies in a microcrystalline sample and a single crystal of 1 revealed a rare two-step hysteresis loop at various low temperatures and field-sweep rates, with the steps located at zero and ±0.26 T fields providing a measure of intermolecular interactions. Extended ab initio calculations unravel the dominant pathways of magnetization relaxation, as well as the type and magnitude of the magnetic exchange interactions between the DyIII centers and the orientation of their anisotropy axes, thus rendering the {Dy3} unit of 1 as a rare triangle among its congeners with a nontoroidal magnetic state. ... mehrThe combined results demonstrate the potential of heterometallic lanthanide/post-transition metal chemistry to provide molecule-based materials with unprecedented structures and compelling methods to rationalize the obtained magnetic properties.