Crystal structure, assembly process, and single-molecule magnet behavior of a triangular prismatic {Co} cluster

Using the polydentate ligand of H 4 L with the Co II ion, a triangular prism-type nine-nucleus cluster [Co 9 (L) 3 (CH 2 OCH 2 OH) 6 ]·3.5H 2 O ( {Co 9 }-Eg , H 4 L = 6,6′-(1 H ,1′ H -[3,3′-bi(1,2,4-triazole)]-5,5′-diyl)dipicolinic acid) was constructed. Ion fragmentation during the formation of the {Co 9 }-Eg cluster was tracked using time-dependent electrospray ionization mass spectrometry. In addition, we proposed two possible formation processes (i) H 4 L → CoL → Co 2 L → Co 6 L 3 → Co 7 L 3 → Co 9 L 3 and (ii) H 4 L → CoL → Co 2 L → Co 3 L → Co 5 L 2 → Co 7 L 3 → Co 9 L 3 . Magnetic studies show that {Co 9 }-Eg exhibits slow relaxation under a static zero field at low temperature, which is the main characteristic of single molecule magnets (SMMs). The crystal structure, assembly process and magnetic properties of a triangular prismatic [Co 9 (btdpa) 3 (CH 2 OCH 2 OH) 6 ]·3.5H 2 O were reported: the cluster exhibits slow magnetization relaxation of single molecule magnets at zero field.