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

Using the polydentate ligand of HL with the Co ion, a triangular prism-type nine-nucleus cluster [Co(L)(CHOCHOH)]·3.5HO ({Co9}-Eg, HL = 6,6'-(1,1'-[3,3'-bi(1,2,4-triazole)]-5,5'-diyl)dipicolinic acid) was constructed. Ion fragmentation during the formation of the {Co9}-Eg cluster was tracked using time-dependent electrospray ionization mass spectrometry. In addition, we proposed two possible formation processes (i) HL → CoL → CoL → CoL → CoL → CoL and (ii) HL → CoL → CoL → CoL → CoL → CoL → CoL. Magnetic studies show that {Co9}-Eg exhibits slow relaxation under a static zero field at low temperature, which is the main characteristic of single molecule magnets (SMMs).