Inorganic Chemistry, Vol.57, No.15, 9182-9189, 2018
Hierarchical Assembly of a {Co-24} Cluster from Two Vertex-Fused {Co-13} Clusters and Their Single-Molecule Magnetism
We present the synthesis, structural characterization, and magnetic properties of two high-nuclearity cobalt clusters formulated as [Co13 (mu3 -OH)3 (mu3 -CI)(dpbt)5 (ptd)-Cl10 ] [Co(H2 O),CI2 ] center dot(CH3 )2 CHOH (1) and [Co24 (mu3 -OH)6 (mu3 -CI)2 (dpbt)10 (ptd)2 CI16 ]center dot 2CH3 CH2 OH (2), respectively (H2 dpbt = 5,5'-bis(pyridin-2-yI)-3,3'-bis(1,2,4-triazole) and H2 ptd = 3-(pyridin-2-yI)-1,2,4-triazine-5,6-diol). Compound 1 is composed of an inner [Co4 (mu3 3 (mu3 -CI)] cubane and an outer [Co9 (dpbt)5 (ptd)Cl10 ] defective adamantane. Compound 2 reveals a giant {Co24 } cluster possessing a dual-[Co12 ] skeleton from 1. The hierarchical assembly from 1 to 2 has been established and tracked through high-resolution electrospray ionization (HRESI-MS) analyses from the solvothermal reaction mother solution. Magnetic studies of 1 and 2 revealed the highly correlated spins, a glasslike magnetic phase transition at ca. 8 K, and slow relaxation behavior of SMM nature in the lower-temperature region (below 4 K).