Syntheses, structures, and magnetic properties of the face-centered cubic clusters [Tp(8)(H(2)O)(12)M(6)Fe(8)(CN)(24)](4+) (M = Co, Ni).
Reactions between K[TpFe(CN)3] (Tp- = hydrotris(1-pyrazolyl)borate) and M(ClO4)2 x 6H2O (M = Co or Ni) in a mixture of acetonitrile and methanol afford, upon crystallization via THF vapor diffusion, [Tp8(H2O)12Co6Fe8(CN)24](ClO4)4.12THF x 7H2O (1) and [Tp8(H2O)12Ni6Fe8(CN)24](ClO4)4.12THF x 7H2O (2). Both compounds contain cyano-bridged clusters with a face-centered cubic geometry, wherein octahedral CoII or NiII centers are situated at the face-centering sites. The results of variable-temperature magnetic susceptibility measurements indicate the presence of ferromagnetic exchange coupling within both molecules to give ground states of S = 7 and 10, respectively. Low-temperature magnetization data reveal significant zero-field splitting, with the best fits for the Co6Fe8 and Ni6Fe8 clusters yielding D = -0.54 and 0.21 cm-1, respectively; ac magnetic susceptibility measurements performed on both samples showed no evidence of the slow relaxation effects associated with single-molecule magnet behavior.
Jiang
Long
L
MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, State Key Laboratory of Optoelectronic Materials and Technologies, and Instrumentation Analysis and Research Center, Sun Yat-Sen University, Guangzhou 510275, China.
Choi
Hye Jin
HJ
Feng
Xiao-Long
XL
Lu
Tong-Bu
TB
Long
Jeffrey R
JR
D003460:Crystallization; D018360:Crystallography, X-Ray; D008280:Magnetics; D008670:Metals / Q000138:chemical synthesis* / Q000737:chemistry; D008958:Models, Molecular
D008670:Metals