ja0263846_si_002.cif (20.32 kB)
A Cyano-Bridged Single-Molecule Magnet: Slow Magnetic Relaxation in a Trigonal Prismatic MnMo6(CN)18 Cluster
datasetposted on 06.06.2002, 00:00 by Jennifer J. Sokol, Allan G. Hee, Jeffrey R. Long
We report the synthesis of the first well-documented example of a cyano-bridged single-molecule magnet. An assembly reaction parallel to that employed in producing the trigonal prismatic [(Me3tacn)6MnCr6(CN)18]2+ (Me3tacn = N,N‘,N‘‘-trimethyl-1,4,7-triazacyclononane) cluster affords K[(Me3tacn)6MnMo6(CN)18](ClO4)3 (1), containing an analogous molybdenum(III)-substituted cluster. Fits to the DC magnetic susceptibility and magnetization data for 1 show that the MnMo6 cluster possesses weak antiferromagnetic coupling (J = −6.7 cm-1), leading to an S = 13/2 ground state with significantly enhanced magnetic anisotropy (D = −0.33 cm-1 and E = −0.018 cm-1). Consistent with these results, AC magnetic susceptibility measurements show the molecule to exhibit slow magnetic relaxation indicative of a single-molecule magnet with an energy barrier of 10 cm-1 for spin reversal.