A series of tetranuclear lanthanide complexes comprising two edge-sharing triangular units with field-induced slow magnetic relaxation for Dy_4 species

摘要

The syntheses, crystal structures and magnetic studies are reported for a series of Ln_4 clusters formulated as Ln_40(μ_3- OH)_2(php)_2(OAc)_6(H_2O) _2]·4MeOH·nH_2O (Ln = Gd (1), Tb (2), Dy (3) (n = 2) and Ho (4) (n = 0); H_2php = 2,6-(picolinoylhydrazone) pyridine). The overall metal core of each cluster is comprised of two edge-sharing triangular Ln_3 units linked by μ_3-OH bridges. Direct-current (dc) magnetic susceptibility studies reveal that the Ln~III ions are very weakly coupled in all four compounds. Alternating-current (ac) magnetic susceptibility studies for 3 indicate that field-induced slow relaxation phenomenon occurs for this compound.