Synthesis, Structures, and Magnetic Properties of Three Series of Discrete or 1D Compounds based on Pyramidal [ LnCu4] ( Ln = Gd and Dy) Cluster and Formate Ligand.

With formate as ligand, one discrete dragonfly-like 3d-4f cluster showing beautiful pyramidal metal skeleton, [GdCu4(HCOO)5(μ3-OH)4(NO3)2(H2O)7](H2O) ( 1Gd), was obtained by a self-assembly reaction of Gd(NO3)3, Cu(NO3)2, and formate ligand. The two nitrates could be treated as the 'wings' of the 'dragonfly', and the formate with a free oxygen atom could be regarded as the 'tail'. When using perchlorate instead of nitrate, two series of 1D compounds based on the similar pyramidal [ LnCu4] unit, linear {[GdCu4(HCOO)5(μ3-[OH)4(H2O)8](ClO4)2(H2O)2} n ( 2Gd) and zigzag {[ LnCu4Na2(HCOO)4(μ3-OH)4(H2O)9(ClO4)5](H2O)2} n [ Ln = Gd, ( 3Gd); Dy, ( 3Dy)] were synthesized by controlling the formate amount. They used μ5-η1:η4 formate or [Na2(ClO4)4]2- unit as connectors to link the neighboring [ LnCu4] units together, respectively. Magnetic analyses reveal that these four compounds all show ferromagnetic interactions, and 3Dy displays slow relaxation of the magnetization. [ABSTRACT FROM AUTHOR]