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)(mu(3)-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 [LnCu(4)] unit, linear {[GdCu4(HCOO)(5)(mu(3)-[OH)(4)(H2O)(8)](ClO4)(2)(H2O)(2)}(n) (2Gd)and zig-zag {[LnCu(4)Na(2)(HCOO)(4)(mu(3)-OH)(4)(H2O)(9)(ClO4)(5)](H2O)(2)}(n) [Ln = Gd, (3Gd); Dy, (3Dy)] were synthesized by controlling the formate amount. They used mu 5-eta(1):eta(4) formate or [Na-2(ClO4)(4)](2-) unit as connectors to link the neighboring [LnCu(4)] units together, respectively. Magnetic analyses reveal that these four compounds all show ferromagnetic interactions, and 3Dy displays slow relaxation of the magnetization.