摘要

Assembly reaction of 1,3-diamino-2-hydroxy-propane-N,N,N',N'-tetraacetic acid (H(5)hdpta), sodium acetate and Cr3+ ion at pH 6.7 in aqueous solution leads to the formation of Na[Cr-2(hdpta)(Ac)(2)] (1). Single crystal X-ray analysis show that 1 bears a 3D (4,4)-connected lon framework based on mononuclear Na+ nodes and dinuclear [Cr-2(hdpta)(Ac)(2)](-) complex ligands in which two Cr3+ ions are chelated by one hdpta(5-) and also bridged by two acetate auxiliary ligands. Further assemble of 1 with Gd3+ ions give rise to [Gd(NO3)(3)(H2O)(4)][Cr4Gd(hdpta)(2)(OH)(4)(H2O)(5)]center dot(NO3)center dot 32H(2)O (2). The [Cr4Gd(hdpta)(2)(OH)(4)(H2O)(5)](+) cation of 2 exhibit a 1D chain structure based on [Cr-4(hdpta)(2)(OH)(4)](2-) complex ligands and mononuclear Gd3+ nodes. [Cr-4(hdpta)(2)(OH)(4)](2-) has a tetranuclear {Cr-4} rectangular metal skeleton. Detailed synthesis experiments indicate heating is a simple and effective way to activate the inert Cr3+ ions to prepare oxygen-bridged Cr-Ln heterometallic compounds. Magnetic studies reveal that compound 2 shows overall antiferromagnetic interaction. Stepwise synthesis of a Cr-Na compound based on dinuclear {Cr2} unit and a Cr-Gd compound bearing tetranuclear {Cr4} unit are presented. [GRAPHICS]