title: Novel polyoxometalate-templated, 3-D supramolecular networks based on lanthanide dimers: synthesis, structure, and fluorescent properties of [Ln2(DNBA)4(DMF)8][Mo6O19] (DNBA = 3,5-dinitrobenzoate).
abstract: The spherical Lindquist type polyoxometalate, Mo(6)O(19)(2)(-), has been used as a noncoordinating anionic template for the construction of novel three-dimensional lanthanide-aromatic monocarboxylate dimer supramolecular networks [Ln(2)(DNBA)(4)(DMF)(8)][Mo(6)O(19)] (Ln = La 1, Ce 2, and Eu 3, DNBA = 3,5-dinitrobenzoate, DMF = dimethylformamide). The title compounds are characterized by elemental analyses, IR, and single-crystal X-ray diffractions. X-ray diffraction experiments reveal that two Ln(III) ions are bridged by four 3,5-dinitrobenzoate anions as asymmetrically bridging ligands, leading to dimeric cores, [Ln(2)(DNBA)(4)(DMF)(8)](2+); [Ln(2)(DNBA)(4)(DMF)(8)](2+) groups are joined together by pi-pi stacking interactions between the aromatic groups to form a two-dimensional grid-like network; the 2-D supramolecular layers are further extended into 3-D supramolecular networks with 1-D box-like channels by hydrogen-bonding interactions, in which hexamolybdate polyanions reside. The compounds represent the first examples of 3-D carboxylate-bridged lanthanide dimer supramolecular "host" networks formed by pi-pi stacking and hydrogen-bonding interactions encapsulating noncoordinating "guest" polyoxoanion species. The fluorescent activity of compound 3 is reported.
authors.affiliation: Institute of Polyoxometalate Chemistry, Department of Chemistry, Northeast Normal University, Changchun, 130024, P. R. China.
authors.forename: Xiuli
authors.initials: X
authors.lastname: Wang
authors.forename: Yaqin
authors.initials: Y
authors.lastname: Guo
authors.forename: Yangguang
authors.initials: Y
authors.lastname: Li
authors.forename: Enbo
authors.initials: E
authors.lastname: Wang
authors.forename: Changwen
authors.initials: C
authors.lastname: Hu
authors.forename: Ninghai
authors.initials: N
authors.lastname: Hu