title: Reticular three-dimensional 3d-4f frameworks constructed through substituted imidazole-dicarboxylate: syntheses, luminescence and magnetic properties study.
abstract: A family of heteronuclear metal organic frameworks (MOFs) using lanthanide and transition metal ion based on a rigid ligand of substituted imidazoledicarboxylic acid, namely, {[Ln2Zn2 (μ3-Hmimda)2 (μ3-mimda)2·4H2O]n·mn H2O}, Ln = Nd, m = 2 (1), Ln = Ho, m = 3 (2), Ln = Er, m = 2 (3), Ln = Yb, m = 3 (4), [Tb2Co2(μ3-Hmimda)2 (μ3-mimda)2·4H2O]n·2nH2O} (5) and [Dy2Co2 (μ3-Hmimda)2 (μ3-mimda)2·4H2O]n·nH2O} (6), (H3mimda = 1H-2-methyl-4,5-imidazole-dicarboxylic acid), have been developed and characterized. All the complexes (except for a little disparity for 1) are isostructural, and all crystallize in the monoclinic system. They possess an extended reticular-like porous structure constructed from corrugated 2D layers. Direct current (dc) magnetic susceptibility measurements for 1-5 indicated depopulation of the Stark components at low temperature and/or possible weak anti-ferromagnetic interactions within hetero-nuclear MOFs. Alternating current (ac) susceptibility studies reveal that the Dy(III)-Co(II) complex exhibits both possible ferromagnetic couplings and frequency-dependent out-of-phase signals, behaviour of single-ion magnet nature. Fluorescence properties of series complexes both in near-infrared (NIR) and visible regions have been comparatively studied.
authors.affiliation: College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang, 471022, P. R. China. fengx@lynu.edu.cn.
authors.forename: Xun
authors.initials: X
authors.lastname: Feng
authors.forename: Yu-Quan
authors.initials: YQ
authors.lastname: Feng
authors.forename: Jun Jing
authors.initials: JJ
authors.lastname: Chen
authors.forename: Seik-Weng
authors.initials: SW
authors.lastname: Ng
authors.forename: Li-Ya
authors.initials: LY
authors.lastname: Wang
authors.forename: Jin-Zhong
authors.initials: JZ
authors.lastname: Guo