Reticular three-dimensional 3d–4f frameworks constructed through substituted imidazole-dicarboxylate: syntheses, luminescence and magnetic properties study. Issue 2 (18th November 2014) - Feng, Xun
Abstract : Series of heteronuclear metal organic frameworks (HMOF) combination of lanthanide and Zn/Co ions based on a rigid substituted imidazoledicarboxylic acid ligand have been successfully isolated and characterized systematically. 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, {[Ln2 Zn2 (μ3 -Hmimda)2 (μ3 -mimda)2 ·4H2 O] n · mn H2 O}, Ln = Nd, m = 2 (1 ), Ln = Ho, m = 3 (2 ), Ln = Er, m = 2 (3 ), Ln = Yb, m = 3 (4 ), [Tb2 Co2 (μ3 -Hmimda)2 (μ3 -mimda)2 ·4H2 O] n ·2 n H2 O} (5 ) and [Dy2 Co2 (μ3 -Hmimda)2 (μ3 -mimda)2 ·4H2 O] n · n H2 O} (6 ), (H3 mimda = 1 H -2-methyl-4, 5-imidazole-dicarboxylic acid), have been developed and characterized. All the complexes (except for a little disparity for1 ) 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 for1–5 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.