A Promising Mg II ‐Ion‐Selective Luminescent Probe: Structures and Properties of Dy–Mn Polymers with High Symmetry

Two Dy–Mn polymers, {[Dy(L 1 ) 3 Mn 1.5 (H 2 O) 3 ]⋅3.125 H 2 O} n ( 1 , L 1 =pyridine‐2,6‐dicarboxylic acid) and {[Dy(L 2 ) 3 Mn 1.5 (H 2 O) 6 ]⋅8.25 H 2 O} n ( 2 , L 2 = 4‐hydroxylpyridine‐2,6‐dicarboxylic acid), with high symmetry ( S 6 ) have been prepared. Polymer 1 has a nanoporous 3D framework with channel of about 17.6 Å diameter, while 2 has a honeycomb‐type 2D structure with the cavity of approximately 14.4 Å diameter. In the construction of multidimensional porous polymers with 3d–4f mixed metals, it is the first observation that a ligand substituent effect leads to dramatic differences in the structures formed. Luminescent studies reveal that the emission intensities of 1 and 2 increase significantly upon the addition of Mg 2+ , whereas the introduction of other metal ions leaves the intensity unchanged or even weakens it; hence, both of them may serve as good candidates of Mg 2+ luminescent probes. To our knowledge, complex 1 is also the first example of a 3d–4f metal‐based nanoporous polymer to exhibit luminescent selectivity for Mg 2+ . Magnetic susceptibility measurements reveal a rather rare ferromagnetic interaction in 2 . Thermal gravimetric analyses and powder X‐ray diffraction investigations have also been performed, suggestive of high thermal stability of 1 .