New coordination polymers from 1D chain, 2D layer to 3D framework constructed from 1,2-phenylenediacetic acid and 1,3-bis(4-pyridyl)propane flexible ligands

The hydrothermal reactions of Cd, Zn, or Cu(II) acetate salts with H2PHDA and BPP flexible ligands afford three new coordination polymers, including [Cd(PHDA)(BPP)(H2O)]n(1), [Zn(PHDA)(BPP)]n(2), and [Cu2(PHDA)2(BPP)]n(3) (H2PHDA=1,2-phenylenediacetic acid, BPP=1,3-bis(4-pyridyl)propane). The single-crystal X-ray diffractions reveal that all three complexes feature various metal carboxylate subunits extended further by the BPP ligands to form a diverse range of structures, displaying a remarked structural sensitivity to metal(II) cation. Complex 1 containing PHDA-bridged binuclear cadmium generates 1D double-stranded chain, complex 2 results in 2D→2D interpenetrated (4,4) grids, and complex 3 displays a 3D self-penetrated framework with 48668 rob topology. In addition, fluorescent analyses show that both 1 and 2 exhibit intense blue-violet photoluminescence in the solid state.

Graphical AbstractWe show diverse supramolecular frameworks based on the same ligands (PHDA and BPP) and different metal acetate salts including 1D double-stranded chain, 2D → 2D twofold interpenetrated layer, and 3D self-penetration networks.Figure optionsDownload as PowerPoint slideHighlights
► Three metal(II = 2 \⁎ ROMAN ) coordination polymers were synthesized using H2PHDA and BPP.
► The diversity of structures show a remarked sensitivity to metal(II) center.
► Complexes show the enhancement of fluorescence compared to that of free ligand.