LAUSR

Abstract An imide-based O-donor ligand, 4-carboxyphenyl-1,3-dioxoisoindoline-5-carboxylic acid (H2In-4-ba), and one Zn(II) coordination polymer, [Zn(In-4-ba)(py)2]n (1, py = pyridine), have been synthesized. Single-crystal X-ray diffraction indicates that 1 has a quasi-31 helical chain structure, which shows one-dimensional to one-dimensional (1D → 2D) extension to be a homochiral layer of consecutively interweaving poly-helices with the same helicity. Coexistence of such homochiral layers in opposite chirality makes individual crystal of 1 to be in a racemic manner. Thermogravimetric (TG) analysis indicated that 1 shows high thermal stability approaching 440 °C. Thermal activation of 1 gives a desolvated phase, [Zn(In-4-ba)]n (1′), as supported by TG trace. Of particular note, reversible crystal-to-crystal transformations between solvated 1 and desolvated 1′ have been achieved upon decoordination and recoordination of the py ligands, as evidenced by XRPD patterns, IR spectra, and TG diagrams. The photoluminescence properties of as-synthesized 1, desolvated 1′, and resolvated 1′/py have also been studied. All of them exhibit an emission band centered at 486, 492, and 486 nm, respectively, which is originated from the ligand-centered charge transfer. Further, the emission intensity of 1′ is weaker than that of 1 and 1′/py, implying the influence of coordinated py ligands and/or structure regulation on photoluminescence.