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As a biodegradable and biocompatible polymer material, polyglycolic acid is attracting more and more attention in the field of polymeric and biomedical materials. Consequently, the study of the transformation between different crystal forms of glycolide, the monomer of polyglycolic acid, is of great importance, because crystal forms of glycolide determine the stabilities and properties of polyglycolic acid products polymerized under different conditions in industry. Herein, this article reports the synthesis and crystallization of α‐ and β‐glycolide controlled by the type of organic solvents and/or temperatures, during which an intermediate crystal form of β′‐glycolide is newly observed. The transformation between α‐, β‐, and β′‐glycolide is investigated in detail, and the stabilities of different crystal forms are illustrated via the controlled experiments under different relative humidity (RH) as well as the theoretical calculations, which should provide fundamental concepts and guidance for the industrial production of glycolide and optimization of polyglycolic acid products. [ABSTRACT FROM AUTHOR]

Three 1D/2D HgII coordination polymers (CPs), namely {[Hg3(L)2Cl6](H2O)}n (1), [Hg(L)Br2]n (2), and [Hg(L)I2]n (3) were prepared by assembly of 3,4‐bis(3‐pyridyl)‐5‐(4‐pyridyl)‐1,2,4‐triazole (L) with different inorganic HgII salts (i.e. HgCl2, HgBr2 or HgI2). Single‐crystal X‐ray diffraction analysis reveals two types of bimetallic subunits [(Hg)2C6N4] and [(Hg)2C12N6] in CP 1, which are further extended to a 2D coordination network. Both of CPs 2 and 3 show 1D zigzag arrays bridged by L ligands. Notably, the L ligands take the (η4, μ4) coordination fashion in 1 but (η2, μ2) binding mode in 2 and 3. The structural differences of CPs 1–3 indicate that the L ligand can adjust its coordination fashions to meet the requirements of HgII centers, relying on the presence of distinct halide anions. In addition, 1 can be applied to fabricate an electrochemical biosensor for the detection of penicillin. [ABSTRACT FROM AUTHOR]

A series of silver(I) supramolecular complexes, namely, {[Ag(L24)](NO3)}n (1), [Ag2(L24)(NO2)2]n (2), and {[Ag1.25(L24)(DMF)](PF6)1.25}n (3) were prepared by the reactions of 1‐(2‐pyridyl)‐2‐(4‐pyridyl)‐1,2,4‐triazole (L24) and silver(I) salts with different anions (AgNO3, AgNO2, AgPF6). Single‐crystal X‐ray diffraction indicates that 1–3 display diverse supramolecular networks. The structure of dinuclear complex 1 is composed of a six‐membered Ag2N4 ring with the Ag···Ag distance of 4.4137(3) Å. In complex 2, the adjacent AgI centers are interlinked by L24 ligands into a 1D chain, the adjacent of which are further extended by the bridged nitrites to construct a 2D coordination architecture. Complex 3 shows a 3D (3,4)‐connected framework, which is generated by the linkage of L24 ligands. All complexes were characterized by IR spectra, elemental analysis, and powder X‐ray diffraction. Notably, a structural comparison of the complexes demonstrates that their structures are predominated by the nature of anions. Additionally, 1 and 2 show efficient dichromate (Cr2O72–) capture in water system, which can be ascribed to the anion‐exchange. [ABSTRACT FROM AUTHOR]