“SOFT–HARD” STRATEGY TO CONSTRUCT A PYRAZINE SULFONIC ACID COPPER(II) SUPRAMOLECULAR STRUCTURE AND A STUDY OF ITS FLUORESCENT PROPERTY

An asymmetric mononuclear cobalt(II) compound derived from 3-bromo-pyridine-2,6-dicarboxylic acid involving in-situ hydrothermal decarboxylation: structure, magnetic property and Hirshfeld surface analysis

A new cobalt(II) compound with the formula [Co(5-Br-pyc)(2,2′-bipy)(H2O)(Cl)]·2H2O (1·H2O) (5-Br-Hpyc = 5-bromo-pyridine-2-carboxylic acid, 2,2′-bipy = 2,2′-bipyridine) has been hydrothermally synthesized and well characterized. The X-ray single-crystal diffraction analysis showed that 1⋅2H2O has crystallizes in the monoclinic system, space group P21/c (no. 14). The Co(II) center was octahedrally bonded by one bidentate chelate 5-Br-pyc anion and one 2,2′-bipy, one water molecule as well as one chloride anion to form the mononuclear structure of 1⋅2H2O. Complex 1⋅2H2O forms a 3D network through abundant O–H⋅⋅⋅O hydrogen bonds and π⋅⋅⋅π stacking interactions. Notably, the 5-Br-Hpyc ligand was in situ generated by decarboxylation of the 3-bromo-pyridine-2,6-dicarboxylic acid (3-Br-H2pydc) precursor selectively on 2-position under hydrothermal conditions. The magnetic properties, the Hirshfeld surface structure and the synthetic process for 1⋅2H2O have been carefully described and discussed.

A new copper(II) complex containing triclopyr: one-pot crystallization, structure, conformation and Hirshfeld surface analyses

A new copper(II) complex [Cu(3,5,6-tcpa)(2,2′-bipy)Cl] (1) has been obtained through the one-pot hydrothermal reaction of copper chloride dihydrate with triclopyr (systematic name 2-((3,5,6-trichloropyridin-2-yl)oxy)acetic acid, abbreviation 3,5,6-Htcpa) and 2,2′-bipyridine (2,2′-bipy) coligands. 1 has crystallized in triclinic crystal system, P 1 ‾ $\overline{1}$ space group. The central copper(II) ion displayed a distorted square–pyramidal geometry and was connected by one chlorido co-ligand (Clˉ), one 3,5,6-tcpa anionic chelator and one chelating 2,2’-bipy ligand to afford a mononuclear structure. 1 is further extended into a 3D network by the non-covalent interactions of H⋯Cl, H⋯O hydrogen bonds, aromatic π⋯π stacking together with Cl⋯Cl halogen bond interactions. The co-crystallization process, the crystal structure of 1 as well as the Hirshfeld surface analysis for 1 have been analyzed and described. In addition, the flexible conformation of phenoxy methylene group among 1, triclopyr acid and its previously reported co-crystallized compound also have been carefully compared and discussed.

The synthesis, crystal structure and conformation analysis of triclopyr ethyl ester

Triclopyr ethyl ester (1) has been co-synthesized through one-pot solvothermal reaction and the crystal structure has been determined by single crystal X-ray structure analysis. The compound C18H16Cl6N2O6 crystallizes in the monoclinic crystal system, P21/c space group with unit-cell parameters: a = 4.9615(2) Å, b = 30.9297(14) Å, c = 15.9155(10) Å, β = 91.466(4)° and Z = 4. Each unit cell is composed of two discrete, similar but reversely arranged triclopyr ethyl ester organic molecules. In the 3D packing plot, 1 is further assembled into a network structure via rich Cl⋯Cl halogen bond interactions. In addition, the crystal structure, the flexible conformation of phenoxy methylene group of 1 has been carefully compared and discussed with those of triclopyr acid.

A (4,4)-connected zinc(II) coordination polymer constructed with the flexible 2-carboxy phenoxyacetate ligand: synthesis, conformation alteration and fluorescent properties

A new binary ZnII coordination polymer, [Zn(2-cpa)(H2O)] n (2D-Zn) has been prepared by a 120 °C hydrothermal reaction of zinc(II) sulfate heptahydrate and 2-carboxy phenoxyacetic acid (2-H2cpa) in the presence of potassium hydroxide. Single-crystal X-ray diffraction analysis shows that the ZnII ion is located in a deformed ZnO6 octahedron bonded by one water and three 2-carboxy phenoxyacetate (2-cpa) ligands. The 2-cpa exhibits pentadentate double bridging chelate-μ 3 coordination mode and connects adjacent ZnII ions to generate a corrugated (4,4)-connected layer structure. The structures, conformation of 2-cpa and photoluminescence spectra for 2D-Zn have been carefully analyzed and compared with its two closely related compounds ̶ 1D [Zn(2-cpa)(H2O)] n (1D-Zn) and mononuclear [Zn(2-cpa)(H2O)3] (0D-Zn). The results showed that the conformation of 2-cpa in 2D-Zn has the maximum alteration and the corresponding fluorescence emission peak of 2D-Zn has the largest red-shift of 62 nm compared with that of free 2-H2cpa.