Journal of Structural Chemistry最新文献

Optically transparent single-crystal blocks are prepared by the fusion of a barium fluoride charge with yttrium and erbium fluorides using sodium fluoride as a flux. The crystal structures were solved and composition of the following phases were determined: Na_0.75Ba_1.26Er_1.99F_9.24 (cubic crystal system, (Fmbar{3}m) space group, a = 11.4192(4) Å), Na_0.25BaY_2.75F_10.5 (cubic crystal system, (Fmbar{3}m) space group, a = 11.4350(19) Å), Na_0.05Ba_0.9Y_1.05F₅ (orthorhombic crystal system, Cmmm space group, a = 5.7205(5) Å, b = 17.2348(11) Å, c = 5.7648 (4) Å).

A new asymmetrical Schiff base ligand, (E)-4-chloro-2-{[(2,6-dimethylphenyl)amino] methyl}phenol (HL), and its mononuclear Cu(II) complex are synthesized. The molecular structures and spectroscopic properties of the ligand and its complex are experimentally characterized by single crystal X-ray diffraction, elemental analysis, FTIR, NMR and UV-Vis spectroscopic techniques. The analysis confirms that the Cu atom is generally four-coordinated in the complex by one imino N and one phenolic O atoms of the Schiff-base ligand, adopting a trans-configuration of N₂O₂ donor atoms around the metal ion, forming a square planar geometry. The density functional calculation is carried out for both HL and the copper(II) complex to investigate changes in the structural parameters and HOMO and LUMO energies. The results demonstrate that the HOMO and the LUMO are effectively separated by the benzene ring of 2,6-dimethylbenzenamine as a donor unit and the benzene ring of 5-chlorosalicylaldehyde as an acceptor unit. The effective HOMO–LUMO separation helps to induce intramolecular charge transfer from the HOMO to the LUMO. The HOMO–LUMO energy gap becomes smaller when the Schiff base ligand is coordinated with the Cu(II) ion, which is most likely to be due to the interaction of copper(II) d orbitals with the HOMO and/or LUMO of the ligand. These theoretical calculations support the experimentally observed results. The biological assay reveals that both the Schiff base and the complex have different antimicrobial activities. The complex has the MIC value of 0.0781 mmol/L against Escherichia coli.

In this work, a new organic charge-transfer compound, namely 1-benzyl 2-aminopyridinium picrate [Bz-2-NH₂Py][PIC] (1), is prepared and characterized by single crystal X-ray diffraction (SC-XRD), powder X-ray diffraction (PXRD), FTIR, ¹H NMR and Raman spectroscopy. The title compound crystallizes in the monoclinic system with space group P2(1)/c and contains one [Bz-2-NH₂Py]⁺ cation and one [PIC]^– anion. The cations are stacked into a columnar structure through C–H⋯π interactions, and the N–H⋯O and C–H⋯O hydrogen bonds between the anions and cations stabilize the crystal stacking of [Bz-2-NH₂Py][PIC] (1). The frontier molecular orbitals HOMO and LUMO are computed by the DFT approach (using the B3LYP/6-31G (d,p) basis set) to understand the chemical reactivity and kinetic stability of the title compound. The geometrical parameters obtained from the XRD experiment are in good agreement with the simulated values from the single crystal structure. In addition, the organic material shows two main emission peaks at about 390 nm and 469 nm upon 241 nm excitation in the solid state at room temperature. The Hirshfeld surface analysis is performed to quantify the contributions of different intermolecular interactions.

The Ga-doped Li₇La₃Zr₂O₁₂ (LLZO) solid state electrolyte (SSE) is synthesized via the solid-state reaction. The structural study of the SSE is conducted with the help of X-ray diffraction and the Rietveld method. The SSE crystallizes in the Li_6.25Ga_0.15La_2.90Zr₂O₁₂ phase with cubic space group number 220 and the unit cell parameter of 13.02081 Å, and the La₂Zr₂O₇ impurity phase with cubic space group number 227 and the unit cell parameter of 10.79475 Å. The obtained lattice planes in the refinement are confirmed by TEM. The core of the Li ion migration channel is defined as the loop formed by Li32, Li1, Li2, and Li22 sites with the minimum Li⋯Li distance and occupational disorganization of Ga-doped LLZO SSE. The electron density plots of the Li_6.25Ga_0.15La_2.90Zr₂O₁₂ phase show the maximum electron distribution inside the unit cell for lanthanum atoms. XPS confirms the presence of all the precursors, i.e., Li, La, Zr, Ga, and O in the synthesized compound. The elemental composition is confirmed by EDX. In the direct current charge-discharge behaviour of the Li symmetric cell, no voltage breakdown is observed even at 6 mA/cm² current density and after 400 charge/discharge cycles for over 200 h.

A 0D Cu-based complex (1) (Cu(L)₂(EDA)₂]_n, L = 3-phenylpropylmalonic acid, EDA = ethylenediamine) is synthesized by the solvent-thermal synthesis using 3-phenylpropylmalonic acid as the ligand. It is characterized and analyzed by powder X-ray diffraction, IR and UV diffuse reflectance spectroscopy, and other techniques. Complex 1 crystallizes in the triclinic crystal system with space group (Pbar{1}), and each Cu²⁺ is coordinated with two ligands and a water molecule, respectively. The cyclic voltammetry curve of the electrode modified by 1 (1+CPE) is tested in the PBS buffer solution (pH = 6.5). The found pair of reversible redox peaks belonging to Cu(II)/Cu(I) prove that 1 can be used in electrochemical applications.