Journal of Structural Chemistry最新文献

The [Ni(L1)₂(H₂O)₂](BF₄)₂(1-H₂O) and [Ni(L2)₂](BF₄)₂ (2) bis-chelate nickel(II) complexes based on 1,5-N,O-ligands, namely, (diisopropyl(pyridin-2-ylmethyl)phosphine oxide L1 and diisopropyl(quinolin-2-ylmethyl)phosphine oxide L2) are prepared. The structure and composition of 1-H₂O and 2 are confirmed by mass spectroscopy, IR spectroscopy, thermogravimetric analysis, and elemental analysis. The compounds dissociate in solutions so that aqualigands in 1-H₂O are replaced by acetonitrile to form the [Ni(L1)₂(CH₃CN)₂](BF₄)₂(1-CH₃CN) complex and phosphine oxide ligands in 2 are replaced by six water molecules to form the [Ni₂(L2)₄(H₂O)₁₂](BF₄)₂ hydrogen-bonded hexaaquanickel(II) agglomerate (3). The structure of 1-H₂O, 1-CH₃CN, and 3 in crystals are determined by XRD. Cytotoxic properties of the synthesized nickel(II) complexes against M-HeLa and HuTu80 cancer cells and normal Chang Liver cell lines are studied.

The dependence of unit cell parameters (UCPs) of LnCrO₃ (Ln = La–Lu, Y) orthochromites on effective ionic radii of Ln³⁺ cations is analyzed. It is shown that these dependences can be described by the following equations: (a = {69}.{831}R_{text{Ln}}^{3}-{223}.{91}R_{text{Ln}}^{2}text{+} {238}.{76}{{R}_{text{Ln}}}-{79}.{162}) Å; b = 1.5893R_Ln + 5.9242 Å, c = 1.8469 R_Ln + 3.3691 Å, and V = 121.85R_Ln + 93.97 Å³, where R_Ln is the effective ionic radius of the Ln³⁺ cation with a confidence probability of 0.775, 0.989, 0.998, and 0.990, respectively. The obtained equations can be use in a priory calculations of the UCPs of isovalent solid substitution solutions of REE orthochromites (including high-entropy ones) using average effective radii of substituted Ln³⁺ cations. The tolerance factors of REE-, bismuth-, thallium-, and indium orthochromites are calculated. The possibility that an orthorhombic perovskite structure can be formed by the interaction of REE orthochromites with non-isostructural BiCrO₃ and ScCrO₃ chromites is considered.

Ethyl-2-amino-1-(hetarylamido)-4-oxo-5-(2-oxo-2-phenylethylidene)-4,5-dihydro-1H-pyrrole-3-carboxylates are synthesized, their antiradical and antioxidant activities are studied, and the quantum chemical calculations are performed. The nitrogen atom position in the pyridine moiety of the derivatives is found to change the toxicity of synthesized compounds and to affect the ability to bind free radicals. The results can facilitate the further determination of the structure – activity relationship in the considered types of the biological activity.

Metal-organic coordination polymer {[Zn₇O₂(tr₂btd)₂(1,4-ndc)₆]·2tr₂btd}_n representing an inclusion compound of free ligand molecules in the pores of the 3D framework is synthesized by the interaction of zinc 4,7-di(1,2,4-triazol-1-yl)-2,1,3-benzothiadiazole (tr₂btd) nitrate and 1,4-naphthalene dicarboxylic acid (1,4-H₂ndc). Features of the interaction of guest molecules with the framework are investigated by single crystal X-ray diffraction, IR spectroscopy, and quantum chemical calculations. The study of the luminescent properties of compounds shows a bathochromic shift of the emission maximum that is unusual for coordination polymers with tr₂btd as a linker. Quantum chemical calculations at the density functional theory level reveals charge transfer between the guest molecule and the framework during emission.

We discuss the methodological questions of measuring unit cell parameters of small crystals in Bond’s scheme on a commercial diffractometer equipped with a three-circle goniometer and a 2D detector. The effect of the sample eccentricity on the positions of X-ray diffraction reflections during rotation about φ and ω axes is examined. The approach is developed to eliminate the effect of the sample eccentricity related to rotation about the φ axis by positioning one of the crystallographic directions along the ω axis. The unit cell parameters are measured for the reference Si and Ge single crystals used in this work with relative error Δa/a no worse than 6.5·10^–5.

New complexes of magnesium with asymmetric fluorinated β-diketones are synthesized: pentafluoropropionyl (Hpfpac, 6,6,6,5,5-pentafluorohexane-2,4-dione) and heptafluorobutyrylacetone (Hhfbac, 7,7,7,6,6,5,5-heptafluoroheptane-2,4-dione). The [Mg(H₂O)(EtOH)(pfpac)₂] 1 and [Mg(H₂O)₂(hfbac)₂]·H₂O 2 phases are characterized by a number of methods. The structures of crystals of 1, 2, and [Mg(EtOH)₂(hfbac)₂] 3 are determined by the single crystal X-ray diffraction analysis. Magnesium atoms have a distorted octahedral environment, and neutral ligands are in the trans-position. Molecules are involved in systems of OH⋯O_dik hydrogen bonds, forming layers (2) or chains (1, 3). A relative evaluation shows that 2 is more volatile than 1. Structures of molecules and packing characters are compared with those of a series of related β-diketonate complexes. The effect of an increase in the ligand perfluoroalkyl chain (L = tfac, trifluoroacetylacetonate ion), including isoformular [Mg(H₂O)₂(L)₂]·H₂O, is shown.

A series of complexes [Ln(Np^BrOON)₃]₂ (Ln = Nd, Eu, Gd, Yb) were synthesized by the reaction of the corresponding lanthanide silylamides with 2-(2-benzoxazol-2-yl)-7-bromo-3-naphthol. The structure of the initial phenol, Eu and Yb complexes was established using X-ray diffraction analysis, which showed that the resulting compounds have a centrosymmetric dimeric structure. All the obtained complexes in the solid state upon excitation by light with a wavelength of 365 nm revealed ligand-centered photoluminescence (PL) in the visible region of 450-700 nm. The complexes of Nd and Yb in addition exhibit the metal-centered emission in the near-infrared (NIR) region of high intensity.

The novel Schiff base derivative (E)-2-(((4-bromothiophen-2-yl)methylene)amino)-5-methylphenol (HL) was synthesized and characterized via FTIR, elemental analysis, UV-Vis, ¹H NMR and ¹³C NMR techniques. Quantum chemical calculations were performed with the density functional theory at the B3LYP level with the 6-311++G(d,p) basis tuned in the gas phase of the isolated compounds in the ground state. The HL Schiff base crystallizes in the monoclinic crystal system with C2/c (no. 15) space group, Z = 8, a = 14.286(2) Å, b = 6.4736(9) Å, c = 26.256(4) Å. The thermal properties of HL Schiff base were investigated via DTA/TGA/TG curves. The antibacterial activity of the HL Schiff base against ESBL E. coli and MRSA was investigated. In the disk diffusion test, the zone of inhibition was determined against MRSA while it was not determined against ESBL E.coli. In addition, different levels of antibacterial activity were observed against all bacteria in the broth microdilution test.

The structural and spectroscopic properties of a new –ONNO– type Schiff base were analyzed. The compound 6,6′-((1E,1′E)-(hexane-1,6-diylbis(azaneylylidene))bis(phenylmethaneylylidene))bis(3-(octyloxy) phenol) was synthesized by condensing a diamine and a ketone in tetrahydrofuran, resulting in a high yield. The symmetric Schiff base, in which both amine ends converted to the imine structure, was examined using XRD, NMR, IR and UV-Vis spectroscopies. The theoretical calculations were done successfully using DFT approach at 6-31G(d,p) basis set to investigate the properties of the title compound that cannot be studied by experimental analyses. NBO analysis was used to study hyper-conjugative interactions involving the overlap of σ or π electrons and electron density between adjacent atoms and to determine the stabilization energy. The DFT theoretical parameters and XRD experimental parameters were compared and showed good agreement. 2D fingerprint and 3D Hirshfeld surface plots were obtained to determine the intermolecular interactions. The features of the optimized structure were investigated by several analyses such: NBO, Frontier molecular orbitals, ESP, MEP and ECT which cannot be studied by theoretical methods. The UV-Vis spectroscopy was used to investigate the interaction of the synthesized benzophenone Schiff base compound with lyotropic media. The synthesized compound is significantly compatible with the prepared lyotropic medium due to its highly symmetrical and amphiphilic structure.

Composition, structure, energy parameters, and regions of existence of hydrate complexes formed in the H₃PO₄–H₂O system are determined by IR spectroscopy and quantum chemical methods. It is established that dilute solutions up to the 1:5 molar component ratio contain hydrates bearing one orthophosphoric acid molecule. In solutions with H₃PO₄:H₂O ≤ 1:6, the main structural unit is the H₃PO₄·6H₂O complex with a completely filled first hydration shell. Concentrated solutions (1:4-1:0) contain H-bonded 2H₃PO₄·nH₂O complexes (n = 1-8), each having a cycle of two acid molecules. Pure phosphoric acid is composed of the fragments of polymer chains made up of 2H₃PO₄ dimers as the chain links. Changes in the IR spectra of H₃PO₄–H₂O solutions in the whole concentration range are explained using the calculated data for the structure of mH₃PO₄·nH₂O hydrates.