Synthesis and X-Ray Crystal Structure Determination of Pyridine-2,6-Dicarboxylate Ligand-Based 2D Complex with Heterometallic Ions

<div><p>This title compound, <b>[C₁₄H₂₀N₂NaO₁₅Sm]_n</b>, is synthesized by reacting Sm(NO₃)₃ and 2,6-pdca in the presence of 1M NaOH. The 2D sheet-based complex is formed, where Sm(III) ion occupied nine coordinating sites and Na (I) ion occupied six coordination sites. The Sm(III) atom is coordinated by two pyridine N atoms and four carboxylate O atoms from two doubly deprotonated pyridine-2,6-dicarboxylate ligands in a distorted octahedral geometry. There are three water molecules coordinated with Sm(III) ions. One Na(I) cation is coordinated by three carboxylate O atoms and two water molecules and the other is coordinated by five carboxylate O atoms and two water molecules in an irregular geometry. In this complex, Na(I) cations are connected with Sm(III) ions through bridging coordinated water molecules O1W and O3W. Topologically, structure consists of layers (1 0 0) with point symbol for Na(I) ion is (3².4.5.6².7⁴) and for net is (3.4.5)(3².4.5.6².7⁴) and 3,5-c 2-nodal net with topological type is gek1.</p></div

3-(benzo[<i>d</i>]thiazol-2-YL)phenol and 4-(benzo[<i>d</i>]thiazol-2-YL)phenol: Crystal Structure Determination, DFT Calculations and Visualizing Intermolecular Interactions Using Hirshfeld Surface Analysis

<p>This article describes the synthesis and X-ray crystal structure analysis of <b>3-(benzo[<i>d</i>]thiazol-2-yl) phenol (I) and 4-(benzo[<i>d</i>]thiazol-2-yl)phenol (II)</b>, crystallized in centrosymmetric triclinic and orthorhombic space groups respectively. The packing in the unit cell of these two positional isomers are different resulting difference in various types of intermolecular interactions (C-H…S, O-H…O_w and O-H…N) connect the molecules into 2D frameworks. Due to presence of lattice water in compound (<b>I</b>), H-bonding interactions are strong and melting point of (<b>I</b>) is comparatively higher than (<b>II</b>). The DFT optimized molecular geometries in (<b>I</b>) and (<b>II</b>) agree closely with those obtained from crystallographic studies.</p> <p></p> <p>The compounds <b>(I)</b> and <b>(II)</b> have been crystallized in centrosymmetric space groups. The DFT optimized molecular geometries in both compounds agree closely with those obtained from the crystallographic studies. An interplay of O-H…O_w and O-H…N type strong hydrogen bonds and C-H…S type weak interactions connect the molecules of (<b>I</b>) and (<b>II</b>) into 2D framework. Hirshfeld surface analysis of (<b>I</b>) indicates that the H…H and H…π contacts can account for 47.4% and 18.7%, respectively, of the Hirshfeld surface area, whereas the corresponding fraction in (<b>II</b>) is 36.5% and 29.5%, respectively.</p

Synthesis, Characterizations, Crystal Structure Determination of μ⁶ Coordinated Complex of Co (III) with EDTA and Its Thermal Properties

<div><p>The monomeric coordination complex (<b>I)</b> is having formula <b>{[Co(III)-μ⁶-(H-EDTA-κ⁵ N1,N2,O2,O6,O8)·H₂O]·2H₂O}</b>, which has been crystallized in distilled water and characterized by elemental analyses, FT-IR spectrum and Powder X-ray diffraction analyses. Single-crystal X-ray diffraction analysis revealed that complex (<b>I</b>) crystallized in triclinic space group <b>P-1</b> (space group no. 2) having μ⁶ coordination modes of complex with EDTA and Co (III) transition metal ion. The coordination number of Co (III) ion is six, occupied distorted octahedral geometry, where three carboxylate oxygen atoms, two nitrogen atoms, and one water molecule O1W are coordinated. There are two lattice water molecules are present in the molecular structure of complex (<b>I</b>) responsible for strong H-bonding interactions.</p></div

Sol–gel synthesis, structural and magnetic properties of nanoscale M-type barium hexaferrites BaCo_xZr_xFe_(12-2x)O₁₉

We have accomplished a low temperature sol–gel synthesis of nanocrystalline M-type hexaferrites BaCoxZrxFe(12-2x)O19 (x=0, 0.2, 0.4, 0.6, 0.8 and 1.0). These compounds were characterized by TGA–DTA, FT-IR, XRD, EDS and TEM. X-ray diffraction patterns demonstrate that the compounds are single phase M-type barium hexagonal ferrites (BHF) and maximum substitution is attained at x=1.0. The average size of the hexagonal platelets is 41.62 nm. MS is employed to probe the magnetic properties at microscopic levels. MS studies suggest that both the nature and concentration of dopant ions control site preferences in the crystal lattice. Substitution is preferred at 4f2 and 2b sites at x=0.4, 4f1 and 4f2 sites at x=0.6 and 2a and 2b sites at x=1.0 levels. M vs H studies reveal that on substitution MS vary only slightly from 63.63 to 56.94 emu/g while a drastic reduction has been observed in HC from 5428 to 630 Oe. High MS and low HC values of these materials make them particularly suitable for application in data recording. Our results also show that HC can be monitored independently while retaining high saturation magnetization of BHF by making coupled substitution of divalent (Co2+) and tetravalent (Zr4+) cations for Fe3+ ions

Effect of fuel on the synthesis, structural, and magnetic properties of M-type hexagonal SrFe₁₂O₁₉ nanoparticles

The aim of this work is to compare the formation temperatures, structural, and macroscopic magnetic properties of Sr-hexaferrite (SrM) in the presence of different fuels. In this research, SrM powder was synthesized by a sol–gel auto-combustion route using different hydroxycarboxylic acids: citric acid, tartaric acid, sucrose (gluconic acid), and lactic acid. Completion of reaction was followed by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The obtained powders were further characterized by thermal gravimetric analysis–differential thermal analysis (TGA–DTA), energy-dispersive spectroscopy (EDS), and scanning electron microscopy (SEM). Their magnetic properties were studied using Mössbauer spectroscopy and magnetic measurements were done by vibrating sample magnetometer (VSM). The influence of different fuels was reflected on the formation temperature, phase purity, and morphology of crystallites as well as on their magnetic properties. The results show the finest crystallite size has been obtained as 27.85 nm (from XRD) in the case of sucrose sample. The lowest calcination temperature of 800 &#176;C is obtained in the case of citric acid and tartaric acid samples, while sintering at 900 &#176;C is necessary when sucrose was applied as a fuel. Lactic acid sample results in low phase purity even at 1000 &#176;C. All the four samples show high level of magnetic properties. However, the sample prepared by citric acid as fuel has the highest specific saturation magnetization (M_S) and that with sucrose has the highest coercivity (H_C) while the sample prepared using lactic acid has the lowest magnetic parameters

Effect of site preferences on structural and magnetic switching properties of CO–Zr doped strontium hexaferrite SrCo_xZr_xFe_(12-2x)O₁₉

The aim of this work is to investigate the correlation between the distribution of cations over five crystallographic sublattices and magnetic properties of Sr-hexaferrites in the coupled substitution of magnetic Co²⁺ and non-magnetic Zr⁴⁺ for Fe³⁺. During present work, we have synthesized a series of SrCo_xZr_xFe_(12-2x)O₁₉ ferrites (x=0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) using sol–gel route at a much lower temperature of 800 &#176;C. These compounds were characterized by TGA, FT-IR, XRD, EDS and TEM. XRD data reveal the formation of polycrystalline magnetoplubite structure for all the compounds of the series. The crystallite size of nanoparticles lies in the range of 30–55 nm. M&#246;ssbauer spectroscopy was employed to probe magnetic properties at microscopic level. M&#246;ssbauer analysis indicates that dopant ions largely prefer 12k, 4f₁ and 2b sites at x=0.2 and 0.4 levels whereas at higher concentrations substitution takes place at 12k and 4f₂ sites. Magnetic measurements reveal that the values of coercivity (H_C) reduced from 6082 (x=0) to 1104 Oe (x=1.0) but the net magnetization of the samples is not correlated with dopant level. The saturation magnetization (MS) values are in the range of 64.8–56.8 emu/g. Our results suggest that magnetization and magneto-crystalline anisotropy are closely related to the distribution of Co–Zr on the five sublattices of the crystal