Coordination Numbers of Bivalent Ions in Organic Solvents

Orekhov, M. A.

doi:10.1134/s0036024421100204

Cited by 6 publications

(7 citation statements)

References 36 publications

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“…The chloride ions test in all complexes was done with the AgNO 3 solution, and a negative result was obtained [18]. The molar conductance values of the complexes in DMSO solvent indicated that [ML 1 L 2 ] complexes are non-electrolytes, while complex 2 is a 1:1 electrolyte [19][20]. These results support the proposed formula of the complexes (Fig.…”

Section: ■ Results and Discussionsupporting

confidence: 55%

Synthesis, DFT Calculations, DNA Interaction, and Antimicrobial Studies of Some Mixed Ligand Complexes of Oxalic Acid and Schiff Base Trimethoprim with Various Metal Ions

Abdalrazaq

Jbarah²,

Al‐Noor³

et al. 2022

Indones. J. Chem.

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Mixed ligand metal complexes are synthesized from oxalic acid with Schiff base, and the Schiff base was obtained from trimethoprim and acetylacetone. The synthesized complexes were of the type [M(L1)(L2)], where the metal, M, is Ni(II), Cu(II), Cr(III), and Zn(II), L1 corresponds to the trimethoprim ((Z)-4-((4-amino-5-(3,4,5-trimethoxybenzyl)pyrimidine-2-yl)imino)pentane-2-one) as the first ligand and L2 represent the oxalate anion ( ) as a second ligand. Characterization of the prepared compounds was performed by elemental analysis, molar conductivity, magnetic measurements, 1H-NMR, 13C-NMR, FT-IR, and Ultraviolet-visible (UV-Vis) spectral studies. The recorded infrared data is reinforced with density functional theory (DFT) calculations. Also, the recorded and calculated IR spectra of the complexes suggested that the coordination of Schiff base is a bidentate ligand with Cu and Ni complexes and a tridentate ligand with Co, Cr, and Zn complexes. The electronic structures of the complexes were investigated by DFT calculations, showing several degrees of HOMO-LUMO energy gaps between complexes. The complexes were studied for their DNA interaction activities. The synthesized ligand and its metal complexes were evaluated for antimicrobial properties against bacterial strains of Bacillus subtilis (G+), Enterobacter cloacae (G-), and Staphylococcus aureus (G+). These complexes considered in this study showed good antimicrobial activity.

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Section: ■ Results and Discussionsupporting

confidence: 55%

Synthesis, DFT Calculations, DNA Interaction, and Antimicrobial Studies of Some Mixed Ligand Complexes of Oxalic Acid and Schiff Base Trimethoprim with Various Metal Ions

Abdalrazaq

Jbarah²,

Al‐Noor³

et al. 2022

Indones. J. Chem.

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“…According to different sources, the ionic radii for Ca 2+ and Mg 2+ ions have the value r(Ca 2+ ) = 0.99-1.14 Å, while for Mg 2+ , it is smaller: r(Mg 2+ ) = 0.69-0.89 Å [39,[70][71][72]. This difference is responsible for the observed shrinkage of the cell.…”

Section: Unit Cell Parametersmentioning

confidence: 99%

“…When all positions of substitutions of Mg/Ca1 ions around the axis of the OH channel become occupied (the case of 16 Mg/Ca1, x = 2), the symmetry is practically restored (last column in Table S2.2). The Mg ions in Ca1 positions at a Mg concentration x = 2 already strongly interact with the oxygen ions of the surrounding PO 4 groups (Figure 5b), forming saturated ionic bonds up to an amount corresponding to their coordination number, which is equal to 6 [72].…”

Section: Distances From Oh Channel To Atoms In the Ca1 Positionsmentioning

confidence: 99%

“…However, since these minimum distances remain at the level of r > 2.25 Å (see Table S2.3), no direct chemical bonds are formed in this case (Figure 5e). More precisely, according to the data from [72,73], the distance between the Ca 2+ ion and the oxygen ion in oxides is d = 2.43 Å.…”

Section: Distances From Oh Channel To Atoms In Ca2 Positionsmentioning

confidence: 99%

“…Using the value r(O 2− ) = 1.3 Å [72], we obtain r(Ca 2+ ) = (2.43-1.3) Å = 1.13 Å. Taking into account that the coordination number of calcium is 8, in the Magnus-Goldschmidt model [72], we find that it will be r(Ca 2+ )~0.95 Å, and then d = r(O-Ca2) = (0.95 + 1.3) Å = 2.25 Å, i.e., r c ~2.25 Å, is the critical value, where a chemical bond occurs. In our case, the minimum calculated distance turns out to be r(O-Ca2) = 2.30-2.35 Å (Table S2.3), which is greater than r c .…”

Section: Distances From Oh Channel To Atoms In Ca2 Positionsmentioning

confidence: 99%

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Effect of Magnesium Substitution on Structural Features and Properties of Hydroxyapatite

Bystrov,

Paramonova,

Avakyan

et al. 2023

Materials

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Hydroxyapatite (HAP) is the main mineral component of bones and teeth. It is widely used in medicine as a bone filler and coating for implants to promote new bone growth. Ion substitutions into the HAP structure highly affect its properties. One of the most important substituents is magnesium. This paper presents new results obtained using high-precision hybrid density functional theory calculations for Mg/Ca substitutions in HAP in a wide magnesium concentration range within a 2 × 2 × 2 supercell model. Experimental data on the mechanochemical synthesis of HAP-Mg samples with different Mg concentrations are also presented. A comparison between the experiment and the theory showed good agreement: the HAP-Mg unit cell parameters and volume decreased with increasing degree of Mg/Ca substitution. The changes in the distances between the Ca and O, Ca and H, and Mg and O ions upon Mg/Ca substitution in different calcium positions was analyzed. The resulting asymmetry and distortion of the cell parameters were evaluated. It was shown that bulk modulus, energy levels, and band gap depend on the degree of Mg substitutions in the Ca1 and Ca2 positions. The formation energies of Mg/Ca substitutions showed non-monotonic behavior that was different for Ca1 and Ca2 positions. The Ca2 position had a slightly higher probability (~5 meV/f.u.) of substitution than Ca1 position at a Mg concentration x = 0.5. At x = 1, substitution in both positions can coexist. The simulated IR spectra for different Mg/Ca substitutions showed that Mg in the Ca2 position changes the IR spectrum more significantly than Mg in the Ca1 position. Similar changes were recorded in the IR spectra of the synthesized samples. The electronic structure is shown to be sensitive to the number and position of substitutions, which may be used to tweak the optical properties of the HAP-Mg material.

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Properties of hydroxyapatite with various substitutions: specific effects of Mg/Ca substitution in different Ca1 and Ca2 positions

Bystrov,

Paramonova,

Avakyan

et al. 2024

Ferroelectrics

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Coordination Numbers of Bivalent Ions in Organic Solvents

Cited by 6 publications

References 36 publications

Synthesis, DFT Calculations, DNA Interaction, and Antimicrobial Studies of Some Mixed Ligand Complexes of Oxalic Acid and Schiff Base Trimethoprim with Various Metal Ions

Synthesis, DFT Calculations, DNA Interaction, and Antimicrobial Studies of Some Mixed Ligand Complexes of Oxalic Acid and Schiff Base Trimethoprim with Various Metal Ions

Effect of Magnesium Substitution on Structural Features and Properties of Hydroxyapatite

Properties of hydroxyapatite with various substitutions: specific effects of Mg/Ca substitution in different Ca1 and Ca2 positions

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