Synthesis and structural characterizations of tris(hydroxymethyl)aminomethane complexes with group IIA metals

Herein, this article aimed to investigate the tendency of tris(hydroxymethyl) aminomethane (THAM) to form stable complexes with group IIA metals. Four new colorless solid complexes of group IIA metals [Ba(II), Ca(II), Sr(II) and Mg(II)] with THAM were prepared and well characterized. The chemical reactions between group IIA metals and THAM were conducted by stoichiometry of 2:1 (Ligand: Metal ion) at 65 °C and pH of ~ 8.5. Under these conditions, the THAM molecule (C4H11NO3) was deprotonated and converted to the (C4H10NO3-; L-) chelate with the metal ions. The structures of these complexes were suggested by UV-visible, IR, Raman and 1H NMR spectroscopies and other physicochemical and analytical methods (elemental analysis, thermogravimetry, and SEM). The results shows that the general composition of the complexes obtained with Ba(II), Ca(II), Sr(II) and Mg(II) ions are [BaL2(H2O)2], [CaL2(H2O)2]·2H2O, [SrL2(H2O)2], and [MgL2(H2O)2]·4H2O, respectively, and in all complexes, the geometry was octahedral.

Synthesis and Characterization of Some Complexes of Azo-Chalcone Ligand and Assessment of their Biological Activity

The azo-chalcone dye of theophylline namely (E)-1-(4-((E)-(theophyllin-8-yl) diazenyl)phenyl-3-(4-dimethylaminophenyl)prop-2-en-1-one (TDPP) has been prepared and characterized by H-NMR, infrared, and electronic spectra, elemental analysis. Three solid complexes Mn(II), Ni(II) and Cu(II) of TDPP dye have been prepared and characterized by IR, electronic spectra, magnetic and conductivity measurements. The antibacterial and antifungal activities of the TDPP ligand and metal (II) complexes of Ni, and Cu are notable, with the copper(II) complex being more potent than the others. The TDPP ligand has interesting spectral properties as a pH sensor, solvent polarity sensor, and switches.

Facile Charge Transfer between Barbituric Acid and Chloranilic Acid over g-C3N4: Synthesis, Characterization and DFT Study

The molecular complexes between barbituric acid (BU) and chloranilic acid (ChA) over graphitic nitride (g-C3N4) are investigated. The molecular complexes and the nanocomposite were investigated both in solid state and in methanol. The solid complexes and the corresponding nanocomposite were investigated using FTIR, TGA, and UV-Vis spectroscopy. The structures were explored using DFT calculations using wB97XD/ and def2-TZVP basis set. The DFT calculations revealed the formation of hydrogen-bonded complexes, which initiate the proton transfer from ChA to BU. Immobilization of the BUChA complex over the g-C3N4 sheet was stabilized by weak non-covalent interactions, such as π–π interactions. g-C3N4 facilitated the charge transfer process, which is beneficial for different applications.

Comprehensive Characterization of Linalool-HP-β-Cyclodextrin Inclusion Complexes

The objective of the present study is to obtain linalool- cyclodextrin (CDs) solid complexes for possible applications in the food industry. For this purpose, a detailed study of linalool complexation was carried out at different pH values, to optimize the type of CDs and reaction medium that support the highest quantity of encapsulated linalool. Once demonstrated the ability of hydroxypropyl-β-cyclodextrin (HP-β-CDs), to form inclusion complexes with linalool (KC = 921 ± 21 L mol−1) and given their greater complexation efficacy (6.788) at neutral pH, HP-β-CDs were selected to produce solid inclusion complexes by using two different energy sources, ultrasounds and microwave irradiation, subsequently spraying the solutions obtained in the Spray Dryer. To provide scientific solidity to the experimental results, the complexes obtained were characterized by using different instrumental techniques in order to confirm the inclusion of linalool in the HP-β-CDs hydrophobic cavity. The linalool solid complexes obtained were characterized by using 1H nuclear magnetic resonance (1H-NMR) and 2D nuclear magnetic resonance (ROSEY), differential scanning calorimetry, thermogravimetry and Fourier transform infrared spectrometry. Moreover, the structure of the complex obtained were also characterized by molecular modeling.

The structure and composition of solid complexes comprising of Nd(III), Ca(II) and D-gluconate isolated from solutions relevant to radioactive waste disposal

Certain complexing agents (such as D-gluconate, D-isosaccharinate, etc.) as well as actinides and lanthanides are simultaneously present in cementitious radioactive waste repositories and (in the presence of water) are capable of forming complex compounds. Such processes may immobilize radionuclides and are of importance in the thermodynamic modelling of the aqueous chemistry of waste repositories. Nd(III) is considered to be a suitable model for trivalent lanthanides and actinides, due to the similarity of their ionic radii. In the current work, solid complexes isolated from aqueous solution containing Nd(III), Ca(II) and D-gluconate (Gluc−) were investigated. In an aqueous solution containing Nd(III) and Gluc−, the formation of a precipitate was observed at pH ≥ 8. This precipitate was found to redissolve around pH ~ 11, but reprecipitated when Ca(II) ions were added to the solution. In order to gain an insight in binary and ternary aqueous systems, in the present work we report the structure of these solid complexes obtained from XRD, FT-IR, Raman, SEM-EDAX and UV-DRS measurements. The structure of these solids, where possible, was compared with those identified in solution. The compositions of these complexes are suggested to be NdGlucH−1(OH) · 2H2O and CaNdGlucH−1(OH)3 · 2H2O, respectively. In these, the chemical environment of the Nd(III) was found to be the same as that in the NdGlucH−1(OH)0(aq) solution species.

THERMAL STUDY OF SOLID COMPLEXES OF CERIUM, PRASEODIUM AND NEODIUM

Взаимодействием водных растворов хлоридов соответствующих редкоземельных элементов и натриевой соли цефазолина (NaCzl) были получены и выделены в твердом виде комплексные соединения цефазолина. Полученные комплексы имеют состав Me(Czl)•3HO, где Me = Ce+, Pr+, Nd+. Полученные соединения исследованы методом синхронного термического анализа. By the interaction of aqueous solutions of the chlorides of the corresponding rare-earth elements and the cefazolin sodium salt (NaCzl), complex compounds of cefazolin were obtained. The resulting compounds were investigated by synchronous thermal analysis.

Viscoelasticity of Quartz and Kaolin Slurries in Seawater: Importance of Magnesium Precipitates

In this study, the viscoelastic properties of quartz and kaolin suspensions in seawater were analysed considering two distinct conditions: pH 8 and 10.7. Creep and oscillatory sweep tests provided the rheological parameters. An Anton Paar MCR 102 rheometer (ANAMIN Group, Santiago, Chile) was used with a vane-in-cup configuration, and the data were processed with RheoCompassTM Light software (ANAMIN Group, Santiago, Chile). The outcomes were associated with the formation of solid species principally composed of magnesium precipitates. The magnesium in solution reduced in the presence of quartz (68 wt %), from 1380 to 1280 mg/L. Since the difference was not large regarding the solid-free seawater, the disposition of solid complexes at pH 10.7 was expected to be similar. The jump in pH caused both yield stress and viscoelastic moduli to drop, suggesting that the solid precipitates diminished the strength of the particle networks that made up the suspension. For the kaolin slurries (37 wt %), the yield stress raised when the pH increased, but unlike quartz, there was significant adsorption of magnesium cations. In fact, the concentration of magnesium in solution fell from 1380 to 658 mg/L. Dynamic oscillatory assays revealed structural changes in both pulps; in particular, the phase angle was greater at pH 8 than at pH 10.7, which indicates that at more alkaline conditions, the suspension exhibits a more solid-like character.

Cobalt(II) chloride complexes with some phosphine oxides: compatibility between structural data for the solid complexes and their stability constants in acetone medium

Binary complexes of general formula CoCl2L2, where L = triphenylphosphine oxide (TPPO), benzyldiphenylphosphine oxide (BDPPO), dibenzylphenylphosphine oxide (DBPPO) and tribenzylphosphine oxide (TBPO) were considered concerning X-ray structural data for the complexes in the solid state and their stability constants in acetone solution. Compatibility between structural data and stability constants are pointed out. Previous investigations showed that in acetone medium, with CoCl2 as reference acceptor, the following basicity order is obeyed: TBPO > DBPPO > BDPPO > TPPO. This sequence is supported by X-ray diffraction data of the solid complexes and by electrolytic conductance values for these complexes both in acetone and in nitromethane media.