Studies on Coördination Compounds. XII. Calculation of Thermodynamic Formation Constants at Varying Ionic Strengths

1954 ◽  
Vol 58 (12) ◽  
pp. 1133-1136 ◽  
Author(s):  
Reed M. Izatt ◽  
Charles G. Haas ◽  
B. P. Block ◽  
W. Conard Fernelius
Molecules ◽  
2019 ◽  
Vol 24 (20) ◽  
pp. 3768
Author(s):  
Silvia Berto ◽  
Eugenio Alladio ◽  
Pier Giuseppe Daniele ◽  
Enzo Laurenti ◽  
Andrea Bono ◽  
...  

Hydroxypyrone derivatives have a good bioavailability in rats and mice and have been used in drug development. Moreover, they show chelating properties towards vanadyl cation that could be used in insulin-mimetic compound development. In this work, the formation of coordination compounds of oxovanadium(IV) with four kojic acid (5-hydroxy-2-(hydroxymethyl)-4-pyrone) derivatives was studied. The synthetized studied ligands (S2, S3, S4, and SC) have two or three kojic acid units linked through diamines or tris(2-aminoethyl)amine chains, respectively. The chemical systems were studied by potentiometry (25 °C, ionic strength 0.1 mol L−1 with KCl), and UV-visible and EPR spectroscopy. The experimental data were analyzed by a thermodynamic and a chemometric (Multivariate Curve Resolution–Alternating Least Squares) approach. Chemical coordination models were proposed, together with the species formation constants and the pure estimated UV-vis and EPR spectra. In all systems, the coordination of the oxovanadium(IV) starts already under acidic conditions (the cation is totally bound at pH higher than 3–4) and the metal species remain stable even at pH 8. Ligands S3, S4, and SC form three coordination species. Two of them are probably due to the successive insertion of the kojate units in the coordination shell, whereas the third is most likely a hydrolytic species.


2017 ◽  
Author(s):  
Robson de Farias

In the present work, the reliability of the volume-based thermodynamics (VBT) methods in the calculation of lattice energies is investigated by applying the “traditional” Kapustinskii equation [8], as well as Glasser-Jenkins [3] and Kaya [5] equations to calculate the lattice energies for Na, K and Rb pyruvates [9-11] as well as for the coordination compound [Bi(C<sub>7</sub>H<sub>5</sub>O<sub>3</sub>)<sub>3</sub>C<sub>12</sub>H<sub>8</sub>N<sub>2</sub>] [17] (in which C<sub>12</sub>H<sub>8</sub>N<sub>2</sub> = 1,10 phenathroline and C<sub>7</sub>H<sub>5</sub>O<sub>3</sub><sup>-</sup>= <i>o</i>-hyddroxybenzoic acid anion). As comparison, the lattice energies are also calculated using formation enthalpy values for sodium pyrivate and [Bi(C<sub>7</sub>H<sub>5</sub>O<sub>3</sub>)<sub>3</sub>C<sub>12</sub>H<sub>8</sub>N<sub>2</sub>]. For the pyruvates, is verified that none of the considered approach, Kapustinskii, Glasser, Kaya or density, provides values that agrees in an acceptable % difference, with the lattice energy values calculated from the formation enthalpy values. However, it must be pointed out that Kaya approach, with deals with a chemical hardness approach is the better one for such kind of inorganic-organic salts. Based on data obtained for [Bi(C<sub>7</sub>H<sub>5</sub>O<sub>3</sub>)<sub>3</sub>C<sub>12</sub>H<sub>8</sub>N<sub>2</sub>] is concluded that the only one VBT method that provides reliable lattice energies for compounds with bulky uncharged ligands is that one based on density values (derived by Glasser-Jenkins).


2017 ◽  
Vol 58 (8) ◽  
pp. 1534-1542
Author(s):  
V.V. Lukashov ◽  
◽  
M.S. Makarov ◽  
S.N. Makarova ◽  
I.K. Igumenov ◽  
...  

Author(s):  
A. V. Kadomtsevа ◽  
I. V. Zhdanovich ◽  
M. S. Piskunovа ◽  
A. N. Lineva ◽  
A. N. Novikova ◽  
...  

The synthesis of biologically active coordination compounds and the design on their basis of effective pharmacological preparations is currently the promising area. This paper presents the results of the toxicological studies on digermanium and its complex derivatives. It should be noted that the positive medical properties of organometallic compounds of germanium are confirmed by numerous studies, therefore, the development of the methods of synthesis, as well as investigations of physicochemical and pharmacological properties of these compounds are at the center of attention.


2008 ◽  
Vol 59 (7) ◽  
Author(s):  
Madalina Angelusiu ◽  
Maria Negoiu ◽  
Stefania-Felicia Barbuceanu ◽  
Tudor Rosu

The paper presents the synthesis and characterization of Cu(II), Co(II), Ni(II), Cd(II), Zn(II) and Hg(II) complexes with N1-[4-(4-bromo-phenylsulfonyl)-benzoyl]-N4-(4-methoxyphenyl)-thiosemicarbazide. The new compounds were characterized by IR, EPR, electronic spectroscopy, magnetic moments, thermo-gravimetric analysis and elemental analysis.


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