Authors:M. Soliman, Gehad Mohamed, and Eman Mohamed
10 °C min −1 using Shimadzu TG-60H and DTA-60H thermal analyzers.
Synthesis of metalcomplexes
The metalcomplexes were prepared by the addition of hot solution (60 °C) of the appropriate metal chloride salts (0
Authors:Hanan F. Abd El-Halim, F. A. Nour El-Dien, Gehad G. Mohamed, and Nehad A. Mohamed
azolidene carbenes to function as ligands in transition-metalcomplexes is well-established [ 10 , 11 ]. Consequently, biologically relevant molecules containing azoles are candidates as carbine sources for metalcomplexation. We consider the utilization of
Authors:Nahid Nishat, Sumaiya Hasnain, Tansir Ahmad, and Asma Parveen
In the recent years, the synthesis of new polymers with unusual thermal, optical, and mechanical properties has gradually gained regards. The branch of the polymer–metalcomplexes has been developed as an
Metal complexes of Schiff base derived from
2-furancarboxaldehyde and 2-aminobenzoic acid (HL) are reported and characterized
based on elemental analyses, IR, 1H NMR, UV-Vis,
solid reflectance, magnetic moment, molar conductance and thermal analysis.
The ligand dissociation as well as the metal-ligand stability constants have
been calculated pH-metrically at 25C and ionic strength μ=0.1 (1 M
NaCl). The complexes are found to have the formulae [M(HL)2](X)nyH2O
(where M=Fe(III) (X=Cl, n=3, y=4), Co(II)
(X=Cl, n=y=2), Ni(II) (X=Cl, n=y=2), Cu(II)
(X=Cl, n=y=2) and Zn(II) (X=AcO, n=y=2)) and [UO2(L)2]2H2O. The thermal behaviour of these chelates is studied and the
activation thermodynamic parameters are calculated using Coats-Redfern method.
The ligand and its metal complexes show a biological activity against some
Coal-metal complexes obtained by dynamic sorption of cations from water solution on sulphonated and oxidized coals. Complexes
with the following cations were produced: Mg, Ca, Zn, Cd, Ba, Cr, Fe, Co, Ni, Cu, Pb and Ag. DTA curves of sulphonated coal
and sulphonated coal-metal complexes are distinct and can be divided into three groups on the basis of shape and peak temperatures,
the main influence being the type of chemical bondbetween metal cation and functional group of the coal. For metal complexes
with oxidized coal the main exothermic peak shifts either to higher of lower temperatures, depending on the nature of the
cations. The presence of metal chemically bound to carboxylic-and sulpho-groups of the coal causes additional thermal effects
to appear on the DTA curves.
The thermal behaviours of the Ti(II), Mn(II), Fe(II), Ni(II), Cu(II) and Zn(II) complexes of triethanolamine were studied
by means of thermogravimetry, differential thermogravimetry, differential thermal analysis infrared spectrophotometry and
elemental analysis. The sequence of thermal stability of the metal complexes, determined by using the initial decomposition
temperature, was found to be Ti(II)≅Mn(II)>Fe(II)>Ni(II)>Zn(II)>Cu(II). Some of the kinetic parameters, such as the activation
energy and order of reaction for the initial decomposition reaction, were calculated and the relationship between the thermal
stability and the chemical structure of the complexes is discussed.
The atomic superposition and electron delocalization molecular orbital (ASED-MO) theory was used to calculate structures and
relative stabilities of metformin-metal complexes. The relative stabilities and decomposition pathways were discussed in terms
of bond order, binding energy and the nature of charge on the central metal atom. The electronic transitions and their energy
gaps were also studied. The optimization of the structures shows that the most stable state is distorted from planarity for
CoII and NiII complexes.
Authors:L. Oleksenko, V. Yatsimirsky, L. Belyakova, and O. Boldureva
The thermal stability of metal complexes immobilized on the surface of silica and its connection with the catalytic activity
in the oxidation of hydrogen were investigated. High catalytic activity was exhibited by heterogenized platinum and palladium
acetylacetonate near room temperatures in the initial state and by γ-aminopropylsilicas treated with platinum and palladium
complexes. The catalytic activity of the metal complexes correlates with their thermal stability and with the ability to undergo
oxidation to a metal state with high valence.
Authors:M. Gaber, S. S. Al-Shihry, and A. A. El-Bindary
Proton-ligand dissociation constant of 2-mercapto-5-(2-hydroxynaphthylideamino)-1,3,4-thiadiazole (MHT) and the stepwise stability
constants of its metal complexes were determined potentiometrically in 40 mass/mass% ethanol-water mixture containing 0.1
M KCl. The stabilities of the complexes follow the order: Cu2+>Ni2+>Co2+>Mn2+. The dissociation constant (pKH) of MHT and the stability constants (logK) of its metal complexes were determined at different temperatures and the corresponding thermodynamic parameters were calculated
and discussed. The proton dissociation process is non-spontaneous, endothermic and entropically unfavoured. The formation
of the metal complexes was found to be spontaneous, endothermic and entropically favoured.
Authors:Fatih Doğan, Mahmut Ulusoy, Ömer Öztürk, İsmet Kaya, and Bekir Salih
Several mononuclear Co(II), Ni(II), Cu(II), and Fe(II) complexes of tetradentate salpren-type diimine, obtained from 3,5-di-tert-butyl-2-hydroxybenzaldehyde and 1,3-diaminopropane have been prepared and characterized by analytical, spectroscopic (FT-IR,
UV–VIS) techniques, magnetic susceptibility measurements and thermogravimetric analyses (TG). The thermodynamic and thermal
properties of complexes have been investigated. For further characterization Direct Insertion Probe-Mass Spectrometry (DIP-MS)
was used and the fragmentation pattern and also stability of the ions were evaluated. The characterization of the end products
of the decomposition was achieved by X-ray diffraction. The thermal stabilities of metal complexes of N,N′-bis(3,5-di-t-butylsalicylidene)-1,3-propanediamine ligand (L) were found as Ni(II) > Cu(II) > Co(II) > Fe(II).