Authors:Murat Turkyilmaz, Alper Onder, and Yakup Baran
Azomethine metal complexes attract considerable interest and occupy an important role in the development of the chemistry of chelate systems because of the presence of hard nitrogen, oxygen, and soft sulfur donor
Authors:P. Budrugeac, Carmen Racles, V. Cozan, and Maria Cazacu
Thermal and thermo-oxidative stability of some poly(siloxane-azomethine)s obtaining starting from bis(formyl-p-phenoxymethyl)tetramethyldisiloxane and different organic diamines have been investigated by TG+DTG+DSC simultaneous analyses
performed in argon flow and air static atmosphere, respectively. TG, DTG and DSC curves of each polymer showed three or four
successive degradation steps at different temperatures according to the composition of the sample and the gaseous atmosphere
in which the thermal analysis was performed. For each process, the following parameters were evaluated: total mass loss, temperature
corresponding to the maximum reaction rate, maximum reaction rate, temperature corresponding to certain mass loss. In order
to determine the thermal and thermo-oxidative stabilities of investigated polymers, the following values were determined:
Tx% — temperature corresponding to x% mass loss, and %ΔmT — mass loss at a given temperature T. The obtained orders of stability were correlated with the structure of investigated polymers.
Authors:Agnieszka Iwan, Lech Gorecki, and Damian Pociecha
Azomethines called also imines are quite often investigated as liquid crystalline (LC) compounds [ 1 – 4 ]. Azomethine bond (HC=N) incorporated into the molecular structure cause increase the length and
Authors:E. Havránek, A. Bumbálová, M. Komová, M. Beláková, P. Butvin, and V. Kettmann
A series of bidentate and tetradentate ligands with azomethine and Ar–OH functional groups derived from salicylaldehyde and primary alkyl or aryl monoamines and diamines has been synthesized and labeled with99mTc at various pH's using stannous chloride as reducing agent. The labeling efficiency was monitored by thin layer and paper chromatography.
The covalent chemistry of carbon nanostructures has put forth a wide variety of interesting derivatives that widen their potential as functional materials. However, the synthetic procedures that have been developed to functionalize the nanostructures may require long reaction times and harsh conditions. In this paper, we study the continuous flow processing of single-wall carbon nanotubes with azomethine ylides and diazonium salts and demonstrate that this approach is effective to reduce reaction times and tune the properties of the functionalized carbon materials.
New cadmium complexes of the salicylidene-2-amino-thiophenol (I) and 3-methoxysalicylidene-2-amino-thiophenol (II) Schiff bases have been prepared and characterized by elemental analyses, IR, 1H-NMR spectra, conductimetric and thermogravimetric analyses. The results suggested that the Schiff bases are bivalent anions with tridentate ONS donors derived from the phenolic oxygen azomethine nitrogen and thiophenolic sulphur. The formulae are found to be [MLH2O] and [ML2]for the 1:1 and 1:2 non-electrolytic complexes, respectively. The thermal decomposition of the complexes follows first order kinetics and the thermodynamic parameters of the decomposition are reported.
Authors:Lucica Ababei, Angela Kriza, Adina Musuc, Cristian Andronescu, and Elena Rogozea
New complexes of 2-benzoyl-pyridil-isonicotinoylhydrazone (L) with Cu(II), Co(II), Ni(II) and Mn(II), having formula of type
[ML2] SO4·xH2O (M = Cu2+, Co2+, Ni2+, x = 2 and M = Mn2+, x = 3), have been synthesised and characterised. All complexes were characterised on the basis of elemental analyses, IR spectroscopy,
UV–VIS–NIR, EPR, as well as thermal analysis and determination of molar conductivity and magnetic moments. The thermal behaviour
of complexes was studied using thermogravimetry (TG), differential thermal analysis (DTA) and differential scanning calorimetry
(DSC). The structure of L hydrazone was established by X-ray study on single crystal. The ligand works as tridentate NNO,
being coordinated through the azomethine nitrogen, the pyridine nitrogen and carbonylic oxygen. Heats of decomposition, ΔH, associated with the exothermal effects were also determined.
UO2(VI), Sn(IV), Th(IV) and Li(I) complexes of 4-azomalononitrile antipyrine (L) have been isolated and characterized based on
IR spectra, 1H NMR, elemental analyses, molar conductance and thermal analysis (DTA/TG). The study revealed that the ligand behaves as
a neutral bidentate one and coordination takes place via the carbonyl atom of pyrazolone ring >C=O and the azomethine nitrogen
>C=N. The thermal stability of the metal complexes were investigated by thermogravimetry (TG), differential thermal analysis
(DTA) techniques and infrared spectra, and correlated to their structure. The thermal study revealed that Th(IV) complexes
show lower thermal stability than both UO2(VI) and Sn(IV) complexes.
New metal complexes of Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) with salicylidine-2-aminobenzimidazole (SABI) are
synthesized and their physicochemical properties are investigated using elemental and thermal analyses, IR, conductometric,
solid reflectance and magnetic susceptibility measurements. The base reacts with these metal ions to give 1:1 (Metal:SABI)
complexes; in cases of Fe(III), Co(II), Cu(II), Zn(II) and Cd(II) ions; and 1:2 (Metal:SABI) complexes; in case of Ni(II)
ion. The conductance data reveal that Fe(III) complex is 2:1 electrolyte, Co(II) is 1:2 electrolyte, Cu(II), Zn(II) and Cd(II)
complexes are 1:1 electrolytes while Ni(II) is non-electrolyte. IR spectra showed that the ligand is coordinated to the metal
ions in a terdentate mannar with O, N, N donor sites of the phenloic -OH, azomethine -N and benzimidazole -N3. Magnetic and
solid reflectance spectra are used to infer the coordinating capacity of the ligand and the geometrical structure of these
complexes. The thermal decomposition of the complexes is studied and indicates that not only the coordinated and/or crystallization
water is lost but also that the decomposition of the ligand from the complexes is necessary to interpret the successive mass
loss. Different thermodynamic activation parameters are also reported, using Coats-Redfern method.
Some new coordination polymers of Mn(II),
Co(II), Ni(II), Cu(II), Zn(II) and Cd(II), obtained from the interaction of
metal acetate with dipotassium salt of N,N’-di(carboxyethylidene)terephthalaldehydediimine
(K2SB) are described. The products, which have been
characterized by elemental analyses, magnetic measurements, thermogravimetric
analyses, electronic and infrared spectral studies, have composition, [M(SB)(H2O)2]n. These colored coordination polymers are non-hygroscopic and quite stable
at room temperature. On the basis of analytical data and IR studies, a 1:1
metal to ligand stoichiometry has been suggested to these coordination polymers.
The IR studies have also revealed that ligands are coordinated to metal ion
through carboxy oxygen and azomethine nitrogen. All the studies suggested
tetradentate nature of the ligand with octahedral symmetry of the coordination
polymers. All the coordination polymers are insoluble in acetone, ethanol,
chloroform, methanol, benzene, DMF and DMSO. The thermal decomposition of
the coordination polymers is studied and indicates that not only the coordinated
water is lost but also that the decomposition of the ligand from the coordination
polymers is necessary to interpret the successive mass loss.