Ana Emandi

Thermal stability of some azo-derivatives and their complexes

Abstractthis paper deals with the first investigation concerning the thermal stability of two 1-(2-benzothiazolyl)-3-methyl-4-azo-pyrazil-5-one derivatives and their Cu(II) coordination compounds of type ((C4H9)4N)2[Cu(L)2]. The thermal decomposition steps were established.

Laser-Induced Change in the Refractive Index in the Systems Based on Nanostructured Polyimide: Comparative Study with Other Photosensitive Structures

The fullerene- and nanotubes-doping effect on spectral and photorefractive properties of conjugated organic systems based on polyimide have been studied. A fullerene introduction in these materials has been used due to high electron affinity of fullerenes that allows the intermolecular donor-acceptor interaction to be reinforced. The nanotubes doping has been made due to a large increase in photoconductivity of the new composites. Drastic increase in delta n has been observed under condition of nanoobjects introduction. The data presented in the current study testified that these materials could be used as new reversible holographic recording elements, new optical limiting systems, as well as new high-speed switchers.

Synthesis and Spectroscopic Studies of Cobalt(II) and Copper(II) Complex Compounds with 4‐Methoxybenzaldehyde‐N‐[4‐(4′‐chlorophenylenesulfonyl)benzoyl]hydrazone

New complex compounds of Co(II) and Cu(II) with 4‐methoxybenzaldehyde‐N‐[4‐(4′‐chlorophenylenesulfonyl)benzoyl]hydrazone (HL) have been prepared and characterized by elemental and thermogravimetrical analyses, magnetic susceptibility measurements, infrared, electronic and EPR spectra. The ligand coordinates in either the keto or the enol form, depending on the experimental conditions. Cobalt acetate gives a monomeric, distorted‐octahedral compound, while cobalt chloride forms a monomeric penta‐coordinate complex. Copper acetate and copper chloride form dimeric complexes, a monomeric compound having been obtained from copper bromide.

Electronic Studies of The New 2:1 Cu(II) Complexes of 4-Arylazo-Pyrazol-5-one Dyes

The relationship between the solvatochromic behaviour of the 2:1 Cu(II)- complex with 1-(2′-benzthyazolyl)-3-methyl-4-azo(derivatives)-pyrazol-5-ones has studied.The light fastness properties of the ligands and their 2:1 Cu(II)complexes with respect to the symmetry of the coordination polyhedra around Cu(II)cation, the electronic effects of the substituent groups of the ligands and the nature and polarity of the solvents were investigated and explained by means of the Molecular Orbital Theorys.These complexes strongly absorb between 700–1100 nm which is the most favorable wavelength region for semiconductor laser optical recording dye medium.

Synthesis and Characterisation of Some new Lanthanide Hybride Conjugated Monomers

The 1-substituted derivative of 3-methyl-5-pyrazolone, with benzothyazol was investigated in the system with some lanthanide cations: La3+, Ce3+, Pr3+, Sm3+, Gd3+, Ho3+, Eu3+, Tb3+, Er3+. The synthesis of these hybride compounds was found to be influenced by the proton affinity constants of the donors and those of the steric hindrance offered by the three chelate rings of the 1-(2′-benzthyazolyl)-3-methyl-5-pyrazolone(BTMP)around the metal cation to the approaching oxodonor as well as the preference of the lanthanide cations for the nitrogen atom as a donor.The structure of the products was proved by the elemental analysis, IR, UV-VIS spectra, molar conductance and molecular weight data and the thermogravimetrical study and all complexes correspond to a mononuclear monomers with the general formula.[Ln(BTMP)3(H2O)2].H2O. The synthesized compounds are expected to have luminiscent, antibacterial properties as a monomers or in a polymeric matrix.

Metal Complex Monomers of Cu(II) and Ni(II) with Allylacetoacetate and 2-Hydrazinobenzothiazole

Metal complexes of Cu(II)and Ni(II)with allylacetoacetate(allylH)and 2-hydrazinobenzothiazole(hydrH)as ligands were prepared and characterized on the basis of elemental and thermogravimetric analyses, magnetic susceptibility measurements, infrared and ultraviolet-visible spectra. The presence of Cu2+favors the condensation of a carbonyl group of allylacetoacetate with amine group of the hydrazide(a template reaction). Using the copper(II)acetate, a dimeric complex[Cu2(allylhydrH)2(CH3COO)2]was obtained, while copper(II)chloride gives a monomeric complex[Cu(allylhydrH)(H2O)Cl]. The cation Ni2+does not favor the condensation, and the resulted compounds are the mononuclear coordinative compounds having the formulas:[Ni(allyl)(hydrH)(H2O)Cl]and[Ni(allyl)(hydrH)2]Cl.

Magnetic and Morphologic Characterisation of Some Substituted Ferrites Synthesised by a Non-Conventional Method

Substituted ferrites with the chemical composition MxFe1-xFe2O4·nH2O (M: Mn(II), x:0.35, n: 0.4; M: Ni(II), x:0.38, n: 1; M: Zn(II), x:0.45, n: 0.35) have been prepared by a soft chemical method using as starting materials magnetite and suitable acetates. These compounds have been characterised X-ray diffraction on powder and magnetic measurements at room temperature.