StatusThe thesis was presented on the 12 June, 2009
Approved by NCAA on the 1 October, 2009
Abstract– 1.20 Mb / in romanian
References: 126 sourses; Figures: 83; Tables: 2. The dissertation is devoted to the synthesis, properties and structural study of copper(II) complexes with organic ligands, obtained by condensation of salicylaldehyde derivatives with carbohydrazide and thiocarbohydrazide. It was established that these systems behave as flexible hexadentate ligands, binding the copper ions through two donor sets: O,N,N and O,N,O(S). The ligands apper as trideprotonated or tetradeprotonated. The coordinated organic reagents adopts the anti (thio)enolic tautomeric form as consequence of a (thio)keto-(thio)enol equilibrium. The procedures of synthesis of 23 copper(II) coordination compounds have been newly elaborated and firstly performed. The properties and geometrical structure of obtained complexes were established.
There was studied the influence of reaction medium on the composition and stereochemistry of copper(II) complexes with mentioned ligands. The reliability of the obtained results (composition, physico-chemical properties, structure) is based on paralel investigations by means of different modern methods: IR, UV-Vis and NMR spectroscopies, magnetic measurements. Using the X-ray diffraction analysis, the crystal structures of 21 compounds have been determined and characterized, which certainly confirmed the presence of different nuclearity (mono-, bi-, tetra-, octanuclear and polimeric structures). Magnetic properties of selected compounds have been studied and the presence of an antiferromagnetic interaction between paramagnetic centers was demonstrated. The exchange parameters vary from moderate to large values. A difference in the structure of bis(salicylidene)diaminoguanidine relative to other ligands from this group has been found. În the solid state the amine isomer is stabilized and two mononuclear copper(II) complexes are formed. The ligand is coordinated as a uninegative acid by O,N,N donor atoms set.
The results presented in the thesis have been published in the shape of 4 articles and 12
abstracts to international conferences.