The basic task of contemporary chemical synthesis is to obtain materials and
technologies based on new compounds with distinct structure and properties. Due to the
various possibilities of combining inorganic and organic compounds, the coordination
chemistry is a field that obtains new materials with various useful properties. Final products
are often characterized by composition, structure, and properties completely different from
those predicted (a phenomenon that largely depends on the modeling of synthesis conditions).
The combination of transition metals with organic ligands can lead to the emergence of
unexpected properties. Inorganic and organic bridges (dipyridine, dicarboxylic, pyridinecarboxylic,
pyridine-oxime, oxime-carboxylic etc.) are used for the production of polynuclear
compounds with oxime ligands.
There were obtained mono- and polynuclear compounds of manganese(II),
cobalt(II/III), nickel(II), copper(II), zinc(II) and cadmium(II) which composition and structure
had been determined (IR, NMR, X-ray etc.). There were also obtained mono-, bis- and trisoxime
complexes depending on the nature of the ligands and the synthesis conditions [1,2].
The presence of electron donor atoms and their topology in the ligand molecule as well as the
combination of different ligands within the same complex allow the molecular design of the
synthesized complexes to be varied and also influence the coordination number of the metal
atom. The configuration of the polymer chain of some compounds allows the formation of
intermolecular cavities, which lead to obtaining porous materials with adsorbing properties.
There has been studied the influence of the solvent nature on the polymer chain formation.
The use of new oxime-carboxylic ligands, due to coordination with both oximetic and
carboxyl groups (also selectively with different metals) opens perspectives for the synthesis of
heterometallic materials.
In order to investigate the ligand competition capacity in the coordinating process to
the central atom, the substitution properties of ligands in the complex was studied
experimentally and simulation by the quantum-chemical calculation [3]. There was analyzed
the coordination capacity of dioxime, monoxime, pyridine, carboxylic, amine etc. groups to
the metal atom under competitive conditions. On the basis of both commercial and the new
ligands by using block combinations there were assembled binuclear coordinative compounds
[4].
The obtained compounds were studied to determine useful properties: growth
promoters for some organisms, substances with luminescent properties, mechanical hardness,
corrosion inhibitors for steels, etc.
[1] Coropceanu E., Croitor L., Siminel A., Polyhedron, 2016, 109, 107-114.
[2] Croitor L., Coropceanu E., Duca Gh., Polyhedron, 2017, 129, 9-21.
[3] Коропчану Э.Б., Болога О.А., Арсене И., Коорд. xимия, 2016, 42, 8, 480-502.
[4] Coropceanu E., Rija A., Lozan V., Crystal Growth & Design, 2016, 16, 814-820.