Struktura pochodnych benzo[ b]furanu i kumaryny oraz ich kompleksów z miedzią (II) i cynkiem(II)
Journal Title: Wiadomości Chemiczne - Year 2012, Vol 66, Issue 3
Abstract
Selected benzo[b]furan and coumarin derivatives with proven and potential antibacterial, anticancer and antiarrhythmic activities have been investigated [1–3] (Figs. 1 and 2). The stereochemical description of their molecules in the solid and gas phase as well as intra- and intermolecular-interactions in crystals have been determined [4–6]. The structural studies of analyzed molecules indicated the planarity of the benzo[b]furan and coumarin ring systems. The oxygen or carbon atoms of the substituents, –OH, –OCH3, –C(=O)CH3 and –COO H, are nearly coplanar with the aromatic ring. The hydroxyl and acetyl groups, being in the ortho position, are coplanar with the aromatic ring and the formation of the intramolecular O–H…O hydrogen bond in all three states of matter is observed. Its strength is around 18 kcal/mol. Several conformers of studied compounds, differing in the orientation of the methoxy, acetyl and/or carboxyl groups, were analyzed. Next, the electrochemical method was used to synthesize novel copper and zinc complexes with the oxygen donor benzo[b]furan and coumarin derivatives. The Cu(II) and Zn(II) complexes have been obtained with carboxylic acids as ligands whereas hydroxy ligands reacted only with copper [6]. The geometry of metal-ligand interaction of new compounds has been determined using a single crystal X-ray crystallography and an X-ray absorption spectroscopy [7, 8]. The combination of these two methods revealed that for some compounds cation environment could depend on the form of the solid sample. In the microcrystalline zinc complexes (studied by EXAFS) the cation is penta-coordinated (ZnO5) with the Zn–O distances being ca 1.98(3) Ĺ. In the recrystallized complex (analyzed by the X-ray diffraction) it was found that zinc is tetra-coordinated (ZnO4). The Cu(II) cation in the singlecrystal form of the complex with the carboxylic acid 5 is penta-coordinated to the carboxylate groups and the ethanol molecule. The bridging COO – groups stabilize the dinuclear complex center Cu2O10. The powdered form of this complex is based on the Cu2O8 units, indicating the absence of the ethanol molecule in the coordination sphere. In the series of the Cu(II) complexes with the hydroxy derivatives of benzo[b]furan and coumarin a centrosymmetric coordination polyhedron of metal exhibits a square-planar geometry (CuO4). Two ligands are bonded to the copper cation via the acetyl and deprotonated hydroxyl O atoms.
Authors and Affiliations
Aleksandra Drzewiecka
Jubileusz metody miareczkowania kulometrycznego
In 1938, Szebellédy and Somogyi [1–7] have proposed an important methodological innovation in analytical chemistry. This methodology was termed coulometric titration. This paper presents an overview of the principles of...
Nieorganiczne nanocząstki w medycynie nuklearnej
Rapid and widespread growth in the use of nuclear medicine for both diagnosis and therapy of disease has been the driving force for a design of novel radiopharmaceuticals. Particularly, recent progress in nanotechnology...
Ogniwa litowo-jonowe wysokiej mocy : przegląd materiałów katodowych
Due to lack of practical energy sources – ones that are ecological, economic, portable and capable of being regenerated – storage is necessary in modern world for many areas of life to which people became accustomed. Dev...
Okruchy XXV. O kreatywnym autyzmie
brak
Karbeny N-heterocykliczne : synteza i zastosowanie
N-Heterocyclic carbenes (NHCs) are powerful tools in organic chemistry, with numerous applications in academic and industrial laboratories. They are usually defined as singlet carbenes, in which the divalent carbonic cen...