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Badania potencjometryczne, ESI-MS i NMR nad kompleksowaniem magnezu(II) i wapnia(II) wybranymi kwasami bisfosfonowymi w roztworze wodnym

Szpak M., Matczak-Jon E., Kurzak B.

Chemik

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2014

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Vol. 68, nr 4

321--328

PL

Przeprowadzono badania nad równowagami w roztworze układów Mg(II)/Ca(II)-L (L= kwas (cykloheksylo)aminometano-1,1-difosfonowy (1), kwas azepan-1-ylo-metano-1,1-difosfonowy (2), kwas azekan-1-ylo-metano-1,1-difosfonowy (3)) metodami pH-potencjometrii, NMR i ESI-MS. Uzyskane wyniki wskazują, że we wszystkich badanych układach preferowane jest tworzenie kompleksów jednordzeniowych o stechiometrii 1:1. Rozpatrywane związki wiążą koordynacyjnie Mg(II) i Ca(II) poprzez atomy tlenu grup fosfonianowych w szerokim zakresie wartości pH.

EN

Solution equilibrium studies on the Mg(II)/Ca(II)-L systems (L= (cyclohexyl)aminomethane-1,1-diphosphonic acid (1), azepan-1-yl-methane-1,1-diphosphonic acid (2), azecan-1-yl-methane-1,1-diphosphonic acid (3) have been performed by pH-potentiometry, NMR and ESI-MS methods. The obtained results suggest preference for the formation of mononuclear complexes of 1:1 stoichiometry in all studied systems. Compounds under consideration coordinate Mg(II) and Ca(II) through oxygen atoms of the phosphonate groups over a broad pH range.

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Właściwości koordynacyjne ligandów z ugrupowaniem fosfonowym z wybranymi jonami metali

Kamecka A., Kurzak B.

Wiadomości Chemiczne

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2003

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[Z] 57, 9-10

797--825

EN

Aminopolyphosphonic acids and their derivatives have received considerable attention because of their interesting biological activity and a wide range of uses for industrial, chemical, agricultural and pharmacological purposes. The area of metal phosphonate chemistry has developed significantly in the last three decade. The coordination chemistry of this group of ligands is rich due to their versatility in adopting monodentate, bridging and chelating modes of coordination. Phosphonates and aminophosphonates are potent chelating agents for variety metal ions including the alkaline earth ions, the divalent ions as well as the trivalent ions. In this article we are summarizing and discussing the acid-base properties and the metal ion-coordinating properties of compounds involving one, two or more phosphonic groups. This work is aimed at being brief indicating the main achievements in researches over coordination preferences of this group of ligands. The present considerations are restricted to complexes in solution, involving the alkaline earth ions and the divalent ions of the second half of the 3d series as well as Zn2+ and Cd2+. The acid-base properties of the considered ligands depend on many factors such as the number of phosphonic groups in one molecule, the presence of other functional groups (e.g. COOH, NH3+, OH), the distance between functional groups and electronic effects of the substituents. These ligands contain a range of potential donor atoms. As a result, various bonding modes for a given chelating ligand are involved, and are reviewed with reference to ligand structure and the resulting coordination complexes. It is shown that depending on the pH and the nature of the metal ion in solution these ligands can bind to a metal ion via oxygen(s) (mostly with alkaline earth ions), and in a N,O bonding mode (usually with d metals). Coordination properties of phosphonic and aminophosphonic acids are important factors to understand the role of the ligands and metal ions in biological systems.

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Equilibrium StudyofIminodi(methylenephosphonic) Acid Complexeswith Some Metal Ions

Kurzak B., Kamecka A.

Polish Journal of Chemistry

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2003

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Vol. 77 / nr 9

1059-1077

EN

This article discusses coordination preferences of N-substituted iminodi(methylenephosphonic) acids to the different metal ions in an aqueous solution. These ligands exhibit high complexation efficiency towards divalent metal ions. This results from both dinegatively charged phosphonate groups as well as the imino nitrogen present in their structure. A significant preference for an equimolar stoichiometry has been demonstrated in these systems. The only exception is the N-2-methyltetrahydrofuryliminodi( methylenephosphonic) acid with a tetrahydrofuryl moiety, placed in the sterically favoured position that allows its oxygen atom to be an effective metal binding site. Specific interactions between metal ions and furyl oxygen results in higher binding ability of this ligand and a formation of 1:2 species. Coordination properties of iminodi- (methylenephosphonic) acids are important factors to understand the role of the ligands and metal ions in biological systems. A summary presented in this review points on the direction of the research for future work in this area, which should be developed.

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Charakterystyka równowag kompleksowania kwasów iminodi(metylenofosfonowych) z jonami metali(II)

Kamecka A., Kurzak B.

Wiadomości Chemiczne

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2002

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[Z] 56, 3-4

315-339

EN

The aminopolyphosphonic acids are analogues of aminopolycarboxylic acids in which the carboxyl groups (CO2-) are substituted by the phosphonate moieties (PO32-). Aminopolyphosphonic acids and their derivatives have received considerable attention because of their interesting biological activity and a wide range of uses for industrial, chemical, agricultural and pharmacological purposes. This review discusses coordination preferences of N-substituted iminodi(methylenephosphonic) acids to the divalent metal ions (such as magnesium, calcium, manganese, cobalt, nickel, copper and zinc) in an aqueous solution. N-substituted derivatives of iminodi(methylenephosphonic) acids exhibit high complexation efficiency towards divalent metal ions. This results from both dinegatively charged phosphonate groups as well as the imino nitrogen present in their structure. A significant preference for an equimolar stoichiometry has been demonstrated in these systems. The only exeption is the N-2-methyltetrahydrofuryliminodi(methylenephosphonic) acid with a tetrahydrofuryl moiety placed in the sterically favoured position that allows its oxygen atom to be an effective metal binding site. Specific interactions between metal ions and furyl oxygen results in higher binding ability of this ligand and a formation of 1:2 species. The first part of the review deals with the acid-base properties of the considered ligands which are consistent with electronic effect of the substituents attached to the imino nitrogen. The second part of the review describes the binding properties of iminodi(methylenephosphonic) acids in copper(II) complexes. A formation of tridentate bonded species has been demonstrated in these systems. The third part of the review report what is known about magnesium(II), calcium(II) and zinc(II) complexes of the same ligands. While the imino nitrogen is bonded in the predominate complexes in the zinc(II) systems, magnesium(II) and calcium(II) ions prefer a pure phosphonate coordination. Finally, the interactions of manganese(II), cobalt(II) and nickel(II) ions with N-substituted iminodi(methylenephosphonic) acids are described. For these complexes the formation of eight-membered rings is reported. Coordination properties of iminodi(methylenephosphonic) acids are important factors to understand the role of the ligands and metal ions in biological systems.

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Chemiczne i biochemiczne aspekty kompleksów mieszanych

Kroczewska D., Kurzak B.

Wiadomości Chemiczne

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2001

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[Z] 55, 3-4

263-287

EN

During the last two decades thousands of important papers and some excelant review concerning complex equilibria have been published. In fact, most of these papers concern data on complex equilibrium, which does not involve species other than simple complexes with a completely homogenous coordination sphere Because mixed-ligand complexes are the most general and probable forms of existence of the elements in solution, we would like to present the mixed-ligand complexes in the aspect of their role in chemistry and in living systems. In the first part of this text we have lain particular emphasis upon literature data which show that it is worthwhile to assemble information on the formation, stability, structure and on the mutual influence of two ligands bound to the same metal ion, in the next part - on biochemical processes (transport, storage, inhibition of anzyme processes) which might be simulated by mixed-ligand complexes as "model systems" and at last - on own studies upon the mixed-ligand complexes of hydroxamic acid (a- or b-alaninehydroxamic acid) and one of polyamines with different metal ions. In order to find the answer for the following question: what kind of stoichiometry, geometry and binding mode there is in complexes which arrive in studied ternary systems? We used different methods: pH-metric method and spectroscopic ones (UV-VIS, EPR and NMR). The results obtained in our investigations and presented in this text show that the steric effect plays a very important role in the formation of the mixed-ligand complexes. In the case of bulky polyamine bonded in the zink(II) equimolar complex the coordination of a- or b-alaninehydroxamic acid is more favoured than the second polyamine ligand. There is no mixed-ligand complex formation in the case of ternary sestems with nickel(II). The reason for this is in the geometry of parent complexes - octahedral for nickel(II)-amine and square planar for nickel(II)-a-Alaha systems. The tridentate coordination of diethylenetriamine results in five-coordinated mixed-ligand copper(II) complexes in which the aminohydroxamate moiety adopts an equatorial-axial coordination mode.