N-Substituted iminodimethylenediphosphonic acids exhibited high complexation efficiency towards zinc(), magnesium() and calcium() 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 and a formation of tridentate bonded species has been demonstrated in these systems. The only exception is the N-tetrahydrofurylmethyliminodimethylenediphosphonic acid with a tetrahydrofuryl moiety placed in the sterically favoured position that allows its oxygen atom to be an effective metal binding site. Iminodimethylenediphosphonic and N-methyliminodimethylenediphosphonic acids behave quite differently upon zinc() complexation forming presumably layered two-dimensional polymeric species. These species disappear upon dilution. The crystal structure of N-methyliminodimethylenediphosphonic acid has also been determined. A unique 3-D arrangement of this compound with a tetramer as a basic building unit has been indicated.

No abstract

No abstract

Solution equilibrium studies on the Cu(II)-polyamine-(aminomethyl)phosphonic acid (glycinephosphonic acid) ternary systems (polyamine: ethylenediamine (en), diethylenetriamine (dien), N,N,N 0 ,N 0 ,N 00 -pentamethyldiethylenetriamine (Me 5 dien)) have been performed by pH-potentiometry, UV-vis spectrophotometry and EPR methods. The obtained results suggest the formation of the heteroligand complexes with [Cu(A)(Gly(P))] stoichiometry in all studied systems. Additionally, in the systems with dien the protonated [Cu(dien)(H-Gly(P))] ? species also exists in acid solution and in the system with en the [Cu(en)(Gly(P))H -1 ] -species is formed in the basic solution. Our spectroscopic results indicate the tetragonal geometry for the [Cu(en) (Gly(P))] species, the geometry slightly deviated from square pyramidal for the [Cu(dien)(Gly(P))] complex and strongly deviated from square pyramidal towards trigonal bipyramidal for the [Cu(Me 5 dien)(Gly(P))] species. The coordination modes in these heteroligand complexes are discussed.

No abstract