Complexes of cadmium(II) and mercury(II) ions with cytidine or cytidine-5'-monophosphate in ternary systems including tetramines
Titel:
Complexes of cadmium(II) and mercury(II) ions with cytidine or cytidine-5'-monophosphate in ternary systems including tetramines
Auteur:
Bregier-Jarzebowska, Romualda Lomozik, Lechoslaw
Verschenen in:
Journal of coordination chemistry
Paginering:
Jaargang 59 (2006) nr. 12 pagina's 1413-1426
Jaar:
2006-08-05
Inhoud:
Interactions between Hg(II) and Cd(II) ions in binary systems with 3,3,3-tet (1,11-diamino-4,8-diazaundecane) and in ternary systems with Cyd (cytidine) or CMP (cytidine-5'-monophosphate) and 3,3,3-tet or Spm (1,12-diamino-4,9-diazadodecane, spermine) have been studied. The presence of the following species has been detected: MHx(3,3,3-tet), M(3,3,3-tet), M(3,3,3-tet)(OH)x and M(Cyd or CMP)(PA), M(Cyd or CMP)(HxPA) (M = Cd or Hg, PA = 3,3,3-tet or Spm). Overall stability constants (log β) have been determined and equilibrium constants for complex formation (log Ke) calculated. The mode of coordination in these species has been proposed on the basis of the equilibrium and 13C NMR, 31P NMR and IR studies. Unlike the biogenic amine Spm, its homologue 3,3,3-tet coordinates with Cd(II) and Hg(II) ions with the involvement of all available donor nitrogen atoms. In Cd(Cyd)(3,3,3-tet) the {N5} chromophore is formed, while in Cd(Cyd)(Spm) the {N4} chromophore is involved (only three nitrogen atoms from Spm are involved in metallation). Introduction of the polyamine into the system Cd(II)/CMP (at pH below 7) leads to changes in coordination mode in the anchoring Cd(CMP) complex and the phosphate group of CMP is involved in bonding. In ternary systems, Hg(II)/Cyd(or CMP)/tetramine, the nitrogen atom N(3) and the phosphate group of the nucleotide take part in coordination. The presence of PA in the inner coordination sphere does not change the mode of metal-CMP coordination with respect to that in the binary system.
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