Wydział Chemii

Barbara Barszcz

Agnieszka Jabłońska-Wawrzycka

Katarzyna Stadnicka

Julia Jezierska

2008

Polyhedron

27

3500-3508

10.1016/j.poly.2008.07.038

Naukowa

Angielski

Artykuł

The new Cu(II) and Cd(II) complexes of the biologically relevant ligand 2-hydroxymethylbenzimidazole: [CdL₂(NO₃)₂] 1, ([CuL₂(NO₃)](NO₃)(H₂O) 2, [CdL₃](NO₃)₂L(EtOH)_0.25 3, mer-[CuL₃](NO₃)₂(H₂O)(i-PrOH) 4 have been synthesized and characterized by elemental analyses, UV–Vis, IR, Raman, EPR, NMR, X-ray diffraction and magnetic measurements. X-ray studies have confirmed a bidentate fashion of coordination of the 2-CH₂OHBIm to the Cd(II) as well to Cu(II) ions. This results in the formulation of a five-membered chelate ring in which both N(imidazole) and O(hydroxymethyl) donors of ligand are involved. A comparison of Cu(II) 4 and Cd(II) 3 model complexes shows that both metals may form complexes which exhibit identical structures (distorted octahedral) forming chromophores of the MN₃O₃ type. On the contrary, the polyhedra of metal complexes containing two ligands are different. The copper complex 2 is a five-coordinated with tetragonal pyramid as coordination polyhedron (CuN₂O₃) but cadmium forms an eight-coordinated (CdN₂O₆) complex 1. Weak C–H⋯π type interactions which were extracted from X-ray data of 1 were confirmed by the ¹³C NMR method. The IR data indicated that Cd(II) is a considerably better acceptor (Lewis acid) than Cu(II) ion for the N, O-donor ligand. The similarities and differences revealed in the coordination behaviour of Cu(II) and Cd(II) towards N, O-donor ligand should be treated as a test on possibility of the copper(II) ions to be displaced by cadmium(II), for example, in the intracellular sites.

https://doi.org/10.1016/j.poly.2008.07.038

http://www.elsevier.com