Metallo-complexes with functionalised tripodal ligands as molecular recognition devices

 

project PN-II-RU-TE-2011-3-0252 (contract nr. 33/2011)

financed by

The tripodal ligands, as an extension of the podand concept to three dimensions, represent a category of molecules able to encapsulate more fully their guest. The tripodal ligands can act as receptors for different chemical species: transition metal ions, lanthanide ions, anions, or cations and anions in the same time.

A series of 11 mononuclear complexes of 4f metal ions (Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+) with a tripodal ligand derived from tris(2-aminoethyl)-amine and 2-formyl-6-hydroxymethyl-p-cresol was synthesized and structurally characterized by X-ray diffraction on single crystal. The complexes are isostructural with the trivalent lanthanide ion placed in the inner compartment of the ligand.

 

 

The luminescent and magnetic properties for some of the metallocomplexes were investigated.

 

Also three families of 3d-4f binuclear complexes were obtained using two very similar ligands, which result from the condensation reactions between o-vanillin and 2-aminomethyl-pyridine and, respectively, 2-(2-aminoethyl)-pyridine (Hvalampy; Hvalaepy). In order to check their ability to generate heterometal complexes, we have associated the Ln3+ ions with three different 3d metal ions: Ni2+, Cu2+, and Zn2+. For some of these compounds the magnetic and photophysical properties have been investigated.