Synthesis, Structure, Spectroscopic Studies and Magnetic Properties of TetrakisGd(lll)5.7-dichloro-8-quinolinate.
Résumé
The synthesis and structural characterization of the neutral gadolinium tetrakis-type complex with 5,7-dichloro-8-quinolinolato (H5,7ClQ) ligands, [Gd(5,7ClQ)2(H5,7ClQ)2Cl], is reported. The GdIII ion is epta coordinated to one chloride ion and to four ligands: two N,O-chelated monoanions and two as zwitterionic (+NH and O–) monodentate oxygen donors. Electronic and vibrational spectra provide suitable markers to distinguish the presence of deprotonated and protonated ligands. The magnetic behaviour of this compound was in-vestigated and explained by taking into account that π–π stacking interactions between the (H5,7ClQ) ligands give rise to a ferromagnetic interaction between the gadolinium centres. The GdIII derivatives provide magnetic evidence for the presence of stacking interactions, which are usually undetectable in optically active ErIII derivatives.