Lanthanide Complexes of 3-Acetyl-4-Hydroxy-6-Methyl-2H-Pyran-2-One

The title ligand (H(Dh), dchydroacetic acid) reacts with lanthanide(III) acetates in anhydrous methanol to form complexes of formula [M(Dh)3(MeOH)]. When hydra ted lanthanide acetates are used, hydrated compounds such as [Ce(Dh)3(H2O)] or [Eu(Dh)3(H2O)].H2O are obtained. The reaction of lanthanum triacetate with H(Dh) yields the mixed complex [La(Dh)2(O2CMe)], formation of the 1:3 complex also being unfavoured in the presence of a large ligand excess. The complexes have been characterized by infrared and nmr (1H and 13C) spectroscopy and by thermogravimetric measurements.