Mononuclear lanthanide single molecule magnets based on the polyoxometalates [Ln(W5O18)2]9- and [Ln(beta2-SiW11O39)2]13- (Ln(III) = Tb, Dy, Ho, Er, Tm, and Yb).
The first two families of polyoxometalate-based single-molecule magnets (SMMs) are reported here. Compounds of the general formula [Ln(W(5)O(18))(2)](9-) (Ln(III) = Tb, Dy, Ho, and Er) and [Ln(SiW(11)O(39))(2)](13-) (Ln(III) = Tb, Dy, Ho, Er, Tm, and Yb) have been magnetically characterized with static and dynamic measurements. Slow relaxation of the magnetization, typically associated with SMM-like behavior, was observed for [Ln(W(5)O(18))(2)](9-) (Ln(III) = Ho and Er) and [Ln(SiW(11)O(39))(2)](13-) (Ln(III) = Dy, Ho, Er, and Yb). Among them, only the [Er(W(5)O(18))(2)](9-) derivative exhibited such a behavior above 2 K with an energy barrier for the reversal of the magnetization of 55 K. For a deep understanding of the appearance of slow relaxation of the magnetization in these types of mononuclear complexes, the ligand-field parameters and the splitting of the J ground-state multiplet of the lanthanide ions have been also estimated.
AlDamen
Murad A
MA
Instituto de Ciencia Molecular, Universidad de Valencia, Poligono la Coma s/n, 46980 Paterna, Spain.
Cardona-Serra
Salvador
S
Clemente-Juan
Juan M
JM
Coronado
Eugenio
E
Gaita-Ariño
Alejandro
A
Martí-Gastaldo
Carlos
C
Luis
Fernando
F
Montero
Oscar
O
D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008280:Magnetics; D008958:Models, Molecular; D010100:Oxygen / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry*; D013696:Temperature; D014414:Tungsten / Q000737:chemistry*
D028581:Lanthanoid Series Elements; D010100:Oxygen; D014414:Tungsten; D012825:Silicon