Dysprosiacarboranes: A New Type of Organometallic Single‐Molecule Magnet

The dicarbollide ion, nido -C 2 B 9 H 11 2 cyclopentadienyl. Here we make dysprosiacarboranes, namely [(C 2 B 9 H 11 ) 2 Ln(THF) 2 ][Na(THF) 5 ] (Ln = Dy, 1Dy ) and [(THF) 3 ( mu -H) 3 Li] 2 [{ eta 5 -C 6 H 4 (CH 2 ) 2 C 2 B 9 H 9 }Dy{ eta 2 :eta 5 -C 6 H 4 (CH 2 ) 2 C 2 B 9 H 9 } 2 Li] 3Dy and show that dicarbollide ligands impose strong magnetic axiality on the central Dy(III) ion. The effective energy barrier ( U eff ) for loss of magnetisation can be varied by the substitution pattern on the dicarbollide. This is demonstrated by comparing complexes of nido -C 2 B 9 H 11 2- and nido -[ o -xylylene-C 2 B 9 H 9 ] 2- which show U eff of 430(5) K and 804(7) K, respectively. The blocking temperature defined by the open hysteresis temperature of 3Dy reaches 6.8 K. Moreover, the linear complex [Dy(C 2 B 9 H 11 ) 2 ] - is predicted to have comparable properties with linear [Dy(Cp Me3 ) 2 ] + complex. As such, carboranyl ligands and its derivatives may open a new type of organometallic ligands for high-performance single-molecule magnets.