Chelating Guanidinates for Dysprosium(III) Single-Molecule Magnets(dagger)

Main observation and conclusion Two chelating guanidinate-based dysprosium(III) complexes, namely the monomeric {(Me3Si)(2)NC((NPr)-Pr-i)(2)}(2)Dy(mu-Cl)(2)Li(THF)(2) 1 and the dimeric [{(Me3Si)(2)NC((NPr)-Pr-i)(2)}(2)Dy(mu-Cl)](2) 2, have been confirmed to be single-molecule magnets. Moreover, the alteration from 1 to 2 leads to an obvious mitigated quantum tunnelling of magnetization at zero field of the hysteresis loop and much enhanced magnetic relaxation barrier (up to 312 K). 5% dilution with the yttrium(III) analogue for 2 shows no clear change for the hysteresis, indicating the single-ion nature of the magnetic behavior.