Strong Antiferromagnetic Interaction in a Gadolinium(III) Complex with Methoxy-TEMPO Radical: A Relation between the Coupling and the Gd-O-N Angle.

A new compound [Gd(hfac)3(MeOTEMPO)(MeOH)] (MeOTEMPO = 4-methoxy-2,2,6,6-tetramethylpiperidin-1-oxyl) was prepared. From the X-ray crystal structure analysis, the Gd-O-N angle is 170.9(3)°. The magnetic study clarified the Gd3+-radical interaction with 2J/kB = -26.6(3) K (in the H = -2JS1·S2 convention), which corresponds to one of the strongest antiferromagnetic couplings in the Gd-nitroxide systems. Wider Gd-O-N angles seem to favor stronger antiferromagnetic couplings.