Evaluating the magnetic anisotropy in molecular rare earth compounds. Gadolinium derivatives with semiquinone radical and diamagnetic analogues

The magnetic anisotropy of two Gd(III) derivatives has been investigated by multifrequency HF-EPR spectroscopy. The reliability of the method of diamagnetic substitution for the estimation of crystal field effects in rare earth compounds is discussed on the basis of the experimental results and of the estimation of the dipolar contribution to the anisotropy.