High frequency electron paramagnetic resonance (HFEPR) study of a high spin Co(II) complex

Variable high-frequency electron paramagnetic resonance data were collected for a single crystal of Zn(hmp)(dmb)Cl]₄ (1) doped with a small quantity of high spin Co(II), where dmb is 3,3-dimethyl-1-butanol and hmp- is the monoanion of 2-hydroxy-methylpyridine. The lack of solvent in the lattice of complex 1 results in very little disorder. Consequently, the EPR spectra are extremely sharp, enabling precise comparisons with theoretical simulations. We find the ground state of the Co(II) ions to be an effective spin S′ = 1/2 Kramers’ doublet with a highly anisotropic g-tensor. The anisotropy is found to be of the easy-axis type, with the single-ion easy axis directions tilted away from the crystallographic c direction by 58°.