Multiple Orbital Effects and Magnetic Ordering in a Neutral Radical

The
alternating ABABAB π-stacked architecture of the EtCN
solvate of the iodo-substituted, oxobenzene-bridged bisdithiazolyl
radical IBBO (space group Pnma) gives rise to strong
ferromagnetic exchange along the π-stacks, and the material
orders as a spin-canted antiferromagnet with TN = 35 K, with a spontaneous (canted) moment Mspont = 1.4 × 10–3 μB and a coercive field Hc = 1060
Oe (at 2 K). The observation of spin-canting can only be understood
in terms of multiorbital contributions to both isotropic and anisotropic
exchange interactions, the magnitude of which are enhanced by spin–orbit
effects arising from the heavy-atom iodine substituent. Pseudodipolar
interactions lead to a net canted moment along the c-axis, while the sublattice magnetization is predicted to possess
an easy a-axis.