Computational search for molecular magnetic switches based on radical derivatives of sterically hindered dixanthylidenes

Computer modeling (DFT B3LYP-D3BJ/6-311++G(d,p)) of the electronic structure was performed, and the energy characteristics and magnetic behavior of isomers of dixanthylidene derivatives containing stable radicals (tert-butyl nitroxide, 1,2,3,5-dithiadiazolyl, 1,5-dimethyl-6-oxoverdazyl, and fluorenyl) at positions 2 and 2′ were estimated. It was shown that the presence and specific features of interactions of unpaired electron spins in these systems depend on the isomer type and radical group structures. Due to the predicted ability of the fluorenyl radical-bearing compound to change magnetic properties as a result of isomerization, we consider it as a spin switch.