Bisphenalenyl Based Heterospin Molecules: Computer Simulation

We report a quantum chemical study of the electronic structure, energy characteristics, and magnetic properties of isomeric bisphenalenyl radical derivatives with a variable number of six-membered rings in the linker (n = 1, 3, 5). It is shown that the nature and strength of exchange spin–spin coupling between unpaired electrons depends on the type (1,2,3,5-dithiadiazolyl, 1,5-dimethyl-6-oxo-verdazyl, and 2,2,6,6-tetramethylpiperidine-1-oxyl) and the position (central part of the linker fragment or terminal bisphenalenyl atoms) of radicals, and the size of the acene skeleton. It is predicted that there are molecules manifesting exchange interactions (of different types but similar magnitudes) between four paramagnetic centers, thus exhibiting the properties of logical switchers.