The mechanism of antiferromagnetic coupling in an Ag (I) complex of nitronyl nitroxide is investigated by means of the broken-symmetry approach within the density functional method (DFT-BS). The magneto-structural corre-lation and the single-occupied molecular orbital (SOMO) analysis reveal the existence of the antiferromagnetic cou-pling pathway along nitronyl nitroxide units via Ag (I) ion, and that the Ag (I) ion plays an important bridge role. The spin population analysis also shows the existence of spin de-localization along the ONCNO-Ag-ONCNO chain. It is found that the non-typical covalent bonds with major ionic charac-ter between Ag (I) ions and oxygen atoms of nitronyl nitrox-ide units can be used to mediate the spin-spin interaction of nitronyl nitroxides.
