Spin conduction by a molecule-containing nitroxide radicals linked via a phenylene coupling unit was estimated by calculating the transmission of electrons in the molecule when sandwiched between two semi-infinite periodic gold crystals. Nitroxides linked via a m-phenylene coupling unit showed a large splitting in the energy of the transmission peaks of alpha- and beta-spins, whereas this energy splitting was smaller for molecules with extended pi-conjugation, such as nitroxides linked via a p-phenylene coupling unit. The energy splitting of transmission is influenced by spin polarization and constructive/destructive interference of radicals through the phenylene coupling unit. (C) 2014 Elsevier B.V. All rights reserved.