Solid pure ruthenium phthalocyanine, obtained from its adduct [PcRu (DMSO) 2]* 2DMSO, is an amorphous material, and its structure has been examinedby the large-angle X-ray scattering (LAXS) technique. Experimental data are best fitted byassuming that ruthenium phthalocyanine is dimeric, ie (PcRu) 2, with a short intradimer Ru-(II)—Ru (II) contact (2.40 Á), six dimeric units, on average, closely approaching one another and stacked in a monodimensional array.(PcRuh is paramagnetic with a room-temperature magnetic moment (2.54 ps), which is strongly temperature dependent in the range 300—6 K. Interpretation of the magneticbehavior leads to an electronic energy level diagram which locates the highest energy electrons for the dimer in the orbital sequence* 12 3 2** 2. The electricalconductivity value a (RT), 1 x 10-5-1 cm-1, is also considered in the light of the structural features of the complex.(PcRuh, stable to air as a solid material, easily interacts with dioxygen when in contact with tetrahydrofuran. Dioxygen activation and oxygen atom transfer are observed for ruthenium phthalocyanine in the oxidation of 1-octene by O2 in tetrahydrofuran, in the presence of (CeHsCN^ PdCh as the olefin activator, with selective formation of 2-octanone. Catalytic experiments were carried out at room temperature and at ap (C> 2) of 50 atm. The optimized conditions for oxidation involve a Fe: Pd: olefin molar ratio of about 1: 1.7: 40.