Spectroscopic and magnetic properties of Cu2(terpy)Cl4(terpy = 2,2′ : 6′,2″-terpyridine). A magnetic system constructed of two exchange-coupled dimers

The complex Cu2(terpy)Cl4(terpy = 2,2′:6′,2″-terpyridine) has been prepared and characterized through spectroscopic and magnetic properties. The results emphasize the presence of two dimeric moieties, identified as [{Cu(terpy)Cl}2]2+ and [Cu2Cl6]2–. Magnetic susceptibility data show that both dimers are antiferromagnetically coupled, with J1=–1.2 and J2=–54.3 cm–1, giving a satisfactory explanation for the thermal evolution of the e.s.r. spectra. These results are compared with those for similar entities and structural predictions are discussed.