MAGNETIC-BEHAVIOR OF (5,7-DICHLORO-8-HYDROXYQUINOLINATO)OXOVANADIUM(IV)

The magnetic susceptibility of the title compound was measured between 1.9 and 300 K. It shows a Curie-Weiss behaviour in the temperature ra nge between 50 and 300 K. Below 40 K, a ferromagnetic interaction betw een the VO2+ groups is observed, which was also confirmed by an invest igation of the magnetization as a function of the magnetic field, at 5 K. The mechanism of the interactions was analyzed theoretically using a high temperature series expansion. An excellent agreement between e xperimental and theoretical data was obtained with the exchange integr al J = 2.73 cm(-1). The presented results constitute the first direct evidence of the formation of ... V double bond O ... V double bond O . .. V double bond O ferromagnetic chains in certain oxovanadium(IV) com plexes. (C) 1998 Elsevier Science B.V.