Magnetic susceptibility and electron spin resonance of some copper(II) unsaturated carboxylates

Abstract

The magnetic susceptibility of some complexes of the type Cu(O₂CR)₂, Cu(O₂CR)₂L, and [Cu(O₂CR)₂L₂](where R is an unsaturated carboxylic acid and L is either pyridine or pyrazine) are reported. The measurements show that the Cu(O₂CR)₂ and Cu(O₂CR)₂L complexes are dimeric and that the [Cu(O₂CR)₂L₂] complexes are monomeric. In the case of the dimeric complexes a study of the temperature variation of the magnetic susceptibility and of the intensity of the e.s.r. absorption has been used to determine values of the exchange integral (J). The results indicate that the e.s.r. approach provides a useful alternative for determining the value of J, particularly in dilute solution.