Beschreibung:
Electron paramagnetic resonance measurements on nickel(ll) doped copper(ll) acetate monohydrate single crystals have been made. In the liquid helium temperature range, spectra have been observed which may be assigned to Ni2+-Cu2+ strongly coupled mixed pairs in the state of total spin S = 1/2. This result represents a definite difference of magnetic behaviour from the case of the nickel(II) doped dicopper(II) tetra(μ-benzoato-O,O′)bis(quinoline) complex, which has the same sandwich dimeric structure but shows spectra indicative of a S=3/2 state. Apart from this difference, unusual EPR data are found such as pronounced misalignments of g with respect to the relevant pair axes and very large values of the hyperfine coupling constant of the copper nucleus, which characteristically recall that case.