Carbon-13 nuclear magnetic resonance spectra of µ-oxo-bis(disalicylideneiminatoiron) complexes

Abstract

Natural-abundance ¹³C n.m.r. shifts have been measured for a range of paramagnetic iron salicylideneiminato complexes of the type [{(N-R-x-Xsal)₂Fe}₂O](R = Et, Prⁿ, or p-MeC₆H₄ and X = H, 3-Me, 4-Me, or 5-Me). In one case the shifts have been determined over the temperature range 320–225 K and carbon hyperfine-coupling and exchange-coupling constants have been obtained. The present results, together with those of a previous ¹H n.m.r. study, are discussed in terms of spin densities. A π-delocalisation mechanism is dominant, though a paths to certain nuclei are probably involved.