O−17 Nuclear Magnetic Resonance of Manganese (III) Tris(Acetylacetonate)

Abstract

The 17O NMR signal of manganese (III) tris(acetylacetonate) was studied in the temperature range 26°—83°. From the temperature dependence of the shift of this signal, a hyperfine interaction constant of 1.88 G is found. This result is used to estimate the covalent character of the σ metal—oxygen bond. An upper limit of 0.077 is found for the mixing coefficient of the oxygen 2s orbitals in the bonding molecular orbitals of the complex. The electron spin transverse relaxation time is estimated from the linewidths of the 1H and 17O resonances to be in the range 10−11 to 10−12 sec.