Low-temperature magnetic properties of three vanadium(III) and manganese(III) .beta.-diketonate complexes

The low-temperature (2-100 K) polycrystalline magnetic properties of V ( a ~ a c )M~ ,n ( a ~ a c )a~n,d Mn(trop)3 are reported [Hacac = 2,4-pentanedione and Htrop = tropolone]. For V(acac), the zero-field splitting (D) is 7.7 cm-', gI1 = 1.96 and g , = 1.78, all compatible with the reinterpreted optical spectrum. The magnetic data for Mn ( a ~ a c h) a~v e been interpreted with D = 3.1 cm-' and g = 2.00 and are also compatible with ligand field calculations based on the reinterpreted optical spectrum. In Mn(trop), there appears to be a very weak intermolecular coupling through the tropolonate ligands, the magnetic parameters being D = -2.6 cm-], g = 2.00, and J = -0.18 cm-l.