Mixed‐Valence Manganese Carboxylate Clusters, {MnIII6MnII4}, {MnIII7MnII5Na}, and {MnIII7MnII5}, Derived from the Combined Use of Di‐2‐pyridyl Ketone with Selected Aliphatic Diols
The combined use of di-2-pyridyl ketone with the aliphatic diols 1,3-propanediol (pdH2) or 1,4-butanediol (1,4-bdH2) in manganese carboxylate chemistry has afforded three new polynuclear clusters with the {MnIII 6MnII 4} and {MnIII 7MnII 5} nuclearities. The compounds feature unique multilayer cores, not previously observed in manganese cluster chemistry, and possess interesting magnetic properties.
Abstract
Three new polynuclear clusters with the formulae [Mn10O4(OH)(OMe){(py)2C(O)2}2{(py)2C(OMe)(O)}4(MeCO2)6](ClO4)2 (1), Na[Mn12O2(OH)3(OMe){(py)2C(O)2}6{(py)2C(OH)(O)}2(MeCO2)2(H2O)10](ClO4)8 (2) and [Mn12O4(OH)2{(py)2C(O)2}6{(py)2C(OMe)(O)}(MeCO2)3(NO3)3(H2O)(DMF)2](NO3)2 (3) were prepared from the combination of di-2-pyridyl ketone, (py)2CO, with the aliphatic diols (1,3-propanediol (pdH2) or 1,4-butanediol (1,4-bdH2)) in Mn carboxylate chemistry. The reported compounds do not include the aliphatic diols employed in this reaction scheme; however, their use is essential for the formation of 1–3. The crystal structures of 1–3 are based on multilayer cores which, to our knowledge, are reported for the first time in Mn cluster chemistry. Direct current (dc) magnetic susceptibility studies showed the presence of dominant antiferromagnetic exchange interactions within 1–3. Alternating current (ac) magnetic susceptibility studies revealed the presence of out-of-phase signals below 3.0 K for 2 and 3 indicating the slow relaxation of the magnetization vector, characteristic of single-molecule magnets; the Ueff value of 2 was found to be 23 K and the preexponential factor τ0 ~7.6×10−9 s.
