Exploring new synthetic strategies to homo/hetero metallic Mn clusters has been an integral part of the research in our group for many years. The comproportionation reaction between MnII and MnVII is a common way of synthesizing MnIII and mixed MnIIIMnIV cluster compounds, as well as mixed Mn/M clusters where M is another 3d metal or a lanthanide or main group one. One of the most studied Mn clusters, [Mn12O12(O2CMe)16(H2O)4], was made in 1980 by others using comproportionation of Mn2+ salts with KMnO4 in aqueous acetic acid. More recently, our group reported a new procedure that we named ‘reductive aggregation’ involving aggregation of MnO4- into MnIII/IVx/O2-/MeO-/RCO2- clusters triggered by reduction of MnVII by MeOH solvent molecules in the presence of excess carboxylic acid. Many new structural types of various Mnx nuclearities, such as Mn12 and Mn16 were obtained from this new synthetic method. More recently still, reductive aggregation has been used for the first time to obtain mixed-metal products, namely Ce/Mn clusters. The presentation will describe the synthesis and crystal structures of a family of Ce/Mn clusters obtained by reductive aggregation. Also discussed will be a detailed analysis of the magnetic properties of these clusters, which show unusual long-range Mn---Mn exchange interactions mediated by intervening diamagnetic CeIV (f0) ions, a phenomenon which we recently discovered in a Ce3Mn8 cluster reported by our group.

Ce/Mn clusters from reductive aggregation: Unusual long-range Mn---Mn exchange-coupling through CeIV

2019 Spring National Meeting

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