Magnetic phase transitions in manganese(II) pentafluorobenzoate adducts with nitronyl nitroxides

Magnetic phase transitions of molecular materials are currently of large interest, particularly those leading to a permanent magnetic moment. Several different approaches are used in order to obtain three-dimensional order, and among them one particularly interesting is that of assembling in lattice spins with largely different moments, such as S = 5/2 and S = 1/2, in order to take advantage of the large moments which result either from a parallel or an antiparallel orientation of the individual spins. According to this procedure ferrimagnetic chains have been and eventually three-dimensional ordered ferromagnets have been reported. In order to increase the transition temperature we decided to use metal salts which are more suitable to give intermolecular interactions then the previous hexafluoro-acetilacetonates previously used. Our choice fell on carboxylates which are well known to yield complex magnetic structures. The properties of a manganese(II) pentafluorobenzoate system coupled with nytronil nitroxides are reported and discussed.