Ferromagnetic interactions in 0D and 2D Mn(II) coordination complexes containing nitronyl-nitroxide radicals and dicyanamide anions: Mn-II(NITpPy)(2)[N(CN)(2)](2)(H2O)(2) and Mn-II(NITpPy)(2)[N(CN)(2)](2)center dot 2 CH3CN

Two new NITpPy manganese complexes, of formulae Mn(NITpPy)(2)[N(CN)(2)](2)( H2O)(2) (1) and Mn(NITpPy)(2)[N(CN)(2)](2). 2CH(3)CN (2), whereNITpPy stand s for 2-(4-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxy-3-oxide, were synt hesised and structurally and magnetically characterised. Compound 1 crystal lises in the triclinic space group P(1) over bar (#2). The Mn atom is in a distorted octahedral geometry, where the [N(CN)(2)](-) ligands present mu ( 1) coordination sphere being completed by two water molecules and two NIRpP y units. Compound 2 crystallises in the orthorhimbic space group Cmca (#64) . In this compound, the [Mn(NITpPy)(2)](2+) units are linked through mu (2) [N(CN)(2)](-) bridging ligands yielding a two dimensional polymeric struct ure. In both compounds (1) and (2), ferromagnetic interactions are observed but antiferromagnetic interactions dominate at very low temperature. (C) A cademie des sciences. Editions scientifiques et medicales Elsevier SAS.