2D double-layered metal-radical complexes: Crystal structures and magnetic properties

Two new complexes [Mn(NIT4Py)(2,4-PDA)(H2O)2] (1) and [Co(NIT4Py)(2,4-PDA)(H2O)2] (2) (where NIT4Py stands for 2-(4′-pyridinyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, 2,4-PDA stands for pyridine-2,4-dicarboxylate) have been synthesized and characterized. The single-crystal X-ray diffraction demonstrates that complex 1 present dimeric structure with two 2,4-PDA anions function as bridging ligands, connecting two Mn(II) centers. The dimeric units form an infinite 2D double-layered network via hydrogen bonds. Complex 2 consists of infinite 1D chain, in which each 2,4-PDA anion bridges two adjacent Co(II) ions in monodentate-bidentate mode. These 1D chains are further connected together by hydrogen bonds, generating a 2D double-layered structure, too. The variable temperature magnetic susceptibility measurements reveal that the magnetic couplings between Mn(II) and NIT4Py, Co(II) and NIT4Py are weak ferromagnetic and antiferromagnetic interactions for complexes 1 and 2, respectively.