Weak ferromagnetism in 1D coordination polymers: Syntheses, crystal structures, spectroscopic and magnetic properties of [Cu(L)(Memal)]n (Memal2− = the dianion of methylmalonic acid, L = 1,10-phenanthroline, 2,2′-bipyridine)

Investigation of the CuCl2/H2Memal/L (H2Memal = methylmalonic acid, L = 1,10-phenanthroline or 2,2′-bipyridine) reaction system in MeOH and various molar ratios has lead to the isolation of two one-dimensional coordination polymers presenting the [Cu(L)(Memal)] repeating unit (1, L = 1,10-phen; 2, L = 2,2′-bpy). The Memal2− ligand adopts the bidentate [chelating] + unidentate coordination mode between the CuII ions. Magnetic susceptibility measurements on 1 and 2 indicated the existence of weak ferromagnetic intrachain interactions and X-band EPR spectra from powdered samples of 1 and 2 are consistent with the stereochemistry of the CuII ions and with the presence of weak exchange interactions.

Two analogous 1D coordination polymers, presenting the [Cu(L)(Memal)](Memal2− = the dianion of methylmalonic acid, L = 1,10-phen or 2,2′ = bpy) repeating unit have been structurally characterized; their magnetic and EPR properties have been also studied. Both compounds exhibit weak ferromagnetic intrachain interactions attributed to the syn–anti bridging mode of the carboxylato groups of the Memal2− ligand.Figure optionsDownload as PowerPoint slide