Síntese e caracterização de polímeros de coordenação envolvendo Co2+ e ligantes mistos N- e O- doadores

Abstract

This work describes the synthesis and characterization of four coordination polymers, {[Co(adp)(fen)(H2O)]}n (FIL09), {[Co2(azl)2(fen)2(H2O)2]}n (FIL10), {[Co4(O)2(glu)4(fen)4].H2O}n (FIL39) and {[Co4(glu)4(bpp)2]}n (FIL77). All compounds containing dicarboxylic aliphatic ligands classified as O- donors, and N- donor nitrogenous ligands near the Co2+ metal center, in order to obtain coordination networks with mixed ligands. The ligands used were adipic acid (H2adp), glutaric acid (H2glu), azelaic acid (H2azl), 1,10-phenanthroline (fen), 1,3-bis(4-pyridyl)propane (bpp) and pyrazine (pir). Among obtained compounds, 3 are unpublished, and only one the compound (FIL09) was been already reported. All the compounds were characterized by CHN elemental analysis, thermal analysis (TG and DTA), infrared and Raman scattering spectroscopies, Powder X-ray diffraction and single-crystal X-ray diffraction, magnetic susceptibility measurements. A series of one-dimensional coordination polymers was obtained conbining of 1,10-phenanthroline with the aliphatic dicarboxylic ligands. which have three-dimensional supramolecular arrays governed by pi-pi stacking and by hydrogen bonding OH…O FIL09, FIL10 and FIL39 ( the compound FIL39 being a 1D polymer network). The compound FIL77, which was characterized as an interpenetrated three-dimensional polymer network involving the glu and bpp ligands. Through the surface area measurement, it was verified that the compound has a surface area in an order of magnitude much lower than standard porous materials used today. FIL77 have not a considerable N2 gas adsorption capacity with the N2 gas, which can be explained by to treat an interpenetrated network. The magnetic properties of the compound FIL09 have been described in terms of a Co2+ ion with S = 3/2 which interacts with the other Co2+ ions in the crystalline lattice. Compound FIL39 was magnetically described as a Co2+ dimer with S = 3/2 having the presenting intramolecular ferromagnetic and intermolecular ferromagnetic interactions. The presence of different types of triple bonds connecting Co2+ ions in different coordination environments in the FIL77 compound led to the observation of both an antiferromagnetic interaction between Co1 and Co2 ions and the ferromagnetic interaction between Co3 and Co4 ions.