Polímeros de coordenação com ligantes azolatos: síntese, caracterização e estudo das propriedades físico-químicas

Abstract

This work describes the synthesis and characterization of six coordination compounds, [Zn(bbpi)2] (1), [Ni(bbpi)2] (2), [Co2(1,2,3-tz)2] (3), {[Cu(3,4-PDC)(2-imdpi)]}n (4), {[Co(2-oxo)(H2O)2](H2O)2]}n (6) containing ligands of the pyridinedicarboxylic acid family and azole ligands, which may provide interesting coordination modes against selected transition metal ions of the 1st transition series (Co2+, Ni2+, Cu2+ and Zn2+). The ligands used were 1,2,3-triazole-4,5-dicarboxylic acid (1,2,3-tz), 1,3-bisbenzyl-2-oxoimidazolidine-4,5-dicarboxylic acid (2-oxo), 2,6-bis (2-benzimidazolyl) pyridine (bppi), 2- (1H-imidazol-2-yl) pyridine (2-imdpi) and 3,4-pyridinedicarboxylic acid (H2PDC). Of the six compounds described in this work, only compound (1) is described in the literature. The compounds were characterized by elemental analysis, thermal analysis (TG and DTA), infrared vibrational spectroscopy, and X-ray diffraction by single crystal. In these compounds, the spectroscopic data are in agreement with the X-ray diffraction data by single crystal. For the compound (4) the formation of the polymer network was observed and for the compounds (5) and (6) the formation of polymer chains was observed. In all cases, supramolecular arrangements are formed by hydrogen bonds in addition to π-π stacking interaction for compound (4). All the compounds present the central metal in octahedral geometry, except for the compound (3) that presents two crystallographically independent Co2+ ions with square base pyramid geometry. The topological description of the polymer network was also made, with the help of the TOPOS program. The magnetic behavior for compounds (2), (4) and (5) was studied through magnetic susceptibility in addition to EPR for compound (5). Compound (1) had its luminescent property studied by UV-Vis spectrophotometry.