New complexes of light lanthanides with the valsartan in the solid state: Thermal and spectroscopic studies

Ekawa, Bruno; Nunes, Wilhan Donizete Gonçalves; Teixeira, J. A.; Cebim, Marco Aurélio; Ionashiro, E. Y.; Caires, Flávio Júnior

doi:10.1016/j.jaap.2018.08.023

Cited by 8 publications

(1 citation statement)

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“…Thermal analysis is commonly used in the investigations on biologically active compounds to estimate purity, thermal stability, shelf life, as well as mechanisms of decomposition. It is also important to check the possibility of utilizing the compound's waste with a method that is not harmful to the environment, e.g., whether incineration is the correct method [37][38][39][40]. Thus, advanced thermal analyses of KQSA were also performed.…”

Section: Introductionmentioning

confidence: 99%

Potassium Complexes of Quercetin-5′-Sulfonic Acid and Neutral O-Donor Ligands: Synthesis, Crystal Structure, Thermal Analysis, Spectroscopic Characterization and Physicochemical Properties

et al. 2021

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The coordination ability of QSA− ligand towards potassium cations was investigated. Potassium complex of quercetin-5’-sulfonate of the general formula [KQSA(H2O)2]n was obtained. The [KQSA(H2O)2] (1) was a starting compound for solvothermal syntheses of acetone (2) and dimethylsulfoxide (3) complexes. For the crystalline complexes 1–3, crystals morphology was analyzed, IR and Raman spectra were registered, as well as thermal analysis for 1 was performed. Moreover, for 1 and 3, molecular structures were established. The potassium cations are coordinated by eight oxygen atoms (KO8) of a different chemical nature; coordinating groups are sulfonic, hydroxyl, and carbonyl of the QSA− anion, and neutral molecules—water (1) or DMSO (3). The detailed thermal studies of 1 confirmed that water molecules were strongly bonded in the complex structure. Moreover, it was stated that decomposition processes depended on the atmosphere used above 260 °C. The TG–FTIR–MS technique allowed the identification of gaseous products evolving during oxidative decomposition and pyrolysis of the analyzed compound: water vapor, carbon dioxide, sulfur dioxide, carbonyl sulfide, and carbon monoxide. The solubility studies showed that 1 is less soluble in ethanol than quercetin dihydrate in ethanol, acetone, and DMSO. The exception was aqueous solution, in which the complex exhibited significantly enhanced solubility compared to quercetin. Moreover, the great solubility of 1 in DMSO explained the ease of ligand exchange (water for DMSO) in [KQSA(H2O)2].

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Section: Introductionmentioning

confidence: 99%