Synthesis, characterization, spectroscopic and antioxidation studies of Cu(II)–morin complex

New sulfonic derivatives of quercetin as complexing reagents: synthesis, spectral, and thermal characterization

“…The first one is related to dehydration process, whereas the next stages are related with degradation of compounds. In the thermogravimetric analysis of the compounds, the one step of dehydration is observed and related to the endothermic effect on the DTA curve in following temperature range 20-140°C for QSA-8, 20-150°C for NaQSA-8(loss of 4 water molecule), and 20-160°C for the complex (12 molecules of water) [20]. The further increase of temperature causes processes of decomposition of anhydrous compounds.…”

“…The band I is due to the transition localized within the B ring of cinnamoyl system (with the 3C-OH group), and the band II is consistent with the absorbance of the ring A of benzoyl system (with the 5C-OH group). They are related to the p-p * transitions [26,27] and have high absorption coefficients (e), Table 3.…”

Study of thermodynamics of complex formation of flavonoids of steviа (Stevіa rebaudіana Bertonі) leaves

“…2) of dependence of the complex output on the amount of flavonoids of the extract from stevia leaves is characterized by an extreme point (0,65) and indicates the maximum possible concentration of the ligand complex with the aluminium ion. The position of extremum is connected with stoichiometric coefficients [15]. Reducing the content of aluminium ions due to forming complexes with flavonoids of stevia leaves decreases the generation rate of reactive oxygen species, and, as a result, increases protection of biologically active molecules of the body against the oxidizing process [12].…”

Synthesis, Characterization and Biological Activity of Mn(II)-Morin Complex

“…It can also be revealed from data, which shows the absence of this proton. Thus, 1 H NMR and IR studies jointly demonstrate that 3-OH and 4-CO groups of morin are involved in complex formation [31]. Table 5 shows the FT-IR spectral data for morin and Mn(II)-Morin complex.…”

“…10 demonstrates the relative DPPH scavenging activity of pure morin and its Mn(II) complex. Thus, from the graph it can be inferred that the complex exhibits higher antioxidant activity than pure morin and subsequently indicates that metal ion (Mn[II]) shows the significant change in the chemical properties of whole ligand molecule [31]. …”