Equilibrium, thermoanalytical and spectroscopic studies to characterize phytic acid complexes with Mn(II) and Co(II)

Abstract

Estudos potenciométricos foram realizados para determinar o grau de ligação do ácido fítico com os íons Co(II) e o Mn(II), na ausência de dioxigênio. As constantes de equilíbrio para as principais espécies formadas são relatadas, e os resultados são representados na forma de diagramas de distribuição mostrando a concentração individual dos complexos como uma função do pH. Os valores das constantes de formação dos complexos foram elevados para as espécies em que o ligante encontra-se mais desprotonado. Os dados potenciométricos indicam que a espécie [MH 4 L] 6-, encontra-se totalmente formada em pH 7,0 e a partir destes dados os complexos de Mn(II) e Co(II) com o ácido fítico foram sintetizados no estado sólido. Análises de infravermelho, termogravimetria e calorimetria exploratória diferencial foram utilizadas para caracterizar e investigar o comportamento térmico destes compostos. Os resultados conduziram a informações sobre composição, desidratação, estabilidade e decomposição térmica dos complexos. Potentiometric studies were carried out to determine the binding degree of phytic acid with Co(II) and Mn(II) ions, in the absence of dioxygen. Equilibrium constants for all major complexes formed are reported, and the results are presented in the form of distribution diagrams showing the concentrations of individual complexes as a function of pH. The formation constants of the complexes show higher values for the species in which the ligand was more deprotonated. Potentiometric data indicates that the species [MH 4 L] 6-, was totally formed at pH 7.0 and the complexes were synthesized from this data. A solid state complex of Mn(II) and Co(II) with phytic acid was synthesized. Thermogravimetry, differential scanning calorimetry, and infrared spectroscopy were used to investigate and characterize the thermal behavior of these compounds. The results led to information on the composition, dehydration, thermal stability and thermal decomposition of the isolated complexes.

Complexes of Glucosamine Hydrochloride and Phytic Acid in Aqueous Medium and Their Antioxidant Properties in Human Blood Plasma

“…IR spectra of the isolated product also confirmed that the inositol hexakisphosphate group was retained. The complexes of II with I showed bands for the polyatomic alcohol inositol (854 cm -1 ); C-O ester stretching vibrations (1150 -1030 cm -1 ); bands characteristic of II anion [13,21], namely P-O vibrations (889 cm -1 ) shifted relative to the product by Dn = 2 cm -1 ; and phosphoryl vibrations at 1130 and 1643 cm -1 (shifted in the product by Dn = 8 cm -1 ). Furthermore, the spectrum had bands for all bending and stretching vibrations of the protonated form of I and the Cl -band (774 cm -1 ) disappeared.…”

Stretchable self-healing hydrogels capable of heavy metal ion scavenging

“…PA was a natural organic hexaphosphate, and which -P]O group had an obvious stretching vibration peak at 1126 cm À1 . 16,34 When PA/CS gels was formed, the stretching peak of -P]O group at 1126 cm À1 disappeared and split into two peaks at 1134 cm À1 (asymmetric stretching frequency) and 1166 cm À1 (symmetric stretching frequency), which can be ascribed to the phosphoric acid of PA converted into phosphate with the -NH 3 + of CS as the counterions. Moreover, the stretching frequency of -NH 2 group of CS atṽ ¼ 3434 cm À1 became sharping, which further conrmed the -NH 2 of CS had been protonated by the phosphoric acid of PA.…”

“…PA, a cyclic acidic molecule saturated with six dihydrogen phosphate, exerted a strong binding affinity to metallic ions, and the capability of chelate bivalent cations would be increased through inducing phosphate variants in a deprotonating environment. 34 Metallic ions can generate more stable coordination compound with PA than the -NH 3 + /PO 4 H À ion pairs between PA and CS. As a result, the metal ions (Ca 2+ , Cu 2+ , Mg 2+ , Pb 2+ and Ba 2+ ) added to the hydrogels would combine with PA replace the intermolecular interaction between PA and CS, which disrupted the hydrogel structure, leading to the degradation of the hydrogel in about 2 h ( Fig.…”

“…The reason might be that the complexing constant between metal ion and EDTA, K (MY) , was much larger than between metal ions and PA, K (MPA) . 16,34,35 Therefore, the PA was released and the equilibrium of noncovalent interaction between PA and CS reformed, resulting in the recovery of hydrogels. It was worth mentioning that the regenerated hydrogel still exhibited higher mechanical strength and elastic character dominant behavior, as shown in Fig.…”

Комплексы Гидрохлорида Глюкозамина И Фитиновой Кислоты В Водной Среде И Их Антиоксидантные Свойства В Плазме Крови Человека

“…Ýêñïåðèìåíòû âûïîëíåíû íà ÓÔ-ñïåêòðîôîòîìåòðå Specord S100 Bioline (Analytic Jena, Ãåðìàíèÿ); ðÍ-ìåòðå "ðÍ-150Ì" ôèðìû ÐÓÏ (Ãîìåëü, Áåëîðóññèÿ); ßÌÐ-ñïåêòðîìåòðå Agilent DD2 400 (Agilent Technologies, ÑØÀ), D 2 O ñïåêòðû 1 Í, 13 Àíàëèç ôèòèíîâîé êèñëîòû ñ ðåàêòèâîì Âýéäà. Ðàñòâîð, ñîäåðaeàùèé 0,3240 ã ñóëüôîñàëèöèëîâîé êèñëîòû â 100 ìë âîäû (ðàñòâîð À), ñìåøèâàëè ñ ðàñòâîðîì Á, â êîòîðîì áûëî ðàñòâîðåíî 0,0324 ã FeCl 3 × 6H 2 O â 100 ìë âîäû (ñîîòíîøåíèå 1:1 ïî îáú¸ìó), è èñïîëüçîâàëè ñâåaeåïðèãîòîâëåííûì.…”