Study of complexes formation between transition metal ions and amylopectin in DMSO/H₂O solution

Abstract

The complexation ability of amylopectin (starch polymer) treated with ultrasound in DMSO/ H 2 O solution was investigated with respect to several metal ions, with the assistance of a factorial design (experimental planning), in order to establish and optimize the best complexation conditions. Acetate, chloride, and nitrate were counter-ions in the metal salts. The effects of temperature, time, and salt amount were evaluated during the complexation reactions using multivariate analysis, a set of mathematic methods capable of evaluating all system variables at once and, through this, temperature was found to be the most influential variable. Results for pH and conductivity provided evidence of complex formation between amylopectin and metal ions. In addition, small shifts in the vibrational frequency between the pure biopolymer and its metal complexes were detected using principal component analysis by interval (i-PCA, a multivariate analysis method), supporting the formation of complexes. The complexes formed with Cu II and Cr III ions presented the best complexation yield (40.0 and 55.4%, respectively) with the biopolymer.

Use of metal-containing polymers as potential anticancer agents

“…Even so, the effect of the presence of water can have an effect on the biological activity. As noted before, this effect is not large for our polymers [29][30][31].…”

“…In fact, the hafnocene and zirconocene products show EC 50 values in the other studies the polymers are found to be cytotoxic and cell death is by necrosis [6][7][8]. Most organometallic compounds associate with polar solvents such as DMSO and the biological results may be influenced by the presence of the DMSO [27][28][29]. For organometallic polymers covered here, the influence of DMSO on the tumor results is found to be minimal [30][31][32].…”

Green Analysis of the Bromination Reaction of Propiophenone Derivatives Mediated by Cu2+ Complexes

“…Very useful properties of both polymers are nontoxicity, biocompatibility and biodegradability among others. These polymers had been successfully used as ligands for metallic centres …”

The Effect of Rutin on Starch Hydrogels/Aerogels Made from Electrolyzed Barley Flour

“…[2,3] In general, the pH of the slurry decreased from 5.39 after 1 h of mixing to 4.55 after electrolysis, which indicated an increase in hydrogen ions (H + ), and slightly acidic content. From a study on amylopectin (in 90% dimethyl sulfoxide) complexation with metal salts of iron (Fe 2+ ), copper (Cu 2+ ), chromium (Cr 2+ ), nickel (Ni 2+ ), and lead (Pb 2+ ), Peres et al [19] associated the decrease in conductivity and reduction in solution pH to: the release of hydrogen ions (of the hydroxyl groups of the amylopectin molecule), the participation of hydroxyl groups from water molecules in the metal coordination spheres, or the presence of counterions. However, the increase in conductivity in this study is contrary to the reported decrease in conductivity for amylopectin-metal complexation [19] where the decrease in pH was suggested to cause the formation of starch(amylopectin)-metal chelates.…”

“…From a study on amylopectin (in 90% dimethyl sulfoxide) complexation with metal salts of iron (Fe 2+ ), copper (Cu 2+ ), chromium (Cr 2+ ), nickel (Ni 2+ ), and lead (Pb 2+ ), Peres et al [19] associated the decrease in conductivity and reduction in solution pH to: the release of hydrogen ions (of the hydroxyl groups of the amylopectin molecule), the participation of hydroxyl groups from water molecules in the metal coordination spheres, or the presence of counterions. However, the increase in conductivity in this study is contrary to the reported decrease in conductivity for amylopectin-metal complexation [19] where the decrease in pH was suggested to cause the formation of starch(amylopectin)-metal chelates. The total dissolved solids increased from 581 mg L −1 measured after 1 h of mixing to 702 mg L −1 measured after electrolysis, which indicated increased content of minerals, organic materials, phenolic compounds, and salts.…”