Synthesis, fluorescent studies, antioxidative and α-amylase inhibitory activity evaluation of some lanthanide(III) complexes

Abstract

A novel heterocyclic ligand, viz. 1,2-dihydro-1,5-dimethyl-4-[[1-2--oxo-2H-1-benzopyran-3-yl)ethylidene]amino]-2-phenyl-3H-pyrazol-3-one, was prepared by condensing 3-acetylcoumarin with 4-aminoantipyrine. This ligand is versatile in forming complexes with lanthanum(III), praseodymium(III), samarium(III), gadolinium(III) and dysprosium(III) ions. The ligand and the metal complexes were characterized through various physicochemical and spectral studies. The spectral studies revealed that the ligand is coordinated to the metal ion in a bidentate fashion, through the azomethine nitrogen and the oxygen atom of the pyrazolone ring. The powder XRD patterns of ligand and the dysprosium(III) complex were studied. The photoluminescent properties of ligand and metal complexes were evaluated and the relative quantum yields were determined. It was observed that in all cases the metal ions enhanced the luminescence intensity. The α-amylase inhibitory activity of the ligand and the metal complexes was evaluated using the method of Apostolidis. The metal complexes exhibited increased activity compared to the ligand. The antioxidant property was also examined using the DPPH assay and the metal complexes were found to be more potent antioxidants than the ligand.

Absorption spectral study for the interaction of Pr(III) with L-Aspartic acid in various aquated organic solvents through 4f-4f transition spectra: Analysis of reaction pathways and thermodynamic parameters

“…Figure 4 shows the comparative spectra of Pr(III) and Pr(III): amino acid complexes in aquated MeOH, MeCN, dioxane and DMF solvents. Variation of solvents brings a significant effect on the oscillator strengths of the 4f-4f bands and consequently marked variation in the magnitudes of intensity Tλ parameters (λ=2, 4,6). DMF has high polarizability and sensitivity, which means it efficiently enhances 4f-4f electric dipole intensity and hence could show the possibility of highest covalency for the complexation of Pr(III): Ligands among the four solvents followed by the solvents MeCN, Dioxane and MeOH.…”

“…Many of the concepts and hypotheses have been amended or abandoned as the science of coordination chemistry progresses. Complex formation processes are a "key" in several research fields like analytical, bioinorganic, clinical and biochemical aspects of coordination chemistry has an emerging research area [4] [5][6] [7].…”

Benzimidazole-functionalized fluorescent probe for rapid detection of 2,4,6-trinitrophenol and Ag+ in semiaqueous medium

“…7a) shows the typical absorption band at 216 nm (π-π transition) and 281 nm(π-π* transition). 37 The UV-Vis absorbance spectrum of BAQ displayed significant change after addition of Ag + , the absorbance band at 281 nm decreased largely accompanied by emerging of a new absorbance band in the range of 356~407 nm with a peak at 389 nm, which proved BAQ formed a firmed binding with Ag + . The significant changes in the UV-Vis spectra of macrocyclic compounds and their complexes with Ag + suggested the formation of ground-state complexes with charge transfer process.…”

Molybdenum (VI) Complexes and their Dual Role as Antidiabetic and Anticancer Agents

“…One of the in-vitro assays is the α-amylase inhibitor assay. [15] Alpha-amylase's inhibitory activity would lower the glucose concentration rate and absorption of postprandial blood glucose. This would prevent the rise in postprandial blood glucose and reduce the absorption of glucose by delaying the breakdown of starch and oligosaccharides.…”