Thermal behavior, spectroscopic studies and free radical scavenging potential of some mefenamate trivalent lanthanides (Sm, Eu, Gd, Tb and Dy)

Abstract

a b s t r a c tLanthanide Mefenamate compounds were prepared in solid state. TG-DSC coupled to FTIR, elemental analysis, complexometry with EDTA, X-ray powder diffractometry, evaluation of scavenging free radical activity with DPPH (2,2-diphenyl-1-picryl-hydrazine), and a complete spectroscopic study in the ultraviolet, visible, near-, and middle-infrared regions were realized to obtain some physicochemical properties of the synthesized compounds. The thermal stability, minimum formula, thermal behavior and intermediate compounds were indicated by thermoanalytical results. Furthermore, vibrational spectroscopy data suggests that the complexes are binuclear and two modes of coordination are presented. The DR spectra could be reveal the presence of a large ligand-to-metal charge transfer band in the europium mefenamate. This compound also indicated the higher antioxidant activity with DPPH (77.03% at 200 g L −1 ).

Luminescent Analysis of Eu3+ and Tb3+ Flufenamate Complexes Doped in PMMA Polymer: Unexpected Terbium Green Emission under Sunlight Exposure

“…As one can see, the Δν values for the complexes are slightly lower but close to the sodium salt, indicating that the fluf ligand coordinates to Ln 3+ ions through a bidentate chelate coordination mode . These results are corroborated with the FTIR data reported in previous reports. ,, The coordination of ancillary ligands to the Ln 3+ ion was confirmed by the shift of the heteroaromatic C–N mode and the phosphine oxides (ν PO ) and sulfoxide (ν SO ) stretching modes to lower energies when compared with the free organic molecules, − as can be seen in Table S2.…”

“…34 These results are corroborated with the FTIR data reported in previous reports. 27,33,35 The coordination of ancillary ligands to the Ln 3+ ion was confirmed by the shift of the heteroaromatic C−N mode and the phosphine oxides (ν P�O ) and sulfoxide (ν S�O ) stretching modes to lower energies when compared with the free organic molecules, 36−38 as can be seen in Table S2.…”

“…The ν N−H mode of the complex compared with the free Hfluf shows a minimal shift, indicating that there is no coordination through the amine group as reported for other systems based on fenamates. 26,27,33 In addition, the absorption band corresponding to the carbonyl stretching mode of the free ligand (∼1650 cm −1 ) is absent in the [Ln(fluf) 3 (L)] complexes. On the other hand, two new absorption bands are observed in the intervals from 1605 to 1610 cm −1 and from 1390 to 1405 cm −1 , corresponding respectively to the asymmetric (ν as ) and symmetrical (ν s ) carbonyl modes.…”

“…On the other hand, two new absorption bands are observed in the intervals from 1605 to 1610 cm −1 and from 1390 to 1405 cm −1 , corresponding respectively to the asymmetric (ν as ) and symmetrical (ν s ) carbonyl modes. 26,27,33 Therefore, we can infer the effective coordination of the flufenamate ligand to the metal ion by the carboxylate group.…”

Synthesis, thermal behavior, and spectroscopic study of the solid nalidixate of selected light trivalent lanthanides

“…Complexes with molecules used as medications have been extensively studied due to their biological and spectroscopic properties. Recent studies on lanthanide complexes with nonsteroidal drugs, such as mefenamic acid, ketoprofen, and oxyphenbutazone, found that they exhibit unique spectroscopic and biological properties with applications in biological and technological fields [17][18][19][20]. Complexes with enrofloxacin, ciprofloxacin, norfloxacin, Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10973-018-7042-0) contains supplementary material, which is available to authorized users.…”