Synthesis, spectral characterization, thermal and biological studies of lanthanide(III) complexes of oxyphenbutazone

Novel silver(I) complexes with fenamates: Insights into synthesis, spectral characterization, and bioactivity

Six new Ag(I) ions complexes with N-phenylanthranilic, mefenamic, and niflumic acids have been synthesized. Three of them are binary complexes with the [Ag(L)] formula (where L represents N-phenylanthranilate (nfa), mefenamate (mfa), or niflumate (nif) ions), and the other three complexes are ternary with the formula [Ag(L)(phen)2]⋅nH2O (where phen - 1,10-phenanthroline). The complexes were characterized by elemental analysis, differential scanning calorimetry (DSC), X-ray fluorescence, powder X-ray diffraction, and single-crystal X-ray structure analysis. Additionally, techniques such as ESI-MS spectrometry, 1H NMR, UV-Vis, and FTIR spectroscopy were employed. The X-ray crystallography showed that in the solid [Ag(nif)] complex, the cation showed an unusual structure with coordination number 5, i.e. AgO3NC. The silver cation interacts with three niflumate anions, forming a two-dimensional coordination polymer. Complexes have potential antibacterial efficacy with varied minimum inhibitory concentration values (MIC) between 45.96 and 800 μM against multidrug-resistant Pseudomonas aeruginosa. Antibacterial combination therapy of Ag(I) complexes with chloramphenicol (CHL) and kanamycin (KAN) showed a very strong synergistic impact against P. aeruginosa with no cytotoxic effect on normal human fibroblasts. Complexes [Ag(nif)] and [Ag(nfa)] inhibit protein denaturation, bind to BSA via static quenching (kq = 0.65-1.08 × 1013 M-1 s-1). Furthermore, the formation of these complexes enhances the penetration of the drug across human membrane monolayers, which could improve bioavailability and therapeutic potential. The [Ag(nif)] complex demonstrates significant potential for topical dermal application due to its antimicrobial and anti-inflammatory properties. Notably, among all complexes evaluated, it displays the lowest BA/AB ratio (5.41), facilitating the most efficient transdermal permeation.

Potassium Complexes of Quercetin-5'-Sulfonic Acid and Neutral O-Donor Ligands: Synthesis, Crystal Structure, Thermal Analysis, Spectroscopic Characterization and Physicochemical Properties

The coordination ability of QSA^- ligand towards potassium cations was investigated. Potassium complex of quercetin-5'-sulfonate of the general formula [KQSA(H₂O)₂]_n was obtained. The [KQSA(H₂O)₂] (1) was a starting compound for solvothermal syntheses of acetone (2) and dimethylsulfoxide (3) complexes. For the crystalline complexes 1-3, crystals morphology was analyzed, IR and Raman spectra were registered, as well as thermal analysis for 1 was performed. Moreover, for 1 and 3, molecular structures were established. The potassium cations are coordinated by eight oxygen atoms (KO₈) of a different chemical nature; coordinating groups are sulfonic, hydroxyl, and carbonyl of the QSA^- anion, and neutral molecules-water (1) or DMSO (3). The detailed thermal studies of 1 confirmed that water molecules were strongly bonded in the complex structure. Moreover, it was stated that decomposition processes depended on the atmosphere used above 260 °C. The TG-FTIR-MS technique allowed the identification of gaseous products evolving during oxidative decomposition and pyrolysis of the analyzed compound: water vapor, carbon dioxide, sulfur dioxide, carbonyl sulfide, and carbon monoxide. The solubility studies showed that 1 is less soluble in ethanol than quercetin dihydrate in ethanol, acetone, and DMSO. The exception was aqueous solution, in which the complex exhibited significantly enhanced solubility compared to quercetin. Moreover, the great solubility of 1 in DMSO explained the ease of ligand exchange (water for DMSO) in [KQSA(H₂O)₂].

Organometallic complexes of neodymium: an overview of synthetic methodologies based on coordinating elements

Organometallic complexes of neodymium have unique coordinating ability to form both micro and macromolecules as well as metal-based polymers. These complexes have been reported in different fields and play a tremendous role in luminescence, catalytic, biological and magnetic applications. So, the current study will comprise all possible routes for the synthesis of organometallic complexes of neodymium. Neodymium complexes have been synthesized of single, double, triple and tetra linkages with H, C, N, O as well as S, B, and X. The detailed synthetic routes have been classified into four categories but in brief, neodymium forms complexes by reacting metal chloride, nitrate or oxide (hydrated or dehydrated) as precursor along with appropriate ligand. Most applied solvents for neodymium complexes were Toluene and THF. These complexes required a range of temperature based on the nature of complexes as well as linkages. The authors have surveyed the research work published through 2011–2020 and provide a comprehensive overview to understand the synthetic routes of organometallic complexes of neodymium.

A study on enhancing the quantum yield and antimicrobial activity of Pr(iii) by varying the coordination environment

Praseodymium forms complexes easily with nitrogen and oxygen donor pyrazolines and also forms mixed ligand complexes with these pyrazolines and sulfur donor thio ligands such as dithiocarbamates and xanthates. These newly synthesized complexes have been characterized using elemental analysis, FTIR, TGA, SEM, TEM, PXRD and UV-visible spectral measurements. The isotopic studies were performed using DART mass spectrometry. The luminescent properties of these types of complexes were studied using a fluorescence spectrophotometer. The antimicrobial behavior of these praseodymium complexes was studied thoroughly during the present research.

Efficient procedure with new fused pyrimidinone derivatives, Schiff base ligand and its La and Gd complexes by green chemistry

Synthetic strategies were developed for the construction of some newer more potent derivatives of thiobarbituric acid and its Schiff base metal complexes in both bulk and at the nanoscale.