β-Keto-enol Tethered Pyridine and Thiophene: Synthesis, Crystal Structure Determination and Its Organic Immobilization on Silica for Efficient Solid-Liquid Extraction of Heavy Metals

Abstract

Abstract:Molecules bearing β-keto-enol functionality are potential candidates for coordination chemistry. Reported herein is the first synthesis and use of a novel designed ligand based on β-keto-enol group embedded with pyridine and thiophene moieties. The product was prepared in a one-step procedure by mixed Claisen condensation and was characterized by EA, m/z, FT-IR, ( 1 H, 13 C) NMR and single-crystal X-ray diffraction analysis. The new structure was grafted onto silica particles to afford a chelating matrix which was well-characterized by EA, FT-IR, solid-state 13 C-NMR, BET, BJH, SEM and TGA. The newly prepared organic-inorganic material was used as an adsorbent for efficient solid-phase extraction (SPE) of Cu(II), Zn(II), Cd(II) and Pb(II) from aqueous solutions and showed a capture capacity of 104.12 mg¨g´1, 98.90 mg¨g´1, 72.02 mg¨g´1, and 65.54 mg¨g´1, respectively. The adsorption capacity was investigated, in a batch method, using time of contact, pH, initial concentration, kinetics (Langmuir and Freundlich models), and thermodynamic parameters (∆G˝, ∆H˝and ∆S˝) of the system effects.

Highly Selective Removal of Pb(II) by a Pyridylpyrazole-β-ketoenol Receptor Covalently Bonded onto the Silica Surface

“…For SiNH 2 , new bands appeared at 2941 and 1560 cm –1 relative to CH 2 and N–H vibrations, respectively, proving the successful fixation of the aminopropyl group on SiG . 51,52 The reaction of amines on the silica surface with L 1 causes the formation of new bands at 1461 and 1535 cm –1 corresponding to ν(C=C) and ν(C=N) vibrations, respectively. These results confirm that ( Z )-1-(1,5-dimethyl-1 H -pyrazol-3-yl)-3-hydroxy-3-(pyridine-2-yl)prop-2-en-1-one has been successfully grafted on the SiNH 2 surface.…”

Novel β-keto–enol Pyrazolic Compounds as Potent Antifungal Agents. Design, Synthesis, Crystal Structure, DFT, Homology Modeling, and Docking Studies

“…Accordingly, our previously prepared products were exclusively obtained in the -keto-enol tautomer form, governed by the resonance driving force, as confirmed by XRD. [22][23][24][25][26][27] Herein, as proved by its crystal structure determined from the X-ray diffraction study, compound 10 was also found to exist with the -keto-enol tautomer form.…”

“…The bonds lengths and angles in the molecule are comparable to those found in previous works for other similar compounds. [22][23][24][25][26][27]46 Molecular packing in the monoclinic lattice is such that molecules superimpose along the a and b axes as shown by the projections given in Figure 3 against one fungal strain (Fusarium oxysporum f.sp albedinis) by the agar diffusion method. Surprisingly, the antimicrobial assay revealed that all the screened compounds possessed very weak or no antibacterial effect against all used strains.…”

“…The method has experienced rapid growth and many improvements over the last two decades and the number of publications associated with molecular docking studies has increased enormously. 21 In continuation of our recent works in the field of the synthesis of novel -keto-enol heterocyclic derivatives through efficient and simple routes and of the study of their biological activities, 17,[22][23][24][25][26][27][28][29][30][31] we report in the present investigation on the synthesis and the properties of a novel series of pyrazoles with the -keto-enol functionality as powerful moieties especially in fungal activity. To the best of our knowledge, this is the first real study aiming to develop diversified structures of keto-enol pyrazoles.…”

A review: Analytical methods for heavy metals determination in environment and human samples

“…[232][233][234][235] The silica nanoparticles based on ligand of β-ketoenol-pyridine-furan (as a selective adsorbent was used for metal removal from waters (Pb,Cd,Zn,Cu) (Scheme 4). The engineered sorbent had high adsorption capacity for capturing toxic heavy metal in environmental samples [236][237][238][239].…”