Direct Solid-State NMR Observation of Tetrahedral Aluminum Fluorides in Zeolite HY Fluorinated by Ammonium Fluoride

Biocompatible inorganic nanoparticles for [18F]-fluoride binding with applications in PET imaging

“…Selective binding of fluoride ions to various solid state and soluble materials has been a topic of growing interest in recent years for applications including extraction and analysis of fluoride in environmental samples, 1-3 rapid trapping of [ 18 F]-fluoride following its manufacture in cyclotrons and in purification of [ 18 F]-labelled radiopharmaceuticals for positron emission tomography, 4 and most recently as inorganic binding sites for incorporation of [ 18 F]-fluoride into biomolecules. 5-12 Various solid state materials have been used including anion exchange resins, 4 alumina, 13,14 hydroxyapatite, 15-17 porous titania, 18 aluminosilicates, 19,20 molecular materials containing silicon, 10-12,21 boron 2,8,22 and phosphorus, 9 and complexes of aluminium 5-7 and zirconium. 3 Stimulated by the well-known strong adsorption of fluoride ions onto hydroxyapatite, 15,17,23 which occurs even in vivo in the face of competition from, for example, phosphate ions, phosphonates, polyphosphates ( e.g.…”

Synergic Effect of GaO+/Brønsted Acid in Hierarchical Ga/Al-ZSM-5 Bifunctional Catalysts for 1-Hexene Aromatization

“…However, no 27 Al signals near −16 ppm are observed in our 27 Al MAS NMR spectra. Moreover, Hsien-Ming Kao reported that according to the 2D 27 Al– 19 F HETCOR and 19 F– 27 Al CP-MAS NMR spectra, the 19 F signals at −173 and −182 ppm observed in HY zeolite fluorinated by an NH 4 F solution were correlated to the 27 Al signal at 50 ppm and are both assigned to the tetrahedral Al–F complex Figure f illustrates the 71 Ga MAS NMR spectra of the zeolites.…”

“…Moreover, Hsien-Ming Kao reported that according to the 2D 27 Al− 19 F HETCOR and 19 F− 27 Al CP-MAS NMR spectra, the 19 F signals at −173 and −182 ppm observed in HY zeolite fluorinated by an NH 4 F solution were correlated to the 27 Al signal at 50 ppm and are both assigned to the tetrahedral Al−F complex. 39 Figure 4f illustrates the 71 Ga MAS NMR spectra of the zeolites. The tetrahedrally coordinated skeleton Ga species 27 Al MAS NMR spectra of the samples, (c,d) 2D 27 Al 3Q MAS NMR spectra of P-0 and S-2 samples, (e) 19 F MAS NMR spectra of S-2 sample, and (f) 71 Ga MAS NMR spectra of the Ga/Al-ZSM-5 samples.…”

Aluminum Fluoride Modified Beta Zeolite as Highly Selective Catalyst for the Esterification of sec-Butanol with Acetic Acid

“…Fluorine, the most electronegative element, is often used as a modifier of zeolitic catalysts to improve their catalytic activity . Different fluorinating agents such as (NH 4 ) 2 SiF 6 , HF, and NH 4 F have been explored, and the results showed that fluorine modification could significantly impact the catalytic performance of the resulting fluorinated zeolites. , Aneke et al , studied a catalyst consisting of H-form Y zeolite (H–Y), β-AlF 3 , and Cu, and found that the presence of fluorine resulted in the increased selectivity for toluene disproportionation. Becker and Kowalak observed the significantly increased acidity and catalytic activity of zeolites mordenite, Y, and ZSM-5 upon fluorine treatment using an aqueous solution of ammonium fluoride.…”