2024
Lewis Acidic Aluminosilicates: Synthesis, 27Al MQ/MAS NMR, and DFT-Calculated 27Al NMR Parameters
KEJÍK, Martin, Jiri BRUS, Lukas JEREMIAS, Lucie ŠIMONÍKOVÁ, Zdeněk MORAVEC et. al.Základní údaje
Originální název
Lewis Acidic Aluminosilicates: Synthesis, 27Al MQ/MAS NMR, and DFT-Calculated 27Al NMR Parameters
Autoři
KEJÍK, Martin (203 Česká republika, domácí), Jiri BRUS, Lukas JEREMIAS, Lucie ŠIMONÍKOVÁ (203 Česká republika, domácí), Zdeněk MORAVEC (203 Česká republika, domácí), Libor KOBERA, Aleš STÝSKALÍK (203 Česká republika, domácí), Craig E. BARNES a Jiří PINKAS (203 Česká republika, garant, domácí)
Vydání
Inorganic Chemistry, American Chemical Society, 2024, 0020-1669
Další údaje
Jazyk
angličtina
Typ výsledku
Článek v odborném periodiku
Obor
10402 Inorganic and nuclear chemistry
Stát vydavatele
Spojené státy
Utajení
není předmětem státního či obchodního tajemství
Odkazy
Impakt faktor
Impact factor: 4.600 v roce 2022
Organizační jednotka
Přírodovědecká fakulta
UT WoS
001158206500001
Klíčová slova anglicky
Aromatic compounds; Condensation; Ligands; Materials; Nuclear magnetic resonance spectroscopy
Štítky
Příznaky
Mezinárodní význam, Recenzováno
Změněno: 5. 11. 2024 15:57, Mgr. Pavla Foltynová, Ph.D.
Anotace
V originále
Porous aluminosilicates are functional materials of paramount importance as Lewis acid catalysts in the synthetic industry, yet the participating aluminum species remain poorly studied. Herein, a series of model aluminosilicate networks containing [L–AlO3] (L = THF, Et3N, pyridine, triethylphosphine oxide (TEPO)) and [AlO4]− centers were prepared through nonhydrolytic sol–gel condensation reactions of the spherosilicate building block (Me3Sn)8Si8O20 with L–AlX3 (X = Cl, Me, Et) and [Me4N] [AlCl4] compounds in THF or toluene. The substoichiometric dosage of the Al precursors ensured complete condensation and uniform incorporation, with the bulky spherosilicate forcing a separation between neighboring aluminum centers. The materials were characterized by 1H, 13C, 27Al, 29Si, and 31P MAS NMR and FTIR spectroscopies, ICP-OES, gravimetry, and N2 adsorption porosimetry. The resulting aluminum centers were resolved by 27Al TQ/MAS NMR techniques and assigned based on their spectroscopic parameters obtained by peak fitting (δiso, CQ, η) and their correspondence to the values calculated on model structures by DFT methods. A clear correlation between the decrease in the symmetry of the Al centers and the increase of the observed CQ was established with values spanning from 4.4 MHz for distorted [AlO4]− to 15.1 MHz for [THF–AlO3]. Products containing exclusively [TEPO–AlO3] or [AlO4]− centers could be obtained (single-site materials). For L = THF, Et3N, and pyridine, the [AlO4]− centers were formed together with the expected [L–AlO3] species, and a viable mechanism for the unexpected emergence of [AlO4]− was proposed.
Návaznosti
EH22_008/0004572, projekt VaV |
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GJ20-03636Y, projekt VaV |
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LM2023042, projekt VaV |
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MUNI/A/1575/2023, interní kód MU |
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90254, velká výzkumná infrastruktura |
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