Lewis acidic aluminosilicates: synthesis, 27 Al MQ/MAS NMR, and DFT-calculated 27 Al NMR parameters

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389013%3A_____%2F24%3A00583043" target="_blank" >RIV/61389013:_____/24:00583043 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00216224:14310/24:00135477 RIV/62156489:43210/24:43924830

Výsledek na webu

<a href="https://pubs.acs.org/doi/10.1021/acs.inorgchem.3c04035" target="_blank" >https://pubs.acs.org/doi/10.1021/acs.inorgchem.3c04035</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1021/acs.inorgchem.3c04035" target="_blank" >10.1021/acs.inorgchem.3c04035</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Lewis acidic aluminosilicates: synthesis, 27 Al MQ/MAS NMR, and DFT-calculated 27 Al NMR parameters

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

Lewis acidic aluminosilicates: synthesis, 27 Al MQ/MAS NMR, and DFT-calculated 27 Al NMR parameters

Popis výsledku anglicky

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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10404 - Polymer science

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2024

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Inorganic Chemistry

ISSN

0020-1669

e-ISSN

1520-510X

Svazek periodika

63

Číslo periodika v rámci svazku

5

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

16

Strana od-do

2679-2694

Kód UT WoS článku

001158206500001

EID výsledku v databázi Scopus

2-s2.0-85184001568