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.

Department of Chemistry and Biochemistry Mendel University in Brno Brno CZ 61300 Czech Republic

Department of Chemistry Faculty of Science Masaryk University Kotlarska 2 Brno CZ 61137 Czech Republic

Department of Chemistry University of Tennessee Knoxville Tennessee 37996 1600 United States

Department of NMR Spectroscopy Institute of Macromolecular Chemistry Czech Academy of Sciences Heyrovskeho nam 2 Prague CZ 16206 Czech Republic

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Zeolites and Catalysis: synthesis, reactions and applications; Čejka J.; Corma A.; Zones S., Eds.; Wiley, 2010. 10.1002/9783527630295. DOI

Haag W. O.; Lago R. M.; Weisz P. B. The Active Site of Acidic Aluminosilicate Catalysts. Nature 1984, 309 (5969), 589–591. 10.1038/309589a0. DOI

Ravi M.; Sushkevich V. L.; van Bokhoven J. A. Towards a Better Understanding of Lewis Acidic Aluminium in Zeolites. Nat. Mater. 2020, 19 (10), 1047–1056. 10.1038/s41563-020-0751-3. PubMed DOI

Li G.; Pidko E. A. The Nature and Catalytic Function of Cation Sites in Zeolites: A Computational Perspective. ChemCatChem. 2019, 11 (1), 134–156. 10.1002/cctc.201801493. DOI

Xu J.; Wang Q.; Deng F. Metal Active Sites and Their Catalytic Functions in Zeolites: Insights from Solid-State NMR Spectroscopy. Acc. Chem. Res. 2019, 52 (8), 2179–2189. 10.1021/acs.accounts.9b00125. PubMed DOI

Xin S.; Wang Q.; Xu J.; Chu Y.; Wang P.; Feng N.; Qi G.; Trébosc J.; Lafon O.; Fan W.; Deng F. The Acidic Nature of “NMR-Invisible” Tri-Coordinated Framework Aluminum Species in Zeolites. Chem. Sci. 2019, 10 (43), 10159–10169. 10.1039/C9SC02634G. PubMed DOI PMC

Kobera L.; Czernek J.; Abbrent S.; Mackova H.; Pavlovec L.; Rohlicek J.; Brus J. The Nature of Chemical Bonding in Lewis Adducts as Reflected by 27Al NMR quadrupolar Coupling Constant: Combined Solid-State NMR and Quantum Chemical Approach. Inorg. Chem. 2018, 57 (12), 7428–7437. 10.1021/acs.inorgchem.8b01009. PubMed DOI

Yakimov A. V.; Ravi M.; Verel R.; Sushkevich V. L.; van Bokhoven J. A.; Copéret C. Structure and Framework Association of Lewis Acid Sites in MOR Zeolite. J. Am. Chem. Soc. 2022, 144 (23), 10377–10385. 10.1021/jacs.2c02212. PubMed DOI

Chen K.; Gan Z.; Horstmeier S.; White J. L. Distribution of Aluminum Species in Zeolite Catalysts: 27Al NMR of Framework, Partially-Coordinated Framework, and Non-Framework Moieties. J. Am. Chem. Soc. 2021, 143 (17), 6669–6680. 10.1021/jacs.1c02361. PubMed DOI PMC

Brus J.; Kobera L.; Schoefberger W.; Urbanová M.; Klein P.; Sazama P.; Tabor E.; Sklenak S.; Fishchuk A. V.; Dědeček J. Structure of Framework Aluminum Lewis Sites and Perturbed Aluminum Atoms in Zeolites as Determined by 27Al{1H} REDOR (3Q) MAS NMR Spectroscopy and DFT/Molecular Mechanics. Angew. Chemie Int. Ed. 2015, 54, 541–545. 10.1002/anie.201409635. PubMed DOI

Lam E.; Comas-Vives A.; Copéret C. Role of Coordination Number, Geometry, and Local Disorder on 27Al NMR Chemical Shifts and quadrupolar Coupling Constants: Case Study with aluminosilicates. J. Phys. Chem. C 2017, 121 (36), 19946–19957. 10.1021/acs.jpcc.7b07872. DOI

Ghosh N. N.; Clark J. C.; Eldridge G. T.; Barnes C. E. Building Block Syntheses of Site-Isolated Vanadyl Groups in Silicate Oxides. Chem. Commun. 2004, (7), 856.10.1039/b316184f. PubMed DOI

Clark J. C.; Saengkerdsub S.; Eldridge G. T.; Campana C.; Barnes C. E. Synthesis and Structure of Functional Spherosilicate Building Block Molecules for Materials Synthesis. J. Organomet. Chem. 2006, 691 (15), 3213–3222. 10.1016/j.jorganchem.2006.03.028. DOI

Clark J. C.; Barnes C. E. Reaction of the Si8O20(SnMe3)8 Building Block with Silyl Chlorides: A New Synthetic Methodology for Preparing Nanostructured Building Block Solids. Chem. Mater. 2007, 19 (13), 3212–3218. 10.1021/cm070038b. DOI

Lee M.-Y.; Jiao J.; Mayes R.; Hagaman E.; Barnes C. E. The Targeted Synthesis of Single Site Vanadyl Species on the Surface and in the Framework of Silicate Building Block Materials. Catal. Today 2011, 160 (1), 153–164. 10.1016/j.cattod.2010.06.029. DOI

Styskalik A.; Abbott J. G.; Orick M. C.; Debecker D. P.; Barnes C. E. Synthesis, Characterization and Catalytic Activity of Single Site. Lewis Acidic aluminosilicates. Catal. Today 2019, 334, 131–139. 10.1016/j.cattod.2018.11.079. DOI

Saengkerdsub S.Group 4 Metallocene and Half-Sandwich Derivatives of Spherosilicate: Preparation From Si8O20(SnMe3)8 and Their Olefin Polymerization Activity; University of Tennessee, 2002. https://trace.tennessee.edu/utk_graddiss/2195.

Engelhardt L. M.; Junk P. C.; Raston C. L.; Skelton B. W.; White A. H. Unidentate Nitrogen Base Adducts of Aluminium Trichloride. J. Chem. Soc. Dalton Trans. 1996, (15), 3297.10.1039/dt9960003297. DOI

Cowley A. H.; Cushner M. C.; Davis R. E.; Riley P. E. Crystal and Molecular Structure of the 1:2 Aluminum Trichloride-Tetrahydrofuran Complex AlCl3.2THF. Inorg. Chem. 1981, 20 (4), 1179–1181. 10.1021/ic50218a044. DOI

Dixon W.; Schaefer J.; Sefcik M.; Stejskal E.; McKay R. Total Suppression of Sidebands in CPMAS C-13 NMR. J. Magn. Reson. 1982, 49 (2), 341–345. 10.1016/0022-2364(82)90199-8. DOI

Hayashi S.; Hayamizu K. Chemical Shift Standards in High-Resolution Solid-State NMR (1) 13C, 29Si, and 1H Nuclei. Bull. Chem. Soc. Jpn. 1991, 64 (2), 685–687. 10.1246/bcsj.64.685. DOI

Hayashi S.; Hayamizu K. Shift References in High-Resolution Solid-State NMR. Bull. Chem. Soc. Jpn. 1989, 62 (7), 2429–2430. 10.1246/bcsj.62.2429. DOI

Frydman L.; Harwood J. S. Isotropic Spectra of Half-Integer quadrupolar Spins from Bidimensional Magic-Angle Spinning NMR. J. Am. Chem. Soc. 1995, 117 (19), 5367–5368. 10.1021/ja00124a023. DOI

Bräuniger T.; Wormald P.; Hodgkinson P.. Improved Proton Decoupling in NMR Spectroscopy of Crystalline Solids Using the Spinal-64 Sequence. In Current Developments in Solid State NMR Spectroscopy; Springer Vienna: Vienna, 2002; pp 69–74. 10.1007/978-3-7091-3715-4_4. DOI

Adamo C.; Barone V. Toward Reliable Density Functional Methods without Adjustable Parameters: The PBE0Model. J. Chem. Phys. 1999, 110 (13), 6158–6170. 10.1063/1.478522. DOI

Adamo C.; Scuseria G. E.; Barone V. Accurate Excitation Energies from Time-Dependent Density Functional Theory: Assessing the PBE0Model. J. Chem. Phys. 1999, 111 (7), 2889–2899. 10.1063/1.479571. DOI

Weigend F.; Ahlrichs R. Balanced Basis Sets of Split Valence, Triple Zeta Valence and Quadruple Zeta Valence Quality for H to Rn: Design and Assessment of Accuracy. Phys. Chem. Chem. Phys. 2005, 7 (18), 3297.10.1039/b508541a. PubMed DOI

Schäfer A.; Horn H.; Ahlrichs R. Fully Optimized Contracted Gaussian Basis Sets for Atoms Li to Kr. J. Chem. Phys. 1992, 97 (4), 2571–2577. 10.1063/1.463096. DOI

Bergner A.; Dolg M.; Küchle W.; Stoll H.; Preuß H. Ab Initio Energy-Adjusted Pseudopotentials for Elements of Groups 13–17. Mol. Phys. 1993, 80 (6), 1431–1441. 10.1080/00268979300103121. DOI

Metz B.; Stoll H.; Dolg M. Small-Core Multiconfiguration-Dirac–Hartree–Fock-Adjusted Pseudopotentials for Post-d Main Group Elements: Application to PbH and PbO. J. Chem. Phys. 2000, 113 (7), 2563–2569. 10.1063/1.1305880. DOI

Turbomole V7.5 2020, a Development of University of Karlsruhe and Forschungszentrum Karlsruhe GmbH, 1989–2007; Turbomole GmbH, since 2007. http://www.Turbomole.com/.

Grimme S.; Antony J.; Ehrlich S.; Krieg H. A Consistent and Accurate Ab Initio Parametrization of Density Functional Dispersion Correction (DFT-D) for the 94 Elements H-Pu. J. Chem. Phys. 2010, 132 (15), 154104.10.1063/1.3382344. PubMed DOI

Grimme S.; Ehrlich S.; Goerigk L. Effect of the Damping Function in Dispersion Corrected Density Functional Theory. J. Comput. Chem. 2011, 32 (7), 1456–1465. 10.1002/jcc.21759. PubMed DOI

van Lenthe E.; Snijders J. G.; Baerends E. J. The Zero-order Regular Approximation for Relativistic Effects: The Effect of Spin–Orbit Coupling in Closed Shell Molecules. J. Chem. Phys. 1996, 105 (15), 6505–6516. 10.1063/1.472460. DOI

Saue T. Relativistic Hamiltonians for Chemistry: A Primer. ChemPhysChem 2011, 12 (17), 3077–3094. 10.1002/cphc.201100682. PubMed DOI

te Velde G.; Bickelhaupt F. M.; Baerends E. J.; Fonseca Guerra C.; van Gisbergen S. J. A.; Snijders J. G.; Ziegler T. Chemistry with ADF. J. Comput. Chem. 2001, 22 (9), 931–967. 10.1002/jcc.1056. DOI

Van Lenthe E.; Baerends E. J. Optimized Slater-Type Basis Sets for the Elements 1–118. J. Comput. Chem. 2003, 24 (9), 1142–1156. 10.1002/jcc.10255. PubMed DOI

Chong D. P.; Van Lenthe E.; Van Gisbergen S.; Baerends E. J. Even-Tempered Slater-Type Orbitals Revisited: From Hydrogen to Krypton. J. Comput. Chem. 2004, 25 (8), 1030–1036. 10.1002/jcc.20030. PubMed DOI

Czernek J.; Brus J. On the Predictions of the 11B Solid State NMR Parameters. Chem. Phys. Lett. 2016, 655–656, 66–70. 10.1016/j.cplett.2016.05.027. DOI

Blackwell C. S. Investigation of Zeolite Frameworks by Vibrational Properties. 1. The Double-Four-Ring in Group 3 Zeolites. J. Phys. Chem. 1979, 83 (25), 3251–3257. 10.1021/j100488a014. DOI

Marcolli C.; Lainé P.; Bühler R.; Calzaferri G.; Tomkinson J. Vibrations of H8Si8O12, D8Si8O12, and H10Si10O15 As Determined by INS, IR, and Raman Experiments. J. Phys. Chem. B 1997, 101 (7), 1171–1179. 10.1021/jp962742d. DOI

Clark H. C.; O’Brien R. J. Trimethyltin Perchlorate, Trimethyltin Nitrate, and Their Infrared Spectra. Inorg. Chem. 1963, 2 (4), 740–744. 10.1021/ic50008a018. DOI

Baker C.; Gole J. L.; Brauer J.; Graham S.; Hu J.; Kenvin J.; D’Amico A. D.; White M. G. Activity of Titania and Zeolite Samples Dosed with Triethylamine. Microporous Mesoporous Mater. 2016, 220, 44–57. 10.1016/j.micromeso.2015.08.022. DOI

Berg R. W. The Vibrational Spectrum of the Normal and Perdeuterated Tetramethylammonium Ion. Spectrochim. Acta Part A Mol. Spectrosc. 1978, 34 (6), 655–659. 10.1016/0584-8539(78)80067-1. DOI

Lefrancois M. The Nature of the Acidic Sites on Mordenite Characterization of Adsorbed Pyridine and Water by Infrared Study. J. Catal. 1971, 20 (3), 350–358. 10.1016/0021-9517(71)90097-2. DOI

Pieta I. S.; Ishaq M.; Wells R. P. K.; Anderson J. A. Quantitative Determination of Acid Sites on Silica–Alumina. Appl. Catal. A Gen. 2010, 390 (1–2), 127–134. 10.1016/j.apcata.2010.10.001. DOI

Hayashi S.; Suzuki K.; Shin S.; Hayamizu K.; Yamamoto O. High-Resolution Solid-State 13C NMR Spectra of Tetramethylammonium Ions Trapped in Zeolites. Chem. Phys. Lett. 1985, 113 (4), 368–371. 10.1016/0009-2614(85)80383-3. DOI

Dixon W. T. Spinning-Sideband-Free and Spinning-Sideband-Only NMR Spectra in Spinning Samples. J. Chem. Phys. 1982, 77 (4), 1800–1809. 10.1063/1.444076. DOI

Antzutkin O. N.; Song Z.; Feng X.; Levitt M. H. Suppression of Sidebands in Magic-Angle-Spinning Nuclear Magnetic Resonance: General Principles and Analytical Solutions. J. Chem. Phys. 1994, 100 (1), 130–140. 10.1063/1.466983. DOI

Sau A. C.; Carpino L. A.; Holmes R. R. Synthesis and 1H NMR Studies of Some Pentacoordinate Tin(IV) Complexes Derived from Triphenyltin Halides. J. Organomet. Chem. 1980, 197 (2), 181–197. 10.1016/S0022-328X(00)93565-4. DOI

Irwin A. D.; Holmgren J. S.; Jonas J. 27Al and 29Si NMR Study of Sol-Gel Derived aluminosilicates and Sodium aluminosilicates. J. Mater. Sci. 1988, 23 (8), 2908–2912. 10.1007/BF00547467. DOI

Osegovic J. P.; Drago R. S. Measurement of the Global Acidity of Solid Acids by 31P MAS NMR of Chemisorbed triethylphosphine Oxide. J. Phys. Chem. B 2000, 104 (1), 147–154. 10.1021/jp992907t. DOI

Haouas M.; Taulelle F.; Martineau C. Recent Advances in Application of 27Al NMR Spectroscopy to Materials Science A. Prog. Nucl. Magn. Reson. Spectrosc. 2016, 94–95, 11–36. 10.1016/j.pnmrs.2016.01.003. PubMed DOI

Masika E.; Mokaya R. Mesoporous aluminosilicates from a Zeolite BEA Recipe. Chem. Mater. 2011, 23 (9), 2491–2498. 10.1021/cm200706n. DOI

Leonova L.; Moravec Z.; Sazama P.; Pastvova J.; Kobera L.; Brus J.; Styskalik A. Hydrophobicity Boosts Catalytic Activity: The Tailoring of aluminosilicates with Trimethylsilyl Groups. ChemCatChem 2023, 15 (13), e20230044910.1002/cctc.202300449. DOI

Dimitrov V.; Komatsu T. Correlation among Electronegativity, Cation Polarizability, Optical Basicity and Single Bond Strength of Simple Oxides. J. Solid State Chem. 2012, 196, 574–578. 10.1016/j.jssc.2012.07.030. DOI