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Abstract
Abstract
Confinement of molecules in one dimensional arrays of channel-shaped cavities has led to technologically interesting materials. However, the interactions governing the supramolecular aggregates still remain obscure, even for the most common guest molecule: water. Herein, we use computational chemistry methods (#compchem) to study the water organization inside two different channel-type environments: zeolite L – a widely used matrix for inclusion of dye molecules, and ZLMOF – the closest metal-organic-framework mimic of zeolite L. In ZLMOF, the methyl groups of the ligands protrude inside the channels, creating nearly isolated nanocavities. These cavities host well-separated ring-shaped clusters of water molecules, dominated mainly by water-water hydrogen bonds. ZLMOF provides arrays of “isolated supramolecule” environments, which might be exploited for the individual confinement of small species with interesting optical or catalytic properties. In contrast, the one dimensional channels of zeolite L contain a continuous supramolecular structure, governed by the water interactions with potassium cations and by water-water hydrogen bonds. Water imparts a significant energetic stabilization to both materials, which increases with the water content in ZLMOF and follows the opposite trend in zeolite L. The water network in zeolite L contains an intriguing hypercoordinated structure, where a water molecule is surrounded by five strong hydrogen bonds. Such a structure, here described for the first time in zeolites, can be considered as a water pre-dissociation complex and might explain the experimentally detected high proton activity in zeolite L nanochannels.
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Affiliation(s)
- Ettore Fois
- Department of Science and High Technology and INSTM , Università degli Studi dell’Insubria , Via Valleggio 11 , I-22100 Como , Italy
| | - Gloria Tabacchi
- Department of Science and High Technology and INSTM , Università degli Studi dell’Insubria , Via Valleggio 11 , I-22100 Como , Italy
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Eiden-Aßmann S, Schneider A, Behrens P, Engelhardt G, Mändar H, Felsche J. Silver Hydro Sodalite [Ag3(H2O)4]2[Al3Si3O12]2: Synthesis and Structure Determination by Combination of X-ray Rietveld Refinement, Thermogravimetry, FT-IR, and1H-MAS NMR Spectroscopy. Eur J Inorg Chem 2001. [DOI: 10.1002/1099-0682(200106)2001:6<1527::aid-ejic1527>3.0.co;2-f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Wiebcke M, Sieger P, Felsche J, Engelhardt G, Behrens P, Schefer J. Sodium aluminogermanate hydroxosodalite hydrate Na6+x[Al6Ge6O24](OH)x � nH2O (x ? 1.6, n ? 3.0): Synthesis, phase transitions and dynamical disorder of the hydrogen dihydroxide anion, H3O2?, in the Cubic high-temperature form. Z Anorg Allg Chem 1993. [DOI: 10.1002/zaac.19936190728] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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