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Title: Multi‐Step Nucleation of a Crystalline Silicate Framework via a Structurally Precise Prenucleation Cluster
Abstract Hierarchical nucleation pathways are ubiquitous in the synthesis of minerals and materials. In the case of zeolites and metal–organic frameworks, pre‐organized multi‐ion “secondary building units” (SBUs) have been proposed as fundamental building blocks. However, detailing the progress of multi‐step reaction mechanisms from monomeric species to stable crystals and defining the structures of the SBUs remains an unmet challenge. Combining in situ nuclear magnetic resonance, small‐angle X‐ray scattering, and atomic force microscopy, we show that crystallization of the framework silicate, cyclosilicate hydrate, occurs through an assembly of cubic octameric Q 3 8 polyanions formed through cross‐linking and polymerization of smaller silicate monomers and other oligomers. These Q 3 8 are stabilized by hydrogen bonds with surrounding H 2 O and tetramethylammonium ions (TMA + ). When Q 3 8 levels reach a threshold of ≈32 % of the total silicate species, nucleation occurs. Further growth proceeds through the incorporation of [(TMA) x (Q 3 8 )⋅ n  H 2 O] ( x −8) clathrate complexes into step edges on the crystals.  more » « less
Award ID(s):
1719797 2116265
PAR ID:
10456009
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ;
Date Published:
Journal Name:
Angewandte Chemie International Edition
Volume:
62
Issue:
28
ISSN:
1433-7851
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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