Graph similarity drives zeolite diffusionless transformations and intergrowth

Understanding the geometric diversity of inorganic and hybrid frameworks through structural coarse-graining

“…SOAP maps are beginning to be used to identify properties of application interest. 15 In the context of the present work, a central such property is the tetrahedral ("T") density: this is the simplest proxy for possible usefulness in catalysis, because low T densities indicate the presence of voids in the framework, which could be used for the absorption, diffusion, and transformation of guest moleculesnoting that the T density of the re-scaled framework need not directly correspond to the accessible pore volume, nor indeed to the density of catalytically active sites. We show a colour-coded version of our map, illustrating the T density, in Fig.…”

“…37 Such combined models could then extend to application-related properties which are determined by geometry and chemistry (e.g., catalytic activity). In regard to visualisation tools, we used one of the simplest (viz., MDS), which already leads to appreciable results, but one might couple our approach to other, more involved dimensionalityreduction schemes such as the popular sketch-map scheme 38 or t-stochastic neighbour embedding 39 which are also beginning to be used with SOAP, 8,15 and to openly available implementations which are beginning to emerge. 13,40 To this end, our database of all coarse-grained representations will be made openly available online upon publication of this work, with the hope to enable future work in the community.…”

“…14 Very recently, zeolites were studied with SOAP-based maps and assessed regarding synthesisability. 15 These materials are widely described in terms of their topology. Whilst extremely powerful, such approaches do not (by construction) include geometric arguments: two zeolites may differ in their bond lengths and angles yet share identical topologies, or conversely, they may have similar geometric features but different connectivity.…”

“…SOAP combines all the characteristics of the neighbour environment up to a given cut-off: it thereby cannot reproduce the intuitive classication afforded by the wellknown space-group or topology symbols, but in turn gives rise to a comprehensive geometric measure that incorporates bond angles, rings, and other subtleties. 15 Here, we generalise this approach such that it can make direct comparisons across vastly different families of chemical structures, and thereby we develop a framework in which geometric diversity can be quantied, visualised, and better understood. The key enabling step is the realisation that a density-based metric such as SOAP can be applied equally well to coarse-grained and uniformly scaled representations of chemical structures as to the structures themselves: this allows us to compare compounds with inherently different chemistries and bond lengths.…”

Zeolite Synthesis Using Imidazolium Cations as Organic Structure-Directing Agents

“…It is worth noting there are studies that predict new structures, such as those used to collect the database of hypothetical structures, as mentioned previously [44]. Finally, the latest attempt to explain interzeolitic transformations and intergrowth has recently been published by Schwalbe-Koda et al using graph theory [45]. In short, these types of studies are important to explain behaviors and help define new experiments.…”