A long standing problem with many de novo design algorithms is the synthetic accessibility of the generated compounds: by connecting atoms or chemical fragments in an otherwise chemically correct way, the resulting molecules turn out to be very hard or impossible to synthesize. We address this issue by making the synthetic accessibility of the designed compounds an intrinsic part of the algorithm: the molecules are generated together with a synthesis route from available precursors. The compounds are scored based upon stability under synthesis conditions, rigidity, volume, geometric compatibility, and energy of interaction with the target zeolite. We initially illustrated the method on the three zeolites AEI, ITE, and STF. We demonstrated that the introduction of Pareto sorting not only enables the simultaneous optimization of multiple properties but also greatly improves the performance of the algorithm to generate molecules with hard-to-meet constraints.<br/><br/>Through collaboration with Mark Davis, we reported the first successful synthesis of a specified molecular sieve through the use of an OSDA that was predicted from a recently developed computational method that constructs chemically synthesizable OSDAs. We have additionally applied this approach to predict novel OSDAs that collaborators Stacey Zones and others used to synthesize AEI. This zeolite is currently of high industrial significance in catalytic refining applications. We have also utilized this methodology with Mark Davis to screen OSDAs used to synthesize LTA. We applied the approach to predict a novel OSDAs used to synthesize SSZ-52, a zeolite of potential importance in vehicular engine exhaust cleanup.<br/><br/>Finally, we in a collaboration with Mark Davis, we reported the synthesis of enantiomerically enriched samples of a molecular sieve. Enantiopure organic structure directing agents are designed with the assistance of computational methods and used to synthesize enantioenriched, polycrystalline molecular sieve samples of either enantiomer. Computational results correctly predicted which enantiomer is obtained, and enantiomeric enrichment is proven by high-resolution transmission electron microscopy. The enantioenriched and racemic samples of the molecular sieves were tested as adsorbents and heterogeneous catalysts. The enantioenriched molecular sieves showed enantioselectivity for the ring opening reaction of epoxides and enantioselective adsorption of 2-butanol.

Computational prediction of chemically-synthesizable organic structure directing agents for zeolites

255th National Meeting (2018)

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