Bannwarth Lab

Highly enantiopure oxetanes via unprecedented catalytic photochemical method:
In collaboration with @bach-lab.bsky.social and @hauer-lab.bsky.social, our PhD student Mike Pauls helped elucidate the reaction course by quantum chemical calculations! Thanks to all 👏

@jacs.acspublications.org

Check out our pre-print on accelerated semi-empirical electronic structure theory calculations on consumer-grade GPUs! ⬇️

Photochemical Deracemization of 4,7-Diaza-1-isoindolinones by Unidirectional Hydrogen Atom Shuttling By coupling a photochemical and a thermal step, a single chiral catalyst can establish a photostationary state in which the enantiopure form of a chiral compound is favored over its racemate. Following this strategy, 3-substituted 4,7-diaza-1-isoindolones were successfully deracemized (74–98% yield, 86–99% ee) employing 2.5 mol % of a photocatalyst. Key to the success of the reaction is the fact that a chiral benzophenone recruits selectively one enantiomer of the substrate for a photoinduced hydrogen atom transfer. A combination of computational and experimental studies suggests that the hydrogen atom is shuttled via the oxygen atom of the catalyst to the 4-nitrogen atom of the substrate.

Plus, we’ve been involved in some exciting collaborations on photochemistry💡:

- First-time description of Dexter energy transfer via conical intersections: doi.org/10.1021/jacs...

- Shedding light on photocatalytic deracemization (P. Freund, M. Pauls, D. Babushkina): doi.org/10.1021/jacs...

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Tensor Train Optimization for Conformational Sampling of Organic Molecules Exploring the conformational space of molecules remains a challenge of fundamental importance to quantum chemistry: identification of relevant conformers at ambient conditions enables predictive simulations of almost arbitrary properties. Here, we propose a novel approach, called TTConf, to enable conformational sampling of large organic molecules where the combinatorial explosion of possible conformers prevents the use of a brute-force systematic conformer search. We employ tensor trains as a highly efficient dimensionality reduction algorithm, effectively reducing the scaling from exponential to polynomial. In our approach, the conformational search is expressed as global energy minimization task in a high-dimensional grid of dihedral angles. Dimensionality reduction is achieved through a tensor train representation of the high-dimensional torsion space. The performance of the approach is assessed on a variety of drug-like molecules in direct comparison to the state-of-the-art metadynamics based conformer search as implemented in CREST. The comparison shows significant acceleration of up to an order of magnitude, while maintaining comparable accuracy. More importantly, the presented approach allows treatment of larger molecules than typically accessible with metadynamics.

🚂 TTConf (C. Zurek, @nilsvanstaalduinen.bsky.social) - Tensor train optimization for conformational search: doi.org/10.1021/acs....

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MolBar: a molecular identifier for inorganic and organic molecules with full support of stereoisomerism Before a new molecular structure is registered to a chemical structure database, a duplicate check is essential to ensure the integrity of the database. The Simplified Molecular Input Line Entry Speci...

🔍 MolBar - an open-source molecular identifier that captures (almost) all forms of stereoisomerism (@nilsvanstaalduinen.bsky.social): doi.org/10.1039/D4DD...

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Combining low-cost electronic structure theory and low-cost parallel computing architecture The computational efficiency of low-cost electronic structure methods can be further improved by leveraging heterogenous computing architectures. The software package TeraChem has been developed since...

🖥️ Using GPUs for low-cost quantum chemical calculations without significant accuracy loss (P. Steinbach):
doi.org/10.1039/D3CP...

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Hello Bluesky! Here’s a look at what we the Bannwarth Lab has been up to so far:

☀️ Investigating photochemical processes with computational chemistry - efficient sampling of minimum energy crossing points (MECP):
doi.org/10.1021/acs....

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