π -stack optimizer: framework for the design of one-dimensional supramolecular systems.

Area of Science:

• Computational Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Predictive modeling of one-dimensional (1D) supramolecular assemblies is challenging due to vast configurational spaces and complex energy landscapes in non-covalently bonded systems.
• Identifying stable, low-energy configurations is crucial for understanding and designing supramolecular structures.
• Existing methods often require significant computational resources and expertise.

Purpose of the Study:

• To introduce the pi-stack optimizer, a novel open-source framework for generating energetically favorable 1D stacking motifs.
• To enable direct prediction of stable supramolecular assemblies from single monomeric building blocks with minimal computational cost.
• To provide a scalable and practical tool for generating high-quality initial structures for advanced computational studies.

Main Methods:

• The pi-stack optimizer employs global optimization algorithms to explore multidimensional parameter spaces, including rigid-body translations, rotations, and intramolecular torsional flexibility.
• It integrates molecular symmetry constraints to avoid redundant configuration exploration and utilizes metaheuristic algorithms (e.g., Particle Swarm Optimization, Genetic Algorithms) for sampling.
• Candidate geometries are evaluated using semi-empirical quantum-mechanical calculations (GFN2-xTB) with an objective function combining binding energies and steric penalties.

Main Results:

• The framework successfully identified stable low-energy configurations across 14 diverse supramolecular systems, including those with directional hydrogen-bonding networks.
• Comparative analyses showed consistent convergence to similar low-energy minima across different optimization algorithms, demonstrating robustness.
• Automated hyperparameter optimization via Optuna enhances the framework's efficiency and scalability.

Conclusions:

• The pi-stack optimizer is a reliable and computationally efficient tool for predicting 1D supramolecular assembly structures.
• It significantly reduces the overhead associated with generating initial structures for advanced quantum-mechanical calculations and molecular simulations.
• The open-source, modular design makes it a versatile resource for researchers in computational and supramolecular chemistry.