As the tools of computational quantum chemistry have continued to mature, larger and more complex molecular systems have become amenable to computational study. However, studies of these complex systems often require the execution of enormous numbers of computations, which can be a tedious and error‐prone process if done manually. We have developed a suite of free, open‐source tools to facilitate the automation of quantum chemistry workflows. These tools are collected under the organization QChASM (Quantum Chemistry Automation and Structure Manipulation) and include functionality for building and manipulating complex molecular structures and performing routine tasks (AaronTools), a toolkit for automating TS optimizations and predictions of the outcomes of selective homogeneous catalytic reactions, and a plug‐in for UCSF ChimeraX that provides a graphical interface for building complex molecular structures and representing output from quantum chemistry computations. These tools are described below, with a focus on the recent Python implementation of AaronTools. This article is categorized under: Structure and Mechanism > Reaction Mechanisms and Catalysis Software > Quantum Chemistry

We describe a bundle for UCSF ChimeraX called SEQCROW that provides advanced structure editing capabilities and quantum chemistry utilities designed for complex organic and organometallic compounds. SEQCROW includes graphical presets and bond editing tools that facilitate the generation of publication-quality molecular structure figures while also allowing users to build molecular structures quickly and efficiently by mapping new ligands onto existing organometallic complexes as well as adding rings and substituents. Other capabilities include the ability to visualize vibrational modes and simulated IR spectra, to compute and visualize molecular descriptors including percent buried volume, ligand cone angles, and Sterimol parameters, to process thermochemical corrections from quantum mechanical computations, to generate input files for ORCA, Psi4, and Gaussian, and to run and manage computational jobs.

Electron-rich heteroarenes stack with perfluoroarene side chains and twist arylene-ethynylene conjugated oligomers, while electron deficient heterocycles do not. These trends correlate with X-ray structures, optical spectra, and computations.