Decision Trees for the Recognition of Metal-Centered Chirality in Coordination Complexes

While established guidelines exist for chirality in tetrahedral molecules, there is a notable absence of clear rules for recognizing metal-centered chirality in higher-coordination complexes. We develop decision trees to assess the likelihood of chirality-at-metal in coordination complexes with coordination numbers 4-9 with mono and bidentate ligands. Using binary decision rules based on shape, ligand type, and quantity, the trees classify complexes as chiral or achiral. The theoretical formalism employs stereoisomer enumeration via Pólya's theorem, assuming ideal geometries and cis coordination of bidentate ligands. Additionally, analysis of over 2700 crystallographic structures reveals a high prevalence of metal-centered chirality, especially in complexes with higher coordination numbers. These powerful yet easy-to-use decision trees provide chemists with deeper insights into the stereochemistry of metal coordination complexes and with effective tools to identify and understand this often-overlooked stereochemical property and its impact on molecular interactions and crystal packing.