Screening substituent and backbone effects on the properties of bidentate P,P-donor ligands (LKB-PP(screen))

We present a computational exploration of the effect of systematic variation of backbones and substituents on the properties of bidentate, cis-chelating P,P donor ligands as captured by calculated parameters. The parameters used are the same as reported for our ligand knowledge base for bidentate P,P donor ligands, LKB-PP (Organometallics 2008, 27, 1372-1383; Organometallics 2012 31, 5302-5306), but calculation protocols have been streamlined, suitable for an extensive evaluation of ligand structures. Analysis of the resulting LKB-PP(screen) database with principal component analysis (PCA) captures the effects of changing backbones and substituents on ligand properties and illustrates how these are complementary variables for these ligands. While backbone variation is routinely employed in ligand synthesis to modify catalyst properties, only a limited subset of substituents is commonly accessed and here we highlight substituents which are likely to generate new ligand properties, of interest for the design and improved sampling of bidentate ligands in homogeneous organometallic catalysis.