Although we concede that the conformation of the ligand when alone and when in the catalytic complex differs, we aimed to keep our approach computationally inexpensive and attempted to derive descriptors from the isolated molecules (instead of the ligand-metal complex). We chose three levels of chemical parameterization complexity which contained sequentially more chemical information at increased computing time. Initially, one-hot encoding (OHE) was used. This computationally simplistic method merely details the presence or absence of certain reagents, whilst encoding no chemical information. For the inclusion of structural information, Morgan fingerprints (radius of 2, see SI for discussion) were chosen to encode the molecular fragments that were present in a given reaction mixture. These bit vectors contain information on atom types, neighbouring connectivity relationships and bond types. Finally, steric and electronic descriptors were calculated for the set of ligands using density functional theory (DFT) from geometry optimized structures (B3LYP functional and 6-31G(d) basis set, see SI for full details). Within this investigation different sub-sets of descriptors were used and combined to develop hybrid molecular representations, containing information of the fingerprints and DFT descriptors.