The relative σ-donating and π-accepting capacities of a range of synthetically relevant boryl anions have been evaluated by examining the geometric, thermochemical, and electronic properties of their adducts to the Li + cation and Se atom, as compared to the properties of the analogous neutral N-heterocyclic carbenes (NHCs), by theoretical methods. The results indicate that boryl anions have a weaker π-accepting capability compared to NHCs, but it is still a non-negligible factor in the bonding contributions between boryl and the Se atom. The tunability of the πaccepting capacity of boryl anions is similar to that of NHCs, indicating a potential for the modification of the electronic properties of metal complexes incorporating either boryl or NHC ligands. In all cases, the boryl ligands were found to be superior σ-donors to NHCs. Article pubs.acs.org/IC

The relative σ donor and π accepting capacities of a range of synthetically relevant boryl anions have been evaluated by examining the geometric, thermochemical and electronic properties of their adducts to the Li + cation and Se atom, as compared to the analogous neutral NHCs, by theoretical methods. The results indicate that boryl anions have a weaker π accepting capability than NHCs, but it is still a nonnegligible factor in the bonding contributions between boryl and the Se atom. The tuneability of the π accepting capacity of boryl anions is similar to that of NHCs, indicating a similar potential for modification of the electronic properties of metal complexes incorporating either boryl or NHC ligands.In all cases, the boryl ligands were found to be superior σ donors to NHCs.