Singlet Phosphinidene Insertions in H₂O, H₂S, HF, and HC1. Comparisons with Carbene, Nitrene, and Silylene Insertions

The insertion reaction of phosphinidene ¹PH into H₂O, H₂S, HF, and HC1 has been studied by ab initio molecular orbital theory including electron correlation and zero-point energy corrections. Bader’s charge density analysis has been used to delineate the bonding in initially formed donor-acceptor complexes, in the transition structures for hydrogen migration, and in the insertion products. Comparisons with the corresponding nitrene, carbene, and silylene insertions are made. Differences in the geometries and the kinetic stabilities of the ylide structures can be attributed to the electronegativity differences of the singlet (¹A) diradical species.