Spin-philicity and spin-donicity of substituted carbenes, silylenes, germylenes, and stannylenes

Spin potential, spin hardness, spin-philicity, and spin-donicity indices have been extensively studied on a large set of carbenes, silylenes, germylenes, and stannylenes at the B3LYP/6-31G(d) level. The effect of the substituents and that of the central atom have been investigated. The sum of the spin potentials calculated in the singlet and triplet states correlates excellently with the vertical singlet-triplet energy gap. A very good quadratic relationship between the spin-philicity and spin-donicity indices and the vertical singlet-triplet energy gaps is obtained. The analogy of the spin-philicity and spin-donicity indices with the electrophilicity index is discussed in detail.