Conceptual density functional theory based intrinsic radical stabilities: Application to substituted silylenes and p-benzynes

Abstract

Spin-polarized Conceptual DFT descriptors, such as the sum of the spin potentials and the spin-philicity index, are used to characterize the vertical and adiabatic singlet–triplet energy separation of silylenes and p-benzynes. In addition, an (approximately) intrinsic stability scale is constructed for both systems, using a model linking bond dissociation enthalpies to chemical concepts such as the electrophilicity index, Pauling’s electronegativity and the stability of the individual radical fragments, used with success in a recent contribution for radical systems. The new stability scales are compared to other scales in the literature and are correlated with the singlet–triplet gaps and the electrophilicity index values for the examined compounds, investigating the relationship between reactivity and stability.