Abstract

In regard to the worldwide interest in synthesis and application of stable carbenes, DFT calculations (B3LYP/6-311++G**//B3LYP/6-31+G* levels) are employed to reach at a series of phenyl carbenes. The singlet-triplet energy separations (ΔE_S-T), HOMO–LUMO energy gaps (ΔE_HOMO-LUMO), as well as philicity indices (N and ω) and basicity of these carbenes are compared and contrasted with the synthesized N-heterocyclic carbenes. The investigations reveal that F, Cl, Br, NMe₂ and PMe₂ stabilize singlet states more than their corresponding triplet states. The reactivity of the species is discussed in terms of nucleophilicity, electrophilicity and proton affinity. This detailed study offers new insights into the chemistry of these classes of carbenes.

Key words: Stability, phenyl carbenes, nucleophilicity and electrophilicity, proton affinity, DFT.