Effect of substituents on philicity and stability of 1,3-disubstituted imidazol-2-ylidenes (1) and 1,3-diarylimidazol-2-ylidenes (2) was assessed using the following calculations: adiabatic electron affinity (EA) and adiabatic ionization potential (IP), global electrophilicity and differential orbital energy scales for philicity, and ΔES-T, ΔEHyd, ΔEiso and ΔEH-L for stability, with the aid of density functional theory (DFT) and the results were then compared with each other. In the case of 1,3-disubstituted imidazol-2-ylidene, the carbene with CH3 group has the highest nucleophilic character considering all the above scales and the highest thermodynamic stability.
