R1-X-R2 σ-hole Donor | VS,max (kcal·mol−1) | ||
X = S | X = Se | X = Te | |
H3C-X-CH3 | 3.92 | 5.99 | 17.77 |
C6H8X | 8.30 | 12.81 | 22.19 |
NC-X-CN | 44.48 | 51.13 | 61.66 |