Substituent effects in cyanobenzenes

The basic principles utilized to explain substituent effects in the tr-donor/ tr-acceptor family are equally applicable to understanding substituent effects in cyanobenzenes, where the CN group represents a a and tt acceptor. Energy data are listed in Table 12. Interaction energies appear in Table 13, and Mulliken charges and overlap populations appear in Table 14. 

From the interaction energies (Table 13), it appears that a- and TT-donating effects are stabilizing, whereas r- and zr-accepting effects are destabilizing. The 7T donors (CH3, NH2, OH, F) Interact most favorably or least unfavorably at the ortho and para positions. This is because the LUMO for cyanobenzene (Fig. 7) has greater coefficients at these positions and hence the stabilization is more 

Interaction Energies (kcal mole ) for Substituted Cyano- and Lithiobenzenes 

Mulliken Charges and Overlap Populations for Substituted Cyanobenzenes 

Calculated Total Energies and Dipole Moments for Substituted Lithiobenzenes  

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