Tetrazoles as Carboxylic Acid Analogs 



145 



Table 2. Apparent Dissociation Constants of 5-Aryltetrazoles and 

 Substituted Benzoic Acids * 



* Apparent dissociation constants determined by potentiometric titration at 

 25°C. in 50% (by volume) methanol unless otherwise indicated. 6 



t Apparent dissociation constants determined by potentiometric titration in 

 75% (by volume) methanol at 25°C. 5 



X Dissociation constants determined conductimetrieally in 50% methanol 

 (by volume) at 18-20°C. 7 



creasing the number of forms contributing to the hybrid beyond those 

 due only to the resonance of the tetrazolyl portion of the anion (scheme 

 VI). It should also be emphasized that, in addition to forms involving 



HN- 



I 



N 



^n> 



I \ / ^ H+ + 



N 



-rO 



N N 



\ / 



N 



N N 



\ S 



N 



N N- 



\ / 



N 



N C 



N N 



N 



r "tO H 



N N 



% / 



N 



(VI) 



a charge separation, a number of forms in which the benzene ring 

 accepts a charge and effectively withdraws electrons from the tetrazole 

 ring may be w r ritten. Although a series of contributing forms may be 



