Flowing afterglow measurement of the acidities of phosphole and arsole

The acidities of phosphole and arsole, heteroatom analogs of pyrrole (c-C{sub 4}H{sub 5}N), were determined by the proton transfer reactions of c-C{sub 4}H{sub 4}P{sup -} and c-C{sub 4}H{sub 4}As{sup -} with reference acids in a flowing afterglow apparatus. These anions were formed by reaction of OH{sup -} with 1-tert-butylphosphole and 1-tert-butylarsole. Nearly identical results were obtained for both ions, and the acidities are assigned to be {Delta}H{sup 0}{sub acid} = 339 {+-} 3 kcal/mol for both species.