Halobenzenes astatination

Nucleophilic astatination of halobenzenes CgHjX (X = Cl, Br, I) in homogeneous mixtures with -C4H9NH2, (C2H5)2NH, and (C2Hj>3N at 210° C has led to the formation of astatobenzene with radiochemical yields of 75-90% 143, 144). A two-step process has been postulated [Eqs. (10) and (11)], with the latter reaction [Eq. (11)] as the ratedetermining step ... 

Activation Energies for Nucleophiuc Astatination of Halobenzenes The Influence of Aliphatic Amines... 

TABLE 2. Activation energy for homogeneous halogen exchange by astatine in halobenzenes. Reproduced with permission from Reference 24... 

TABLE 3. Yields and reaction times for homogeneous halogen exchange by astatine from halobenzenes (t = 200 °C)25... 

TABLE 6. Yield and isomer distribution for electrophilic hydrogen replacement by astatine in heterogeneous mixtures of benzene and halobenzenes with HCI04. Reproduced with permission from Reference 50... 

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