Structures and stabilities of gas-phase C6H4X–(X = F, Cl and Br) anions: benzyne–halide ion complexes?

Abstract

High-level ab initio calculations predict that C₆H₄X^– anions are stable donor-acceptor complexes with a dramatic decrease of binding energies on going from C₆H₄F^– to C₆H₄Cl^– and to C₆H₄Br^–(226, 96 and 60 kJ mol^–1, respectively); the C₆H₄Br^– ion is calculated to undergo a bromide ion transfer rather than hydrogen abstraction when reacting with methanol, in excellent agreement with experimental observation.