Temperature and energy dependences of ion–molecule reactions: Studies inspired by Diethard Böhme

Abstract

Diethard Böhme has had a long career covering many topics in ion-molecule reactivity. In this review, we describe the work done at the Air Force Research Laboratory (and its variously named preceding organizations) that was inspired by his studies. These fall into two main areas: nucleophilic displacement (S N 2)

Proton transfer-induced competing product channels of microsolvated Y−(H2O)n + CH3I (Y = F, Cl, Br, I) reactions

“…As one of the most important organic chemistry reactions, the bimolecular nucleophilic substitution S N 2 reaction, Y À + RX -RY + X À , attracts a tremendous number of experimental and theoretical studies. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] The gas-phase ion-molecule S N 2 reaction displays a double-well potential, where the central transition state connects the pre-reaction complex Y À Á Á ÁRX and post-reaction complex YRÁ Á ÁX À . Recently, the combination of crossed-beam ion imaging experiments and dynamic simulations has improved our understanding of model S N 2 reactions in the gas phase.…”

Computational Studies of Coinage Metal Anion M− + CH3X (X = F, Cl, Br, I) Reactions in Gas Phase

“…The nucleophilicity of gold is important in oxidative reactions, the Au − anion is more nucleophilic than Au(0), Au(I), and Au(III) species, and thus reactions of atomic Au − anions with hydrocarbons in the gas phase were studied [ 14 , 19 ]. The study of gas-phase ion-molecule reactions provides mechanistic insights into the bond-breaking and -making steps that are often obscured under condensed-phase environments, which are complicated by solvents, counterions, and ligands [ 14 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ]. Although gas-phase obtained information cannot replace that of the condensed phase, understanding the intrinsic unit makes it more feasible to improve chemical reactions or catalysts from a bottom-up approach [ 20 , 22 , 26 , 30 , 31 ].…”