Elucidating the Different Reactivity of Nucleophilic Substitution Reactions Between Ambiguous Nucleophiles MCN (M=Na, Ag) and C2H5Br Through Quantum Chemical Calculations
ZHANG Qiang, ZHANG Dong-Ju**
School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
Abstract Nucleophilic substitution reactions involving ambident nucleophiles are a unique type of reaction that typically results in mixed products due to different attack sites. This study investigates the reactivity of C and N in the cyanide ion as nucleophilic sites through quantum chemical calculations of the nucleophilic substitution reaction between ambiguous nucleophiles MCN (M=Na, Ag) and ethyl bromide (C2H5Br). The results are consistent with experimental data, and the calculations show that, for NaCN, the attack of the C atom as a nucleophile results in a lower energy barrier to form nitriles compared to the attack of the N atom to form isonitriles, leading to the formation of nitriles as the primary product. Conversely, for AgCN, the opposite is true, favoring the formation of isonitriles as the main product. The different reactivity of the two ambident nucleophiles is explained through analyses of the orbital interactions, Fukui functions, and HOMO orbital compositions, which reasonably elucidate the experimental and calculated results.
ZHANG Qiang, ZHANG Dong-Ju. Elucidating the Different Reactivity of Nucleophilic Substitution Reactions Between Ambiguous Nucleophiles MCN (M=Na, Ag) and C2H5Br Through Quantum Chemical Calculations[J]. Chinese Journal of Chemical Education, 2024, 45(2): 111-115.
