Chemical reactions inside structured nano-environment: SN2vs. E2 reactions for the F− + CH3CH2Cl system

Abstract

A new receptor for S_N2 transition states, named NPTROL, is proposed. This molecule has a cavity and four hydroxyl groups that are able to interact with ionic S_N2 and E2 transition states. Its catalytic effect and selectivity was investigated through high level ab initio calculations using the fluoride ion plus ethyl chloride in DMSO solution as a model system. Calculations at the ONIOM[CCSD(T)/6-311+G(2df,2p) : MP2/BASIS1] level of theory and solvent effects, included through a continuum solvation model, indicate that NPTROL is able to catalyze the S_N2 pathway and has an inverse effect on the E2 pathway. Inside the NPTROL cavity, the ΔG^‡ for the S_N2 transition state is 5.00 kcal mol⁻¹ lower than that for E2, and as a consequence this reaction becomes highly selective toward the S_N2 product.