Departamento de Ciências Naturais, Universidade Federal de São João del-Rei, 36301-160, São João de-Rei, MG, Brazil.
Phys Chem Chem Phys. 2011 Jan 14;13(2):779-82. doi: 10.1039/c0cp01182g. Epub 2010 Oct 29.
A new receptor for S(N)2 transition states, named NPTROL, is proposed. This molecule has a cavity and four hydroxyl groups that are able to interact with ionic S(N)2 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(N)2 pathway and has an inverse effect on the E2 pathway. Inside the NPTROL cavity, the ΔG(‡) for the S(N)2 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(N)2 product.
提出了一种用于 S(N)2 过渡态的新型受体，命名为 NPTROL。该分子具有一个空腔和四个羟基，能够与离子 S(N)2 和 E2 过渡态相互作用。通过使用氟离子加乙基氯在 DMSO 溶液中的模型系统进行高水平的从头算计算，研究了其催化作用和选择性。在 ONIOM[CCSD(T)/6-311+G(2df,2p) : MP2/BASIS1]理论水平和溶剂效应下进行了计算，包括通过连续溶剂化模型包含的溶剂效应，表明 NPTROL 能够催化 S(N)2 途径，并对 E2 途径产生相反的影响。在 NPTROL 空腔内，S(N)2 过渡态的 ΔG(‡)比 E2 低 5.00 kcal mol(-1)，因此该反应对 S(N)2 产物具有高度选择性。
