压力对[2]伪轮烷形成和解络及其相应的活化体积的影响。

Effect of pressure on [2]pseudorotaxane formation and decomplexation and their corresponding activation volumes.

机构信息

Department of Materials Science and Engineering, Faculty of Engineering, University of Fukui, Fukui, 910-8507, Japan.

出版信息

J Org Chem. 2010 Aug 6;75(15):4950-6. doi: 10.1021/jo1003955.

PMID:20593805

Abstract

In this study, we investigated the effect of pressure on the formation and decomplexation of [2]pseudorotaxanes. High pressure accelerated the formation of [2]pseudorotaxanes in an aprotic nonpolar solvent (CDCl(3)/CD(3)CN) via the slipping approach when using two crown ether/secondary ammonium salt systems: dibenzo[24]crown-8/bis(cyclohexylmethyl)ammonium salt (1a/2a) and tetrabenzo[24]crown-8/dibenzylammonium salt (1b/2b). The influence of pressure on the rate constants for the formation of the [2]pseudorotaxanes 3a and 3b revealed activation volumes (DeltaV(double dagger)) of -2.5 and -4.6 cm(3) mol(-1), respectively, at 303 K and zero pressure. We also investigated the effect of pressure on the decomplexation of the [2]pseudorotaxanes 3a and 3b in a polar solvent (DMSO-d(6)/CDCl(3)), obtaining activation volumes of -0.9 and -0.4 cm(3) mol(-1), respectively, at 303 K and zero pressure. Moreover, we calculated the activation parameters for the decomplexation processes on the basis of transition state theory at each pressure.

摘要

在这项研究中，我们研究了压力对[2]伪轮烷的形成和解络的影响。在使用两种冠醚/季铵盐体系：二苯并[24]冠-8/双（环己基甲基）铵盐（1a/2a）和四苯并[24]冠-8/二苄基铵盐（1b/2b）时，在非质子非极性溶剂（CDCl3/CD3CN）中，高压通过滑动方法加速了[2]伪轮烷的形成。压力对[2]伪轮烷 3a 和 3b 形成速率常数的影响表明，在 303 K 和零压力下，它们的活化体积（DeltaV(double dagger)）分别为-2.5 和-4.6 cm3 mol-1。我们还研究了压力对极性溶剂（DMSO-d6/CDCl3）中[2]伪轮烷 3a 和 3b 解络的影响，在 303 K 和零压力下，它们的活化体积分别为-0.9 和-0.4 cm3 mol-1。此外，我们根据过渡态理论在每个压力下计算了解络过程的活化参数。