14098-25-0Relevant academic research and scientific papers
Effect of pressure on [2]pseudorotaxane formation and decomplexation and their corresponding activation volumes
Tokunaga, Yuji,Wakamatsu, Nanae,Ohiwa, Norihiro,Kimizuka, Osamu,Ohbayashi, Akihiro,Akasaka, Koichiro,Saeki, Susumu,Hisada, Kenji,Goda, Tatsuhiro,Shimomura, Youji
, p. 4950 - 4956 (2010)
(Figure presented) 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 (CDCl3/CD3CN) 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 (ΔV-) of -2.5 and -4.6 cm3 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-d6/CDCl3), obtaining activation volumes of -0.9 and -0.4 cm3 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.
