Effects of Solvent Fluctuations on the Rate of Thermal Z/E Isomerization of Azobenzenes and N-Benzylideneanilines

Tsutomu Asano, Kevin Cosstick, Hiroyuki Furuta, Kohei Matsuo, Hitoshi Sumi

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30 Citations (Scopus)


Effects of pressure on thermal Z/E isomerization of substituted N-benzylideneanilines and azobenzenes were studied in 2-methyl-2,4-pentanediol. Pressure dependence of the Z/E isomerization of a substituted azonaphthalene was also studied in glycerol triacetate. From the results in this and earlier papers, the following conclusions were reached. 1) It is possible to cast slow thermal reactions into the state of fluctuation control in highly viscous liquid phase realized by a combination of a viscous liquid and high pressure. 2) The viscosity dependence of the rate constant can be rationalized by the two-dimensional reaction-coordinate model developed by Sumi but not by the Grote-Hynes' theory of frequency-dependent friction. Namely, the energy-barrier crossing takes place after the solvent molecules are rearranged to accommodate the transition state. 3) Whether the solvent rearrangement involves chemical transformations with appreciable energy increases depends on the nature of the reaction and the solvent.

Original languageEnglish
Pages (from-to)551-560
Number of pages10
JournalBulletin of the Chemical Society of Japan
Issue number3
Publication statusPublished - Mar 1996
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Chemistry


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