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Article
A pH Activated Configurational Rotary Switch: Controlling the E/Z Isomerization in Hydrazones
Journal of the American Chemical Society (2009)
  • Shainaz M. Landge, Georgia Southern University
  • Ivan Aprahamian
Abstract
The replacement of one of the carbonyl groups in a 1,2,3-triketone-2-naphthylhydrazone with a pyridine ring yields an original molecular switch that can be switched fully, effectively, and reversibly between the E and Z configurations. This hydrazone-based, pH-controlled, molecular switch is the first example of a chemically controlled configurational rotary switch. The bistable switch exists primarily (97%) as the E configuration in solution and can be converted quantitatively to the Z-H+ configuration upon treatment with trifluoroacetic acid. When Z-H+ is passed over a plug of K2CO3, the “metastable” Z configuration is observed using 1H NMR spectroscopy, which thermally equilibrates to give back the E configuration. The rate of this process is dependent on the polarity of the solvent, indicating that the E/Z isomerization takes place via a rotation around the hydrazone C═N bond.
Keywords
  • Rotary Switch,
  • Hydrazones
Disciplines
Publication Date
2009
Citation Information
Shainaz M. Landge and Ivan Aprahamian. "A pH Activated Configurational Rotary Switch: Controlling the E/Z Isomerization in Hydrazones" Journal of the American Chemical Society 131.51 (2009): 18269-18271.
doi:10.1021/ja909149z