Fast thermal cis-trans isomerization depending on pH and metal ions of water-soluble azobenzene derivatives containing a phosphate group

We observed unique thermal cis-trans isomerization properties of water-soluble azobenzene derivatives in which a phosphate group was substituted at ortho position of an azobenzene via an amide linkage. Here, we report the effect of the structure of the phosphate groups (the length and the position), pH, and metal ions on thermal cis-trans isomerization. We revealed that the water-soluble azobenzene derivatives, in which di- or tri-phosphate group was substituted at ortho position of the azobenzene via the amide linkage, showed the fast thermal isomerization in low pH condition. In addition, we showed that the effects of the metal ions on the thermal isomerization rate. (C) 2015 Elsevier Ltd. All rights reserved.