Figure 1: Molecule design and screening for suitable hydrochromic dyes.
From: Hydrochromic molecular switches for water-jet rewritable paper
(a) Structures of the investigated three classes of molecular switches 1–18 in their ring-closed forms and ring-open forms with different substituents and (b) the results of their quick solution tests (Photographs of solutions of 1–18 in 1,4-dioxane (2 ml, C=1 × 10−4 mol l−1) before (above) and after (below) adding 2 ml of water at ambient conditions. The suitable hydrochromic dyes are marked by red frame.
