Photoresponsive crown ethers. 1. Cis-trans isomerism of azobenzene as a tool to enforce conformational changes of crown ethers ... Photoresponsive crown ethers. 2. Photocontrol of ion extraction and ion transport by a bis(crown ether) with a butterfly-like ... Preparation of a crown-ether by photocycloisomerization, Jean-Pierre Desvergne, Henri Bouas-Laurent, J. Chem. Soc., Chem. ... Synthesis of a photochromic crown ether, Tetrahedron Letters, Volume 21, Issue 6, 1980, pp 541-544, Isamu Yamashita, Mieko ...