Synthesis and monolayer study of a new amphiphilic photochromic crown-ether

w . The ionoselective and photosensitive properties of the new amphiphilic crown-ether dye perchlorate of 2- E -2- 2,3,5,6,8,9,11,12-oc- .x 4 tahydro-1,4,7,10,13-benzopentaoxacyclopentadecin-15-yl -5-octadecanoylamino-3-ethyl-1,3-benzothiazolium in monolayers have been studied. The collapse pressure of the dye monolayers is about 53 mNrm on distilled water, slightly increases up to 57-59 mNrm in the presence of Na q ,C a 2q ,M g 2q cations and significantly decreases up to 43-44 mNrm in the presence of K q cations in the aqueous subphases. The area per dye molecule in monolayer is the smallest on water and increases with increasing of the salt concentration in the aqueous subphase. These are evidences for the existence of the dye-cation complexes in monolayers. The reversible changes of the . reflection intensity trans-cis-trans isomerization by dye photoactivation can be observed only for the dye-cation complexes at very low surface pressure in the liquid-expanded state of monolayers. The changes of the reflection intensity by photoactivation in the liquid-condensed state of the dye monolayers on KCl solution are found irreversible that may be due to the photodimerization of the dye to cyclobutane. q 1999 Elsevier Science S.A. All rights reserved.