Synthesis, Characterization and Cation-Induced Isomerization of Photochromic Calix[4](aza)crown-Indolospiropyran Conjugates

Istvan Bitter (1) , Alajos Grün (1) , Peter Kerekes (1)

1 Organic Chemical Technology

Calix[4](aza)crown-5, -6 and -7 ionophores in cone and 1,3-alt conformation carrying photochromic indolospirobenzopyran (SP) signalling group were synthesized and their cation-induced isomerization to the colored merocyanine (Mc) form was studied by UV/vis spectroscopy in the presence of mono-and divalent metal ions. Under dark conditions the SP-Mc equilibrium was remarkably shifted to the colored Mc form by cations of high positive charge density (alkaline earth metal ions), and it was affected by some transition metal ions (Cu2+, Zn2+ and Pb2+) as well. Generally, the extent of isomerization of the cone conformers was larger than that of the 1,3-alt counterparts. The chelation-induced reaction was evaluated by calculating the rate constants of the coloration process.

Mots clés: Physical Sciences

Istvan Bitter, Alajos Grün, Peter Kerekes. Synthesis, Characterization and Cation-Induced Isomerization of Photochromic Calix[4](aza)crown-Indolospiropyran Conjugates. Supramolecular Chemistry, 2008, 20 (03), pp.255-263. ⟨10.1080/10610270601186091⟩. ⟨hal-00513503⟩