Back Cover: Coordination‐Driven Dimerization of Zinc Chlorophyll Derivatives Possessing a Dialkylamino Group (Chem. Asian J. 7/2017)

Abstract

Coordinated movements: A zinc chlorophyll‐a derivative possessing a dimethylamino group at the C31 position showed red‐shifted visible absorption and intensified exciton‐coupling circular dichroism (CD) spectra at room temperature owing to its dimer formation via coordination to the central zinc by the 31‐N atom, whereas its analogs bearing 31‐ethylmethylamino/diethylamino groups did not. The difference was dependent on the steric factor of the substituents in the tertiary amino group, in which an increase of the carbon numbers on the N atom reduced the intermolecular N⋅⋅⋅Zn coordination. UV/Vis, CD, and 1H NMR spectroscopic analyses including DOSY measurements revealed that Zn‐1 formed closed‐type dimers via an opened dimer by single‐to‐double axial coordination with an increase in concentration and a temperature decrease in CH2Cl2. More information can be found in the Full Paper by Hitoshi Tamiaki et al. on page 759 in Issue 7, 2017 (DOI: 10.1002/asia.201700015).