Photochromism and Metal Complexation of a Macrocyclic Styryl Naphthopyran

A macrocyclic benzo-15-crown-5 ether unit tethered to a photochromic naphthopyran by a styryl spacer ( MEN ) is shown to form a 1:1 complex with magnesium(II). The structure and dynamics of the specific host-metal interactions were investigated by PFG-NMR analysis. A combination of UV/Vis and variable temperature multi-dimensional 1H NMR photokinetic analysis of the crown-containing styryl naphthopyran and its metal complex was used to probe the effect of metal complexation on the photochromism.