The synthesis and properties of naphthopyran– boradiazaindacene conjugates

Three new 3,3-diaryl-3H-naphtho[2,1-b]pyran–boradiazaindacene conjugates have been synthesised. The naphthopyran–boradiazaindacene conjugates exhibit a weaker photochromic response relative to the simple naphthopyrans with the photomerocyanines fading relatively quickly. Photochromic switching of the naphthopyran unit results in a decrease in the fluorescence intensity for only the most persistent photomerocyanine. A crystal structure shows that the units are essentially orthogonally disposed and that the boradiazaindacene core is extensively delocalised.

The synthesis, structure and photochromic and fluorescence properties of a series of naphthopyran–BODIPY conjugates are described.Figure optionsDownload as PowerPoint slideHighlights
► Novel naphthopyran – BODIPY conjugates have been synthesised.
► A crystal structure of a 3H-naphtho[2,1-b]pyran – BODIPY conjugate has been obtained.
► The BODIPY and naphthopyran units are orthogonally disposed.
► The photochromic response of the naphthopyran unit in the BODIPY conjugate is diminished.
► Photochemical opening of the pyran ring results in diminished fluorescence intensity.