Photochromic thienylpyridine-bis(alkynyl)borane complexes: toward readily tunable fluorescence dyes and photoswitchable materials.

A series of diarylethene-containing N^C chelated thienylpyridine-bis(alkynyl)borane complexes has been designed and synthesized. Their photophysical and photochromic properties have been investigated and presented. The characteristic low-energy absorption band of their closed forms could be readily tuned from the visible range to the near-infrared region.