Synthesis, photochromic, and computational studies of dithienylethene-containing β-diketonate derivatives and their near-infrared photochromic behavior upon coordination of a boron(III) center

A series of dithienylethene-containing 1-thienyl-3-aryl-propane-1,3-diones (aryl = phenyl (Ph), thienyl (Th), and 4,5-bis(2,5-dimethylthiophen-3-yl)thiophen-2-yl (DTE-Th)) and the corresponding boron(III) diketonates, (O^O)BR(2) (R = F, C(6)F(5), and Ph), have been designed and synthesized. Their photophysical, electrochemical, and photochromic properties have been studied. Upon coordination of a boron(III) center, the closed forms of the dithienylethene-containing β-diketonates show near-infrared response and the photochromic behavior was also found to be affected by the aryl substituents at the 3-position of the β-diketonates. Moreover, computational studies have been performed that help to provide an understanding of the effect of substituents on the photophysical and photochromic properties.