Semiconductor and luminescent properties of boron difluoride curcuminoid crystals

The electrical conductive, paramagnetic, and luminescent properties of boron coordination compounds based on boron difluoride curcuminoid (1-[4′-(dimethylamino)-phenyl]-4-phenyl-but-1-ene-2,4-dionate) (1) were investigated. The single-crystal X-ray diffraction study of compound 1 was performed. The electrical conductivity of complex 1 in the crystalline state (∼10⁻⁴ S cm⁻¹) is similar to the values characteristic of electrically conductive polymers from a number of aromatic amines. The UV irradiation of the crystals of 1 induces the formation of metastable paramagnetic centers, which have a lifetime lasting for hours at low temperatures. The luminescence spectrum of the crystals of 1 at λ_ex = 370 nm shows two bands in the blue and near-IR regions (470 and 800 nm, respectively). The discovered semiconductor, luminescent, and paramagnetic properties of the crystals of 1 may be useful in the development of smart materials for optoelectronics.