9‐Borabicyclononane Bipyridyl Complexes: Synthesis, Luminescence, and Electronic Characterization

Synthesis, structures, and solid-state photoresponsive color change behavior of boronium complexes bearing a pyridine-imine, diimine, or pyridine-ketone bidentate ligand

9-Borabicyclo[3.3.1]nonane-based boronium triflates bearing a N-substituted 2-pyridylmethanimine, N,N'-dialkylethane-1,2-diimine, or 2-arylcarbonylpyridine ligand were synthesized. Their tetracoordinate boron structures were determined using 11B NMR spectra and X-ray crystallography. The pyridine-imine complexes exhibited solid-state photoresponsive color changes upon UV irradiation, which indicated that boronium complexes without a bipyridine moiety also have photoresponsive capabilities. Combination of TD-DFT calculations and measurements of UV-vis absorption and fluorescence properties, diffuse reflectance spectra, and ESR spectra provided suggestions on the determining factor of the photoresponsive color change capabilities and structures of the photoproducts.

A rapid construction of new boron heterocycles and evaluation of photophysical properties of iminoboronates

A green and efficient method for the synthesis of oxadiazaborole, dioxazaborinine, and oxadiazaborinine from the reactions of phenylboronic acid with amidoxime, α-hydroxyl oxime and α-hydroxyl hydrazone, respectively, is described. The reactions were performed under catalyst-free and mild conditions. All products can be rapidly purified by filtration and washing. In addition, a set of iminoboronates were prepared following a one-pot multicomponent reaction procedure using α-hydroxyl hydrazone, salicylaldehyde and boronic acid derivatives as starting materials and their photophysical properties were assessed. Then, cross-coupling reactions can be carried out smoothly on some target compounds, which may help develop new boron masking strategies.