Nitrogen-containing analogues of boron difluoride benzoylacetonate: synthesis,structure, luminescence,and quantum chemical modeling

Nitrogen-containing analogues of boron difluoride benzoylacetonate (1), i.e., boron difluoride ketoiminates (boron difluoride 3-amino-1-phenyl-2-buten-1-onate (2) and 3-methylamino-1-phenyl-2-buten-1-onate (3)), were taken as examples to study the influence of a substituent (H, Me) at the nitrogen atom on structure and spectral-luminescent properties. The replacement of the oxygen atom with the nitrogen atom in compound 1 led to a bathochromic shift of the monomeric luminescence maximum. Quantum chemical modeling of absorption spectra for compound 2 was carried out. In contrast to compounds 1 and 3, crystals of compound 2 are characterized by the formation of J-aggregates and excimers on their basis, which leads to a bathochromic shift of the luminescence spectrum and an increase in the luminescence intensity.