Substituted 2-Phenacylbenzoxazole Difluoroboranes: Synthesis, Structure and Properties

Abstract

Novel fluorescent dyes such as benzoxazole-boron complexes, bearing β-ketoiminate ligands, have been synthesized and characterized with a focus on the influence of a substituent on the basic photophysical properties. 1H, 11B, 13C, 15N, and 19F nuclear magnetic resonance (NMR) spectra of substituted 2-phenacylbenzoxazole difluoroboranes have been recorded and discussed. It is worth mentioning that a high correlation coefficient was found between 15N-NMR parameters and substituent constants. The photophysical properties of these new dyes have been investigated by fluorescence and ultraviolet-visible (UV-Vis) absorption spectroscopy. The geometry optimization, vibrational spectra, and the HOMO and LUMO energies were calculated based on density functional theory with the use of the B3LYP functional and 6-311++G(d,p) basis set.

Recent advances on visible light bodipys and related difluoroborane structures-based photoinitiating systems

“…2-Phenacylbenzoxazole difluoroboranes are a class of fluorescent dyes that are extensively used for biomedical applications such as biolabeling [341][342][343] and chemodosimetry. [344] From the absorption viewpoint, the absorption range of 2phenacylbenzoxazole difluoroboranes is comparable to that of boranils, with absorption maxima ranging between 349 nm for PBX-5 up to 415 nm for PBX-1 comprising the most electron donating group of the series (See Table 7 and Figure 26). Comparison with the reference camphorquinone/N-phenylglycine system [88,[345][346][347] revealed the different PBX/Pyr systems to furnish slower polymerization rates.…”

New BODIPY Dyes Based on Benzoxazole as Photosensitizers in Radical Polymerization of Acrylate Monomers

“…The photosensitizers were synthesized by complexationreaction of 2-phenacylbenzoxazole derivative with boron trifluoride etherate (BF 3 ) in presence of N-ethyldiisopropylamine as is shown in Scheme 1. The details of the synthesis procedures and the correponding 1 H-, 11 B-, 13 C-, 15 N-and 19 F nuclear magnetic resonance (NMR) spectra of the products were described previously [40,41].…”