10,9-Oxaboraphenanthrenes as luminescent fluorophores

Reactions of 9-chloro-10,9-oxaboraphenanthrene (1) with the phenyl-, p-tolyl-, m-xylyl-, mesityl-, 2,4,6-tri-iso-propylphenyl-, 3,5-bis(trifluoromethyl)phenyl-, and pentafluorophenyl-Grignard reagents resulted in the formation of the corresponding oxaboraphenanthrene derivatives namely 9-phenyl- (2), 9-p-tolyl- (3), 9-(3,5-dimethylphenyl)- (9-m-xylyl-) (4), 9-mesityl- (5), 9-(2,4,6-tri-iso-propylphenyl)- (6), 9-(3,5-bis(trifluoromethyl)phenyl)- (7), and 9-(pentafluorophenyl)-10,9-oxaboraphenanthrene (8). 9-Trisyl- (9) and 9-supersilyl-10,9-oxaboraphenanthrene (10) were obtained selectively employing 1 and Li[C(SiMe3)3] or Na[SitBu3] as reactants. The compounds 4–9 were characterized by X-ray crystallography. The fluorescence measurements of 5–9 embedded in PMMA show emission bands with λmax from 341 to 373 nm. [Display omitted]