Synthesis, 11B- and 19F NMR spectroscopy, and optical and electrochemical properties of novel 9-aryl-3-(aryl/heteroaryl)-1, 1-difluoro-7-(trifluoromethyl)-1H-[1,3,5,2]oxadiazaborinino[3,4-a] [1,8]naphthyridin-11-ium-1-uide complexes

A new series of nine examples of 9-ary1-3-(aryl/heteroaryl)-1,1-difluoro-7-(trifluoromethyl)-1H-[1,3,5,21 oxadiazaborinino[3,4-a][1,8]naphthyridin-11-ium-1-uides, which contained 1,8-naphthyridine-based boron complexes with variable ligand structures, were synthesized at yields of 50-65% from the reaction of unpublished 2-benzoylamino-7-aryl(heteroaryl)-5-trifluoromethyl-1,8-naphthyridines in which aryl (heteroaryl) = phenyl, 4-MeC6H4, 4-FC6H4, 4-BrC6H4, 4-OMeC6H4, 4-NO2C6H4, and 2-thienyl with BF3 center dot Et2O and fully characterized by H-1-, C-13-, F-19-, and B-11 NMR spectroscopy and X-ray diffractometry. The optical and electrochemical properties of the new complexes were investigated, and the results for quantum yield calculations, Stokes shift, UV-vis, fluorescence, and redox potential data analysis indicated an important relationship with the aryl(heteroaryl) substituents attached to the 3- and 9-position of the naphthyridine boron complexes. (C) 2016 Elsevier Ltd. All rights reserved.