Photophysics of phenyl pyridines and bipyridines in different media

Syntheses and structures of new luminescent B(III) complexes: BPh2(2-(2-pyridyl)naphtho[b]imidazole) and BF2(2-(2-pyridyl)naphtho[b]imidazole)

“…The other intense band centered at 344 nm shows a vibrational separation of 1300 cm À1 with the m 0,0 transition at 3.03 · 10 4 cm À1 . This lower energy band possesses a reasonably high absorptivity (e $ 10 4 dm 3 mol À1 cm À1 ) and a bathochromic shift with increasing polarity of solvent, which are consistent with the intramolecular charge transfer (ICT) character for the concerned p-p* transition involving the filled p orbital (HOMO) located on the imidazol ring and the unoccupied p* orbital (LUMO) located on the quinoly ring [17][18][19][20][21][22][23]. For the absorption spectrum of 1 (Fig.…”

Synthesis, characterization and electroluminescence of B(III) compounds: BPh2(2-(2-quinolyl)naphtho[b]imidazolato) and BPh2(2-(2-quinolyl)benzimidazolato)

“…The other intense band centered at 351 nm shows a vibrational separation of 1000 cm À1 with the m 0,0 transition at 2.94 · 10 3 cm À1 . This lower energy band possesses a reasonably high absorptivty (e $ 3 · 10 4 dm 3 mol À1 cm À1 ) and a red shift with increasing polarity of solvent, which is typical for a p-p * transition [15,16]. When the solutions became more concentrated, a new absorbing band in a range of 370-450 nm appeared, which are consistent with the intermolecular charge transfer (ICT) character for the concerned p-p * transition involving the filled p orbital (HOMO) located on the imidazol ring and the unoccupied p * orbital (LUMO) located on the quinoly ring [17][18][19][20][21].…”

Fluorescent Oligopyridines and their Photo-Functionality as Tunable Fluorophores

“…For example, 2,6-diphenylpyridine (9) showed notable fluorescence both in aprotic and protic solvents [18a], though it is recently reported that only a certain methoxy derivative of 9 exhibits an efficient fluorescence in acetonitrile [18b]. On the other hand, 2-,3-, and 4-phenyl pyridines (10)(11)(12)(13) showed fluorescence only in protic solvents, which was ascribed to the protonated species in the excited state [19]. There are other fluorescent pyridine derivatives such as fused heteroaromatics and N-alkylated pyridiniums [20].…”