Syntheses and characterizations of 5-nitro-2-(3′,5′di(trifluoromethyl)phenyl)pyridyl-containing iridium(III) complexes and the two-band white photoluminescence properties in solution

A derivative of 2-phenylpyridine (Hppy), 5-nitro-2-(3',5'-di(trifluoromethyl) phenyl) pyridine (HL), is prepared. The L-containing cyclometalated iridium(III) complexes with mono-and bidentate ancillary ligands, [Ir(L)(2)(PPh3)Cl] (1) and [Ir(L)(2)(pic)] (2, pic = picolinic acid), are synthesized and characterized. The photoluminescence (PL) spectra of 1 and 2 in CH2Cl2 solutions show emission maxima at 558 and 560 nm, corresponding to yellow light emission with the Commission Internationale de L'eclairage (CIE) coordinates of (0.45, 0.54) and (0.46, 0.52), respectively. However, the luminescence intensity of 2 with PL quantum yield of 0.71 is obviously stronger that of 1 with PLQY of 0.19. The two-band white PL properties of 2 and [Ir(dfppy)(2)(PPh3)(NCS)] (3, dfppy = 2-(4,6-difluorophenyl) pyridine) with efficient blue light emission are investigated. The CH2Cl2 solutions of 2 and 3 in the molar ratio of 1 : 5 show white light emission with the CIE coordinates of (0.33, 0.41). [GRAPHICS] .