Introduction of a triphenylamine substituent on pyridyl rings as a springboard for a new appealing brightly luminescent 1,3-di-(2-pyridyl)benzene platinum(ii) complex family

Abstract

The preparation and characterization of three new complexes, namely [Pt(1,3-bis(4-triphenylamine-pyridin-2-yl)-4,6-difluoro-benzene)Cl] ([PtL¹Cl]), [Pt(1,3-bis(4-triphenylamine-pyridin-2-yl)-5-triphenylamine-benzene)Cl] ([PtL²Cl]), and [Pt(1,3-bis(4-triphenylamine-pyridin-2-yl)-5-mesityl-benzene)Cl] ([PtL³Cl]), is reported. All of them are highly luminescent in dilute deaerated dichloromethane solution (Φ_lum = 0.88–0.90, in the yellow-green region; the λ_max,em in nm for the monomers are: 562, 561 and 549 for [PtL¹Cl], [PtL²Cl] and [PtL³Cl], respectively).[PtL¹Cl] is the most appealing, being characterized by a very long lifetime (103.9 μs) and displaying intense NIR emission in concentrated deaerated solution (Φ_lum = 0.66) with essentially no “contamination” by visible light < 600 nm. This complex allows the fabrication of both yellow-green and deep red/NIR OLEDs; OLED emissions are in the yellow-green (CIE = 0.38, 0.56) and deep red/NIR (CIE = 0.65, 0,34) regions, for [PtL¹Cl] 8 wt% (with 11% ph/e EQE) and pure [PtL¹Cl] (with 4.3% ph/e EQE), respectively.