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Observation of Room‐Temperature Deep‐Red/Near‐IR Phosphorescence of Pyrene with Cycloplatinated Complexes: An Experimental and Theoretical Study
Author(s) -
Wu Wenting,
Wu Wanhua,
Ji Shaomin,
Guo Huimin,
Zhao Jianzhang
Publication year - 2010
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201000488
Subject(s) - phosphorescence , chemistry , pyrene , photochemistry , luminescence , electroluminescence , moiety , fluorescence , ligand (biochemistry) , time dependent density functional theory , molecule , stereochemistry , organic chemistry , materials science , optoelectronics , biochemistry , physics , receptor , layer (electronics) , quantum mechanics
Pyrene‐containing cyclometallated Pt II complexes, with the pyrene moiety directly cyclometallated ( Pt‐1 ) or connected to a 2‐phenylpyridine (ppy) ligand through a C–C ( Pt‐2 ) or C≡C bond ( Pt‐3 ), and a control complex with a phenyl group attached to the ppy ligand ( Pt‐4 ) have been prepared. Room‐temperature deep‐red/near‐IR (NIR) phosphorescence emission (650–800 nm) was observed for Pt‐1 , Pt‐2 and Pt‐3 , whereas Pt‐4 showed emission at 528 nm. We found that Pt‐2 , in which the pyrene moiety is not directly cyclometallated, shows intense pyrene‐based phosphorescence, which contrasts with a previous report that direct cyclometallation is necessary for the observation of the phosphorescence of pyrene in cyclometallated complexes. Besides the phosphorescence emission in the deep‐red/near‐IR range, a fluorescence emission band at higher energy was observed. Thus, these complexes can be described as unichromophore multi‐emissive materials. Normal 3 MLCT/ 3 IL emission at 528 nm was observed for Pt‐4 . The UV/Vis absorption and phosphorescence emissions of the complexes were rationalized by DFT/TDDFT calculations. Theoretical calculations propose pyrene‐localized T 1 states ( 3 IL) for Pt‐1 , Pt‐2 and Pt‐3 , which is supported by the experimental results. The complexes were used in luminescent O 2 ‐sensing experiments. These studies will be helpful in the development of room‐temperature phosphorescent materials and their application as luminescent molecular sensing or electroluminescent materials are promising.