Photophysical Enhancement of Triplet Emitters by Coordination‐Driven Self‐Assembly. Issue 19 (15th March 2017)

• Record Type: Journal Article
• Authors: Zhang, Yuzhen; Fulong, Cressa Ria P.; Hauke, Cory E.; Crawley, Matthew R.; Friedman, Alan E.; Cook, Timothy R.
• Is Part Of: Chemistry. Volume 23:Issue 19(2017)
• Page Start: 4532
• Page End: 4536
• Publication Date: 2017-03-15
• Subjects: coordination-driven self-assembly -- metallacycle -- phosphorescence -- photophysics -- platinum; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201700614
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: The quantum yields of organic fluorophores used as donors in coordination‐driven self‐assembly often suffer from the heavy atom effect of nearby metal sites. Here, the role of intersystem crossing from a deactivating process to one that delivers emissive triplet states was reversed. A phosphorescent trans bis‐ N ‐heterocyclic carbene platinum(II) compound, Pt(dhim)2 (C≡C‐4‐py)2 (D1 ; dhim=1, 3‐dihexyl‐2‐H‐imidazol‐2‐ylidene), was used along with other linear donors 4, 4′‐bipyridine (D2 ) and 1, 4‐bis(4‐pyridyl ethynyl)benzene (D3) in self‐assembly reactions with Pt(dtbpy)X2 acceptors (dtbpy=4, 4′‐di‐tert‐butyl‐2, 2′‐bipyridine) to afford three metallacycles. Photophysical investigations revealed that, although the building blocks used to constructM1 have relatively low quantum yields ( Φ =1.2 and <1 % forD1 and2, respectively), the metallacycle has a quantum yield of 14 %. This increase reflects a change in radiative rate constant from 3.6×10 4 s −1 forD1 to 2.1×10 5 s −1 forM1 . Abstract : Block party : The use of phosphorescent building blocks in self‐assembly provides access to emissive metallacycles, the properties of which are enhanced relative to parent donors and acceptors. This strategy reverses the role of the heavy atom effect present in metallacycles to boost rather than attenuate emission intensity.