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Published on: October 10, 2018
The influence of charge transfer on the emissive properties of pyridine dipyrrolide bismuth complexes
Katharina L Deuter1, Katharina Vollmar1, Jan Rieser1
1Faculty for Chemistry, University of Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany. rainer.winter@uni-konstanz.de.
Abstract:
We report on the emissive properties of four new pyridine dipyrrolide bismuth complexes Bi(R1PDPR2)Br, modified with electron-donating (-OMe) or electron-withdrawing (-CF3) substituents at the ligand. These complexes exhibit red phosphorescence at cryogenic temperatures with emission wavelengths ranging from 602 to 642 nm as a response to the electronic character of the substituents R1 and R2. A profound similarity between the pairs Bi(CF3PDPCF3)Br and Bi(CF3PDPOMe)Br, and Bi(OMePDPCF3)Br and Bi(OMePDPOMe)Br is attributed to improved conjugation between the respective phenyl ring and the PDP core, as based on TD-DFT calculations and crystallographic studies. The larger quantum yield of Bi(CF3PDPCF3)Br is attributed to the enhancement of the 3LMCT character of the electronic transition through the introduction of the electron-withdrawing -CF3 substituents.
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