Immobilizing Tetraphenylethylene into Fused Metallacycles: Shape Effects on Fluorescence Emission.
Herein, we describe the selective formation of a discrete fused metallarhomboid and a triangle by the careful control of the shape and stoichiometry of the building blocks. A tetraphenylethylene (TPE)-based tetrapyridyl donor is exploited as the bridging component, and coordination immobilization of the TPE unit within the rigid metallacyclic frameworks efficiently suppresses its intramolecular rotational motions. As a result, the fused polygons are innately emissive in dilute solution, representing an alternative to aggregation-induced emission. Upon further molecular aggregation, these metallacycles display aggregation-induced enhanced emissions. Interestingly, the fused rhomboid 7 shows a weaker fluorescence in dilute solutions relative to that of the fused triangle 8, while a reversal of emission intensities was observed in the aggregated state. These markedly different fluorescence efficiencies are likely due to the differences in the shapes of the fused polygons. Thus, this work shows that the properties of supramolecular coordination complexes can be affected by subtle structural factors, which can be controlled easily and precisely at the molecular level.
Department of Chemistry, University of Utah , 315 South 1400 East, Room 2020, Salt Lake City, Utah 84112, United States.
Zhixuan
Z
Zhou
Department of Chemistry, University of Utah , 315 South 1400 East, Room 2020, Salt Lake City, Utah 84112, United States.
Xuzhou
X
Yan
Department of Chemistry, University of Utah , 315 South 1400 East, Room 2020, Salt Lake City, Utah 84112, United States.
Manik Lal
ML
Saha
Department of Chemistry, University of Utah , 315 South 1400 East, Room 2020, Salt Lake City, Utah 84112, United States.
Mingming
M
Zhang
Department of Chemistry and Biochemistry and Materials Science, Engineering, and Commercialization Program, Texas State University , San Marcos, Texas 78666, United States.
Ming
M
Wang
Department of Chemistry and Biochemistry and Materials Science, Engineering, and Commercialization Program, Texas State University , San Marcos, Texas 78666, United States.
Xiaopeng
X
Li
Department of Chemistry, University of Utah , 315 South 1400 East, Room 2020, Salt Lake City, Utah 84112, United States.
Peter J
PJ
Stang