October 27, 2017
ACS South Texas Local Section
Friday, October 27, 2017
Qiang Zhang, Ph.D.
Department of Chemistry, Washington State University
Presentation: Aggregation Induced Emission Red-Shift of E/Z Isomers
Luminescent molecules and materials have been extensively studied in the past decade's thanks to their tunable emission colours and applications in sensing, imaging, and lighting. Within this family, the systems that exhibit aggregation induced emission (AIE) or aggregation-induced emission enhancement (AIEE) behavior have attracted a considerable amount of attention due to the highly emissive nature of their solids. Molecules of AIE type are promising candidates for fabricating devices. Numbers of AIE molecules have been reported in the past, among which tetraphenylethene (TPE) based molecules have been comprehensively studied. The applications of such materials have been focusing on imaging, sensing and lighting owing to their high quantum efficiency nature at aggregated state. In most of these cases, highly symmetric tetra- substituted TPE molecules, on the para positions of the phenyl rings, are used as the starting materials. Disubstituted TPE molecules are usually used as E/Z mixtures, as the separation of isomers is difficult. We have recently discovered two TPE based E/Z isomers with two cyanide functional groups on two of the four para-positions of the phenyls. Interestingly, both isomers exhibit a unique aggregation induced emission red-shift (AIERS) phenomena instead of conventional aggregation induced emission. DFT calculations have been explored to further understand the mechanism. It’s revealed that the orbitals of LUMO for both isomersare primarily located on the cyanide substituted rings due to the electron withdrawing nature of -CN groups. Both isomers, in their aggregated states, have been used as chemosensors for nitroaromatic compounds which serve as a model for explosives. Interestingly, the cis- and trans-isomers show distinct sensitivity in the detection of nitrobenzene.
Meeting Location: STC Pecan Campus- Build H- cafeteria
Order of Events:
Social: 6:00-6:30 P.M. Building H (cafeteria)
Dinner: 6:30-7:20 P.M. Building H (cafeteria)
Speaker: 7:30-8:30 P.M. Building H (cafeteria)
Menu: Beef or Cheese Chile Rellenos, rice and beans
Students & Teachers $5.00 - (only if you are going for the dinner)
Reservations: RSVP only if you want to eat dinner at (956)207-9376 or firstname.lastname@example.org by Wednesday, October 25 at noon.
Bio: Dr. Qiang Zhang obtained his BS degree from Jilin University China in Chemistry in 2008. He then joint Prof. Richard D. Adams research group at the University of South Carolina, Columbia. His Ph. D. work was focused on the design and synthesis of transition metal cluster complexes and use them as models for the study of heterogeneous catalysis. He was the winner of a couple awards in graduate school, including IPMI (International Precious Metal Institute) Metro New York Chapter Award, the Guy F. Lipscomb Award for the Best Graduate Student, and Summer Dissertation Fellowship. He published 20 peer-reviewed publications upon graduation in 2013. After received his Ph.D. degree, Dr. Zhang moved to College Station, Texas and started working with Prof. Hong-Cai Zhou as a postdoctoral researcher in the Department of Chemistry Texas A&M University. Dr. Zhang’s postdoc research was centered on the design and construction of Metal–Organic Frameworks (MOFs) and Metal–Organic Polyhedra (MOPs) for the applications in energy storage, sensing, and catalysis. In 2016, Dr. Zhang started his independent career as an assistant professor in the Department of Chemistry at Washington State University. The current research of Zhang group is focusing on small molecules, nanomaterials and porous materials for applications in catalysis, luminescence, and sensing.