购彩中心

题目：Dynamic Electron Delocalization and Spin-Spin Interactions in Redox-Active Organic Polygons
报告人：Yilei Wu 博士 美国斯坦福大学化学工程系
时间：2019年1月2日（周三）上午10：00 
地点：化学A楼518会议室
邀请人：颜徐州 研究员

报告人介绍：

Yilei Wu is currently a postdoctoral research fellow in Zhenan Bao’s group at Stanford University. He was born in Zhejiang, China, but grew up in Perugia, Italy. In 2012 he moved to USA where he obtained PhD in chemistry (2017) at Northwestern University (NU), under direction of Professor Michael Wasielewski and Professor Fraser Stoddart (2016 Nobel Laureate in Chemistry), working in the fields of organic electronics, spintronics, solar energy conversion and artificial molecular machines. Yilei has co-authored over 42 publications including 22 JACS, 3 ACIE, 1 Nature Chem., 1 PNAS, 1 Adv. Energy Mater. etc. and is recipient of numerous awards and fellowships including a U.S.-Italy Fulbright Fellowship, a NU Ryan Fellowship, a NU Presidential Fellowship nomination and a UK Engineering and Physical Sciences Research Council (EPSRC) Studentship. 


报告内容介绍：

My research interests, which span organic, inorganic, physical and biochemistry, have focused broadly on photo- and redox-active molecules, especially those involving organic electronics, photovoltaics and spintronics, as well as molecular recognition and fluorescence imaging.[1-9] My PhD research under the joint supervision of Professor Wasielewski and Professor Fraser Stoddart has concentrated upon understanding electronic and magnetic coupling among multiple chromophoric and redox units in rigid and well-defined molecular architectures. We have reported on the synthesis, characterization and application of a series of chiral shape-persistent macrocycles comprising two, three and four equivalent rylene diimide units. We have investigated how the molecular geometry of redox-active diimides within these molecular “polygons” affects the physical properties associated with (i) through-space electron sharing, (ii) excited-state dynamics, (iii) spin-spin coupling, (iv) their cooperative solid-state packing and (v) their unusual redox behavior. These investigations demonstrated the potential of shape-persistent diimides-based macrocycles to carry out long distance electron transport required for organic electronics and photovoltaics applications. Moreover, we also studied the role of electron sharing on photoinduced electron transfer reactions, and the related spin coherence transfer dynamics, by utilizing these macrocycles as electron acceptors. Specifically, we have shown that the rapid electron hopping in photogenerated radical pair can shorten the spin coherence lifetime by mean of time-resolved optical, vibrational and electron paramagnetic resonance spectroscopies.[9] In order to furthers my understanding of charge and spin transport in organic materials I have joined Professor Zhenan Bao’s group at Stanford University as a postdoctoral fellow. I am currently working on structure-property relationships in organic semiconductors and their application in flexible electronics and photovoltaics.


References
(1) Wu, Y.; Frasconi, M.; Gardner, D. M.; McGonigal, P. R.; Schneebeli, S.T.; Wasielewski, M. R.; Stoddart, J. F. ‟Electron Delocalization in a Rigid Cofacial Naphthalene-1,8:4,5-bis(dicarboximide) Dimer.” Angew. Chem. Int. Ed. 2014, 53, 9476–9481.
(2) Wu, Y.; Nalluri, S. K. N.; Young, R. M.; Krzyaniak, M. D.; Margulies, E. A.; Stoddart, J. F.; Wasielewski, M. R. “Charge and Spin Transport in an Organic Molecular Square.” Angew. Chem. Int. Ed. 2015, 54, 119771–11977.
(3) Wu, Y.; Shi, R.; Wu, Y.-L.; Holcroft, J. M.; Liu, Z.; Frasconi, M.; Wasielewski, M. R.; Li, H.; Stoddart, J. F. ‟Encapsulation of Polyoxometalates with Cyclodextrins.” J. Am. Chem. Soc. 2015, 137, 4111–4118.
(4) Wu, Y.; Young, R. M.; Frasconi, M.; Schneebeli, S. T.; Spenst, P.; Gardner, D. M.; Brown, K. E.; Würthner, F.; Stoddart, J. F.; Wasielewski, M. R. “Ultrafast Photoinduced Symmetry-Breaking Charge Separation and Electron Sharing in Perylenediimide Molecular Triangles.” J. Am. Chem. Soc. 2015, 137, 13236–13239.
(5) Wu, Y.; Krzyaniak, M. D.; Stoddart, J. F.; Wasielewski, M. R. “Spin Frustration in the Triradical Trianion of a Naphthalenediimide Molecular Triangle.” J. Am. Chem. Soc. 2017, 139, 2948–2951.
(6) Wu, Y.; Zhou, J.; Phelan, B. T.; Mauck, C. M.; Stoddart, J. F.; Young, R. M.; Wasielewski, M. R. “Probing Distance Dependent Charge-Transfer Character in Excimers of Extended Viologen Cyclophanes using Femtosecond Vibrational Spectroscopy.” J. Am. Chem. Soc. 2017, 139, 14265–14276.
(7) Wu, Y.; Han, J.-M.; Hong, M.; Krzyaniak, M. D.; Blackburn, A. K.; Fernando, I. R.; Cao, D. D.; Wasielewski, M. R.; Stoddart, J. F. “X-Shaped Oligomeric Pyromellitimide Polyradicals.” J. Am. Chem. Soc. 2018, 140, 515–523.
(8) Wu, Y.; Zhou, J.; Nelson, J. N.; Young, R. M.; Krzyaniak, M. D.; Wasielewski, M. R. “Covalent Radical Pairs as Spin Qubits: Influence of Rapid Electron Motion between Two Equivalent Sites on Spin Coherence.” J. Am. Chem. Soc. 2018, 140, 13011–13021.