On July 5, 2017, at the invitation of Professor Yang Guang,Professor Wu Wenfang visits the College of Life  And made an academic report titled  “Cationic Iridium(III) and Ruthenium(II) Complexes as Broadband Reverse Saturable Absorbers and/or in vitro Theranostic Photodynamic Therapy (PDT) Reagents”

      Iridium(III) and ruthenium(II) complexes with moderate ground-state absorption in the visible to the near-IR region, long-lived triplet excited states and strong triplet excited-state absorption, and near-IR emission are promising agents for broadband reverse saturable absorption (RSA) and photodynamic therapy as well as bioimaging.  The synthesis, photophysics, reverse saturable absorption, and in vitro photodynamic therapeutic effect and bioimaging of two series of cationic biscyclometalated Ir(III) complexes with extended p-conjugation on the diimine ligand and/or the cyclometalating ligands and one series of Ru(II) complexes with trisdiimine ligands are reported.  Most of the complexes possess moderate charge-transfer absorption bands between 400 and 600 nm; and these bands are extended to 800 nm when the p-conjugation of the cyclometalating ligands increases.  They are all emissive in the red to the NIR region in solutions at room temperature.  The nature and energies of the lowest singlet and emitting triplet excited states are primarily influenced by the degree of p-conjugation of the ligands.  Most of the complexes can generate singlet oxygen efficiently, and exhibit a photodynamic therapeutic effect upon visible or red light activation, with one of the Ir(III) complexes possessing the largest phototherapeutic index reported to date (> 400) for Ir(III) complexes upon white light activation.  Interactions with DNA suggest that other mechanism of action may be at play for the photosensitizing effect.  These complexes also produce strong intracellular luminescence that highlights their potential as theranostic PDT agents.  In addition, many of the complexes exhibit strong RSA for ns laser pulses at 532 nm, and the RSA performance is influenced by the nature of the diimine and/or cyclometalating ligands.

      Prof. Wenfang Sun is the James Meier Senior Professor and the Water F. and Verna Gehrts Presidential Professor at the Department of Chemistry and Biochemistry, North Dakota State University (NDSU).  She received her B.S. degree in 1990 from Wuhan University, China; and her Ph.D. degree in Organic Chemistry from the Institute of Photographic Chemistry, Chinese Academy of Sciences in 1995.  She was employed by this institute as an Assistant Professor in 1995, and then as an Associate Professor in 1996. She joined the Department of Physics, University of Alabama at Birmingham as a Postdoctoral Research Associate in 1997, and was promoted to a Research Assistant Professor in 1999.  In 2001, she joined NDSU as an Assistant Professor, was tenured and promoted to an Associate Professor in 2007, and became a Full Professor and named the Walter F. and Verna Gehrts Professor in 2011. She has published 112 peer-reviewed journal papers and 23 conference full papers.  She obtained over $7,000,000 research grants from NSF, the US Army Research Laboratory, ACS-PRF, USDA, etc.  She received numerious awards, including the NSF CAREER Award (2005-2011), the James A. Meier Senior Professorship (2016), the NDSU Fred Waldron Award for Outstanding Research (2012), the NDSU Walter F. and Verna Gehrts Professorship (2011), the NDSU Bison Ambassadors Apple Polisher Honoree (2009), the NDSU Featured Faculty (2006), and the 2^nd-Class Chinese Academy of Sciences Natural Science Award (2002).  She organized/co-organized, or chaired more than 10 national or international symposiums and presented ~100 invited talks or seminar at conferences and universities.  Currently, she serves on the editorial board of five international chemistry journals.  Her research program covers the organic/organometallic nonlinear optical materials, organic/organometallic light emitting materials, photosensitizers for photodynamic therapy, and optical sensors.