Design Strategies for Luminescent Titanocenes
Abstract: Complexes of d0 transition metals with photoactive ligand-to-metal charge-transfer (LMCT) excited states have recently shown significant promise as photocatalysts involving earth-abundant metals. Arylethynyltitanocenes of the type Cp2Ti(C2R)2 (where R = ferrocene or an aryl substituent) have recently been investigated for their C2R-to-TiIV LMCT states. The first example of a TiIV complex with an emissive (FP ~ 10–4) ligand-to-TiIV LMCT state in RT fluid solution is Cp2Ti(C2Ph)2. However, this complex undergoes photodecomposition with a high quantum yield (Frxn = 0.99). Coordination of CuX between the alkyne ligands to give Cp2Ti(C2Ph)2CuX (X = Cl or Br) has been shown to significantly increase the photostability, but such complexes are not emissive in RT solution. The mechanisms for photodecomposition and nonradiative decay have been investigated and have led to design strategies for luminescent titanocenes. Based on these strategies, we have developed titanocenes with increased photostability, and whose luminescence is visible to the naked eye in room-temperature fluid solution.
Bio: Paul obtained his B.S. in Chemistry from Furman University in 1986 and his Ph. D. from Stanford University in 1991. Following postdoctoral studies at Colorado State University, he accepted a one-year adjunct teaching position at Occidental College in Los Angeles before beginning a tenure track position at San Jose State University in 1996. In 2004, he moved back to his alma mater, Furman University. Over his career, he has secured nearly $3 million in external funding for support of undergraduate research in his group and the chemistry department. Since beginning his independent career with undergraduate researchers, he has published nearly 40 peer-reviewed research articles (mostly with undergraduate coauthors) and two patents. He is the recipient of the Henry Dreyfus Teacher-Scholar Award (2003), the South Carolina Governor’s Award for Excellence in Scientific Research (2020), and the Council on Undergraduate Research ChemCUR Outstanding Mentorship Award (2022). When not in the classroom or laboratory, he enjoys competing on the tennis courts, honing his BBQ skills, and trying to learn guitar.