April Meeting and Awards Banquet of the IN-KY Border Section
Our April Meeting and Annual Awards Banquet will be held on Thursday, April 24. Dinner will be at 5:30 PM (CDT) at Los Bravos West, 4630 West Lloyd Expressway, Evansville, IN. If you will be attending dinner at Los Bravos, please RSVP by Friday, April 18 to Bryan Lynch at chemwood12@icloud.com
Awards presentations will begin after dinner at 7:30 at the University of Southern Indiana in Forum 3 in the Wright Administration Building. Student awardees from local colleges and universities will be honored. We will also present the third annual Jeffery Seyler Service Award to Dr. Roslyn Lampkins, Associate Professor of Chemistry at the University of Evansville.
Following the awards presentations, Dr. Michael Turlington, Assistant Professor of Chemistry at the University of Evansville, will present “Tuning Transition Metal Excited-States through Noncovalent Interactions.”
Abstract:
The charge-transfer excited states of cyclometalated transition-metal complexes, particularly those of ruthenium and iridium, have been the subject of intense research based on their importance in solar energy conversion and storage, catalysis, and light emitting diode technologies. The visible charge-transfer transitions yield long-lived, photoluminescent excited states (hundreds of nanoseconds or greater) that store significant energy (~2 eV) as compared to the ground state. To tune the properties of such transition metal complexes, it has traditionally been necessary to synthesize new ligands that modulate the electron density at the ligand and metal center. However, recent work has indicated that noncovalent interactions with species such as counter ions and electrolyte can also impact the photophysical properties through electrostatic and hydrogen bonding interactions, among others. The majority of the work in this field relies on forming an assembly between an ion and the outer coordination sphere of the metal complex, which results in coulombic interactions that perturb the ground- and excited-state energies with some, albeit minimal (<0.10 eV) control. Herein, a series of ruthenium complexes are proposed that contain functional groups for supramolecular assembly on a cyclometalating ligand. The functional groups for anion assembly are expected to contribute significantly to the frontier orbitals, and direct contact between these orbitals and an assembled ion should maximize perturbations to the ground- and excited-state energies. Work completed to date in the preparation of these complexes, including the synthesis and characterization of precursor ligands, will be presented.