Title

The Design, Syntheses, and Photophysics of Novel Pt(II) Polypyridyl Arylacetylides and Arylthiolates

Date of Award

2012

Document Type

Dissertation

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Photochemical Sciences

First Advisor

Felix Castellano, PhD

Second Advisor

Michael Geusz, PhD

Third Advisor

John Cable, PhD

Fourth Advisor

Pavel Anzenbacher, PhD

Abstract

Herein, the approach towards the modulation of the distinct excited states in Pt(¿¿¿¿¿¿¿¿¿¿) complexes through careful consideration of the nature of the coordination sphere and solvent environment was successfully realized. The developed variety of Pt(¿¿¿¿¿¿¿¿¿¿) polypyridyl arylacetylide complexes possessed the desired dark and emissive charge-transfer or ligand-localized excited states, depending on the nature of ligands. The photophysical properties were studied in detail by UV-Vis absorption spectroscopy, steady-state and time resolved photoluminescence methods (gate pulsing, pulse sampling, and time-correlated single photon counting) in the solutions and glasses. The excited states of compounds, lacking emission from their lowest triplet state, were effectively studied using nanosecond transient absorption spectroscopy together with time-resolved step-scan FT-IR. The analogous DFT calculations showed an excellent agreement with experiment and provided the insights into the frontier orbitals and ultimately the origins of the vibrations in the ground and excited states.

Additionally, the bidentate coordination of terpyridyl in Pt(¿¿¿¿¿¿¿¿¿¿) arylthiolates was studied by the array of static and dynamic spectroscopic methods in combination with electrochemistry. The resulting data unveiled that the Pt(II) terpyridyl bisarylthoilates, where terpyridyl acts as a bidentate chelate, resembles charge-transfer photophysics of Pt(II) bipyridyl arylthiolate rather than Pt(II) terpyridyl arythiolate, where terpyridyl acts as tridentate ligand.

The fine control of the rich photophysical properties of the reported Pt(II) polypyridyl complexes makes them good candidates for a variety of applications, especially in energy related areas.