Chemistry and Chemical Biology ETDs

Publication Date

Summer 7-31-2024

Abstract

Organo-transition metal complexes are being widely studied to understand their photophysical properties for their wide range of applications as efficient emitters in organic light emitting diodes (OLEDs), light emitting electrochemical cells (LEECs), etc. Cyclometalated organo-transition metal complexes such as cyclometalated square planar platinum(II) complexes are becoming suitable candidates for such applications because of their highly efficient luminescence. Understanding the excited properties of such complexes is useful in designing highly efficient and color tunable phosphors with desired excited state lifetimes. We aim to explore the influence of radical substituents on electronic structure, luminescence quantum efficiencies, and excited state lifetimes by synthesizing new radical elaborated donor-acceptor molecular frameworks built on cyclometalated square planar platinum(II) dithiolate and catecholate complexes. The novel radical elaborated molecular frameworks are designed, synthesized, characterized, and studied by numerous spectroscopic and computational methods. This study has explored the effect of an appended radical substituent on the photophysical properties of cyclometalated platinum dithiolate and catecholate complexes with respect to how the S = ½ spin doublet radical interacts with the triplet chromophore and affects the excited state lifetimes through the addition of a new exchange interaction yielding a three-spin excited state manifold. The results of experiments on the cyclometalated platinum(II) dithiolate series with two different cyclometalating ligands showed that emissive properties of these radical substituted complexes are not lost. However, their emission lifetimes are decreased. The results of cyclometalated platinum(II) catecholate complexes demonstrated that their lifetimes are longer than that of the cyclometalated platinum(II) dithiolate series. The variation of the donors and acceptors in Donor-Acceptor Platinum(II) complexes were studied to explore their excited state properties.

Language

English

Keywords

Photoluminescence, Donor-Acceptor Complex, Platinum Complex

Document Type

Dissertation

Degree Name

Chemistry

Level of Degree

Doctoral

Department Name

Department of Chemistry and Chemical Biology

First Committee Member (Chair)

Martin L Kirk

Second Committee Member

Victor Acosta

Third Committee Member

Terefe Habteyes

Fourth Committee Member

Dongchang Chen

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