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theses

After the initial development of pincer complexes in the 1960’s, a significant amount of research has been placed into the understanding and applications of pincer complexes. To this day, new applications of pincer-ligated complexes are being discovered. While most commonly used in catalysis, recently pincer-ligated complexes have expanded to other fields, such organic light-emitting devices (OLEDs). This thesis will focus on the synthesis of several pincer-ligated complexes and their application towards dehydrogenation, nitrogen reduction, and OLEDs.
Synthesis of the reported Nishibayashi molybdenum-dimer, the (tBuPNP)MoNCl, and the (tBuPPP)MoNCl complexes were attempted for use in electrochemical nitrogen reduction. Due to the ability of the Nishibayashi complexes to reduce dinitrogen to ammonia chemically, we synthesized them in attempt to do the reduction electrochemically instead. In addition, synthesis of (tBuPPP)RuNCl and (tBuPPP)ReNCl complexes were attempted for comparison to the molybdenum analogue. Lastly, we attempted to synthesize a pyrene-PNP ligand for potential ligand-electrode interactions. After the attempt reported here, the pyrene-PNP ligand was successful synthesized by a different route in our laboratory.
After DFT calculations and experiments showed that ruthenium was not a good choice for nitrogen reduction, the (tBuPPP)Ru complex was then considered for dehydrogenation work. Several new (tBuPPP)Ru complexes were synthesized and characterized via NMR. Preliminary studies have shown that the (tBuPPP)RuH4 complex is an effective catalyst for alcohol dehydrogenation and has good potential for alkane dehydrogenation as well.
Another aspect of dehydrogenation work is the acceptor that is used during catalysis. With the goal of doing dehydrogenation electrochemically, benzoquinone was chosen as a potential acceptor. The interactions of benzoquinone, and several benzoquinone derivatives, with (tBuPCP)IrH2/H4 were studied. It was observed that quinones are extremely efficient hydrogen acceptors; however, the excess quinone can then strongly bind to iridium, inhibiting any alkane dehydrogenation. We were able to achieve a slow production of ketone from alcohol dehydrogenation, showing that, while strong, the quinone-metal bond can be broken, allowing catalysis.
While (tBuPCP)Ir complexes are extremely well known in the literature for catalysis, their photoluminescence is not usually considered. Several different (tBuPCP)Ir complexes with polycyclic aromatic ligands were studied for their photoluminescence. By making small variations on the polycyclic ligand, we were able to observe the effects these variations had on the emission wavelength. Additionally, each complex was mixed with polymethylmethacrylate (PMMA) and spin coated on a glass surface to examine their performance and lifetime in the solid state, as they would be in an OLED.

ETD_9424

Ph.D.

Includes bibliographical references

by Andrea Frances Koslow Casuras

doi:10.7282/t3-w1wa-r746

ETD doctoral

The author owns the copyright to this work.