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Square planar d8 metal complexes with nitrogen-based ligands: structural analysis, metal-metal cooperativity, and applications

Ringo, Jessica M
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1562842509907911

Abstract Details

2019, PhD, University of Cincinnati, Arts and Sciences: Chemistry.
This dissertation focuses on square planar platinum (II) and palladium (II) complexes. Specifically, complexes bearing the 1,4,7-trithiacyclononane ligand were examined to identify a structure correlation. The reducing capacity of thiols was explored by electrochemical methods using a mercury thin film electrode and spectroscopically via UV-visible absorption spectroscopy using a platinum dye upon reaction with thiol. Mononuclear, dinuclear, and trinuclear platinum and palladium macrocyclic complexes were synthesized and characterized. An educational workshop for students entering ninth grade is presented using platinum sensors from ongoing research projects. A search of the Cambridge Structural Database was conducted for platinum and palladium structures containing 1,4,7-trithiacyclononane. These structures were analyzed using a variety of methods to determine a structure correlation. They were plotted along the Berry pseudorotation coordinate, the percent deviation from ideal square pyramidal and trigonal bipyramidal geometries was calculated, and t5 values were calculated. This indicated that most structures lie in the square pyramidal region, with more palladium structures closer to trigonal bipyramidal. It was found that the donor or acceptor properties of the ancillary ligands influence the interaction between metal and axial sulfur. The palladium structures show interesting results. When plotted along the platinum trendline, it becomes apparent that most of the palladium structures lie above the platinum trendline. This suggests that for a given M•••Sax distance, the palladium atom undergoes a greater displacement from the plane. This may be a result of the palladium structures having a shallower potential energy surface along the square pyramidal distortion coordinate. To streamline the evaluation of candidate reagents to identify targets for hair care applications, strategies were developed for assessing the reducing properties of thiols. The electrochemical techniques used at the mercury thin film electrode include cyclic voltammetry, differential pulse voltammetry, and differential stripping pulse voltammetry. These techniques do not always give completely reversible results, and show multiple anodic waves in some cases, causing interpretation to be challenging. Another method used was indirect measure of the reducing properties of the thiol by observing the absorbance maximum (?max) of a charge transfer (CT) band for the platinum-thiolate complex. The synthesis and characterization of platinum and palladium complexes with an azamacrocyclic ligand, bis-para-xylylBISDIEN, are reported. This ligand was chosen for its ability to incorporate two metal centers so that dinuclear complexes could be synthesized for multi-electron transfer purposes. Five complexes using this ligand are reported, including the first mononuclear complexes of this architecture. A workshop for students entering ninth grade is presented with the goal of engaging them with real research projects. The structure of the workshop was discovery-based, using worksheets with leading questions instead of traditional directions. Students were given the freedom to design a sensor or experiments to answer a research question that had arisen during the week. This workshop showed that students do not need a considerable scientific background to engage in scientific activities and be able to learn and enjoy science.
Hairong Guan, Ph.D. (Committee Chair)
Michael Baldwin, Ph.D. (Committee Member)
William Heineman, Ph.D. (Committee Member)
Daniel Waddell, Ph.D. (Committee Member)
162 p.
Chemistry
platinum,sensors

Recommended Citations

Citations

  • Ringo, J. M. (2019). Square planar d8 metal complexes with nitrogen-based ligands: structural analysis, metal-metal cooperativity, and applications [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1562842509907911

    APA Style (7th edition)

  • Ringo, Jessica. Square planar d8 metal complexes with nitrogen-based ligands: structural analysis, metal-metal cooperativity, and applications. 2019. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1562842509907911.

    MLA Style (8th edition)

  • Ringo, Jessica. "Square planar d8 metal complexes with nitrogen-based ligands: structural analysis, metal-metal cooperativity, and applications." Doctoral dissertation, University of Cincinnati, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1562842509907911

    Chicago Manual of Style (17th edition)

ucin1562842509907911
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© 2019, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.