Term of Award

Spring 2018

Degree Name

Master of Science in Applied Physical Science (M.S.)

Document Type and Release Option

Thesis (open access)

Copyright Statement / License for Reuse

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Department

Department of Chemistry

Committee Chair

Arpita Saha

Committee Member 1

Michele McGibony

Committee Member 2

Jeff Orvis

Abstract

Manganese carboxylate complexes have been well studied in the past, due to their relevance in bioinorganic chemistry and as well as their behavior as nanoscale magnetic materials that is called single-molecule magnets (SMMs). SMMs are special class of magnetic materials in which magnetism is intrinsic to the molecule. Polynuclear manganese clusters often possess high spin ground states as well as large and negative magnetoanisotropy, a combination which leads to an energy barrier for the reversal of the magnetization direction. The paramagnetic nature of manganese at its common oxidation states with an ample number of unpaired electrons often leads to high-nuclearity clusters. These polymetallic coordination complexes are also known for their architectural beauty and symmetry. SMMs are particularly interesting because they have several potential applications in the future such as high-density memory storage, quantum computations, magnetic refrigeration and so on. SMMs have diagnostic features and can be characterized experimentally by the observation of frequency-dependent out-of-phase (χ") signals in ac magnetic susceptibility measurements, and hysteresis loops in the magnetization vs dc field scans. Since the initial discovery of the [Mn12] family of SMMs, a number of different structural types have been discovered. The synthesis of such polynuclear metal clusters involves the incorporation of multiple metal ions supported by organic ligands. In this regard, alkoxide-based ligands play a pivotal role since this functionality is an excellent bridging group that fosters higher nuclearity product formation. Our research focuses on the initial investigation of new synthetic methods, combining rarely explored alkoxide-based ligands with various carboxylates in Mn coordination chemistry. In this regard, potentially bidentate (N, O), 2- hydroxymethyl pyridine and potentially tridentate (N, O, O), 4,5-bis(hydroxymethyl)-2-methylpyridin-3-ol ligand have been used. Herein, the synthesis, crystal structure (single crystal X-Ray), elemental and magnetic analysis, thermogravimetric analysis, and spectroscopic (IR, UV-Vis, and 1H NMR) characterizations of four polynuclear Mnx (x = 3, 4, 6, & 7) complexes will be discussed.

Research Data and Supplementary Material

Yes

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