ANALYSIS OF LOW DIMENSIONAL MAGNETIC SYSTEMS CONTAINING CHROMIUM(III) AND COBALT(II) LIGATED BY THE SQUARATE LIGAND: MAGNETIC CHARACTERIZATION, BIOLOGICAL CHARACTERIZATION, INSTRUMENTAL DEVELOPMENT, AND SOFTWARE DEVELOPMENT

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Description

A large series of Chromium(III) and Cobalt(II) complexes containing the C4O4 (squarate) ligand have been synthesized and characterized magnetically. These complexes include simple dimeric Cr(III) systems that display a wide range of isotropic exchange couplings. One of these dimers shows... Show moreA large series of Chromium(III) and Cobalt(II) complexes containing the C4O4 (squarate) ligand have been synthesized and characterized magnetically. These complexes include simple dimeric Cr(III) systems that display a wide range of isotropic exchange couplings. One of these dimers shows interesting biological activity pertaining to the cellular uptake of glucose. This same compound also enhanced proton relaxation in T1 and T2 NMR studies. Computational work done on these dimeric systems showed excellent agreement with experimental results, and was used to confirm the structure of the complexes. The effect of the bridging squarate ligand was also studied computationally. The squarate ligand significantly contributed to the exchange coupling in the dimeric systems, and was shown to behave countercomplementary to the μ-hydroxo bridges. This is the first explicit observation of countercomplementarity in Chromium(III) systems. Co3(OH)2(C4O4) · 3H2O, a cobalt chain structure featuring an interesting low temperature spin-idle phase, was also synthesized. It was found that based on storage conditions, this compound either stays stable after grinding or transforms into the structure Co(C4O4)(H2O)2. In addition, grinding the sample shows an out-of-phase maxima at ≥6 K that has a frequency dependence characteristic of a spin glass. A new software package was also developed to simulate Electron Paramagnetic Resonance (EPR) spectra using full numerical diagonalization of the secular equation. This program was written using Wolfram Mathematica, and holds several advantages over currently available software. These advantages include a graphical user-interface and parallelization capabilities
PH.D in Chemistry, July 2013 Show less

Details
Department

CHEM / Chemistry

Title

ANALYSIS OF LOW DIMENSIONAL MAGNETIC SYSTEMS CONTAINING CHROMIUM(III) AND COBALT(II) LIGATED BY THE SQUARATE LIGAND: MAGNETIC CHARACTERIZATION, BIOLOGICAL CHARACTERIZATION, INSTRUMENTAL DEVELOPMENT, AND SOFTWARE DEVELOPMENT

Institution

Illinois Institute of Technology

Creator(s)

Mcneely, James Halley

Advisor(s)

Cage, Brant

Date

2013
2013-07

Description

A large series of Chromium(III) and Cobalt(II) complexes containing the C4O4 (squarate) ligand have been synthesized and characterized magnetically. These complexes include simple dimeric Cr(III)... Show moreA large series of Chromium(III) and Cobalt(II) complexes containing the C4O4 (squarate) ligand have been synthesized and characterized magnetically. These complexes include simple dimeric Cr(III) systems that display a wide range of isotropic exchange couplings. One of these dimers shows interesting biological activity pertaining to the cellular uptake of glucose. This same compound also enhanced proton relaxation in T1 and T2 NMR studies. Computational work done on these dimeric systems showed excellent agreement with experimental results, and was used to confirm the structure of the complexes. The effect of the bridging squarate ligand was also studied computationally. The squarate ligand significantly contributed to the exchange coupling in the dimeric systems, and was shown to behave countercomplementary to the μ-hydroxo bridges. This is the first explicit observation of countercomplementarity in Chromium(III) systems. Co3(OH)2(C4O4) · 3H2O, a cobalt chain structure featuring an interesting low temperature spin-idle phase, was also synthesized. It was found that based on storage conditions, this compound either stays stable after grinding or transforms into the structure Co(C4O4)(H2O)2. In addition, grinding the sample shows an out-of-phase maxima at ≥6 K that has a frequency dependence characteristic of a spin glass. A new software package was also developed to simulate Electron Paramagnetic Resonance (EPR) spectra using full numerical diagonalization of the secular equation. This program was written using Wolfram Mathematica, and holds several advantages over currently available software. These advantages include a graphical user-interface and parallelization capabilities Show less

Type

Dissertation

File type

application/pdf

Access

Restricted Access

Rights

In Copyright
http://rightsstatements.org/page/InC/1.0/

Identifier

http://hdl.handle.net/10560/3177

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