Metalloenzymes catalyze remarkable reactions in Nature using transition metal ions. Common earth-abundant metals like copper, iron, zinc, and magnesium catalyze reactions that are the basis of life. These metal sites lend their chemistries to facilitate these reactions, making studying the structure and properties important in understanding the enzymes' abilities and...
The invention of GdIII-based magnetic resonance imaging (MRI) probes substantially expanded the capability of MRI in visualizing details in tissue. Building upon the achievement of GdIII-based complexes, more ideal probes should feature contrast that is responsive to biomarkers, such as redox status and ion concentrations. The abnormality of these biomarkers...
Contained in the following dissertation are detailed investigations regarding the thermodynamics of small molecule activation by metalloporphyrin complexes isolated within metal-organic frameworks (MOFs). Chapter 1 provides a description of the role metalloporphyrin complexes play in biological systems and the challenges associated with studying small molecule activation by metalloporphryin sites in...
Many metal ions are of critical importance in many cellular functions. The very properties of these metal ions that make them useful also make them toxic to the cell. In the course of evolution, many metal ion homeostasis systems have developed to provide balance between the necessity and toxicity of...
Magnetic Resonance Imaging is a non-invasive modality that allows for deep-tissue imaging. Contrast agents decrease image acquisition time and increase the intrinsic contrast between different types of tissue. A new family of enzyme-activated contrast agents is emerging that has the ability to report on enzymatic processes in vivo. Towards this...
Polyvalent oligonucleotide functionalized gold nanoparticle conjugates (DNA-AuNPs) possess unusual properties, which derive from their particle and oligonucleotide subunits as well as their three-dimensional architectures. This dissertation explores the role each chemical component plays in the conjugate's architecture and assembly and recognition capabilities. It also describes their application as probes in...
My thesis focuses on the design and synthesis of lanthanide coordination complexes as Zn(II)-responsive magnetic resonance imaging (MRI) contrast agents. These agents produce an increase in MR intensity upon binding of Zn(II) through water modulation to Gd(III) chelates. To this end, several Zn(II)-responsive contrast agents have been synthesized and studied...
The early transition metal oxide fluoride molecular anions with the general formula [MOxF6-x]n- with x = 1 for M = V5+, Nb5+, Ta5+ (n = 2) and x = 2 for M = Mo6+, W6+ (n = 2) feature distorted octahedral coordinations, that arise from electronic dπ pπ metal oxide...
Copper serves as a cofactor for many proteins and enzymes involved in important biological processes, but at the same time, excessive copper is toxic to cell. Thus, the intracellular copper concentration must be tightly controlled such that copper is provided to essential enzymes but does not accumulate to toxic levels....
Chapter 1 describes the homopolymerization of styrene and the copolymerization of ethylene and styrenic comonomers mediated by the single-site bimetallic "constrained geometry catalysts" (CGCs), (µ-CH2CH2-3,3'){(η5-indenyl)[1-Me2Si(tBuN)](TiMe2)}2 [EBICGC(TiMe2)2; Ti2], (µ-CH2CH2-3,3'){(η5-indenyl)[1-Me2Si(tBuN)](ZrMe2)}2 [EBICGC(ZrMe2)2; Zr2], (µ-CH2-3,3'){(η5-indenyl)[1-Me2Si(tBuN)](TiMe2)}2 [MBICGC(TiMe2)2; C1-Ti2], and (µ-CH2-3,3'){(η5-indenyl)[1-Me2Si(tBuN)](ZrMe2)}2 [MBICGC(ZrMe2)2; C1-Zr2], in combination with the borate activator/cocatalyst Ph3C+B(C6F5)4- (B1). Under identical styrene homopolymerization conditions,...