When attached to another species (e.g. a nanoparticle), the sequence specificity of DNA can be repurposed to program interactions between such entities and to direct their formation into ordered structures. The research presented in this thesis aims to push the boundaries of structures that can be made via this approach....
Polyolefins are the most versatile and widely used polymers worldwide. Depending on the polymer microstructure, polyolefins can exhibit a wide range of useful and tailored properties and applications. Metal-catalyzed coordinative olefin polymerization plays a center role in advancing polyolefin synthesis. This dissertation explores two strategies to modulate the polymer microstructures...
This work examines important heterogeneous processes of organic molecules on surfaces, in the contexts of atmospheric and indoor environments. In large forest ecosystems, biogenic secondary organic aerosols (SOAs) constitute a dominant fraction of organic particulate matter in the atmosphere. The formation of SOAs starts from the emission of volatile organic...
The discovery of abundant reserves of shale gas over this past decade has reshaped the world’s energy landscape. It has renewed interests in the activation and conversion of methane as well as other light alkanes. While the oxidative coupling of methane (OCM) and oxidative dehydrogenation (ODH) of ethane and propane...
Recent advances in combinatorial chemistry, synthetic biology, and ‘omics’ research require high-throughput methods for performing and analyzing thousands to millions of reactions in one day. However, it is a challenge to engineer high-throughput systems that can autonomously conduct and analyze such a large number of reactions in a generalizable and...
The effective capture and detoxification of chemical warfare agents (CWAs) is a pressing need in the modern world. Materials are needed for both the destruction of weapon stockpiles and personal protection via fabric coatings or respirators. Attractive candidates for these applications include metal–organic frameworks (MOFs) – highly crystalline materials composed...
Self-Assembled Monolayers for MALDI-TOF Mass Spectrometry (SAMDI-MS) is a technique that combines self-assembling molecules of alkane disulfides on gold and MALDI-TOF mass spectrometry. By using well-defined monolayers with functionalizations that both prevent non-specific adsorption onto the surface and presents immobilization handles, it is possible to pull out analytes of interest,...
Despite prevention and treatment, substantial risk for cardiovascular disease(CVD) remains in the population and CVD has been the leading global cause-of-death in past years.While high-density lipoprotein (HDL) markers such as HDL cholesterol (HDL-C) and HDL efflux (a cholesterol-transport-function assay) are associated with decreased risk of CVD, the mechanism of this...
Extensive study of nanomaterial chemical and optical properties has enabled their integration into a variety of applications. However, less thoroughly investigated are the heat generation and dissipation processes of nanomaterials following optical excitation. These phenomena are of immense importance as thermal energy can distort a material’s structure, which has profound...
In this thesis, I present the development and benchmarking of several theoretical methods designed to enable the rigorous modeling of magnetic properties of molecules containing one or a few heavy atoms, particularly single-molecule magnets. The new methods use a full four-component treatment of relativity, allowing spin–orbit effects to be taken...
Many transcription factors (TFs) regulate oncogenic processes and are therefore desirable targets for drug intervention. However, few TF inhibitors have been developed to date due to a lack of specificity and few TF binding pockets. The Meade Lab has overcome these challenges by using cobalt-based complexes that disrupt Cys2His2 zinc...
Organic chromophores show great promise for energy and optoelectronic devices, due to their synthetic tunability and low production costs. In order to achieve this potential, their fundamental photophysical processes must be better understood. It has long been documented that chromophore packing at the molecular level has dramatic effect on electronic...
Natural gas is likely to become one of the main sources of carbon-based chemicals in the next century due to rapidly increasing natural gas production levels. This has created new incentives to find materials that are active and selective towards alkane partial oxidation reactions that are relevant for natural gas...
This work combines the use of high-throughput mass spectrometry with peptide arrays for to monitor reactions on peptides. The Mrksich lab introduced a high-throughput, label-free, biochemical assay that relies on self-assembled monolayers on gold and matrix-assisted laser desorption/ionization mass spectrometry, termed SAMDI-MS. This dissertation introduces new applications of SAMDI-MS and...
It is said across numerous disciplines, from biology to architecture to software engineering, that “form ever follows function.” This adage highlights the intimate relationship between structural characteristics and functional properties in many disparate fields of work. Here, we discuss how the catalytic activity and compressibility of metal–organic frameworks (MOFs) are...
Molecular-oriented single-site heterogeneous catalysis is a powerful approach to address the long-lasting challenge of the structure-activity relationship in catalysis, as it allows molecular level control of the catalytic centers and thus the elucidation of reaction mechanisms. In this dissertation, single-site molybdenum-dioxo species have been immobilized on carbon supports, i.e. activated...
Hybrid Organic-inorganic halide perovskites are emerging semiconducting materials that have shown over 23% in power conversion efficiency (PCE) for solar cells. The most prominent materials, three-dimensional (3D) perovskites, have limited scope for structural engineering and exhibit instability when encounter with moisture and heat. Here, we focus on studying the structure-property...
Molecules are highly social: they recognize one another and form bonds with those they are attracted to and repel those they are not. Some molecules establish strong bonds, while others form weak, transient associations. These interactions are ubiquitous in Nature and are integral to life. For at the basis of...
This dissertation seeks to explore how physical forces, notably through the use of magnetic nanoparticles and applied fields, can influence the structural outcomes of colloidal crystals engineered with DNA. Chapter 1 describes how both DNA and magnetic fields can direct the assembly of nanoparticles into periodic and sometimes crystalline materials....
Deciphering the targets of axonal projections plays a pivotal role in interpreting neuronal function and pathology. Neuronal tracers are indispensable neurobiology tools for elucidating advanced functions and interactions between different subregions of the brain. Commercially available neuronal tracers include small molecule dyes, viruses, and synthetic nanoparticles. Among these options, viral...
The mammalian oocyte undergoes large fluctuations in zinc content as it matures from a prophase I arrested oocyte to a metaphase II egg and finally is fertilized to become a zygote. These changes in total zinc content are necessary for proper progression, as disruption to egg’s ability to acquire and...
Among the most valuable applications of organometallic chemistry is its implementation in the field of catalysis. Many industrial processes rely heavily on catalysis, employing organometallic complexes in the production of commodity chemicals, fine chemicals, materials, and even in the discovery and development of pharmaceuticals. Through decades of intense study, homogeneous...
The Controlled, Site-Isolated Synthesis of Polyelemental Nanostructures in Polymer Nanoreactors Pengcheng Chen Polyelemental nanoparticles are an attractive class of materials due to their potential applications, which span the fields of catalysis, plasmonics, electronics, magnetics, targeted drug delivery, and bio-imaging. However, conventional synthetic methods for such structures are limited, especially when...
Self-assembled monolayers for matrix-assisted laser desorption/ionization mass spectrometry (SAMDI-MS) is a platform that combines self-assembled monolayers of alkanethiolates on gold and MALDI mass spectrometry analysis to report mass changes resulting from surface reactions. The synthetic flexibility of the monolayer and the use of mass spectrometry as a generalizable readout method...
Noble metal nanoparticles (NPs) have shown promise as imaging agents, drug delivery platforms, and plasmonic sensors. Anisotropic gold NPs, such as gold nanostars, have particularly received attention due to their shape-dependent optical and spectral properties. With their 3D anisotropic structure with branches protruding into different directions and high surface areas,...
Organic semiconductors have shown great promise for optoelectronic applications, particularly solar photovoltaics. Critical to their success is the ability to understand and manipulate the relationship between molecular structure and bulk properties. Substantial progress on understanding structural influences on electronic properties has been made for the conjugated polymers and small molecules...
Organic semiconductors are an active area of research with great promise for delivering next generation electronics and clean energy technologies. As the field matures, understanding the connection between molecular structure, materials’ properties, and device performance will be critical in finding the right material for an intended application. An effective strategy...
Continuous and coordinated materials discovery efforts have amassed a wealth of knowledge concerning many general classes of materials. The number of known phases of all structure-types, however, is far less than number of possible materials dictated by the elements on the periodic table. Recently, with improved computational abilities and well-developed...
Thermoelectric modules that convert heat into electrical energy are attractive for improving global energy management. This thesis reports the synthesis and characterization of two new families of lead and tin chalcogenide alloys and focuses on the impact of the grain boundaries, phase segregation, and atomic vacancies on the electronic and...
Peptides consists of a series of amino acids connected via an amide type of covalent chemical bond. A diverse field of applications such as biosensors,2 catalysis,4 and biomedicine6 include the oligomeric forms of peptides due to their genuine features comparing to other biomacromolecules. Particularly, peptides in the field of biomedical...
This dissertation describes investigations into the two primary mechanisms by which the optical bandgap of colloidal quantum dots (QDs) may be post-synthetically modified: (i) by the quantum-confined Stark effect and (ii) by exciton-delocalizing surface capping ligands. This work demonstrates that through the use of ligand-exchange strategies that enable either of...
This thesis describes the synthesis and photophysical characterization of low-dimensionalmaterials—including thin-film semiconductors, colloidal quantum dots, and molecules—with the
broader motivation of integrating them into mixed-dimensional heterostructures with novel
responses to external stimuli. Due to their high surface area to volume ratio and incomplete
dielectric screening, mixed-dimensional heterostructures have high sensitivity...
The idea that structure determines the properties of a material is a powerful concept in chemistry and in all fields in which chemistry is important, including engineering, medicine, and materials science. My research aims to better understand the structure-property relationships of a class of materials known as metal–organic frameworks (MOFs)....
Photovoltaic devices containing organic semiconducting chromophores are a promising technology for the conversion of solar energy into electricity. Research into the molecular design and processing of these materials has propelled the power conversion efficiency of laboratory-fabricated organic polymer solar cells (PSCs) to over 17%, which exceeds the 10% threshold deemed...
In an era of personalized medicine, the clinical community has become increasingly focused on understanding diseases at the cellular and molecular level. Magnetic resonance imaging (MRI) is a powerful imaging modality for acquiring anatomical and functional information. However, it has limited applications in field of molecular imaging due to low...
Chirality and polarity describe orthogonal mechanisms of inversion symmetry breaking, which is the origin of valuable properties in crystalline materials including nonlinear optical activity, ferroelectricity, and piezoelectricity. Noncentrosymmetric (NCS) materials have numerous applications yet opportunities remain for cooperative coupling between chiral and polar basic building units to realize high-performance materials....
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...
Harnessing the metabolic potential of methanotrophic bacteria is a compelling strategy for the bioremediation of environmentally harmful methane gas. Methanotrophs can activate a 105 kcal/mol C-H bond in methane at ambient conditions using metalloenzymes called methane monooxygenases (MMOs). Particulate methane monooxygenase (pMMO) is a copper-dependent, membrane-bound enzyme that is the...
Metal-organic frameworks (MOFs) are a class of highly modular materials with welldefined three-dimensional architectures, permanent porosity, and diverse chemical functionalities, which show promise for a wide range of applications, including gas storage and separation, drug delivery, chemical sensing, and catalysis. Nanoparticle forms of MOFs have similar properties but are dispersible...
Oxidation is an important process in synthesizing a broad range of useful products such as polymers, pharmaceuticals, and fine chemicals. While H2O2 is a highly attractive oxidant for oxidative chemistry due to its high percentage of oxygen and environmentally friendly water byproduct, it is often used in excess due to...
Biological therapeutics have revolutionized the way we treat cancer due to their ability to target tumors discriminately, leaving healthy cells unaffected. However, our inability to tailor the structure of biologics may hamper their optimization for efficacy. This lack of programmability contributes to factors such as immunogenic responses, inability to penetrate...
Increasing industrialization and the resulting negative environmental impacts highlight the need to develop alternative renewable energy sources. The Sun is a massive source and organic solar cells are a growing field of study. As new materials are synthesized, the efficiencies of organic solar cells continue to grow, but without an...
This thesis describes fundamental photophysical studies of quantum dot (QD)-molecule complexes, aimed at discovering strategies for enhancing the efficiency of QD-photocatalyzed and QD-sensitized multi-electron catalytic reactions, for the purpose of solar fuels production. Photosensitization of molecular catalysts that are active for reactions such as the reduction of carbon dioxide or...
High-throughput methods enable rapid experimentation and/or screening of thousands of samples simultaneously. Mass-spectrometry based methods are of particular interest since they provide a label-free way to detect all species present in a given reaction mixture. To circumvent sample preparation and purification—which is typically a slow process—the Mrksich group developed a...
The development of new catalytic methodologies for the precision synthesis of carbon-carbon bonds is central to the advancement of synthetic organic chemistry. Significant focuses of these efforts are made on the enantio- and diastereoselective synthesis of carbon frameworks, especially as chemists and biologists become more aware of the impact of...
The study of solid-state organic chromophores has been soaring in the last decade owing to their wide applications in organic photovoltaics. These organic chromophores can absorb light in the visible region and form free charge carriers with proper design in molecular structure and device fabrication. In solid state, chromophores are...
Crystalline and Framework materials make up a broad class of structures which are known for their precise and regular nature. Because these materials have predictable structures and compositions to their networks, they are widely used for several applications including electronics, optics, and catalysis. While these materials are of particular interest,...
The opposing activities of phosphatases and kinases determine the phosphorylation status of proteins, yet kinases have received disproportionate attention in studies of cellular processes, with the roles of phosphatases remaining less understood. This dissertation describes the use of self-assembled monolayer laser desorption/ionization mass spectrometry (SAMDI-MS) together with peptide arrays to...
While Li-ion batteries are currently the preferred energy storage technology, multivalent alternatives such as Mg should be considered. Magnesium metal has a high volumetric capacity and has been shown to cycle with no dendrite formation. However, the highly charged Mg2+ ion cannot easily diffuse into the oxide cathodes favored in...
The translation of proteins as effective intracellular drug candidates is limited by the challenge of cellular entry and their vulnerability to degradation. To advance their therapeutic potential, cell-impermeable proteins can be readily transformed into protein spherical nucleic acids (ProSNAs) or encapsulated into liposomal spherical nucleic acids (L-SNAs), structures defined by...
