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...
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...
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...
Wireless power strategies are critical to system level implementation of bio-integrated devices. To achieve mechanically robust, manufacturable systems, batteries are often integrated as an on-board power source to support sensing, wireless communication and signal conditioning. Unfortunately, most sources of battery power use hazardous and environmentally harmful materials, which frustrate incorporation...
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...
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...
The objective of molecular imaging is to noninvasively visualize biochemical events in a living system at the cellular level. Magnetic resonance imaging (MRI) is a promising modality for this goal due to its excellent resolution, unlimited depth penetration, and absence of harmful ionizing radiation. MRI techniques frequently use Gd(III)-based contrast...
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...
Many processes in nature and human-made settings rely on the unique properties of charged metal oxide:aqueous interfaces. Despite their ubiquity, these buried interfaces are challenging to study, since any analytical technique aiming to overcome the relatively small number density of interfacial versus bulk species must be highly sensitive and surface-selective....
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...
This dissertation focuses on the study of the superionic state in multicomponent systems, where the smaller component exhibits delocalization and mobility while still maintaining system compactness through component attractions. Superionic behavior is widely observed in various systems and plays a crucial role in ceramic superionic conductors, which offer high ion...
One of the greatest challenges in heterogeneous catalysis is the rational design and development of new catalytic systems, due to synthetic limitations in the design of solid catalysts and inhomogeneity of chemical sites at solid surfaces. This obfuscates understanding of catalyst behavior and slows improvements of processes. One approach to...
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...
Clean water supplies are required for industry and general life. However, water shortages dueto pollution and human activity are increasingly common, and new, more efficient, materials need
to be made to increase clean water supplies. To do this, fundamental information on the interaction
of water with ions at the atomic...
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...
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...
The continuing increase in atmospheric CO2 to concentrations exceeding 400 ppm has attracted considerable attention from both scientists and policymakers. Industrial fossil fuel consumption generates a significant amount of CO2 emissions, and in particular, energy-intensive molecular separations that require thermal processes, such as distillation, drying, or evaporation, are responsible for...
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...
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...
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...
One of the grand challenges in materials chemistry and nanochemistry is the development of functional materials through ordered, hierarchical structures using synthetic building blocks. Nature has done this through evolution of molecular components such as nucleic acids, saccharides, lipids, amino acids, and inorganic crystals. The precise spatial positioning of these...
Carbon nanomaterials, such as graphene and graphene oxide, have outstanding mechanical strength, stiffness, and toughness that surpass those of materials currently used to build structures. However, these properties are limited to the nanoscale and have not yet been attained in macroscopic composites containing carbon nanomaterials. To integrate the mechanical properties...
Total synthesis of natural products provides an avenue for investigation of complex chemical scaffolds, not only delivering access to biologically impactful molecules but also lending a deeper understanding of their inherent chemical reactivity. Expansion of reaction methodology, optimization of biological activity, and absolute structural confirmation can all be accomplished via...
Two-dimensional (2D) hybrid halide perovskites have been the response to their exciting but woefully unstable 3D counterparts. These 2D perovskites have been shown to have respectable stabilities as photovoltaic absorbers, yet they lag behind the 3D perovskites in terms of efficiency. With the need to catch up to the efficiencies...
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...
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...
Dynamic covalent chemistry (DCC) combines the strength and directionality of covalent bonds with the reversibility of supramolecular interactions. The formation and stability of these bonds are typically regulated by parameters such as temperature, pH, concentration, catalyst loading and light. Light is an exceptionally powerful stimulus because it can be applied...
The ubiquitous role of water in biochemical, electrochemical, and geochemical systems has driven scientific interest in studying the fundamental hydrogen-bonding interactions that water molecules exhibit in the presence of different materials.Specifically, we focus on the interactions characterizing water at the interface between two bulk media, as these are essential to...
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...
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....
Cyclodextrin-based polymers (CDPs) are adsorbents based on supramolecular receptor chemistry and have emerged as a promising technology for organic micropollutant remediation. Micropollutants are small organic molecules which contaminate water systems from human related activities. The occurrence of micropollutants in water sources is associated with many negative health, economic, and ecological...
Surface-enhanced Raman scattering (SERS) spectroscopy has been demonstrated to be a powerful analytical tool. Its chemical specificity, rapidity, and portability make it an attractive technique for biosensing, but its application to this field has been limited by the fundamental distance dependence of the surface-enhancement effect. Many biological molecules of interest...
This dissertation describes the study of photoinduced charge transfer between QDs and molecular acceptors as a probe of the defects within ligand shells of QDs and as means to photocatalyze redox reactions. For charge transfer reactions to occur between QDs and molecules in bulk solution, the molecules must interact with...
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...
Triplet excited state chemistry has enabled a range of important organic transformations by accessing reaction pathways inaccessible to photoredox chemistry. Such photoreactions are triggered by triplet photosensitizers, which absorb visible-light photons and transfer the energy to the substrate or to a co-catalyst through triplet-triplet energy transfer (TT EnT). The most...
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...
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,...
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...
A fundamental understanding of the photophysics involved in solar energy capture and conversion is crucial to the development of carbon-neutral energy technologies. Taking inspiration from nature, the photosynthetic reaction center (PSRC) is often modeled by simpler versions of its elements to allow for better control over the system and for...
Soft materials are inherently fluxional, with morphologies and behaviors that are dictated by their solvation state. Thus, many organic systems cannot be reliably imaged by static dry state or cryogenic-transmission electron microscopy (TEM). This motivated us to pursue liquid cell (LC) TEM method development to study our own materials and...
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...
Part I:Current approaches to synthesize π-conjugated polymers are dominated by thermally driven, transition-metal-mediated reactions. Herein we7 show that electron-deficient Grignard monomers readily polymerize under visible-light irradiation at room temperature in the absence of a catalyst. The product distribution can be tuned by the wavelength of irradiation based on the absorption...
Atomic layer deposition (ALD) is a gas-phase synthesis technique employed to manufacture thin films and metallic nanoparticles of various compositions and sizes, as well as individual, isolated species on various supports. An understanding of the dynamic surface chemistry that takes place during various ALD processes is vitally important for achieving...
Cobalt(III) Schiff-base complexes (Co(III)-sb) have been utilized in the literature as antibacterial, antiviral, and inhibitory agents. Recent work has utilized their ability to displace endogenous metals from metalloproteins that exhibit aberrant gain of function pathologies in human disease. Specifically, in this dissertation Co(III)-sb has been applied as inhibitors of pathogenic...
Uranium is a unique, multifaceted element that possesses rich chemistry and promise for challenging reactions. Pressing demands within nuclear stockpile stewardship and the nuclear energy sector call for development of this relatively understudied element. Uranium metal–organic frameworks (U-MOFs), a class of nanoscale hybrid materials, harness the exceptional attributes of uranium...
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,...
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...
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...
Proteins are the nanoscale building blocks of life. Their sophisticated but well-defined architectures result in complex biological functions, including ones involved in metabolism, photosynthesis, transcription, translation, and immunity. To study and improve upon the natural functions of proteins, it is desirable to develop methodology for organizing proteins into targeted architectures....
Per- and polyfluoroalkyl substances (PFAS) are man-made compounds containing multiple carbon–fluorine bonds. The unique properties of this strong bond simultaneously make PFAS useful for a number of industrial and consumer applications, toxic to living organisms, and difficult to remediate. Because the pervasive pollution of water sources with PFAS occurs at...