Inorganic Chemistry Commons^™

Earth Abundant Catalyst For Evironmental Sustainability Applications, Javier Hernandez

Open Access Theses & Dissertations

The development of experimental methodologies for synthesizing a diverse range of metallic and metal oxide nanoparticles tailored for sustainable water treatment applications was investigated. These nanoparticles are prepared using environmentally friendly and scalable synthesis methods, underscoring their potential for large-scale production. Synthesized nanoparticles are harnessed for various processes, including catalysis and electrocatalysis, with a primary objective of degrading and removing organic pollutants from water. Key to this research is the encapsulation of nanoparticles within solid supports. Multiple methodologies are explored to engineer supports that ensure nanoparticle stabilization, monodispersion, and prevent unintended release into the environment. Two alternative approaches were evaluated …

Computational Investigation Of Transition Metal Photoredox Catalysis: Redox Property Tuning Via Ligand Modification, Christian Fernando Sandoval Pauker

Open Access Theses & Dissertations

In the last decade, photoredox catalysis has become a powerful tool in synthetic chemistry. It relies on the ability of catalytic systems that facilitate energy-demanding redox reactions thanks to photoinduced electron transfer processes. This dissertation focuses on the computational investigation of the redox properties of transition metal photoredox catalysts using density functional theory (DFT) calculations. The research systematically explores the effects of altering redox-active ligands on the thermodynamics of electron transfer events in the photoredox cycle. The electronic structure changes throughout oxidative and reductive quenching cycles are analyzed, with a particular focus on Cu(I) complexes. Through computational techniques, insights into …

Sterically Encumbering Ligands For The Synthesis And Stabilization Of Iron Nitride And Iron Oxo Compounds, Asiel Mena

Open Access Theses & Dissertations

The study of iron-nitrides has been found to be very attractive due to their potential role in processes like Haber-Bosch and nitrogen fixation by nitrogenase. The role of iron-nitrides in these processes is yet not well understood, and the fact that only handful of terminal iron-nitrides have been isolated or spectroscopically detected motivates us to study this type of systems, since much remains to be learned about the electronic and structural factors that affect the chemistry of the Feâ?¡N bond. Recently in our group, by using a super-bulky guanidinate ligand (LAr*), the obtention of an iron-nitride ([LAr*]FeN(py) (LAr* = (Ar*N)2C(NCtBu2), …

Synthesis, Characterization, And Reactivity Studies Of Highly Reduced Early-Metal Complexes Supported By Imidazolin-2-Iminato Ligands, Maria Alejandra Gomez Torres

Open Access Theses & Dissertations

Our group has shown that reduction of titanium complexes supported by the sterically encumbering N-donor ligands 1,3â??bis(Dipp)imidazolinâ??2â??iminato (ImDippNâ??) and ketimine guanidinate (ketGuan = [(tBuC=N)C(NDipp)2]-) gives access to electron rich platforms featuring a metal coordinated, reduced, dearomatized arene substituent, which act as an electronic reservoir capable of facilitating multi-electron transfer chemistry driven by the rearomatization driving force. For instance, the arene-masked Ti(II) synthon (DippketGuan)(η6-ImDippN)Ti (Dipp = 2,6-iPr2C6H3) (TiDipp) is a versatile and potent one- and two-electron reductant capable of distinctive late-metal type reactivity such as transfer hydrogenation and catalytic olefin hydrogenation. Interestingly, TiDipp can mediate the reversible cleavage of thiophene and, …

Rational Design Of Composite Nanomaterials For Water Treatment Applications, Mariana Marcos-Hernandez

Open Access Theses & Dissertations

Water quantity and quality have been affected in communities all around the world due to population growth, pollution, changes in land use, and climate change. In order to cope with existing and anticipated water demands and shortages, the use of treated or reclaimed water is an ongoing alternative that has helped communities all over the world address this problem. The adaptation of nanotechnology to traditional water and wastewater treatment processes offers new opportunities in technological developments. Unique size-dependent properties such as: high surface to mass ratio, high reactivity, high sorption capacities, fast dissolution, superparamagnetism, among others, provide high-tech efficient materials …

Rational Design Of Multifunctional Nanocatalysts For Environmental Remediation And Energy Conversion Technologies, Md Ariful Ahsan

Open Access Theses & Dissertations

The discovery of efficient and sustainable carbon-based nanotechnologies to solve both the scarcity of drinking water and global energy crisis has become a paramount task in the last decades. Owed to the fast population growth and industrialization of the modern society, access to potable water and clean energy technologies is becoming very hard around the globe. Water pollutants have become a serious threat to the environment and ecology because of their toxic nature. Parallelly, the current hydrocarbon-based fuel industries are generating high levels of contamination across the planet, making imperative the development of cleaner energy technologies. In this regard, the …

Low-Valent Synthons Of Titanium : Investigations On Structure-Reactivity Relationships, Rolando Aguilar

Open Access Theses & Dissertations

Strategies for the functionalization of abundant, small molecules into products with added value provide a powerful approach to address environmental sustainability issues. Dinitrogen (N2), and carbon oxides (CO, CO2), are examples of the ample, yet, underutilized atmospheric feedstock of nitrogen and carbon building blocks to produce a variety of chemicals. Although, potentially valuable, small molecules are inert under most conditions, and as such, their industrial activation often requires heterogeneous catalysts operated under high pressures (200 atm) and temperatures (450-600 ºC).

To this end, great efforts in synthetic inorganic chemistry have been devoted to the generation of well-defined and highly reactive …

Gravimetrically Characterizable Common Alkali Reducing Agents And Ligand Design Of A New Electron Rich Guanidinate, Efrain Maximiliano Castillo

Open Access Theses & Dissertations

SynThesis, isolation and characterization of 12 new alkali arenides was performed by the addition of the chelating base 18-crown-6. Electrochemistry, UV-vis/NIR spectroscopy and XRD studies were performed.

The incoorporation of an imidazolin-2-iminato group to the background of a guanidinate showed that this kind of ligand is electronically flexible and metal dependent. It was found that is more electron donating than some previously reported guanidinates and ketimine guanidinates.

Preparation Of Cobalt/Nickel Molybdenum Sulfide Catalysts Supported By Aqueous Media Soluble Multi-Wall Carbon Nanotubes., Hassan Ahmad Bleibel

Open Access Theses & Dissertations

Multi-walled carbon nanotubes (MWCNTs) have been subjected to chemical treatment in order to introduce hydrophilic functional groups on their surfaces. These covalently bonded groups did enhance the solubility of MWCNTs in aqueous media as expected. Functionalized MWCNTs were characterized using FTIR, Raman spectroscopy, TGA, X-ray diffraction, dispersion test and TEM. Then, functionalized MWCNTs were incorporated in the hydrothermal synthesis method of transition metal sulfide catalysts (CoMo, NiMo, and Ethylenediamine-CoMo Sulfides). Catalysts were characterized using X-ray diffraction, TEM, SEM, N2 Gas adsorption-desorption, elemental analysis, and Hydrodesulfurization (HDS) reaction of dibenzothiophene (DBT). The objective was to study the functionalized MWCNTs' effect; being …

Bimetallic Systems As Platforms For Supramolecular Chemistry And Metal Organic Frameworks, Jose M. Veleta, Dino Villagrán

COURI Symposium Abstracts, Summer 2012

Homonuclear M₂ units (M = Ru, Mo) with tetraacetate ligands are used as starting materials to react with a wide variety of electron rich molecules; HDAniF (N,N’-di-p-anisylformamidine) has been used as a bridging ligand for the M-M units, and bisbidentate carboxylate and carboxamidate ligands have been used as linkers between M₂ units. Special interest is focused in the study of compounds with multiple bonds between bimetallic units, as well as paramagnetic and electrochemical active complexes. The reactivity of these bimetallic complexes leads to the synthesis of monomeric and dimeric species, which are building blocks for the design of …

Redox Potential Tuning By Mixed-Ligand Quadruply Bonded Dimolybdenum Compounds, Nathalie Valdez, Dino Villagran

COURI Symposium Abstracts, Summer 2012

Oxidation-reduction reactions are crucial in chemistry. They are vital for biochemical reactions such as cellular respiration and photosynthesis. Redox reactions are also important in industrial processes, such as the reduction of ores to obtain metals and to produce electrochemical cells. While this field of chemistry has been studied extensively, this project attempts to get a better understanding of electron donor properties of basic ligands attached to bimetallic units. The more basic a ligand is, the better its electron donor properties are which allows us to stabilize higher oxidations states. Guanidine ligands have been found to be able to stabilize higher …

Synthesis Of Metal Organic Framework Composites For Improved Porosity, Jesse Murillo, Venkata P. Neti, Luis Echegoyen*

COURI Symposium Abstracts, Summer 2012

The synthesis of new highly porous composite materials, by combining Metal Organic Frameworks (MOFs) and graphene derivatives is described. The porosity of these composite materials is confirmed by pore volume, nitrogen uptake, BET and Langmuir surface area calculations. Structural information for the composites is accomplished through powder x-ray diffraction measurements, thermal gravimetric analysis and scanning electron microscopy. MOF-210, reported by Yaghi et al. in 2010, was chosen for composition with a graphene oxide composite due to its record holding pore size and internal surface area. The synthetic route to creation of precursors for MOF-210, as well as MOF-210 synthesis, is …

Pcet With Bimetallic Systems, Maripaz A. Calderon, Dino Villagran

COURI Symposium Abstracts, Summer 2012

Electron-transfer (ET) is one of the simplest chemical events, yet it is a vital process for chemical reactivity. Proton-coupled electron transfer (PCET) is the concerted transfer of protons and electrons which is fundamental in chemical and biological systems and processes in electrochemistry, photosynthesis, and enzymatic activity. Similarly, mixed-valence (MV) systems are pervasive in nature and provide a platform for multiple electron transfers systems in nature. While both fields have been studied extensively, little work has been done on the intersection of the two. This project explores the elegant use of MV bimetallic systems through hydrogen-bonded networks. Using standard Schlenk and …

Study Of Multielectron Redox Chemistry Through Multiple Bonded Bimetallic Species Of The Type M2-L-M, Nancy Rodríguez, Dino Villagrán

COURI Symposium Abstracts, Summer 2012

Multielectron redox chemistry is fundamental for the activation of small molecules, such as H₂O, N₂ and CO₂. Currently, these multielectron redox processes are not well understood and are presently the subject of active research throughout the world due to the evident energy and environmental implications of these small molecules. The goal of this project is the study of multielectron redox chemistry on compounds of the type M₂-L-M. We want to manipulate the reactivity of a M (M=Zn, Co, Ni, Rh, Ir) redox center by a quadruply bonded Mo₂ dimolybdenum core through a …

Electronic Communication Between Dimolybdenum Units And Ruthenium As A Metal Center Linked By Dimethyloxamide, Daniel D. Anchondo, Dino Villagran

COURI Symposium Abstracts, Summer 2012

Multi-electron redox reactions are important in chemistry. They are crucial in biochemical reactions such as photosynthesis and in many enzymatic processes in nature. Typical examples can be the electrolysis of water which is a four electron process, nitrogen fixation which is a six electron process. Multi-electron redox reactions are also important in industrial processes, such as the reduction of ores to obtain metals and to produce electrochemical cells. Therefore it is vital to study multi-electron redox reactions. We use dimolybdenum units bridged to a ruthenium atom as a platform to study these reactions by measuring the electron communication between two …

Proton-Coupled Electron Transfer (Pcet) With Bimetallic Systems, Maripaz A. Calderon ^, Dino Villagran *

COURI Symposium Abstracts, Spring 2012

Electron-transfer (ET) is one of the simplest chemical events, yet, it is a vital process for chemical reactivity. Proton-coupled electron transfer (PCET) is the concerted transfer of protons and electrons which is fundamental in chemical and biological systems and processes in electrochemistry, photosynthesis, and enzymatic activity. Similarly, mixed-valence (MV) systems are pervasive in nature and provide a platform for multiple electron transfers systems in nature. While both fields have been studied extensively, little work has been done on the intersection of the two. This project explores the elegant use of MV bimetallic systems through hydrogen bonded networks. A variety compounds …

Metal Catalyzed Activation Of E-H Bonds, E = Si, Ge, Sn, Renzo Nelson Arias Ugarte

Open Access Theses & Dissertations

The present project covers the use of complexes of the type: (C5H5)M(CO)nLMe, (M = Fe, n = 1; L = CO, Ph3P; M = Mo, n = 2; L = CO, Ph3P); M(CO)6, (M = Cr, Mo, W) and M(CO)5NMe3 as catalysts for the activation of E-H bonds (E = Si, Ge and Sn). The work is divided in three sections; the first two involves dehydrogenation and the last one amide reduction.

Dna-Inks For 3-D Printing: Dna Composites For The Rapid Prototyping Of Scaffold In Bioengineering Applications, Jimena I. Aguirre^, Ryan B. Wicker, Mireya A. Perez, Juan C. Noveron*, Juan M. Sanchez

COURI Symposium Abstracts, Spring 2011

Rapid-prototyping has become an incredible technique that manufactures three-dimensional objects with intricate complexity down to 8µm of resolution. We are developing materials that can be used by rapid-prototyping instruments to make scaffolds for bioengineering applications. Our molecular design involves the polymerization of a  (vinylbenzyl)trimethyl-ammonium chloride and DNA solution. Upon UV illumination, the composite polymerizes and forms DNA-hybrid materials.  The end result becomes a ductile transparent material with a thin cross-section. The synthesis, characterization and application of rapid prototyping will be described. Scanning Electron Microscopy (SEM), Light Scattering Detector (LDS), Nuclear Magnetic Resonance (NMR), and Infrared Spectroscopy indicate the structure, characteristics, …

Metal Carbonyl Catalysts For The Transformation Of Silicon Hydrides To Siloxanes In The Presence Of Dmf, Eduardo Cervantes^, Renzo Arias Ugarte, Hemant K. Sharma, Keith H. Pannell*

COURI Symposium Abstracts, Spring 2011

It has recently been reported that, upon photochemical irradiation, tertiary silanes (R₃SiH) react with DMF to form disiloxanes (R₃Si-O-SiR₃) and Me₃N, using the transition metal alkyl complex (η⁵-C₅H₅)Fe(CO)₂Me as a catalyst. Intermediates of the type R₃SiOCH₂NMe₂ were proposed as the important first step via a hydrosilylation reaction but no evidence was obtained for this suggestion. By changing the catalyst to Mo(CO)₆ we have now observed that not only do we form the expected  disiloxanes, but for the first …

Supramolecular Organization Of Nanoparticles, Brenda M. Porta Linnell

Open Access Theses & Dissertations

The study of supramolecular structures with nano-architectures has become an active area of research in recent years. They have the potential to generate functional materials with applications in medicine and emerging technologies. In this dissertation, the supramolecular organization of gold nanoparticles (AuNP) and other nano-scale structures such as discrete styrene-based polymers was investigated. The synthesis and characterization of metal-mediated AuNPs systems using pendant ligands on the AuNP such as 11-diethylenetriamine-undecane-1-thiol, 11-Mercapto-undecanoic acid [2-(2-amino-ethylamino)-ethyl]-amide, Bis(11-oxo-nicotinic acid, undecine)disulfide, and 11-mercaptoundecanoic acid, and using Cu(II) to mediate the formation of supramolecular AuNP systems with sizes of 200 nm ¡V 3 fÃ?m, are …

Understanding The Promotion Effect: A Density Functional Theory Study Based On High Resolution Transmission Electron Microscopy Images For Mos2-Cobalt Promoted Interfaces, Manuel A. Ramos

Open Access Theses & Dissertations

Many studies had been done in order to understand promotion effect and structure/function in unsupported catalyst. Results indicated that d-electrons play an important role promoting catalytical active sites at the edges of MoS2 catalytically structures. Sulfur removal from crude oil, occurs on the edge of molybdenum di-sulfide (MoS2) nano structures, due to promotion of MoS2 nano structures with nickel or cobalt in sulfur-terminated or molybdenum-terminated edge planes. The promotion leads to formation of so-called CoMoS phase (MoS2/Co9S8) first discovered by meaning of Mössbauer spectroscopy, much more CoMoS phase usually called unsupported catalytical particles, have been topic of great interest in …

Coordination Directed Self Assembly Of Pt/Pd Mono-And Multinuclear Complexes, Robert Moreno

Open Access Theses & Dissertations

This research focuses on the development of mononuclear platinum complexes; multinuclear platinum complexes, both of which self assemble into micelles in the presence of water. This work also involved the synthesis of a reverse micelle that allows for detection of water nanocrystals within a defined size molecular envelope. The novel synthesis of these compounds allows for ligand substitution and the creation of a library of compounds.

Oxidation Of Dibenzothiophene To Dibenzothiophene Using Metal Nanoparticles Supported On Silica, Karina Castillo

Open Access Theses & Dissertations

Silica and nanoparticles of Pt, Au, and Ag supported on silica were tested for the ability to oxidize dibenzothiophene (DBT) to sulfone. High performance liquid chromatography was used to study the removal of DBT from solution. In addition, X- ray diffraction, infrared spectroscopy and Raman Spectroscopy were used to characterize the product of the oxidation reaction. Further studies involved the use X-ray absorption spectroscopy to characterize the nanoparticle catalysts before and after the oxidation reaction.

To better understand the reaction, silica was synthesized at different pHs using three different acids. The acids used to synthesize the silica were HCl, HNO3, …

Computational Modeling Studies Of The Structures And Properties Of Organotin(Iv) And Stannyl-Thioether Systems With Comparisons To X-Ray Crystallography, Michelle R. Stem Joseph

Open Access Theses & Dissertations

Controlling the toxic effects of organotin(IV) compounds involves engineering the structure of the molecules to optimize their properties. Molecular engineering, coupled with improved capabilities to generate reliable computational optimization models (COMs), will enable researchers to have greater success at harnessing the highly specific cytotoxicity of organotins. For example, as the thio_n ligand phenyl groups were replaced with Cl atoms, the S-Sn intramolecularity was strengthened, the bond distance decreased, and the stannyl tetrahedral structure was deformed from its triphenyl conformation. With each substitution, conformation deformations lowered the damaging bioactivity levels of thio_n. Bonding various ligands to organotin(IV) compounds …

Silica Removal From Brine By Using Ion Exchange, Carlos R. Acevedo

Open Access Theses & Dissertations

Local governments have been forced to look for additional water sources to satisfy the ever increasing demand for fresh water. Very often, the new water sources such as the underground water in continental territories have high salt content. Currently, reverse osmosis technology (RO) is one of the most common processes for water desalination. However, this process is limited by high silica and salt concentrations in water. At high concentrations silica clogs the membranes used in the RO process, reducing their life and increasing operational costs. In this study, quaternary ammonium resins and sulfonic acid resins were used to remove silica …

Synthesis And Characterization Of Acetylenic Derivatives Of The Actinide Extractant (Aryl) N,N Di (Alkyl)Carbamoylmethylphosphine Oxide (Cmpo), Mario Ivan Baeza

Open Access Theses & Dissertations

We have used the reaction between the sodium salt of (diaryl)-N,N-di-(isobutyl)carbamoylmethylphosphine oxides {[Aryl)2P=O][iBu2NC=O]CH}-Na+ and chloromethylacetylenes to produce the first acetylenic derivatives of the carbamoylmethylphosphine oxide (CMPO) actinide extractants. The new compounds - CMPO-CH2C2H (1) {aryl = phenyl}, (2) {aryl = tBu-phenyl}; CMPO-CH2C2Me (3) {aryl = phenyl}; and CMPO-CH2C2CH2Cl (4) {aryl = phenyl}, (5) {aryl = tBu-phenyl} - have been characterized by spectroscopy (1H, 13C, 32P NMR) and also by single crystal X-ray diffraction. These new extractants lead the way to new derivatives aimed at using the materials as both optical and electrochemical actinide and other metal sensors.

Transition Metal Catalysts For Hydrodesulfurization Reactions Applied To Petroleum Industry, Brenda Torres

Open Access Theses & Dissertations

Catalysis plays a fundamental role in petroleum refining and basic petrochemical industries creating new routes in the development of industrial processes. Moreover, catalysis has become indispensable to the solution of environmental pollution problems and therefore on public health. World wide concerns for preservation of the environment has motivated the development of "Green" catalyst based technologies, to achieve a better utilization of petroleum resources and demands for cleaner transportation fuels. These environmental concerns have led to increasingly drastic regulations on sulfur, nitrogen and aromatics content in fuels. Sulfur content in the motor and diesel fuels is continuously reduced by regulations to …

In-Vivo Delivery Of Dna Vaccines Using Metallo-Lipid Nanoparticles, Clarissa Sara Gomez

Open Access Theses & Dissertations

There has been a rapidly growing area of research in the design and synthesis of molecules that self-organize in water to form functional nanosystems and due to the high interest in the area metal ligand complexes were tested as drug delivery systems with a Leishmania vaccine. Herein, we present the design, synthesis and functional activity of Cu(II) and Zn(II) complexes that self-assemble in water to form spherical nanoscale structures that exhibit an affinity to bind DNA and deliver it into eukaryotic cells with a high percent efficiency in-vitro. In order to assess the effectiveness of these nanoparticles to deliver DNA …

Optical And Vibrational Spectroscopic Studies Of Synthetic Maya Pigments As A Function Of, Swati Kumar

Open Access Theses & Dissertations

Pigments developed by the Mayan civilization around 8th century, represent some of the most versatile pigments known to date. Several derivatives of these pigments are popular subjects of current research interest. This is due to the characteristic stability which is provided by a bonding mechanism between the dye and the clay. One such pigment "Maya Blue", a mixture of Indigo and Palygorskite, provides a dramatic background for murals and ceramics throughout Mesoamerica. Several research groups have devoted time and interest in unlocking its particular features.1-3

The work embodied in this Thesis is focused on the synThesis and characterization of three …

A Study Of The Interaction Of Thioindigo Dye, With Several Inorganic Host Materials, Alejandra Ramirez

Open Access Theses & Dissertations

Maya Blue has been the focus of numerous studies and is believed to be a mixture of palygorskite clay and indigo dye.^1,2 Several derivatives of this pigment have been developed with intriguing properties. For instance, the dye thioindigo reacts with the palygorskite clay to exhibit a broad range of colors from red to blue under UV-Vis excitation. Based on FT-Raman and computer simulation, previous work performed in our group could relate indigo and thioindigo interaction to the aluminum sites in the framework. super>3,4

The work performed with other inorganic host materials such as, layer structures and zeolites have …