Chemistry Commons^™

Luminescent Group 11 Metal (I) Chalcogen Clusters With A Conjugated Diphosphine Ligand, Kai Yu Jeffrey Li

Electronic Thesis and Dissertation Repository

Polynuclear Au (I) complexes exhibit rich photochemical properties and have the potential to find applications as molecular sensors, switches, or energy storage devices. Although dinuclear Au (I) complexes with bridging diphosphines have been extensively examined, most of those reported do not contain rigid-diphosphine ligands.

This thesis examines how the rigid diphosphine, 4,6-bis(diphenylphosphino)dibenzofuran (DBFDP) can be incorporated for the controlled assembly of photoluminescent gold (I) metal – chalcogenolate (chalcogenolate = RS^-, RSe^-; R = organic moiety) and gold (I) chalcogenide (chalcogenide = S^2-, Se^2-) bimetallic complexes. In these studies, the chalcogen …

Excitation-Dependent Photoluminescence Of Bazro3:Eu3+ Crystals, Santosh K. Gupta, Hisham Abdou, Carlo U. Segre, Yuanbing Mao

Chemistry Faculty Publications and Presentations

The elucidation of local structure, excitation-dependent spectroscopy, and defect engineering in lanthanide ion-doped phosphors was a focal point of research. In this work, we have studied Eu³⁺-doped BaZrO₃ (BZOE) submicron crystals that were synthesized by a molten salt method. The BZOE crystals show orange–red emission tunability under the host and dopant excitations at 279 nm and 395 nm, respectively, and the difference is determined in terms of the asymmetry ratio, Stark splitting, and intensity of the uncommon ⁵D₀ → ⁷F₀ transition. These distinct spectral features remain unaltered under different excitations for the BZOE …

Investigating The Influence Of Synthetic Environments On The Electronic Structure And Luminescence Of Cr-Doped Zinc Gallate, Xincheng Li

Electronic Thesis and Dissertation Repository

Cr doped ZnGa₂O₄ (Cr-ZGO) has shown potential in the field of bioimaging. To achieve the nano-size suiting for bioimaging, Cr-ZGO is normally synthesized using a hydrothermal method. There are few studies on how the hydrothermal conditions influence the structure and optical properties of the Cr-ZGO. The first two parts of this thesis study how different hydrothermal temperatures and pH environments will affect the optical properties of Cr-ZGO by photoluminescence spectroscopy. By combining the electronic structure information extracted from X-ray absorption near-edge structures (XANES) and extended X-ray absorption fine structure (EXAFS), a relationship among hydrothermal conditions, optical properties …

Disorder Driven Asymmetry And Singular Red Emission In Doped Lu2hf2o7 Nanocrystals With No Charge Compensating Defects, Santosh K. Gupta, Mitzy A. Penilla Garcia, Jose P. Zuniga, Bhupendra B. Srivastava, Yuanbing Mao

Chemistry Faculty Publications and Presentations

High performance luminescent materials possess low symmetry, high color purity, no charge compensating defects, and high quantum yield. In this work, we have synthesized Lu2Hf2O7 (LuHO) and Lu2Hf2O7:Eu3+ (LuHOE) nanocrystals (NCs) using a molten salt synthesis and confirmed that both are stabilized in defect fluorite structure with a high degree of structural disordering. The LuHO NCs depicted green emission under ultraviolet irradiation, which decreases and increases after being treated in oxidizing and reducing environments, respectively, confirming the role of oxygen vacancies in the emission process. The LuHOE NCs (i) show excitation wavelength-dependent host to dopant energy transfer efficiency, …

Poly(Pyridinium Salt)S Containing 2,7-Diamino-9,9'-Dioctylfluorene Moieties With Various Organic Counterions Exhibiting Both Lyotropic Liquid-Crystalline And Light-Emitting Properties, Pradip K. Bhowmik, Tae S. Jo, Jung J. Koh, Jongwon Park, Bidyut Biswas, Ronald Carlo G. Principe, Haesook Han, András F. Wacha, Matti Knaapila

Chemistry and Biochemistry Faculty Research

A series of poly(pyridinium salt)s-fluorene main-chain ionic polymers with various organic counterions were synthesized by using ring-transmutation polymerization and metathesis reactions. Their chemical structures were characterized by Fourier Transform Infrared (FTIR), proton (1H), and fluorine 19 (19F) nuclear magnetic resonance (NMR) spectrometers. These polymers showed a number-average molecular weight (Mns) between 96.5 and 107.8 kg/mol and polydispersity index (PDI) in the range of 1.12-1.88. They exhibited fully-grown lyotropic phases in polar protic and aprotic solvents at different critical concentrations. Small-angle X-ray scattering for one polymer example indicates lyotropic structure formation for 60-80% solvent fraction. A lyotropic smectic phase contains 10 …

Luminescent Metal-Organic Frameworks For The Detection Of Alcohols, Lucas Stehle, Kristi A. Kneas, Jeffrey A. Rood

Summer Scholarship, Creative Arts and Research Projects (SCARP)

Metal-organic frameworks (MOFs), porous materials composed of metal ions and organic linkers, have broad applications in separation, small molecule storage, and catalysis. Luminescent metal-organic frameworks (LMOFs) hold great potential in the development of sensors, and, with their relatively straightforward syntheses that produce predictable, homogeneous, extended structures, should result in good sensor-to-sensor reproducibility and uniform response. In addition, subtle differences in overall LMOF structure, metal ion coordination, pore surfaces, and host-guest interactions within pores should have significant impact on observed photoluminescence and provide numerous strategies for analyte detection, which shows promise for the detection of alcohols. Highlighted here is the development …

Incorporation Of Luminescent Osmium Complexes Into Metal-Organic Frameworks: Optimization Of Osmium Complex Synthesis And Effect Of Mof Structure On Complex Inclusion And Emission, Brandon A. Molina, Lucas Stehle, Jeffrey A. Rood

Summer Scholarship, Creative Arts and Research Projects (SCARP)

Metal-Organic Frameworks (MOFs) are materials that contain metal centers coordinated by organic molecules that form an extended, porous lattice. These MOFs are of interest in the field of sensing for their unique properties such as high stability, high surface area, high crystallinity, and ability to perform small molecule exchange. Luminescent metal-organic frameworks (LMOFs) are of specific interest since they contain the potential to detect odorless volatile organic compounds (VOCs) via adsorption into the porous framework. Luminescent properties can be imparted to MOFs in several ways. This project focused on the inclusion of a luminescent osmium complex into the MOF scaffold. …

The Effects Of Coordination Environment On The Spectroscopic And Electrochemical Properties Of Divalent Lanthanides, Tyler C. Jenks

Wayne State University Dissertations

The research projects in this dissertation pertain to the properties of molecular divalent lanthanide complexes with a focus on luminescence properties in solution. Most available research in lanthanide chemistry focuses on either the trivalent oxidation state or the divalent oxidation state in solid inorganic host matrices. The results described herein contribute to the body of knowledge regarding the effects of coordination environment on the spectroscopic and electrochemical properties of divalent lanthanides in solvated molecular complexes.

The divalent-europium-containing complex Eu(II)23 was evaluated as a visible-light-excited photoredox precatalyst. Stoichiometric and catalytic carbon–carbon bond forming reactions of Eu(II)23 with benzyl chloride in the …

Lanthanide-Doped Lanthanum Hafnate Nanoparticles As Multicolor Phosphors For Warm White Lighting And Scintillators, Santosh K. Gupta, Jose P. Zuniga, Maya Abdou, Melonie P. Thomas, Manisha De Alwis Goonatilleke, Beth S. Guiton, Yuanbing Mao

Chemistry Faculty Publications and Presentations

Designing luminescent materials especially nanomaterials with multifunctional applications is highly challenging and demanding. In this work, we explored pyrochlore La2Hf2O7 nanoparticles (NPs) singly and triply codoped with Eu3+, Tb3+ and Dy3+. Under both ultraviolet and X-ray irradiations, the La2Hf2O7 NPs singly doped with Eu3+, Tb3+ and Dy3+ displayed red, green and yellowish-blue emission, respectively. The concentration quenching study revealed a non-radiative energy transfer in Eu3+ doped La2Hf2O7 NPs, which takes place via dipole-quadrupole mechanism. On the other hand, a dipole-dipole interaction prevails in Tb3+ and Dy3+ doped La2Hf2O7 NPs. Lifetime spectroscopy reveals the stabilization of Eu3+ and Dy3+ ions at …

Nanodiamonds And Carbon Nano-Onions Ceramic Composites And Their Applications, Ibrahim Munkaila Abdullahi

Masters Theses

"Luminescent nanodiamonds are photostable non-blinking fluorescent biocompatible, non-toxic, functional Zable materials made from high-pressure high temperature (HPHT) microcrystalline diamonds. For long, the scientific community has been investigating for a clean, efficient and cost-effective technique to reduce the size of fluorescent microcrystalline diamond into nanodiamonds. Their color center, responsible for the fluorescent properties are crucial for their applications, including biomedical imaging, nano sensing, quantum computing etc, and therefore should not be affected significantly by the method of size reduction applied. A novel size reduction technique that is based on explosive fragmentation was developed and the corresponding fragmented diamonds obtained were characterized …

Alginate/Cucurbit [7] Uril/Dequalinium–Basedb Supramolecular Carbohydrates: Modulation Of Fret Signal By Temperature Control, Amir Sohail Noor Alam Jan

Chemistry Theses

Herein, we describe the synthesis of a bioactive, inexpensive, and easy-tohandle supramolecular carbohydrate polymer by grafting of cucurbit [7] uril macrocycle (CB7)-encapsulated dequalinium chloride hydrate (DCH) onto alginic acid carbohydrates (ALG) via amide linkage formation and show that light energy transfer based on energy migration can be controlled by altering polymer temperature without changing polymer composition. DCH (donor) and 2-anilinonaphthalene-6- sulfonic acid (acceptor) were used to generate Förster resonance energy transfer (FRET) signals. Stationary and time-resolved photoluminescence spectra of the modified carbohydrate platform revealed that FRET resulted in a color change from violet (~387 nm) to blue (~429 nm), which …

Optical Memory Behavior, Metallophilic Luminescence, And Chemical Sensing Ability Of Inorganic And Organometallic Complexes: Development Of Optoelectronic Materials, Aaron D. Nicholas

Electronic Theses and Dissertations

This dissertation is divided into three sections: (1) optical memory, (2) metallophilic-based luminescence, and (3) chemical sensors. (1) Optical memory behavior of d¹⁰metal Cu(I) thiocyanate salts are investigated to explore their potential use in the development of digital data storage devices. From this study we have discovered a new class of CuSCN(3-BrPy)₂optical memory material which undergo a reduction in emission intensity upon laser irradiation. This loss of emission intensity can be reversed simply by heating the sample to room temperature. The mechanism by which this emission loss occurs has been studied, revealing a migrating Br atom …

Luminescence Antenna Behavior In Lanthanide Complexes And Luminescence Sensing In Group 11 Iodides, Francis Barnes

Electronic Theses and Dissertations

In this thesis luminescent materials are studied. The luminescent materials studied are lanthanide complexes and group 11 iodide sensing abilities. Emission intensity of the lanthanide complexes through direct excitation of the lanthanide ion are relatively weak. To overcome this, three unique organic ligands were utilized to synthesize lanthanide nitrate complexes in which higher emission intensity can be observed via the antenna effect. Increased emission intensity resulted for Eu^III and Tb^III complexes for each ligand except triphenylphosphane oxide (only the Tb^III complex demonstrated increased emission intensity). Latva’s empirical rule allows for the antenna effect to occur, in which …

Rare-Earth-Activated Group Vi D0 Metal Oxides As Thermosensitive Phosphors, Samarage Sameera Perera

Wayne State University Dissertations

ABSTRACT

RARE-EARTH-ACTIVATED GROUP VI d0 METAL OXIDES AS

THERMOSENSITIVE PHOSPHORS

by

SAMARAGE SAMEERA PRASAD PERERA

AUGUST 2019

Advisor: Dr. Federico A. Rabuffetti

Major: Chemistry

Degree: Doctor of Philosophy

Thermosensitive phosphors are solid-state materials that demonstrate distinct dependence of luminescence emission on temperature. These materials enable optical temperature sensing in environments where conventional thermometry is not possible (e.g., gas turbines, combustion engines, surface temperature distributions). However, the design of thermosensitive phosphors that show adequate sensitivity and low thermal quenching in the intermediate temperature range (i.e., 500–1000 K) remains challenging. This challenge can be addressed by understanding how to rationally manipulate the …

Photoluminescent Zirconium Complexes For Visible Light Photoredox Catalysis, Yu Zhang

Graduate Theses, Dissertations, and Problem Reports

Early transition metals like zirconium are attractive candidates for the design of luminescent molecules based on earth-abundant elements. Here, a series of zirconium complexes carrying two pyrrolyl-based ligands have been synthesized and characterized. These complexes are photoluminescent upon excitation with visible light and exhibit remarkably long emission lifetimes of hundreds of μs in solution at room temperature. Computational studies using time-dependent density functional theory (TD-DFT) were conducted to identify the nature of the luminescent excited states as mixed intra-ligand/ligand-to-metal charge-transfer (ILCT/LMCT) states. The electrochemistry studies revealed multiple reversible redox events for each zirconium complex. Furthermore, the excited state of the …

Effect Of Molten Salt Synthesis Processing Duration On The Photo- And Radioluminescence Of Uv- Visible- And X-Ray-Excitable La 2 Hf 2 O 7 :Eu 3+ Nanoparticles, Jose P. Zuniga, Santosh K. Gupta, Maya Abdou, Yuanbing Mao

Chemistry Faculty Publications and Presentations

Ln 3+ -ion-doped nanomaterials possess excellent properties because of their high color purity, longer excited state lifetime, narrow emission, and large Stokes shifts. In this work, we studied the correlation between the luminescence properties of La 2 Hf 2 O 7 :Eu 3+ pyrochlore nanoparticles (NPs) synthesized by a molten salt synthesis (MSS) method at a relatively low temperature and several MSS processing durations (from 1 to 12 h). We synthesized these NPs with different sizes just by changing the MSS processing time without subjecting to high temperature. Raman spectroscopy confirmed the stabilization of the ideal pyrochlore structure of the …

The Synthesis And Characterization Of Photoluminescent Conjugated Frameworks Containing Silicon And Germanium, Douglas William Hammerstroem

Dissertations

Siloles and 9-heterofluorenes (Si, Ge) are conjugated π-electron systems containing Group 14 atoms which demonstrate unique properties such as high electron affinity, mobility, and bathochromically shifted optical spectra relative to their all-carbon analogs. This is due to their low-lying lowest-unoccupied molecular orbital (LUMO) which is resultant of the σ*-π* conjugation between the exocyclic groups at the Group 14 center and the butadiene unit of the ring. As a consequence, they have received considerable attention for their use as components for a wide variety of optical and electronic applications such as organic light emitting diodes (OLEDs), photovoltaic devices, field-effect transistors (FETs), …

Photophysics Of Organic Semiconductors: From Ensemble To The Single-Molecule Level, Rebecca Grollman, Whitney E. B. Shepherd, Alexander Robertson, Keshab R. Paudel, John E. Anthony, Oksana Ostroverkhova

Chemistry Faculty Publications

We present photophysical properties of functionalized anthradithiophene (ADT) and pentacene (Pn) derivatives, as well as charge and energy transfer properties of donor-acceptor (D/A) pairs of these derivatives. All molecules studied were fluorescent and photostable enough to be imaged on the single-molecule level in a variety of polymeric and in a functionalized benzothiophene (BTBTB) crystalline host using room-temperature wide- field epifluorescence microscopy. Flexibility of functionalization of both guest (ADT, Pn) and host (BTBTB or polymer) molecules can be used for systematic studies of nanoscale morphology and photophysics of D/A organic semiconductor bulk heterojunctions, as well as in applications relying on FRET, …

Luminescence Of Lanthanide Ions In Octahedral Coordinations With Comparison To The Centroid Shift And Host Lattice Exciton Energy, Sam J. Camardello

Legacy Theses & Dissertations (2009 - 2024)

In this dissertation, we have studied the luminescence of the lanthanide ions (Ce3+, Eu2+, Eu3+, Tb3+, and Pr3+), specifically in the highly symmetric octahedral coordination. This high symmetry coordination readily permits the optical properties of the luminescent ions to be determined spectroscopically. Relevant optical parameters such as the Stokes Shift (∆S), red shift (D(2+, 3+, A), crystal field splitting (Ɛcfs), and centroid sift (Ɛc), along with the excitation and emission spectra, are presented. Three different crystal structures were studied, namely, M2+Al2B2O7 (M2+ = Ca, Sr, Ba) doped with Eu2+ and Ce3+, KBaLn3+(BO3)2 (M3+ = all lanthanides, Y, Sc) doped with …

Synthesis And Characterization Of New Light Emitting Probes For Sensitive Detection Of Bio-Molecules And Live Cells, Shyamala Pravin Pillai

Dissertations

A variety of contemporary analytical platforms in technical and biological applications take advantage of labeling the objects of interest with fluorescent or luminescent tracers. Luminescent tracers take advantage of the unique property of some lanthanide metals to absorb and emit light. Long lifetime of lanthanide emission allows temporal gating of the signal, which avoids the short-lived background of interfering sample components. This property in combination with large Stokes shift contributes to extreme sensitivity of detection (ca. 10^-13-10^-14 M), which makes lanthanide-based probes suitable for large variety of challenging tasks ( e.g., intracellular detection of single DNA/RNA, or …

Section Abstracts: Chemistry

Virginia Journal of Science

Abstracts of the Chemistry Section for the 90th Annual Meeting of the Virginia Academy of Science, May 23-25, 2012, Norfolk State University, Norfolk, Virginia.

The Synthesis, Photophysical Characterization, And X‐Ray Structure Analysis Of Two Polymorphs Of 4,4′‐Diacetylstilbene, Ralph Isovitsch, Cameron Pye, Frank R. Fronczek

Chemistry

A palladium(II) acetate‐catalyzed synthesis of 1 that utilizes the novel triazene 1‐{4‐[(E)‐morpholin‐4‐yldiazenyl]phenyl}ethanone as a synthon is described. The room temperature absorption spectra of 1 in various solvents exhibited a π→π* transition in the range of 330–350 nm. Compound 1 was observed to be luminescent, with room‐temperature solution and solid‐state emission spectra that exhibited maxima in the range 400–500 nm. All room‐temperature absorption and emission spectra exhibited some degree of vibrational structure. The emission spectrum of 1 at 77 K in propanenitrile glass was broad and featureless with a maximum at 447 nm. Compound 1 crystallized …

Development Of Metal-Based Luminescent Probes For Applications In Biomolecular Structure And Dynamics, Ayesha Sharmin

Graduate Student Theses, Dissertations, & Professional Papers

New transition-metal complexes containing luminescent properties have been designed and synthesized for application as structural probes for biomolecules. Potential DNA intercalators, 2- amino-anthracene substituted triosmium clusters, were synthesized by the reactions of 2-aminoanthracene with [Os3(CO)10(CH3CN)2]. The products [Os3(CO)10(μ-η2-(N-C(1))-NH2C14H8)(μ- H)], [Os3(CO)10(μ-η2-(N-C(3))-NHC14H9)(μ-H)], [Os3(CO)9(μ-η2-(N-C(3))-NHC14H8)(μ-H)2] and [Os3(CO)9(μ3-η2-(N-C(3))-NHC10H9)(μ-H)] obtained from this reaction have been structurally characterized by spectroscopic, photophysical and electrochemical techniques. Solid state structures are also reported for the complexes [Os3(CO)10(μ-η2-(N-C(3))-NHC14H9)(μ-H)] and [Os3(CO)9(μ-η2-(N-C(3))-NHC14H8)(μ-H)2]. To investigate bio-macromolecular dynamics on the sub-microsecond-to-microsecond timescale, a series of ruthenium based mono-nuclear metalligand charge-transfer complexes (MLCs) of formula [XRu(CO)(L–L)(L′)2][PF6] (X = H, TFA, Cl; L–L = 2,2′-bipyridyl, 1,10-phenanthroline, 5-amino-1,10-phenanthroline …

Singlet Oxygen Generation Using New Fluorene-Based Photosensitizers Under One- And Two-Photon Excitation, Stephen James Andrasik

Electronic Theses and Dissertations

Molecular oxygen in its lowest electronically excited state plays an important roll in the field of chemistry. This excited state is often referred to as singlet oxygen and can be generated in a photosensitized process under one- or two-photon excitation of a photosensitizer. It is particularly useful in the field of photodynamic cancer therapy (PDT) where singlet oxygen formation can be used to destroy cancerous tumors. The use of two-photon activated photosensitizers possesses great potential in the field of PDT since near-IR light is used to activate the sensitizer, resulting in deeper penetration of light into biological tissue, less photobleaching …

Analytical Potential Of Polymerized Liposomes Bound To Lanthanide Ions For Qualitative And Quantitative Analysis Of Proteins, Marina Santos

Electronic Theses and Dissertations

One of the intriguing features of biological systems is the prevalence of highly selective and often very strong interactions among different cellular components. Such interactions play a variety of organizational, mechanical, and physiological roles at the cellular and organism levels. Antigen-antibody complexes are representative examples of highly selective and potent interactions involving proteins. The marked specificity of protein-antibody complexes have led to a wide range of applications in cellular and molecular biology related research. They have become an integral research tool in the present genomic and proteomic era. Unfortunately, the production of selective tools based on antigen-antibody interactions requires cumbersome …

Spectroscopic And Luminescence Properties Of An Isonicotinic Acid, Nurdoğan Can, Ahmet Ataç, Fehmi̇ Bardak, Şebnem Esen Sözerli̇ Can

Turkish Journal of Chemistry

An isonicotinic acid N-oxide Zn(II) compound was characterized on the basis of elemental analysis. FTIR spectra of the compound and free isonicotinic acid N-oxide (INO) were recorded in the range 4000--400 cm^{-1}. Cathodoluminescence (CL) spectra from the Zn(INO)_2 complex were recorded. The luminescence data were interpreted in terms of the emission band at 470 nm. The green luminescence (\sim 470 nm) arises from Zn^{2+} transition ^4T_1 (^4G) \to ^6A_1 (^6S). It shows a weak vibronic structure, and short lifetimes less than 150 \mu s. The lifetime and intensity of the signal are temperature dependent, and the parameters are reported for …

Stability And Concentration Effects In The Use Of Siloxene As A Chemiluminescent Indicator In Redox Titrations, William F. Burkhardt

Chemistry Honors Papers

This 22 page thesis attempts to determine the limitations of, and to extend the applicability of siloxene as a chemiluminescent indicator in redox titrations.