Symposium Abstracts
2026
Poster Session 1
12:30pm-1:30pm
| Name | Title |
| Natalie Bacallao | Airborne Pollen as Atmospheric Particles: Size Distribution and Cloud Interactions |
| Colin Cheeseman | Synthesis of Novel Hypervalent Iodine Reagents through Ligand Exchange Reactions |
| Alden Dexter | Synthesis of a Non-Fullerene BODIPY Acceptor for Organic Solar Cell Applications |
| Brendon LeStrange | Topologically Motivated Chemical Fingerprints |
| Ryan Millsaps | Synthesis and characterization of N-heterocyclic carbene ligated gold nanoparticles via solution-state NMR. |
| Lindsey Morgan | Photolytic Decomposition of Δ3-1,3,4-Oxadiazoline Precursors for in situ Generation of Dialkyl Metal Carbenes to Catalyze Intermolecular Si–H Insertions. |
| Braden Penuel | An Investigation of the Interplay of Subsurface Oxygen and Chlorine Promotion in Silver-Catalyzed Ethylene Epoxidation. |
| Loudon Rogers | Synthesis of a Zwitterionic Polymer via Post-polymerization Modification |
| Alli Rumbaugh | Synthesis of Oligomeric Functionalized N-Heterocyclic Carbenes for Gold Nanorods |
| Peyton Stiles | Effects of Core-Shell Morphology and Insoluble Inclusions on Ice Nucleation |
Oral Presentation Session
1:30pm-2:30pm
| Name | Title |
| Michael Gutierrez | Study of Novel Molecular Rotor BODIPY and its Non-Covalent Supramolecular Assembly with Zinc Porphyrinoids |
| Lynn Nguyen | Cysteine-Responsive Liposome for Cellular Delivery |
| Rahil Parikh | Investigating the Effects of Activator Byproducts on Ethylene Polymerization Catalysis |
Poster Session 2
3:00pm-4:00pm
| Name | Title |
| Shelby Belt | Influence of Molecular Structure, Contact Chemistry, and Electrode Composition in Polyacene Single Molecular Junctions |
| Emily Cameron | Transition Metal Heliphyrin Complexes as Electrocatalysts for CO2 Reduction |
| Benjamin Childs | Spectroscopic Investigation of Cobalt (II) and Cobalt (III) Phthalocyanine Amine Complexes |
| Ashton Dy | Multi-Objective Reinforcement Learning for NLRP3 Inhibitor Discovery in Alzheimer’s Disease |
| Anna Mahar | N-heterocyclic olefins for gold nanoparticle functionalization |
| Emily Major | Phthalocyanine Europium Double Decker Complex |
| Neil Parek | Electronic Characterization and Comparison of Tetracyanometallates |
| Caleb Russell | Engineering Bis-triphenylphosphonium Based Lipid Switch for Tunable GTP/TPi Responsive Liposomes Through Membrane Modulation |
| Karlotta Schley | Synthesis and characterization of pore-expanded metal-organic nanotubes (MONTs) |
Poster Session 1 Abstracts
Airborne Pollen as Atmospheric Particles: Size Distribution and Cloud Interactions
Natalie Bacallao, Peyton Stiles, Jack Smith, Ziying Lei
Airborne particles such as pollen represent an important yet often under characterized component of atmospheric particulate matter. While pollen is widely recognized for its role in allergic disease, its behavior as an atmospheric particle and potential air pollutant is less well understood. In particular, its size distribution and its interactions with cloud processes remain poorly constrained. In regions such as southeastern Tennessee, where diverse vegetation produces abundant seasonal pollen, these particles can contribute significantly and may contribute substantially to local aerosol populations during peak season. Although many laboratory studies have characterized the pollen particles, our current understanding on pollen particles and their role in cloud formation are limited due to limited measurements in real atmospheric settings.
This study investigates the physical and chemical properties of particles collected at the Great Smoky Mountains National Park during peak pollen season from February 26th to April 2nd. We deployed different online instruments to the Look Rock site at the Great Smoky Mountains National Park to measure the size distribution and cloud properties using a Scanning Mobility Particle Sizer (SMPS) and a Cloud Condensation Nuclei (CCN) counter. Ambient particles were also collected on silicon substrate for chemical composition characterization and atmospheric behavior of pollen particles collected from trees in southeastern Tennessee. Analysis of data obtained from SMPS measurements was used to determine particle size distributions by measuring aerosol concentration as a function of particle diameter over time. This data allowed characterization of the size ranges of pollen particles and fragments.
Our results suggest variability in pollen particle size distributions and CCN activity which suggests that pollen and pollen fragments may contribute more significantly to regional aerosol populations than previously recognized. These findings improve understanding of the physical characteristics of aerosols and highlight the need for further investigation into the role of pollen in atmospheric chemistry.
Synthesis of Novel Hypervalent Iodine Reagents through Ligand Exchange Reactions.
Colin Cheeseman, Alexis Pugh, Ampofo Darko
This research focuses on performing ligand exchange reactions and synthesizing hypervalent iodine reagents with chiral ligands that will be used for further applications. Hypervalent iodine reagents have been used in organic chemistry as oxidants and facilitate several useful reactions. One of the main methods of their synthesis is through ligand exchange reactions, in which one of the functional groups of the hypervalent iodine compound is replaced by a new group. The objective of this research was to create new hypervalent iodine reagents using established ligand exchange reactions conditions. Phenyliododiacetate (PIDA) was the hypervalent iodine reagent used as the starting material, in which the acetates would be replaced by a functionalized carboxylic acid derived from phenylalanine. PIDA is an established precursor that has been used to synthesize more complex hypervalent iodine reagents, so this technique has merit. The reaction was optimized by changing the temperature, time, and using different solvents such as chloroform, toluene, chlorobenzene and acetonitrile. Various methods such as thin layer chromatography and nuclear magnetic resonance were used to verify product formation. The new hypervalent iodine reagent will be used as a new way to functionalize transition metal compounds such as heteroleptic rhodium paddlewheel complexes.
Synthesis of a Non-Fullerene BODIPY Acceptor for Organic Solar Cell Applications
Alden Dexter, Edward Gilbreth, Victor Nemykin
Organic solar cells (OSCs) have gained recent attention in solar energy technologies due to their electron transport capabilities via donor-acceptor assemblies. However, low power conversion efficiency has led to exploration into non-fullerene acceptors (NFAs). The electron accepting properties, broad visible-to-NIR absorption, strong molar absorptivity, and the functionalizability of boron dipyrromethene (BODIPY) make this organic dye a viable option as an NFA. Functionalizing the BODIPY core with an electron-withdrawing pyridone group allows the BODIPY to behave as a better electron acceptor. Additional functionalization of the meso position will then allow for the interaction of the BODIPY acceptor with an electron donating unit. Therefore, the synthesis of a novel meso-functionalized pyridone-fused BODIPY is presented with improved electron withdrawing properties for supramolecular charge transfer. The synthetic route is outlined, and structures are characterized using 1H NMR, 13C NMR, and UV-Vis spectroscopy.
Patil, Y, Emerging BODIPY-Based NonFullerene Acceptors: Innovations for Organic Solar Cells. Chemistry-A European Journal2025, 31 (70). doi.org/10.1002/chem.202502963
Topologically Motivated Chemical Fingerprints
Brendan LeStrange, Johnathan Campbell, Konstantinos Vogiatzis
Modern computational chemistry relies heavily on reliably encoding molecular structure into computer-readable representations that preserve chemical properties. Designing representations that can capture both the global morphological and chemical fingerprint of a molecule remains a challenging task in molecular machine learning and cheminformatics. Persistent homology (PH), provides a framework for characterizing the geometric structure of molecular data by identifying multiscale features within point clouds. In particular, PH can be used for exploring molecular spaces as it can aid in the identification and representation of pairwise interactions, rings, and cavities within fingerprints. However, these geometric patterns are based purely on molecular geometry, unless augmented by chemical weights. Here we can incorporate chemical information such as radial basis, partial charge, atomic mass, ultimately leading to a more chemically expressive representation. Accurate fingerprinting methods are crucial for drug discovery pipelines. We further generalize this approach to predict quantum mechanical properties—such as HOMO–LUMO gaps or atomization energies—ultimately aiming to provide a versatile framework that bridges molecular geometry with chemical and quantum properties.
Synthesis and characterization of N-heterocyclic carbene ligated gold nanoparticles via solution-state NMR.
Ryan Millsaps, Gurkiran Kaur, David M. Jenkins
N-heterocyclic carbenes (NHCs) have emerged as powerful ligands due to their strong σ-donation to metal centers. Unlike thiols, NHCs are resistant to degradation in harsh chemical environments making them durable ligands for gold nanomaterial functionalization. In particular, recent studies of NHCs on gold nanoparticles (AuNPs) have demonstrated their remarkable tunability and biocompatibility expanding their role in catalysis, sensing, and biomedical applications. However, while the previous studies have examined the dynamics and stability of NHCs ligated to gold surfaces, analogous studies on NHC-coated AuNP’s in solution remain underexplored.
In this work, we synthesize NHC-gold complexes with isopropyl and dodecyl wingtips to coat AuNPs. To minimize the NHC desorption from AuNP surface, we employ chelating strategy to synthesize bi- and tri-dentate NHC-gold complexes in conjunction with the traditional monodentate NHC gold complexes. The synthesized NHCs are deposited onto small sized (~3-5 nm) oleylamine-capped AuNPs using top-down approach. The NHC coated AuNPs are then characterized using solution-state NMR experiments (1H, 13C, and DOSY). Future work aims to explore ligand exchange and desorption dynamics of NHC-AuNPs by utilizing solution phase NMR studies. This study aims at establishing NMR as a powerful tool for nanoparticle surface characterization.
Photolytic Decomposition of Δ3-1,3,4-Oxadiazoline Precursors for in situ Generation of Dialkyl Metal Carbenes to Catalyze Intermolecular Si–H Insertions.
Lindsey Morgan, Blake Day, Ampofo Darko
Metal carbene chemistry composes a robust class of reactions that can effect key organic functionalization like X–H insertion (X = C, S, O, N, Si). Of interest to the Darko lab are metal carbenes made from dirhodium (II) catalysts, which boast excellent selectivity and can accommodate a variety of substrates. Though most metal carbene catalysis requires diazo precursors, dialkyl diazo compounds are yet underexplored due to their instability, which poses handling and storage concerns. The present work explores a new method of obtaining dialkyl metal carbenes in situ through the photochemical decomposition of oxadiazoline precursors. A small library of oxadiazolines was synthesized and subjected to photolytic decomposition by 310 nm light, forming diazo compounds that were then trapped with Rh2(esp)2 catalysts to form metal carbenes. We found that the method can be used to execute Si–H insertion using dimethylphenylsilane in good yields, suggesting further exploration may reveal new ways to obtain challenging products of industrial and pharmaceutical relevance.
An Investigation of the Interplay of Subsurface Oxygen and Chlorine Promotion in Silver-Catalyzed Ethylene Epoxidation.
Braden Penuel, Bright Daniel, Sharani Roy
Ethylene oxide (EO) is a major industrial intermediate used in the production of plastics, antifreeze, polyester materials, and sterilization agents. Industrial ethylene epoxidation proceeds via selective oxidation of ethylene over silver catalysts, where adsorbed surface oxygen (Osurf)) and promoters play critical roles in determining reaction pathways and selectivity. The reaction is widely accepted to proceed through an oxametallacycle (OMC) intermediate en route to EO formation. While previous studies have explored the effects of Osurf and promoters, recent experimental evidence suggests the presence of subsurface oxygen (Osub) under reaction-relevant conditions. However, the role of Osub, its interaction with Osurf and its interplay with promoters remain insufficiently understood.
In this study, density functional theory (DFT) calculations with the climbing image nudged elastic band (CINEB) method were used to investigate the effects of oxygen coverage, subsurface oxygen, and first to third nearest-neighbor Osub interactions on EO formation in the presence of chlorine (Cl) as a promoter. The results show that Cl stabilizes the EO product relative to the reactants and lowers the activation barrier toward EO formation, with these effects becoming more pronounced at higher oxygen coverages. For example, at an oxygen coverage of 0.33 ML, the exothermicity shifts from −0.049 eV (unpromoted) to −0.379 eV (promoted), while the activation barrier decreases from 0.611 eV to 0.432 eV. This promotional effect is strongest when subsurface oxygen is in proximity but becomes less pronounced at larger separations. Overall, Cl and subsurface oxygen act cooperatively to enhance EO formation by improving both thermodynamics and kinetics.
Synthesis of a Zwitterionic Polymer via Post-polymerization Modification
Loudon Rogers, Sourav Pan, Bin Zhao
Zwitterionic polymers are macromolecules with each monomer unit containing a cation and an anion, yielding a net charge of zero. This structure imparts unique properties, including superhydrophilicity, temperature responsiveness, biocompatibility, and efficient ionic conductivity. Such properties allow for applications in antifouling, drug delivery, lubrication, and resource-energy systems. In this study, we aim to synthesize zwitterionic polymers via post-polymerization modification. First, N-methylaminoethanol was reacted with 2-bromoethyl methyl ether to generate an intermediate which was converted to a methacrylate monomer using methacryloyl chloride. The monomer was purified by vacuum distillation, and the molecular structure was confirmed by 1H NMR spectroscopy. We then performed reversible addition-fragmentation chain transfer polymerization of the monomer. 1H NMR spectroscopy showed a monomer conversion of 68.2%, which gave a degree of polymerization of 82, considering the molar ratio of the monomer to the chain transfer agent. Size exclusion chromatography demonstrated that the polymerization was controlled as indicated by the narrow dispersity of the obtained polymer. The polymer was then betanized with 1,3-propanesultone; 1H NMR analysis showed that the conversion was almost complete, yielding a zwitterionic polymer that is soluble in water. This zwitterionic polymer could be useful in applications such as antifouling.
Synthesis of Oligomeric Functionalized N-Heterocyclic Carbenes for Gold Nanorods
Alli Rumbaugh, Lydia Lang, David Jenkins
Gold nanorods (AuNRs) have unique optical features used for a variety of applications such as optical devices and therapeutics. A polymeric ligand can be used to prepare the nanorods for these applications by coating the surface, increasing stability of the AuNR over time. Previous research utilized thiolated polymers, though this was inefficient due to the extreme excess of thiol ligands (1000x) and extreme dilutions of the AuNR (100x) needed to functionalize the surface. N-heterocyclic carbenes (NHCs) are being studied as a replacement for these thiolated polymers. NHCs have shown to have increased thermal and chemical stability compared to thiols, which makes them more attractive for optical device fabrication. By switching to NHCs, the need for excess ligands and diluted AuNR is eliminated.
In this work, two different approaches are being taken when it comes to appending the NHCs to the AuNRs. The first approach is the “graft-from” approach, which attaches the NHC to the AuNR before adding varying lengths of oligomers through post-synthetic modification of the NHC. The second approach, the “graft-to” method, attaches the oligomer to the NHC before appending it to the AuNR. Oligomers of up to 20 carbon alkyl chains are used and characterized by NMR and mass spectrometry. Current research is focused on synthesizing and characterization of these oligomeric NHCs for the graft-to approach. Future research will focus on using polymers in place of the oligomers for increased surface coating on the AuNRs in comparison to the previous work by the United States Air Force.
Effects of Core-Shell Morphology and Insoluble Inclusions on Ice Nucleation
Peyton Stiles, Rebecca Conner, Ziying Lei
Ice formation in mixed-phase clouds plays a critical role in precipitation, cloud lifetime, and Earth’s energy balance. Although heterogeneous freezing by ice nucleating particles (INPs) is known to occur at warmer temperatures than homogeneous freezing, the influence of complex core-shell particle morphology on ice nucleation behavior remains uncertain and is not well understood. This study aimed to determine how insoluble inclusions and core-shell structure influence freezing temperatures in model microdroplets. We conducted laboratory experiments using ultrapure water and diethyl sebacate to generate microdroplets with distinct structures, including homogeneous and core-shell microdroplets. Different INP types were introduced into the microdroplets such as K-feldspar, silver iodide, and black carbon. Freezing temperatures were measured using a customized cooling stage coupled with high-resolution optical microscopy and the composition was characterized using optical photothermal infrared spectroscopy. Results show freezing behavior depended strongly on morphology. Homogenous droplets have an average onset freezing temperature at -23°C, whereas the droplets with core-shell morphology freeze at -20°C. Black carbon lowers the freezing temperature when it is located in the droplet core, whereas placing black carbon in the shell shows negligible influence on freezing. Both silver iodide and K-feldspar in core-shell droplets exhibited lower onset than those in homogeneous droplets with onset freezing temperatures at -10°C and -15°C, respectively. These findings demonstrate that particle composition and core-shell structure significantly influence ice nucleation and should be considered in atmospheric models to improve predictions of cloud formation and climate patterns.
Oral Presentation Abstracts
Study of Novel Molecular Rotor BODIPY and its Non-Covalent Supramolecular Assembly with Zinc Porphyrinoids
Michael D. Gutierrez, Victoria Villarreal, David Blank, Victor N. Nemykin
We propose the preparation and investigation of a novel non-fullerene electron acceptor based on a previous study of viscosity-sensitive molecular rotor BODIPYs.[1] In non-viscous solvents, quenched fluorescence was observed, attributed to twisted intramolecular charge transfer (TICT). Increasing the viscosity of the solution drastically increasedthe fluorescence lifetime of the molecular rotor BODIPYs due to inhibited TICT. Introducing terminal pyridine substituents via Knoevenagel condensation at the 3,5-methyl positions of the BODIPY core allows for axial coordination to electrophilic zinc porphyrinoid donors through the nitrogen lone pair. This incorporation of pyridine also extends the π-conjugation of the BODIPY structure, resulting in a more panchromatic non-covalent supramolecular assembly.
The novel molecular rotor BODIPY acceptor will be characterized using 1H-NMR, high-resolution mass spectrometry (HRMS), single-crystal X-ray diffraction (XRD), and electrochemical methods. Subsequently, the effect of meso-isoxazolyl rotation on the stability of the charge-separated (CS) state following photoinduced electron transfer (PET) from the zinc porphyrinoid electron donor to the BODIPY acceptor will be investigated using time-resolved absorption and emission spectroscopies in viscous and non-viscous solvents.
Figure 1. Synthetic scheme for the proposed novel molecular rotor BODIPY.
References Zatsikha, Y. V.; Didukh, N. O.; Swedin, R. K.; Yakubovskyi, V. P.; Blesener, T. S.; Healy, A. T.; Herbert, D. E.; Blank, D. A.; Nemykin, V. N.; Kovtun, Y. P. Preparation of Viscosity-Sensitive Isoxazoline/Isoxazolyl-Based Molecular Rotors and Directly Linked BODIPY–Fulleroisoxazoline from the Stable Meso-(Nitrile Oxide)-Substituted BODIPY. Org. Lett.2019, 21 (14), 5713–5718
Cysteine-Responsive Liposome for Cellular Delivery
Lynn Nguyen (Vu Phuong Linh Nguyen), Caitlyn Lindell, Michael D. Best
Liposomes utilize lipid bilayers to encapsulate therapeutics, yet achieving site-specific release remains a challenge. This study develops a novel cysteine-responsive lipid, CL-3, using a charge-balance strategy to enhance delivery in cancer environments where cysteine is significantly upregulated. The CL-3 lipid was synthesized via a multi-step route featuring a DOPE scaffold, achieving high yield in the final conjugation step. Characterization techniques included NMR spectroscopy to verify structural integrity, alongside TLC to monitor reaction progress. Liposomes will be prepared through film formation, hydration, and extrusion. The liposome formulation includes PC (a bulk lipid), our CL-3 synthetic lipid, and DOTAP lipid. Stability and charge of the formula will be evaluated using Dynamic Light Scattering (DLS) to monitor changes in zeta potential and size upon addition of cysteine.
Investigating the Effects of Activator Byproducts on Ethylene Polymerization Catalysis
Rahil H. Parikh, Mason Jones, Brian K. Long
Understanding the role of activator byproducts in ethylene polymerization is critical to achieve greater control over polymer yield and properties. This study investigates how activator systems influence catalytic activity through the formation of byproducts resultant from precatalyst activation. Four precatalysts were evaluated in combination with three activators, where each were tested under standardized conditions to assess baseline activity. To further elucidate the influence of activator-derived species, a second series of polymerizations was conducted with the addition of one equivalent of N,N-dimethylaniline, a known byproduct when using [PhNMe2][B(C6F5)4]. Comparisons between the baseline and modified systems allowed for evaluation of how these byproducts affect overall polymerization activity. Activator-mediated alkyl abstraction and protonolysis are key steps in generating the active catalyst species, so the presence of additional compounds capable of occupying the active site generated at the metal center can alter catalyst reactivity. Here in, we report findings that suggest the activator identity and their resulting byproducts can have measurable impacts on catalytic performance.
Poster Session II Abstracts
Influence of Molecular Structure, Contact Chemistry, and Electrode Composition in Polyacene Single Molecular Junctions
Shelby Belt, Dakota Landrie, Sharani Roy
The development and application of single molecule junctions represents a significant leap forward in nanotechnology since the seminal idea by Avriam and Ratner [1]. Theory and computation offer an avenue to explore fundamental electronic properties, enabling a deeper understanding of the underlying mechanisms of quantum transport in these junctions. By constructing molecular junctions using linear acenes with systematically increasing numbers of connected rings – benzene, naphthalene, anthracene, tetracene, and pentacene – we analyzed the effects of increasing conjugation and inter-electrode distance on conductance and current. Additionally, we varied the contact atom from S, Se, to Te, and the electrodes from Au, Ag, to Cu to explore effects of the molecule-electrode interface on transport properties. Using an ab initio tunneling model for coherent transport, we investigated the effects of the molecule, contact, and electrode using density functional theory. We found that conductance decreases with acene length and increases with the work function of the metal electrode, i.e., the higher the work function, the greater the conductance. Moreover, conductance decreases with increasing size of the contacts, more so for longer acenes than for shorter acenes.
[1] A. Aviram and M. A. Ratner. Molecular Rectifiers. Chem. Phys. Lett., 29(2):277–283, 1974.doi: 10.1016/0009-2614(74)85031-1.
Transition Metal Heliphyrin Complexes as Electrocatalysts for CO2 Reduction
Emily Cameron, Haleigh Grace, Brendon McNicholas
Heliphyrins are porphyrinoid-based ligands with open ring structures and broken reflective planes of symmetry. Due to large steric hindrance from the ligand, heliphyrins exhibit slipped stack configurations. Late transition metal heliphyrins were synthesized in accordance with literature precedent, and early transition metal syntheses were attempted to expand the library of heliphyrin-based complexes. Characterization methods such as UV-vis-NIR, ESI-MS, and X-ray crystallography were used for product characterization. Electrochemical and spectroelectrochemical studies were used to investigate redox activity and localization of charge. Preliminary electrocatalytic CO2 reduction studies were performed using various electrolyte combinations to determine effects on activities and product distributions.
Spectroscopic Investigation of Cobalt (II) and Cobalt (III) Phthalocyanine Amine Complexes
Benjamin C. Childs, Breanna E. Muldowney, Micheal D. Gutiérrez, Michael P. Hendrich, Viktor N. Nemykin
Metallated phthalocyanines are generally known in literature for their functional redox properties, leading to their wide usage as dyes, pigments, and catalysts. Thus, it is imperative to investigate the effects of multiple L-/X- type axial ligands on the metal center. Previous investigations show a series of cobalt (I), cobalt (II), and cobalt (III) complexes elucidating charge transfer and trip-mulitplet transitions along with general spectroscopic trends [1]. We further this investigation by analyzing the effects of coordinating environments on the oxidative properties of cobalt (II) phthalocyanine[2]. Herein we report another thorough investigation on a series of cobalt (II) and cobalt (III) phthalocyanine complexes with axial coordination of alkyl- and aryl- amines and amino acid ligands. Through the use of amines with varying basicity and steric properties such as n-butylamine, secbuytlamine, isobutylamine, isopropylamine, tertbutylamine, 4-dimethylaminopyridine, pyridine, piperidine, morpholine, histamine, and tryptamine we can discuss general spectroscopic trends and redox properties of multiple cobalt(II) and cobalt (III) phthalocyanine species. Spectroscopic techniques such as UV-vis-NIR, Magnetic Circular Dichroism, Electronic paramagnetic resonance, nuclear magnetic resonance, Spectroelectrochemistry, electrochemistry, and X-Ray Diffraction were used for collecting data on these cobalt (II) and cobalt (III) phthalocyanine anime complexes.
REFERENCES
1. Muldowney, B. E.; Nevonen, D. E.; Jeaydi, T. I.; Ziegler, C. J.; McNicholas, B. J.; Nemykin, V. N. Identifying charge transfer and trip-multiplet states in Co(I), Co(II), and Co(III) phthalocyanines using (magneto)optical spectroscopy and (TD)DFT calculations. Dalton Trans. 2025, 54, 8846- 8869.
2. Muldowney, B. E.; Grace, H.M; McNicholas, B. J.; Nemykin, V.N. Investigation of solvent and electrolyte anion dependency on the Co(II)/Co(III) versus Pc(2-)/Pc(1-) oxidation preference in tertbutyl substituted cobalt phthalocyanine by electrochemical and spectroelectrochemical methods. J. Porphyrins Phthalocyanines 2025, 29,1164-1176
Multi-Objective Reinforcement Learning for NLRP3 Inhibitor Discovery in Alzheimer’s Disease
Ashton Dy, Mohamed Abdelaty, Konstantinos Vogiatzis
Alzheimer’s affects over 7 million Americans each year and is driven by chronic neuroinflammation. The NLRP-3 inflammasome contributes to this neuroinflammation, making it a promising therapeutic target for neurodegenerative diseases. To accelerate inhibitor discovery, we developed a transformer-based molecular generation pipeline guided by reinforcement learning. We are introducing our workflow for curating a specialized dataset to train an XGBoost regression model on predicting the binding affinity between small molecules and the NLRP-3 protein. This model achieved a mean absolute error of 6.7 kcal/mol. The trained model was embedded into a multi-objective reinforcement learning framework built on top of a transformer based molecule generator to generate candidate molecules as inhibitors. This multi-objective reward function consists of the predicted binding affinity, druglikeness properties, volumetric constraints, synthesizability, and batch diversity. These criteria ensure that the generated molecules not only bind to the protein, but also pass downstream drug validation tests. The fine-tuned molecule generator generated over 8000 candidates with a maximum predicted binding affinity of -47.99 kcal/mol. To build on these computational results, we have secured a synthetic chemist collaborator that will experimentally validate our top candidates.
N-heterocyclic olefins for gold nanoparticle functionalization
Anna G. Mahar, Kyle A. Schulmeister, Jon P. Camden, David M. Jenkins
Gold surfaces and nanoparticles are highly adaptable platforms widely used for supporting molecules via adsorption, leading to the formation of self-assembled monolayers (SAMs). Among the various ligands that can be immobilized on gold, N-heterocyclic olefins (NHOs) stand out as a new class of carbon-based ligands for surface modification due to their unique electronic properties. Unlike N-heterocyclic carbenes (NHCs), the binding mode of NHOs to metals involves a zwitterionic ylide form. As a result, NHOs show strong σ-donation and negligible π-backbonding, adopting an sp3 electronic conformation. This σ-bond character has been shown to allow structural flexibility on metal surfaces and enhance the thermal stability of the monolayer.
Our research aims to synthesize a new library of NHOs and employ them to functionalize gold nanoparticles. NHOs with varied wingtips and backbone saturation were synthesized. These compounds were characterized by 1H and 13C NMR. The NHOs were reacted with gold(I) salts to make gold-NHO complexes that were characterized by NMR and single crystal X-ray diffraction. These gold complexes are being tested on gold nanoparticles to form NHO monolayers.
Phthalocyanine Europium Double Decker Complex
Emily Major, Duygu Tekdas, Victor N. Nemykin
Phthalocyanines, in particular those of the double-decker structure, are known for their electrochemical and optoelectronic properties. Altering the specific metal center in these structures greatly impacts the compounds’ electrochemical capabilities.[1] Changing both redox potential and electronic structure leads to these strong electrochemical potentials. In this study, both Eu and Lu metal centers were used to synthesize double-decker phthalocyanines. The physical distance between the two decks of the phthalocyanines also impacts the electrochemical properties of the compounds.
In order to synthesize these compounds, the 3-nitrophthalonitrile was reacted with the corresponding alcohol, K2CO3, and DMF. Through this substitution reaction, 3-(pyridin-4-yloxy)phthalonitrile was synthesized and then combined with a Europium salt (Eu(III)Cl3) in the final step of the double-decker synthesis. Through this cyclotetramerization, the 3-(pyridin-4-yloxy)phthalonitrile was reacted with either octanol or pentanol to synthesize molecules with Eu or Lu metal centers.
The synthesized molecules were then further characterized through UV-Vis spectroscopy and 1H-NMR analyses.
Figure 1. Synthetic scheme for the formation of 3-(pyridin-4-yloxy)phthalonitrile
Figure 2. Synthetic scheme for the formation of double-decker phthalocyanines
REFERENCES
- Ishikawa, N.; Kaizu, Y. Synthetic, Spectroscopic and Theoretical Study of Novel Supramolecular Structures Composed of Lanthanide Phthalocyanine Double-Decker Complexes. Coord. Chem. Rev. 2002, 226 (1–2), 93–101.
Electronic Characterization and Comparison of Tetracyanometallates
Neil Parek, Ryan Arnold, Alexander Ellis, Brendon J. McNicholas
Prussian blue analogs (PBAs) are widely studied for energy storage and conversion applications due to their tunable lattice structures. Control over structural parameters, particularly vacancy control, is commonly achieved using homoleptic cyanometallate precursors. However, exploration of alternative homoleptic cyanometallate systems has led to the formation of cluster-type lattice structures with weakened metal–nitrogen bonding, limiting their electronic performance. As a result, heteroleptic cyanometallates can be seen as promising alternatives due to their distinct reactivity and tunable electronic properties. Here we discuss the synthesis and characterization of several homoleptic and heteroleptic tetracyanometallates and compare their structural and electronic properties to borane-decorated analogues. These comparisons provide insight into new electronic structures that may enable improved energy storage performance and lattice modulation.
Engineering Bis-triphenylphosphonium Based Lipid Switch for Tunable GTP/TPi Responsive Liposomes Through Membrane Modulation
Caleb G. Russell, Brooke Smith, Michael D. Best
Liposome nanocarriers have proven effective delivery systems for targeted treatments, but their current degree of specificity leaves much room for improvement. Diseased cells can often be differentiated from healthy ones by dysregulation of metabolite concentrations, which could be used to selectively release drug cargo in diseased cells and even be used to differentiate between diseases. This research has focused on the synthesis of a bis-phosphonium-based lipid switch (BPLS) and its application in liposomal systems to maximize its potential efficacy and selectivity of cargo release. This switch has been shown to selectively release in the presence of GTP, which is upregulated in certain strains of fast-growing cancers. The switch can also be fine-tuned to be responsive to TPi as well. The effectiveness of BPLS in driving selective release was verified by dynamic light scattering, transmission electron microscopy, kinetic cargo release, and both hydrophobic and hydrophilic dye release assays. The ability of this system to be fine-tuned represents a new versatile method of stimuli-responsive liposome treatments.
Synthesis and characterization of pore-expanded metal-organic nanotubes (MONTs)
Karlotta S. Schley, Phattananawee Nalaoh, Patrick F. Luciani, and David M. Jenkins
Metal-organic nanotubes (MONTs) are crystalline, one-dimensional, porous materials that are highly adjustable, due to their wide variety of organic linkers that can be used to connect the metal centers. MONTs exhibit anisotropy, like carbon nanotubes (CNTs), resulting from their one-dimensional structure. MONTs have been demonstrated to be effective for size-dependent gas adsorption as well as molecular sensors for a variety of guest molecules. As a result, MONTs are beginning to constitute an important new class of tunable anisotropic materials. Despite these advantages, MONTs have major limitations in gas adsorption applications because most reported MONTs possess relatively small pore sizes. Drawing inspiration from strategies used to construct large-pore metal-organic frameworks (MOFs), we proposed that elongating the organic linkers in an isoreticular approach could increase pore dimensions and improve adsorption behavior while retaining their anisotropic structure.
To further this goal, we expanded the length of our previous ligand, 1,4-bis((4H-1,2,4-triazol-4-yl)methyl)benzene, by incorporating additional phenyl rings in the backbone. We synthesized di-1,2,4-triazole-functionalized ligands with 1,1′:3′,1”-terphenyl and 1,4-bis(phenylmethyl)benzene cores and employed them in MONT synthesis with group 11 metal salts. The resulting MONTs were characterized by single crystal X-ray diffraction (SCXRD), powder XRD, and gas adsorption to confirm their MONT structures and to assess the role of pore expansion in governing MONT properties.