10:15-11:45 AM Oral Competition Presentations
B3: Chemistry / Physics / Earth Sciences (Mulder Hall 146)
10:15-11:45 AM Oral Competition Presentations
B3: Chemistry / Physics / Earth Sciences (Mulder Hall 146)
10:18-10:30 Trithiol-triacrylate gel system with tunable flexibility that support frontal polymerization
Dominic Adrewie (LSU A&M)
Dominic Adrewie, John Pojman
Gels are valuable in a range of applications because of their nature, which permits the development of diverse shapes prior to frontal polymerization. This work investigated thiol-acrylate gel systems for frontal polymerization to establish the gelation time, shelf life and frontal kinetics. Trimethylolpropane tris(3-mercaptopropionate) and excess trimethylolpropane triacrylate are reacted via triethyl amine-catalyzed Michael addition to form a rubbery gel, after which the excess trimethylolpropane triacrylate functionality is then frontally polymerized using free radicals generated from the thermal degradation of Luperox 231. Reduction in cracks generated by the spiral front, as well as improvement in mechanical properties was achieved by the addition of Zoltek PX35 and reduction in front speed because of homo-polymerization during storage was reduced by the addition of phenothiazine. Gels with varying flexibility were formulated by varying trithiol and triacrylate ratios and the effects of stress forces like compression on the front kinetics were studied. This system is potentially useful in situations where molding and reshaping geometries are required prior to frontal polymerization, as well as enabling the ability to examine how mechanical forces can affect frontal kinetics in the real world.
10:33-10:45 Trisphosphine-Modified Cationic Cobalt(II) Complexes: Highly Stable Hydroformylation Precatalysts
Chidera Nnadiekwe (LSU A&M)
Chidera Nnadiekwe, Matthew Chambers
Hydroformylation is a high-temperature and pressure industrial process that generates aldehydes from the reaction of olefins with syngas which are then used to make vital commodities such as plastics, pharmaceuticals, and perfumes. The unmodified HCo(CO)4 and the phosphine-modified HCo(PR3)(CO)3 complexes are two canonical classes of Co-based hydroformylation catalysts that exploit Co(I) centers but require high temperatures and pressures to achieve the desired activities. Recently proposed bisphosphine-modified cationic Co(II) catalyst ([HCo(CO)3(DPPBz)]+) was reported to be more active than neutral Co(I) systems at lower temperatures and pressures and comparable to the expensive and scarce Rh-based catalysts. However, the Co(I)/Co(II)-based catalysts are significantly affected by instability in the air. Hence, we have prepared cationic Co(II) hydroformylation precatalysts supported by trisphosphine ancillary ligands namely, Bis(2-diphenylphosphinoethyl)Phenylphosphine cobalt(II) acetylacetonate, [Co(acac)(DPPEPP)]BF4, and 1,1,1–Tris(diphenylphosphinomethyl)ethane cobalt(II) acetylacetonate, [Co(acac)(DPPME)]BF4. The structure and purity of the precatalysts were confirmed with mass spectrometry. The paramagnetic features of Co(II) and the resonance peaks of the triphosphine ligands were revealed by NMR spectroscopies. UV-Vis spectroscopy was employed to determine their stability. Catalytic assays showed that these systems are competent hydroformylation catalysts.
10:48-11:00 Light Activation of Molecular Motor in Polymersome Bilyers
Soumya Dawn (LSU A&M)
Soumya Dawn
Light-activated molecular motors have shown potential in disrupting cell membranes and modulating synthetic vesicles for drug delivery applications. While prior studies suggest that motor-induced effects arise from their rotation, the exact frequency of this motion in membrane environments remains unclear. To address this, we designed a molecular motor with an overcrowded alkene core, featuring a fluorenyl-based stator and a five-membered ring rotor, optimized for rotational frequencies in the mHz range. This allows for kinetic monitoring via NMR and UV-Vis spectroscopy.
Our study integrates these motors into diblock copolymer-based polymersomes, which mimic biomimetic membranes. UV light irradiation induces real-time photoisomerization and subsequent thermal helix inversion, enabling direct observation of motor dynamics within the bilayer. Utilizing low motor concentrations ensures membrane stability while capturing rotation over time. Our findings suggest that the motors exhibit rotational frequencies comparable to those in organic solvents, reinforcing their functional viability in biological-like systems.
These results offer critical insights into the interplay between molecular motor behavior and membrane properties. Future studies will explore motors with varying rotation speeds, activated by visible or near-infrared light, to design advanced polymersomes for therapeutic delivery, nanoreactors, and artificial organelles operating out of equilibrium.
11:03-11:15 Uncovering and optimization of the anticancer activity of N1-phenylbenzene-1,2-diamines.
Lara Boudreaux (SLU)
Jean Fotie, Lara Boudreaux
Cancer is a serious public health issue by any measure and is estimated to cause about one in six deaths worldwide. Additionally, approximately 400,000 children under the age of 14 are diagnosed with cancer each year globally, with another one million children becoming orphans due to maternal deaths, primarily from breast and cervical cancers. Unlike many other diseases, the overall incidence of cancer is higher in developed countries compared to transitioning or low-income countries. The situation is further worsened by the growing resistance to numerous available therapies, compounded by their pervasive side effects.
As part of our effort to design and develop new scaffolds with selective anticancer properties, our research group recently discovered a lead compound, N1-phenylbenzene-1,2-diamine derivative (JFSC-1) with a strong inhibitory activity against melanoma and non-melanoma skin cancer cell lines. The anticancer properties of this molecule were further confirmed through dose-response curves obtained from additional assays conducted by the National Cancer Institute's Developmental Therapeutics Program. This presentation highlights efforts towards further validation of the observed activities and the development of a more comprehensive structure-activity relationship through the preparation and biological evaluation of analogs.
11:18-11:30 Thiol/Vinyl Ether Frontal Polymerization: Applications and Properties on Wood.
Jacob Russell (LSU A&M)
Jacob Russell
Polymers have shown to have many applications in various fields. An exploration of the applications and properties of a composition of a tri thiol, a divinyl ether, a cationic superacid generator, a free-radical thermal initiator, and fumed silica induced with frontal polymerization thermally on the substrate wood. Frontal polymerization is a type of polymerization that starts at a small point and spreads as a wave through monomers converting them into polymers. The benefits to using this polymer system as compared to others is that it is one-pot, it can be used in thin layers, there is no additional cure time, and it polymerizes fast. Wood has many benefits and problems when it is used as a substrate because of its flaws with water absorbance and its non-homogeneous structure waves may have a hard time starting but with woods low thermal conductivity, it shows its benefits because it doesn’t act as a heat sink. The polymer system and its properties on wood will be tested for adhesion with shear strength testing, or pulling it apart, and its front properties will be tested with recordings of its front velocity and temperature.
11:33-11:45 Synthesis of syn-β-hydroxy-α-aryl carboxylic acid esters via 9-borabicyclo[3.3.1]nonyl trifluoromethanesulfonate (9-BBNOTf)-mediated aldol reactions of arylacetates
Sophie Lee (SLU)
Prem Chanda, Sophie Lee
Dicyclohexylboron triflate (Chx2BOTf)-mediated aldol reactions of methyl phenylacetates provided good yields of syn-β-hydroxy-α-phenyl carboxylic acid esters with relatively low diastereoselectivities (76-90%) and the use of dibutylboron triflate (n-Bu2BOTf) improved diastereoselectivities (90-95%) with poor yields (51-64%). To improve both yields and diastereoselectivities simultaneously, we studied the effects of steric of a boron reagent on diastereoselectivities and yields in the boron-mediated aldol reactions of arylacetates. In this presentation, we will discuss the 9-borabicyclo[3.3.1]nonyl trifluoromethanesulfonate (9-BBNOTf)-mediated aldol reactions of arylacetates, which resulted an efficient synthesis of syn-β-hydroxy-α-aryl carboxylic acid esters.