• Aggregation Properties of Ionic Liquids in Low Polarity Solvents

      Hoffmann, Markus M.; Cade, Elise; The College at Brockport (2015-05-18)
      Ionic liquids are salts that are liquid below 100oC. Ionic liquids are of very low volatility and especially those ionic liquids with high conductivity and lower viscosities are used as medium for chemical synthesis and electrochemistry. Normally, salts do not dissolve in solvents of low polarity. However, many ionic liquids are very soluble or completely miscible in low polarity solvents and the physical chemistry of the resulting solutions is not well understood. The goal of our ongoing research is to elucidate the speciation (freely dissolved ions, ion pairs and aggregates) present for ionic liquids dissolved in solvents of low polarity. In prior work in Dr. Hoffmann’s laboratory, it was found that the ionic liquid 1-­?hexyl-­?3-­?methylimidazolium bis(trifluoromethylsulfonyl)amide ([C6mim][NTf2]), which is completely miscible in chloroform (CHCl3), displays an aggregate size maximum at surprisingly dilute concentrations of 0.1 molal (m). In Dr. Hoffmann’s lab, this was interpreted as an apparent re-­?dissolution by a change of mass transport mechanism from ion pairs and aggregates self-­?diffusing as individual species to a “hopping” motion of single ion pairs between aggregates. These results motivated further research to discern if this particular behavior can be observed for other pairs of molecular solvent and ionic liquid solutes. This thesis work presents experimental results for concentration and temperature dependent self-­?diffusion coefficients measured by NMR spectroscopy in conjunction with viscosity measurements to determine the average hydrodynamic radii of the present species. Five systems were investigated: [C6mim][NTf2] dissolved in dichloromethane (CH2Cl2), tetrahydrofuran (THF), and chlorobenzene (C6H5Cl), and two other ionic liquids, 7 1-­?butyl-­?3-­?methylimidazolium bis(trifluoromethylsulfonyl)amide [C4mim][NTf2] and 1-­? ethyl-­?3-­?methylimidazolium bis(trifluoromethylsulfonyl)amide [C2mim][NTf2] in CH2Cl2. Our findings thus far show that similar behavior to that of [C6mim][NTf2] in CHCl3 occurs in three systems: [C4mim][NTf2] in CH2Cl2, [C2mim][NTf2] in CH2Cl2, and [C6mim][NTf2] in C6H5Cl . Specifically, for the three systems we observe a maximum of the average radius size, and the corresponding concentration varies from system to system, from about 0.10 molal for [C6mim][NTf2] in C6H5Cl to about 0.18 molal for [C2mim][NTf2] in CH2Cl2.The remaining two systems, [C6mim][NTf2] in CH2Cl2 and [C6mim][NTf2] in THF, did not indicate a maxima in the hydrodynamic radius.
    • Effects of Ionic Liquids on Nucleic Acid Secondary Structures

      Blose, Joshua; Shaine, Miranda L.; The College at Brockport (2018-05-03)
      The effects of ionic liquids (ILs) on DNA are not well understood. Ionic liquids are important to the chemistry of DNA because they could serve as a long-term storage buffer for DNA, contribute to the use of DNA in nanotechnology and sensors, and influence the use of DNA as a platform for designing catalysts. In this research, imidazolium chloride ionic liquids with varying alkyl chain lengths were tested for their effects on the stability and structure on a representative DNA duplex. Thermal denaturation and ionic liquid titration experiments using Circular Dichroism spectroscopy were performed to assess the stability and conformation of DNA duplexes. Results of the experiments suggested that the imidazolium ionic liquids were interacting directly with the DNA, altering its structure and causing it to precipitate out of solution by the end of our titrations. This behavior was dependent on both the alkyl chain length of the ionic liquid as well as the concentration of the DNA and suggests that precipitation of the DNA comes after ionic-liquids are saturating DNA interaction sites.
    • Elucidation of the Effects of the Cellular Environment on the UNCG Hairpin Motif

      Blose, Joshua; Whittum, Michelle; The College at Brockport (2016-05-13)
      The effects of osmolytes on nucleic acid chemistry are generally not as well understood as for their protein counterparts. Recent studies have shown that these effects are rather complex and show significant dependencies on the chemical and structural properties of both the nucleic acid and the cosolute. Osmolytes have the potential to affect the stability of secondary structure motifs and alter preferences for conserved stable nucleic acid sequences. The goal of this research is to contribute to the understanding of the in vivo function of nucleic acids by studying the effects of different classes of osmolytes on the UNCG tetraloop motif. UNCG tetraloops are the most common and stable of the RNA tetraloops and are nucleation sites for RNA folding. UNCG loops have also been found to have a thermodynamic preference for a CG closing base pair. The thermal denaturation of UNCG containing hairpins was monitored using UV-Vis spectroscopy in the presence and absence of a series of polyols and amine-based osmolytes. Generally, the osmolytes had little effect of the thermodynamic preference for a CG closing base pair, except for PEG 200, which significantly destabilized the loops with a CG closing base pair relative to those with a GC closing base pair. Moreover this significant difference appears to be specific to UNCG loops when compared to other related sequences, suggesting that PEG 200 may have preferential interactions with the UNCG sequences in the presence of a CG closing base pair.
    • Functional Analysis of Wild-Type LGN and T450 Mutants

      Sreenilayam, Brandy; Elnicki, Ryan; The College of New Rochelle (2016-05-19)
      The protein LGN, named for the many repeats of the amino acids leucine (L), glycine (G) and asparagine (N), is crucial for mammalian cellular division. Specifically, LGN plays a significant role in cell polarity and alignment of the mitotic spindles and in its absence, the organism ceases to develop. In breast cancer, LGN is upregulated due to phosphorylation of T450 and the knockdown of LGN activity has been shown to suppress growth of breast cancer cells. Furthermore, a mutation to alanine at the 450th position also suppressed breast cancer cell growth. The goal of this project was to explore the biochemistry of both wild-type LGN and two T450 mutants of LGN in hope of gaining insight as to how LGN phosphorylation proliferates cancer. LGN was transiently expressed in BHK-570 tissue culture cells using a pCMV-LGN plasmid and LipoD 293 reagent. Protein expression of wild-type LGN was confirmed by both Western blot and immunocytochemistry of fixed, permeabilized cells using anti-GPSM2 antibody. Furthermore, the T450A and T450D mutants, which mimic the unphosphorylated and phosphorylated forms of LGN respectively, are being generated by PCR and will be sent for sequencing analysis to confirm the completed mutagenesis. Future experiments will determine the effect of phosphorylation of T450 on LGN function; specifically, additional localization studies of T450A and T450D mutants will be conducted and compared to that of wild-type LGN. Characterization of LGN function relative to the phosphorylation status of T450 could lead to the development of novel treatments for breast cancer.
    • Molecular Solvation in Phosphonium Ionic Liquids

      Heitz, Mark P.; Barra, Kathleen M.; The College at Brockport (2011-05-01)
      The goal of this research is to understand the solvation dynamics of coumarin 153 (C153) in an environmentally-friendly room temperature phosphonium ionic liquid (RTPIL) solvent. With virtually no vapor pressure, ILs are attracting attention as potential “green” replacements for conventional volatile organic solvents. ILs are also known for chemical stability, non-flammability and recycling potential. C153 is a prototypical fluorescent molecule known for its spectral sensitivity when in solution making it ideal for these studies. Neat trihexyltetradecyl phosphonium chloride (PIL-Cl) and methanol (MeOH) solvents were used to form an array of PIL-Cl mixtures spanning the complete range of mol fraction, in which C153 was dissolved. Solvation of C153 was determined using steady-state and time-resolved fluorescence spectroscopy. The C153 steady-state data shows a systematic blue shift as PIL-Cl is added to solution. The system is at net higher energy at high mol fraction PIL-Cl implying that C153/PIL-Cl interactions are less favorable compared to C153/MeOH. The solute emission intensity is quenched most effectively at a mol fraction of ~0.03 PIL-Cl suggesting that the solvent-solute interactions are most unique in this range of mol fraction. Similarly, the lifetime data show a minimum value at ~0.03 mol fraction PIL-Cl, also implying quenching of the probe at this relative solution composition. C153 is better solvated, more relaxed, at MeOH-rich mol fractions. Solvation dynamics are characterized by time-resolved Stokes shift measurements. The time-resolved center of gravity and associated solvation correlation function, C(t), show that solvation of C153 occurs at a faster rate in solutions of lower mol fraction PIL-Cl. The solvation times correlate to solvent viscosity. PILs showed slower solvation due to much larger viscosities than MeOH.
    • Palladium Catalyzed Hydrodechlorination of 4-Chloroanisole in Phosphonium Ionic Liquids

      Logan, Margaret E.; Hennig, Joseph (2016-06-24)
      Until their production was banned in 1979, polychlorinated biphenyls (PCB’s), formed as complex mixtures, were used in electrical equipment. Although they are no longer manufactured, some PCBs are still in service—albeit, in closed or semi-closed systems such as dielectric fluids for transformers and capacitors, or are still present in the environment. The continued presence of PCBs is problematic, due to their toxicity. Their hydrophobic nature and resistance towards metabolism leads to bio-accumulation up the food chain. resulting in long term effects in chronically exposed persons, like firefighters, factory workers or persons whose food have accumulated appreciable levels of PCBs. Efficient dechlorination of polychlorinated biphenyls (PCBs) has relevance in the environment, as it would reduce the toxicity of these pollutants. The chemistry described in this thesis is a model study for dechlorinating PCBs using 4- chloroanisole as a model compound. In this fundamental study, palladium-catalyzed dechlorination of chloroanisole was studied in ionic liquids (ILs), where the catalyst was expected to be more stable than in methanol, the previously used solvent. This thesis describes the hydrodechlorination efficacy and longevity of palladium catalysts with ligands 4 (2-(di-tert-butylphosphino)biphenyl) and 5 (2-(di-tertbutylphosphino)-2 ’ ,4’ ,6’ -triisopropylbiphenyl) in methanol and ILs 6 (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide), 7a (trihexyl(tetradecyl)phosphonium chloride), and 7b (trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide) (Scheme 9). Additionally, this thesis focuses on improving the logistical aspects of determining the water content in the ILs, sampling reactions to follow their progress, data reproducibility, and analysis of reaction progress, as well as the impact of water on the rate of hydrodechlorination reactions in ionic liquids. After excluding results from obviously compromised reactions, it appears that reactions in IL 7b proceed faster on average than those in IL 7a, that reactions performed with ligand 5 run faster than those with ligand 4, and that there may be a bell curve to the concentration of water vs rate of reaction, with the reaction proceeding best at intermediate water concentrations. Further experiments would be needed to confirm these results.
    • The Effects of the Storage Conditions of the Juice and the Effects of Nutrient Supplementation on Wine Fermentation

      Godleski, Stephen; Geer, Stephanie; The College at Brockport (2011-05-01)
      Storage conditions of Concord grape juice prior to fermentation and types of supplementation during fermentation were studied. Two batches of juice were stored, one at ambient temperature and one at 4.4°C, and were then fermented using four different nitrogen supplementation methods: a control with no supplementation, addition of 100 mg/L nitrogen using diammonium phosphate (DAP), a total target level of 250 mg/L nitrogen using DAP, and complex supplementation using Go-Ferm, Fermaid-K, and DAP. Prise de Mousse yeast was used for fermentation, which is a yeast strain of Saccharomyces cerevisiae. Upon completion of fermentation, the wine was analyzed for residual sugar, nitrogen, bound and total SO2, pH, titratable acidity, volatile acidity, organic acids, and phenols. Sensory evaluation was also performed. There were some significant differences between the different wines, but none of the wines were considered significantly better than the others during sensory analysis.