Peer-Led Team Learning and Student Success

Peer-Led Team Learning (PLTL), a nationally recognized teaching and learning model, was introduced into the General Chemistry course at Pace University in 2014. The objective of this study was to determine the effect of the introduction of PLTL on the students’ final exam scores, and through surveys, determine how students viewed both the PLTL program and their Peer Leaders. In addition, this study sought to monitor the progress of Peer Leaders as they entered an upper-level Inorganic Chemistry class to determine whether the experience of being a Peer Leader helped their success in this course. The biggest difference, when comparing exam scores from two separate years before and after PLTL implementation, was found to be 10%. However, upon averaging exam scores over several years before and after the introduction of the PLTL program, a more modest average increase of 4% was determined. It was found that students with Peer Leader experience performed better in an upper-level Inorganic Chemistry class compared to those with no Peer Leader experience. Results from surveys administered to both students and Peer Leaders regarding their experiences, as well as the results from students evaluating their Peer Leaders, are reported here. Overall, the implementation of PLTL has led to greater interactions between the Instructor, Peer Leaders, and undergraduate students, thereby furthering a greater interest in chemistry and increasing the students’ sense of community

Mass Spectrometric Analysis of Oxidized Eicosapentaenoic Acid Sodium Salt

Eicosapentaenoic acid (EPA) is an omega-3 polyunsaturated fatty acid (PUFA) with 20 carbon atoms and 5 carbon-carbon double bonds. Mammalian cells cannot synthesize long chain PUFAs such as EPA de novo, and, thus, the most effective way to enrich cells in EPA is by dietary intake of fish oils. EPA supplementation causes an increase in its concentration in plasma lipids and in cell membrane phospholipids. Many beneficial effects of EPA supplementation have been noted, including (1) the potential to sensitize cancerous tumors towards chemotherapy, (2) the promotion of cardiovascular health, and (3) the alleviation of some mental disorders, but results from clinical trials have sometimes been disparate. In this study, we report the use of mass spectrometry to investigate the autoxidation of EPA, thereby demonstrating the formation of a variety of oxidized products. The oxidative stress of the patient may affect the response to EPA and may, in part, explain divergent results from clinical trials

Crystal structure of di-μl-chlorido-bis[chloridobis( 1,2-dimethyl-5-nitro-1H-imidazole-κN3)- copper(II)] acetonitrile disolvate

1,2-Dimethyl-5-nitroimidazole (dimetridazole, dimet) is a compound that belongs to a class of nitroimidazole drugs that are effective at inhibiting the activity of certain parasites and bacteria. However, there are few reports that describe structures of compounds that feature metals complexed by dimet. Therefore, we report here that dimet reacts with CuCl2•H2O to yield a chloridebridged copper(II) dimer, [Cu2Cl4(C5H7N3O2)4] or [Cu(μ-Cl)Cl(dimet)2]2. In this molecule, the CuII ions are coordinated in an approximately trigonal– bipyramidal manner, and the molecule lies across an inversion center. The dihedral angle between the imidazole rings in the asymmetric unit is 4.28 (7)℃ . Compared to metronidazole, dimetridazole lacks the hydroxyethyl group, and thus cannot form intermolecular O•••H hydrogen-bonding interactions. Instead, [Cu(μ-Cl)Cl(dimet)2]2 exhibits weak intermolecular interactions between the hydrogen atoms of C—H groups and (i) oxygen in the nitro groups, and (ii) the terminal and bridging chloride ligands. The unit cell contains four disordered acetonitrile molecules. These were modeled as providing a diffuse contribution to the overall scattering by SQUEEZE [Spek (2015). Acta Cryst. C71, 9–18], which identified two voids, each with a volume of 163 A ° 3 and a count of 46 electrons, indicative of a total of four acetonitrile molecules. These acetonitrile molecules are included in the chemical formula to give the expected calculated density and F(000). 1

Crystal structure of bis[1-(2-hydroxyethyl)-2-methyl-5-nitro- 1H-imidazole-κN3]silver(I) tetrafluoridoborate methanol monosolvate

1-(2-Hydroxyethyl)-2-methyl-5-nitro-1Η-imidazole (metronidazole, MET) is a medication that is used to treat infections by a variety of anaerobic organisms, but there are relatively few reports of the structures of metal compounds that exhibit coordination of metronidazole. We have demonstrated that MET reacts with AgBF4 to give [Ag(MET)2]BF4•CH3OH, in which the AgI cation is coordinated by two MET ligands with a trans arrangement. The structure of [Ag(MET)2]BF4 exhibits some interesting differences from its nitrate counterpart, [Ag(MET)2]NO3 [Fun et al. (2008). Acta Cryst. E64, m668]. For instance, although the two MET ligands of both [Ag(MET)2]BF4 and [Ag(MET)2]NO3 are almost coplanar, the former compound has an anti-like geometry with a molecular inversion center, but the latter has a syn-like arrangement. In the crystal, the BF4− anion is linked by an O—H•••F hydrogen bond to the methanol solvent molecule, which is, in turn, linked to the cation by an O— H•••O hydrogen bond; the components of the structure are linked by O—H•••O hydrogen bonds, forming chains along [001]. One of the MET ligands and the BF4 − anion are disordered over two sets of sites with ratios of refined occupancies 0.501 (17):0.499 (17) and 0.539 (19):0.461 (19), respectively

Mass Spectrometric Analysis of Oxidized Eicosapentaenoic Acid Sodium Salt

Eicosapentaenoic acid (EPA) is an omega-3 polyunsaturated fatty acid (PUFA) with 20 carbon atoms and 5 carbon-carbon double bonds. Mammalian cells cannot synthesize long chain PUFAs such as EPA de novo, and, thus, the most effective way to enrich cells in EPA is by dietary intake of fish oils. EPA supplementation causes an increase in its concentration in plasma lipids and in cell membrane phospholipids. Many beneficial effects of EPA supplementation have been noted, including (1) the potential to sensitize cancerous tumors towards chemotherapy, (2) the promotion of cardiovascular health, and (3) the alleviation of some mental disorders, but results from clinical trials have sometimes been disparate. In this study, we report the use of mass spectrometry to investigate the autoxidation of EPA, thereby demonstrating the formation of a variety of oxidized products. The oxidative stress of the patient may affect the response to EPA and may, in part, explain divergent results from clinical trials

Teaching Green Chemistry Principles to Undergraduate Students

The environment is affected by the actions of mankind in multitudinous ways, many of which are detrimental, giving rise to pollution and toxic waste, ultimately making our planet less inhabitable. While remediation and new regulations help to prevent pollution and toxic waste, there is also a need to change the behavior of future generations of consumers and producers of new products. Future chemists and innovators are charged with the responsibility of developing new chemical processes and products that not only meet the needs of our growing population (in terms of energy, clean water and food), but also protect human health and the environment. Green Chemistry is a revolution in the design of molecules that provides new opportunities for economic development while considering the impact on health and the environment. Green Chemistry utilizes a set of guiding principles, originally provided by Anastas and Warner (Green Chemistry: Theory and Practice, 1998), aimed at decreasing/removing the use/generation of hazardous substances in the design, manufacture and application of products. To help improve the creative and innovative thinking behind Green Chemistry, it is important to expose chemistry students to these principles at the undergraduate level. While suitable Green Chemistry experiments are known, successful implementation requires running test trials and performing additional basic research. We have embarked upon the testing and further design of experiments for implementation into an undergraduate laboratory course and report our results in this endeavor

Coordination of metronidazole to Cu(II): Structural characterization of a mononuclear square-planar compound Joshua H.

The reaction between metronidazole [1-(2-hydroxyethyl)-2-methyl-5-nitroimidazole, MET] and CuCl2•2H2O in methanol solution has allowed isolation of blue crystals of composition Cu(MET)2Cl2•MeOH. These crystals have been shown by X-ray diffraction to consist of mononuclear square-planar trans-Cu(MET)2Cl2 molecules in which the metronidazole ligands are trans to each other, as are the Cl ligands. The structure of this compound is very different from other compounds that have been obtained from the reaction between CuCl2•2H2O and metronidazole, namely [Cu(MET)2(μ-Cl)Cl]2 and [Cu(MET)2(μ-Cl)(OH2)]2[Cl]2, which are dimers featuring bridging chloride ligands

Crystal structure of hexakis(dimethyl sulfoxide-κO)cobalt(II) bis[trichlorido(quinoline-κN)cobaltate(II)]

There are few reports that describe crystal structures of compounds containing cobalt complexed to either dimethyl sulfoxide (Me2SO) or quinoline (C9H7N). The title compound, [Co(C2H6OS)6][CoCl3(C9H7N)]2, is a cobalt salt in which the metal ion is complexed to both Me2SO and quinoline. In particular, we observed that anhydrous cobalt(II) chloride reacts with quinoline in Me2SO to form a salt that is to be formulated as [CoII(Me2SO)6]2+{[CoIICl3quinoline]2 ‾ }. The CoII atom in the cation portion of this molecule lies on a inversion center and is bound to the O atoms of six Me2SO moieties in an octahedral configuration, while the CoII atom in the anion is attached to three chloride ligands and one quinoline moiety in a tetrahedral arrangement

Crystal structure of hexa-μ-chlorido-μ4-oxido-tetrakis{[1-(2-hydroxyethyl)-2- methyl-5-nitro-1H-imidazole-κN3]copper(II)} containing short NO2· · ·NO2 contacts

The title tetranuclear copper complex, [Cu4Cl6O(C6H9N3O3)4] or [Cu4Cl6O- (MET)4][MET is 1-(2-hydroxyethyl)-2-methyl-5-nitro-1Η-imidazole or metronidazole], contains a tetrahedral arrangement of copper(II) ions. Each copper atom is also linked to the other three copper atoms in the tetrahedron via bridging chloride ions. A fifth coordination position on each metal atom is occupied by a nitrogen atom of the monodentate MET ligand. The result is a distorted CuCl3NO trigonal–bipyramidal coordination polyhedron with the axial positions occupied by oxygen and nitrogen atoms. The extended structure displays O− H ⋅ ⋅ ⋅O hydrogen bonding, as well as unusual short O⋅ ⋅ ⋅ N interactions [2.775 (4) A ˚ ] between the nitro groups of adjacent clusters that are oriented perpendicular to each other. The scattering contribution of disordered water and methanol solvent molecules was removed using the SQUEEZE procedure [Spek (2015). Acta Cryst. C71, 9–16] in PLATON [Spek (2009). Acta Cryst. D65, 148–155]