Theses and Dissertations at Montana State University (MSU)
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Item Mechanistic studies and new methodologies relevant to palladium-catalyzed chemodivergent cross-coupling reactions(Montana State University - Bozeman, College of Letters & Science, 2021) Reeves, Emily Kathryn; Chairperson, Graduate Committee: Sharon NeufeldtPalladium-catalyzed cross-couplings are powerful methods for constructing new carbon-carbon bonds in organic molecules. While the mechanism of these reactions are generally well studied, complexities are introduced when the starting materials involved in the reaction contain several possible sites at which the new C-C bond can be made. It is often desirable for the palladium catalyst to facilitate (chemo)selective cross-coupling at just one of the reaction sites while leaving the other(s) intact. This can be challenging and often requires extensive tuning of the palladium catalyst and the reaction conditions. In this work, we describe efforts to better understand the properties causing palladium catalysts to react chemoselectively at aryl chloride (C-Cl) or triflate (C-OTf) reaction sites. Using a combined approach of computational and experimental chemistry, we demonstrate that solvent plays a critical role in the reaction selectivity by coordinating to the palladium catalyst and promoting reaction at C-OTf sites via formation of bisligated palladium. Anionic additives like inorganic bases play a complementary role in promoting reaction at C-OTf sites. We additionally describe efforts to develop new chemodivergent cross-coupling methodologies using palladium-N-heterocyclic carbene precatalysts. These catalysts demonstrate robust reactivity under mild conditions, allowing for a greatly expanded scope of chemoselective cross-coupling products, especially biaryl triflates.Item Wetland biodiversity in Grand Teton National Park(Montana State University - Bozeman, College of Letters & Science, 2022) Levandowski, Mary Lynn; Chairperson, Graduate Committee: Andrea Litt; Andrea R. Litt was a co-author of the article, 'Spatial and temporal isolation and size of wetlands influence richness and functional composition of aquatic macroinvertebrates' which is contained within this thesis.; Andrea R. Litt, Megan F. McKenna, Shan Burson and Kristin L. Legg were co-authors of the article, 'Multi-method biodiversity assessments from wetlands in Grand Teton National Park' in the journal 'Ecological indicators' which is contained within this thesis.Freshwater wetlands support high biodiversity, yet many wetlands are subject to shifts in precipitation and temperature under projected climate patterns. These changes can alter wetland hydrological regimes, potentially leading to longer or more frequent dry periods, with effects that differ among taxa. In this thesis we aim to build on the understanding about biodiversity in wetlands and how these species may be affected by climate change, in hopes of providing information for land management. To accomplish these goals, we first focused on macroinvertebrates, a group that employs diverse strategies for surviving wetland drying. We explored the roles of wetland size, spatial isolation, and temporal isolation on macroinvertebrate richness and community composition. In summer 2018, we collected macroinvertebrates from 18 wetlands in Grand Teton National Park. We found macroinvertebrate family richness increased with wetland depth and slower rates of drying. We also found the interaction between spatial and temporal isolation explained the most variation in community composition for all the life history strategies we examined. Second, we explored the utility of different automated tools to monitor biodiversity in wetlands. In 2017, we placed wildlife cameras, as well as acoustic (audible and ultrasonic) recorders at 4 permanent wetlands in Grand Teton National Park for a week in June and August; we also completed a visual survey during each of these time intervals. We compared the number and type of species detected by each method over the summer to evaluate the effectiveness of each method for monitoring. Using wildlife cameras, in addition to visual surveys, increased the observation time at surveyed wetlands, captured complementary species, and recorded dynamics in the water level during the summer. These two chapters provide insights about how changes resulting from increased drying may affect one of the most biodiverse taxa and offer methods that allow monitoring of many taxa simultaneously.Item Hybrid objects(Montana State University - Bozeman, College of Arts & Architecture, 2021) Figueroa, Casey Curran; Chairperson, Graduate Committee: Jim Zimpel and Walter Fleming (co-chair)What follows is an exploration of praxis in Studio Art informed by research and application of methodologies and paradigms found within Indigenous culture. By examining the roles of Relationality, Sovereignty, and Positionality found in Native American Studies, and applied in conjunction with the methods found in Contemporary Art, insight can be gained into how art and culture responds to contemporary circumstances and future changes, as well as how this can provide value to the fields of Native American Studies and contemporary art.Item Improving experimental methods: exploring procedural mechanisms affecting participant behaviors(Montana State University - Bozeman, College of Engineering, 2016) Page, Lenore Trinette; Chairperson, Graduate Committee: David ClaudioResearch with human participants involves a complex combination of procedural elements in order to establish internal, external and measurement validity. Examining the accuracy of research equipment and methods that elicit similar behaviors as the general public is difficult. This research used driving as a model to address elements in the procedures that participants experience to elicit realistic behaviors. An instrumented vehicle (IV) and driving simulator (SIM) measured experimental behaviors for average approach speed (in the 20m before the legal stop line); lateral distance from curb at 20m; lateral distance from curb at legal stop line (0m) and the stopping location (distance before or after 0m); and, compared with measured general driving public behaviors at stop-controlled intersections. The linear mixed effect analyses combined two experiments. In both, surveys were administered to gather driver's trait anxiety, driving anxiety and social desirability scores. Experiment One drivers (36% female) were grouped as Novice (5, 16-17 year olds who just obtained driving license), Young (4, 16-17 year olds who obtained license over a year ago) and Adult (5, 30-55 year olds licensed near age 16). Experiment Two drivers (47 SIM, 44 IV; 35% female) were College age (18-21 year olds licensed near age 16) and exposed to 1 of 16 different combinations (one of those treatments matched Experiment One's procedure) of procedural changes for: researcher attire (casual or formal), researcher proximity (control room, front or rear passenger seat), mode of instruction delivery (spoken, read or video) and hypothesis statement (none or explicit). At the end of Experiment Two, participants' understanding of the experiment was coded into three debriefing variables. Absolute behavioral validity of the IV to public behavior was achieved in one treatment (formal, front seat, spoken and no hypothesis) and including the debriefing variables in the model; no SIM combination achieved this. Trait anxiety scores appeared to explain behaviors in the IV or SIM and improved result interpretation as interactions with other independent variables. For improved research methods, it is recommended that coded debriefing variables, specific procedural elements, and trait anxiety scores be included and used to explain interactions or differences in participant behaviors.Item RSVP cycles(Montana State University - Bozeman, 1976) Conner, Mitchell S.Item Methods to improve environmental monitoring network design(Montana State University - Bozeman, 1987) Cunnane, Mark; Chairperson, Graduate Committee: Howard S. PeavyItem Extraction of Colstrip coal using supersolvents in conjunction with the water-gas shift reaction(Montana State University - Bozeman, College of Engineering, 1986) Losinski, Sylvester John