Synthesis of 5,6-Diaminoacenaphthylene by Reduction of Sterically Crowded Nitro Groups with Sodium Dithionite

5,6-Diaminoacenaphthylene was synthesized in four steps from acenaphthene. This seemingly simple molecule provides unique synthetic challenges because it is relatively difficult to reduce the nitro groups and the molecule contains a particularly reactive double bond. It was determined that the only feasible sequence for the synthesis was to nitrate acenaphthene, then brominate, eliminate, and finally selectively reduce. Several reduction methods were attempted before finding one that would completely reduce both nitro groups while leaving the double bond intact

Asking \u3cem\u3eWhy\u3c/em\u3e: Analyzing Students\u27 Explanations of Organic Chemistry Reaction Mechanisms using Lexical Analysis and Predictive Logistic Regression Models

In order to evaluate student understanding of chemical reactions and reaction mechanisms, it is necessary to ask students to construct written or oral explanations of mechanistic representations. Studies have shown that students can reproduce pictorial representations of organic chemistry mechanisms without understanding the meaning of the representations. Grading written assessments is time-consuming, which limits their use in large-lecture courses. To address this limitation, lexical analysis and logistic regression techniques can be used to develop models that predict human scoring for constructed-response items. In this dissertation, students’ responses to constructed-response items about what is happening and why in organic chemistry reaction mechanisms are explored. Specifically, student responses about an acid−base proton-transfer mechanism (Chapter 3) and a unimolecular substitution (i.e., SN1; Chapter 5) mechanism are examined. The acid−base proton-transfer item was scored for use or non-use of the Lewis acid−base model. The SN1 item was scored for three levels of explanation sophistication. The utility of predictive text analysis models for the development of instructional materials is exemplified in Chapter 4. A research-based tutorial was designed to increase student use of the Lewis acid−base model in their written responses. The predictive model was employed to efficiently analyze students’ responses before and after the tutorial to assess the effectiveness of the tutorial. The tutorial was found to have a positive impact on use of the Lewis model. The lexical analysis and logistic regression techniques used in this dissertation can be applied to many other contexts to produce predictive models. Such models can be used in the classroom to help instructors and students evaluate the quality of their explanations. Instructional tools such as the Lewis acid−base tutorial in Chapter 4 can be used to help students construct the knowledge necessary to appropriately explain reaction mechanisms. As many have called for the use of writing in the science classroom, techniques like those presented in this dissertation could pave the way for open-access, efficient ways to provide feedback for writing prompts in organic chemistry courses and classes in the sciences as whole

ChatGPT Convincingly Explains Organic Chemistry Reaction Mechanisms Slightly Inaccurately with High Levels of Explanation Sophistication

The chemistry education research community values and emphasizes the role of constructing explanations and mechanistic reasoning to support students’ learning of organic chemistry. Emerging large language model (LLM) and generative artificial intelligence (GAI) technologies are uniquely equipped to advance the teaching and learning of chemistry. GAI-based chatbots, such as ChatGPT, have the potential to help students learn mechanistic reasoning through their generated responses. This study investigates the extent to which 255 ChatGPT-generated responses are accurate explanations of 85 different reaction mechanisms and exhibit mechanistic reasoning as categorized by the levels of explanation sophistication framework. The study also explores the effects of prompt engineering on mechanism accuracy and explanation sophistication through three types of prompt cueing. Study findings show that (1) a quarter of responses are fully accurate explanations of reaction mechanisms and the majority contain predominantly accurate explanations of chemical phenomena and identification of nucleophiles and electrophiles, (2) responses exhibit high levels of explanation sophistication, and (3) prompt engineering plays a significant role in eliciting high levels of explanation sophistication but not mechanism description accuracy. Results are situated in mechanistic reasoning and prompt engineering frameworks with a focus on how these new technologies can be integrated into the chemistry classroom

Development and Evaluation of a Lewis Acid-Base Tutorial for Use in Postsecondary Organic Chemistry Courses

A well-developed understanding of the Lewis acid-base model is highly important for the understanding of organic chemistry. As such, students should receive instruction and be assessed on use of the model. Online tutorials and constructed-response items provide a means for confirming that students have a well-developed conceptualization of the Lewis acid-base model. In a prior study, a predictive logistic regression model was presented that can be used with constructed-response assessment items to determine use of a Lewis acid-base model in written responses. In this study, we use that predictive model to evaluate the effectiveness of a tutorial designed to promote meaningful understanding of the Lewis acid-base model in three different instructional contexts: first-semester organic chemistry students before summative assessment, first-semester organic chemistry students after summative assessment, and second-semester organic chemistry students. Additionally, we evaluated the learning gains of one set of first-semester students after a three-week time delay. McNemarâ s test results suggest that the tutorial had a net positive impact in all three instructional contexts, with the most significant impact observed with the second-semester students. This work has implications for further development of literature-based tutorials to promote meaningful understanding of organic chemistry reaction mechanisms assessed by constructed-response items.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author