A 3-week module incorporating the principles of green chemistry was developed for a large-enrollment, introductory organic chemistry laboratory course. An emphasis was placed on students planning their own experiments with the goal of obtaining a greener reaction (week 1). Students executed their designed experiments in week 2 and were given an opportunity to repeat the experiment or further optimize the reaction conditions to improve the yields during week 3. A postlab writing assignment as well as pre-and postsemester surveys were used to evaluate student learning and confidence. These data revealed an increase in students' understanding of green chemistry concepts as well as their confidence in their ability to modify a reaction to improve the results. We anticipate that this overall framework can be adapted to other large-and small-enrollment laboratory courses.

Catalyst-transfer polycondensation (CTP) is a relatively new method for synthesizing conjugated polymers in a chain-growth fashion using transition metal catalysis. Recent research has focused on screening catalysts to broaden the monomer scope. In this effort, small molecule reactions have played an important role. Specifically, when selective difunctionalization occurs, even with limiting quantities of reaction partner, it suggests an associative intermediate similar to CTP. Several new chain-growth polymerizations have been discovered using this approach. We report herein an attempt to use this method to develop chain-growth conditions for synthesizing poly­(2,5-bis­(hexyloxy)­phenylene ethynylene) via Sonogashira cross-coupling. Hundreds of small molecule experiments were performed and selective difunctionalization was observed with a Buchwald-type precatalyst. Unexpectedly, these same reaction conditions led to a step-growth polymerization. Further investigation revealed that the product ratios in the small molecule reactions were dictated by reactivity differences rather than an associative intermediate. The lessons learned from these studies have broad implications on other small molecule reactions being used to identify new catalysts for CTP.

Introductory-level laboratory courses provide students with hands-on experience using the discipline's tools and theories. These courses often rely on recipebased experiments due to the constraints of large enrollments, short lab periods, and the desire to minimize complexity. In addition, covering a breadth of topics can lead to a fragmented curriculum with little carryover in learning from week to week. Herein, we describe an overhaul of an introductory organic chemistry laboratory curriculum, informed by the strategies of meaningful learning and a desire to make the course experience mimic a research lab. This new course, primarily taught to first-year undergraduate students at the University of Michigan, is framed with three interconnected modules. We present herein the first module, which focuses on thinlayer chromatography (TLC). In the first week, students learn how to perform TLC using a variety of compounds and solvent mixtures, gaining an understanding of how intermolecular interactions affect their retention. In the second week, they practice using TLC to distinguish reagents and reaction byproducts and in the third week apply TLC to monitor reaction progress and test their hypothesis. We assessed student learning through a writing assignment at the end of the three-week module. We also assessed how the overall course affects student comprehension of TLC concepts and confidence. Our findings suggest that this learn, practice, apply approach toward teaching introductory organic chemistry laboratory concepts leads to learning gains and increased confidence.

Synthesizing conjugated polymers via catalyst‐transfer polymerization (CTP) has led to unprecedented control over polymer sequence and molecular weight. Yet many challenges remain, including broadening the monomer scope and narrowing the molecular weight dispersities. Broad polymer dispersities can arise from nonliving pathways as well as slow initiation. Previously, slow initiation was observed in Ni‐mediated CTP of phenylene monomers. Although precatalysts with faster initiation rates have been reported, the rates still do not exceed propagation. Herein a second‐ and third‐generation of reactive ligands are described, along with a simple method for measuring initiation rates. A precatalyst with an initiation rate that exceeds propagation is now reported, however, the resulting polymer samples still exhibit broad dispersities, suggesting that slow initiation is not the most significant contributing factor in Ni‐mediated phenylene polymerizations. In addition, initiation rates measured under authentic polymerization conditions revealed that both exogenous triphenylphosphine and an ortho‐trifluoroethoxy substituent on the reactive ligand have a strong influence. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 1530–1535

Infographics are increasingly used to communicate complex topics to the public. By coupling visually appealing graphics with compelling narratives, infographics can both engage and inform the audience. We designed an assignment wherein students create infographics with the dual purpose of helping them connect course concepts to their daily lives and practice science communication. Most students focused on compounds found in food, beverages, cosmetics, and medicine. The infographics were assessed based on the effectiveness of the layout, the quality and clarity of the graphical and textual content, and the reliability of the cited sources. Student reflections on the assignment revealed strong connections between their course learning and their infographic topics. Although this assignment was part of a college laboratory course, it can be adapted for alternative settings.