Author Profile

Proton Conduction Studies of Pyridyl Diimide-Based Metal-Organic Frameworks

Pius Adelani, St. Mary's University, San Antonio

Location: Texas

Abstract

Materials with high proton conductivity are useful for various practical applications such as in electrocatalysis, thermoelectrics, sensing devices, and proton-exchange membrane fuel cells. The conductivity of most metal-organic frameworks (MOFs) is attributed to H3O+ ions generated through the water molecules. However, these materials suffer from declining conductivity as the temperature increases above 80 ᴼC because of decreasing relative humidity and dehydration. This project focuses on the use of the tools of synthetic chemistry to develop MOFs, replacing the water molecules with protogenic guest molecules such as imidazole and 1,2,4-triazole. Our findings may help students to understand the roles of protogenic guest molecules in proton conductivity of pyridyl diimide-based MOFs. Students in the Advanced Inorganic Chemistry class design an experiment based on literature reports, collect and interpret the data, formulate a hypothesis, and present results in writing and poster presentations during a college-wide symposium. Thereafter, research findings are incorporated into ongoing summer research project with undergraduate researchers over 10 weeks of full-time work (40 hrs/wk).

Student Goals

  1. Design an experiment based on prior knowledge to synthesize pyridyl diimide-based MOFs.
  2. Utilize best laboratory practices for responsible research conduct, including safe lab practice, good lab notebook practices, appropriate use of references, and ethical conduct of research.
  3. Communicate research outcome in writing and orally according to ACS style.

Research Goals

  1. Study the roles of imidazole in proton conduction studies of various pyridyl diimide-based MOFs (i.e. N,N-bis(4-pyridyl)-1,4,5,8-aryltetracarboxydiimide) (aryl = pyromellitic, naphthalene, perylene).
  2. Study the roles of other protogenic guest molecules (e.g., 1,2,4-triazole, etc.) in proton conduction studies of various pyridyl diimide-based MOFs.

Context

This CURE is a second semester Advance Inorganic Chemistry course required for chemistry majors. General Chemistry II is a prerequisite; this course introduces students to different chemical concepts and their applications in solving chemical problems. Most students have extensive background in synthetic organic laboratories. Students meet once a week for 4 hours over a 16-week semester. This class enrolls 5-10 students who are mostly sophomores.

Target Audience: Major, Non-major, Upper Division
CURE Duration: Full term

CURE Design

The goal of this research project is to investigate proton conduction in MOFs. The larger research question is how to achieve high proton conductivity in the absence of water. Students work in pairs assigned based on grades obtained from organic chemistry I & II. In order to help students design their own project, they are asked open ended questions and allowed enough time to think and come up with the answers. They are guided through their responses until they come up with a logical solution. Student reporters are assigned for each group by weekly rotations. Students' projects are monitored to make sure that they are goal oriented and feasible to complete in a semester. Summer research students make use of the data obtained from this CURE for their research and build upon it.

Core Competencies: Synthesis, crystallization, spectroscopy, and interpretation of data
Nature of Research: Basic Research

Tasks that Align Student and Research Goals

Research Goals →
Student Goals ↓
Research Goal 1: Study the roles of imidazole in proton conduction studies of various pyridyl diimide-based MOFs (i.e. N,N-bis(4-pyridyl)-1,4,5,8-aryltetracarboxydiimide) (aryl = pyromellitic, naphthalene, perylene).
Research Goal 2: Study the roles of other protogenic guest molecules (i.e. 1,2,4-triazole, etc.) in proton conduction studies of various pyridyl diimide-based MOFs.

Student Goal 1: Design an experiment based on prior knowledge to synthesize pyridyl diimide-based MOFs
  • Summarize using a schematic diagram the synthetic approaches used in the provided literature.
  • Describe a refluxing apparatus setup and process.
  • Use Google Scholar to find 5 relevant research articles published in the past 10 years on the use of pyridyl diimides to design metal-organic frameworks.
  • Use UTSA library to download papers.
  • Create an annotated diagram of two of the papers on pyridyl diimide-based MOFs using provided examples.
  • Write a paragraph describing MOFs and their importance.
  • Outline two different approaches used for the synthesis of pyridyl diimide-based MOFs.
  • Design the experiment including plans for synthesis of ligands, characterization using spectroscopic techniques (UV-Vis, FTIR, NMR), and synthesis of MOFs as well as an experimental timeline.
  • Explore various conditions for growing the MOFs crystals, such as hydrothermal and solvothermal techniques, including parameters such as temperature, solvent, reaction time, cooling rate, etc.
  • Examine the crystals under the microscope and describe the morphology of the MOFs.

  • In addition to the tasks listed in column one (aligning research with student goal 1), design an experiment for replacing the imidazole guest molecule with 1,2,4-triazole.
  • Compare the proton conduction properties with different protogenic guest molecules.

 


Student Goal 2: Utilize best laboratory practices for responsible research conduct, including safe lab practice, good lab notebook practices, appropriate use of references, and ethical conduct of research
  • Follow proper laboratory safety standards and etiquette, including use of goggles, lab aprons, etc.
  • Keep records of all procedures performed in the laboratory.

  • Follow proper laboratory safety standards and etiquette, including use of goggles, lab aprons, etc.
  • Keep records of all procedures performed in the laboratory.

Student Goal 3: Communicate research outcome in writing and orally according to ACS style
  • Summarize the current status of an experiment and associated inferences, including an evaluation of whether an experiment is working or not.
  • Use references to defend inferences.
  • Defend and propose the next step for the experiment.
  • Compare and contrast research outcomes with other groups.
  • Prepare and present research outcomes to the class using Powerpoint.
  • Prepare and present the research as a poster at the School of Science, Engineering and Technology (SET) research symposium.
  • Write a draft manuscript using ACS template/style.

  • Summarize the current status of an experiment, inferences, and whether experiment is working or not?
  • Use references to defend inferences.
  • Defend and propose the next step for the experiment.
  • Compare and contrast research outcomes with other groups.
  • Prepare and present research outcomes to the class using Powerpoint.
  • Prepare and present the research as a poster at the SET research symposium.
  • Write a draft manuscript using ACS template/style. 


Instructional Materials

Preparing an Annotated Bibliography.pdf (Acrobat (PDF) 200kB Aug18 21)

Assessment

Assessment in CURE (Microsoft Word 2007 (.docx) 13kB Aug18 21)

Grading rubric for presentation.xlsx (Excel 2007 (.xlsx) 18kB Mar10 23)

Instructional Staffing

Linda Raabe is the laboratory coordinator.

Author Experience

Pius Adelani, St. Marys University

My motivation is to increase the number of students that benefit from undergraduate research experience during their studies here at St. Mary's University. I thrive on creating a hands-on learning environment where students can apply their knowledge to solve real-world problems using synthetic inorganic tools.

Advice for Implementation

It is important to let students know that research projects don't always yield positive results. The most important takeaways for them are the development of research skills and having first-hand experience with how research projects are conducted. This CURE can be adapted to different synthetic projects. Grading should be focused on the steps involved and not on the end results. Another option is to let students investigate various transition metal salts for crystal growth to determine those that crystalize with the ligands.

Iteration

This research project was designed for students to have the freedom to design their own project, troubleshoot, and solve a real-world problem. Students learn to perform certain synthetic techniques such as refluxing, solvent removal with rotary evaporator, recrystallization of ligands, spectroscopic analysis, and crystal growth of metal-organic frameworks. These techniques are performed multiple times. Crystal growths with different transition metal cations are unpredictable, and we need to vary the synthetic conditions in order to achieve a significant success. Students enter their experimental data in a laboratory notebook on multiple occasions, giving them the opportunity to repeat the process and make improvements after feedback. Grading is based on the various steps involved and not on the merit of the end results. The students submit the rough draft of the reports and then spend some weeks on revisions, allowing them to present better final reports.

Using CURE Data

The data generated by the students is stored in OneDrive by the instructor. The results provide preliminary data for external grant proposals. The students share their research outcomes with their colleagues and with other students at the SET research symposium. Successful projects are continued in independent summer research projects, where undergraduate research interns expand upon them and then write them up for publication.

Resources


  1. Castaldelli, E.; Jayawardena, K. D. G. I.; Cox, D. C.; Clarkson, G. J.; Walton, R. I.; Le-Quang, L.; Chauvin, J.; Silva, S. R. P.; Demets and G. J.-F.. "Electrical Semiconduction Modulated by Light in a Cobalt and Naphthalene Diimide Metal-Organic Framework." Nature Communications 2017, 8, 2139. https://doi.org/10.1038/s41467-017-02215-7.
  2. Dinolfo, P. H.; Williams, M. E.; Stern, C. L.; Hupp, J. T. "Rhenium-Based Molecular Rectangles as Frameworks for Ligand-Centered Mixed Valency and Optical Electron Transfer." Journal of the American Chemical Society 2004, 126, 40, 12989–13001. https://doi.org/10.1021/ja0473182
  3. Ye, Y.; Zhang, L.; Peng, Q.; Wang, G.-E.; Shen, Y.; Li, Z.; Wang, L.; Ma, X.; Chen, Q.-H.; Zhang, Z.; Xiang, S. High Anhydrous Proton Conductivity of Imidazole-Loaded Mesoporous Polyimides over a Wide Range from Subzero to Moderate Temperature. J. Am. Chem. Soc. 2015, 137 (2), 913–918. https://doi.org/10.1021/ja511389q