During our first fellows workshop, the first cohort of VIPEr fellows pulled together learning objects that they've used and liked or want to try the next time they teach their inorganic courses.
I have not yet implemented this LO. As with other literature discussions, instructors could collect the completed worksheets (by an individual student or in groups of students) for evaluation.
I have not yet implemented this LO so there are currently no evaluation results to share.
This literature discussion focuses upon two journal articles by the Rebek group on the synthesis and host-guest chemistry observed with the "tennis ball."
After completing this literature discussion, students will be able to:
- provide examples of supramolecular systems in nature that use reversible, weak noncovalent interactions
- define terms in supramolecular chemistry such as host, guest, and self-complementary
- identify the number and location of hydrogen bonds within the "tennis ball" assembly
- draw common organic reaction mechanisms for the synthesis of the "tennis ball" subunits
- describe the physical and spectroscopic/spectrometric techniques used to provide evidence for assembly of a host-guest system
- explain the observed thermodynamic parameters that are important for encapsulation of small molecule guests by the "tennis ball"
This LO could be used at the end of a traditional 2-semester organic chemistry sequence as an introduction to organic supramolecular systems, as an organic chemistry example within a discussion about inorganic supramolecular chemistry, or in an upper-division elective course about supramolecular chemistry. The LO topic, the "tennis ball," has a published laboratory experiment in J. Chem. Educ. (found here). Time permitting, instructors could have students read the article and complete the literature discussion before executing the experiment in the lab.
As usual, instructors may wish to mix-and-match questions to suit their learning goals.
I have yet to use this resource with students and therefore have no assessment of student learning to share at this time.
I have yet to use this resource with students.
The Rebek Laboratory homepage contains information on and molecular visualizations of a variety of host-guest systems developed by the research group over several decades. The theme behind this set of examples is the use of hydrogen-bonding to achieve self-assembly. Under the "Research" tab, one can find four videos with narration: an introduction to molecular assembly and three videos of specific examples of self-assembled host systems (the cavitand, the cylinder and the volleyball). In addition, at the bottom of the tab, there are links to JSmol files for 5 host systems (tennis ball, jelly donut, cylindrical capsule, softball, and tetrameric capsule) that allow the assemblies to be visualized interactively.
This is a great resource for faculty looking for ways to incorporate the new ACS Committee on Professional Training guidelines to discuss macromolecular, supramolecular, mesoscale and nanoscale systems within the framework of their existing curricula.
I have not yet used this resource with students but here are some possible relevant learning goals.
After viewing the Rebek Laboratory Homepage web source, students will be able to:
1) classify various self-assembled host-guest systems by the number of molecular components forming the assembly
2) identify the number and position of the hydrogen bonds that are responsible for the assembly of each host
3) identify the functional groups on the components of the host systems that are responsible for hydrogen bonding
4) state the experimentally determined percent volume of space generally occupied by guests that are encapsulated in these host systems
I have yet to use this website in my teaching but I hope that it may be a resource in expanding our curriculum in supramolecular chemistry.
I typically evaluate this activity through class participation although the answer key is posted after class to let the students evaluate their own understanding of concepts. The students do know that they will be tested on the material within the activity and usually I have a density problem on the exam.
This activity is designed to give the students more freedom as they move from the first density calculation to the last set of calculations. Within the last set of calculations, they encounter a hexagonal unit cell so that may require some additional intervention to get them to think about how to calculate the volume of a hexagonal unit cell.
This activity is designed to relate solid-state structures to the density of materials and then provide a real world example where density is used to design a new method to explore nanotoxicity in human health. Students can learn how to calculate the density of different materials (gold, cerium oxide, and zinc oxide) using basic principles of solid state chemistry and then compare it to the centrifugation method that was developed to evaluate nanoparticle dose rate and agglomeration in solution.
A student should be able to calculate a unit cell volume from structural information, determine the mass of one unit cell, and combine these two parameters to calculate the density for both cubic and hexagonal structures. In addition, students will have an opportunity to read a scientific article and summarize the major findings, place data in a table, and explain the similarities and differences between the densities calculated in the activity and the experimental values that are reported in the literature.
I have used this activity in our first semester inorganic chemistry course when we cover solid-state materials. One thing to note is that I do use 2-D projections to describe structures and we cover that in a previous activity. You could remove 2-D projections from this activity if it is not something that you previously covered.
Students are evaluated on their participation in lab, lab safety, lab notebook pages, and a lab report turned in a week after the last day of the experiment.
This lab was first run in spring of 2016, and again in spring of 2017 and 2018 (a different instructor carried out the lab in 2018).
In general, students do well on the lab report and seem to enjoy the experiment.They often need guidance when interpreting the Analytical Chemistry article and selecting the correct equations. Discussing their values with them in office hours ("does that make sense?") helps them understand their calculations.
A sample lab report that scored above 90% is included in the faculty-only files.
This is a nanochemistry lab I developed for my Junior and Senior level Inorganic Chemistry course. I am NOT a nano/matertials person, but I know how important nanochemistry is and I wanted to make something where students could get an interesting introduction to the area. The first time I ran this lab was also the first time I made gold nanoparticles ever!
We do not have any surface/nano instrumentation here (AFM, SEM/TEM, DLS, etc... we can access them at other universities off-campus but that takes time and scheduling), so that was a key limitation in making this lab.
While it was made for an upper-division course, I think It could be adapted and implemented at many levels, including gen chem. I do not spend much time on nano in the lecture (none in fact), so this lab was made to have students learn a bit about nanochemistry somewhere in inorganic chemistry. We have one 10-week quarter of inorganic lecture and lab, offered every spring quarter.
This lab takes approximately 2-3 hours if students are well prepared and using their time well, but is usually spread over 2 days. Students are concurrently doing experiments for another lab or two because we have a lab schedule that overlaps multiple labs, and can do these during one day or across two days. The lab space is an organic chemistry laboratory, so we have access to the usual lab synthetic equipment
Students in thelaboratory write lab reports,which are the due the week after the last day of the lab experiment. In the lab report they use their UV-Vis data to calculate information about the AuNP.
The lab has been posted, as well two photos from students' ferrofluids (these were posted with permission on our departmental blog). A rubric has been posted as a faculty-only file. I have also included a student submission that received over 90% on the lab with their identifying information removed. Students write and introduction and need to cite journal articles in their report, so they are expected to do reading on nanochemistry topics outside of the lab period as they write their reports.
I am sure the lab can be improved, this was what i came up with the materials and time I had. I plan on continuing to revise and edit it as time goes on. Any suggestions are very welcome!
A student should be able to perform a chemical laboratory experiment safely and follow proper lab notebook protocol.
A student should be able to determine the average size of AuNPs from spectroscopic data and primary literature.
A student should determine atomic and nano-scale information from physical properties.
A student should be able to construct a lab report in the style of an ACS article (Students in my lab wrote lab reports for each experiment).
For this experiment, you need
The chemical materials - HAuCl4, trisodium citrate,
UV-Vis spectrometer (mainly Vis)
A laser pointer
Strong magnets (the stronger and larger the better)
The syntheses are relatively straightforward, although we've had some problems getting "spikes" for the ferrofluid. Anecdotally, adding the reagents and doing the steps faster tends to give better "spiking". Some students just see a blob moving around in response to the magnet, which was fine in terms of their report.
The AuNP synthesis can also be done with an ultrasonicator or by addition of sodium borohydride, among other methods. We don't have them make a calibration curve of chloride addition, but that could be a possibility.
I like having a pre-made solution of a red oroganic dye to shine the laser pointer through to compare versus the laser shining through the AuNP solution.
One year, the AuNP synthesis was going very slow. We realized it was because the Au(III) was diluted in acid, so it was protonating the citrate. Boiling for a while before adding the citrate solution helped fix this problem.
KAuCl3 is also a good source of Au(III) for this lab.