My Notes
Categories
In this experiment, students will synthesize and characterize a series of Ru(II) p-cymene piano-stool complexes. Each complex will contain p-cymene as the "seat" and two chloride donors in addition to a phosphine or phosphite with varying amounts of fluorine, which together serve as the "stands". There are a total of four phosphine ligands and three phosphites, which include triphenylphosphine and trimethylphosphite that do not contain any fluorine. This experiment combines complex synthesis, characterization, data analysis and data sharing.
| Attachment | Size |
|---|---|
| Student Handout | 48.21 KB |
A student should be able to:
- Prepare a series of Ru(II) phosphine and phosphite complexes
- Characterize the complexes by multi-nuclear NMR spectroscopy
- Characterize the complexes by UV-vis spectroscopy
- Analyze structural data in Mercury
- Use physical characterization data to formulate trends
- Use data tables when appropriate
- Express conclusions
- Write a full ACS journal style lab report
Standard laboratory equipment/glassware
Rotary evaporator
FT-NMR with multinuclear capablity
UV-vis spectrophotometer
This experiment will be piloted during the 2016-2017 school year. If others in the VIPEr community try this experiment please post your comments and/or consider filling out the feedback file attached and sending to john-lee@utc.edu
Students will synthesize and characterize one compound each, and should share spectral and other characterization data in order to perform a complete study for their report. All complexes are air-stable and can be prepared without the need for anaerobic techniques. Students should form a hypothesis on the donor ability of the ligand and then use their characterization data along with the structure of the phosphine or phosphite to support and/or refine their original predictions.
Evaluation
When implemented during the 2016-2017 school year a formal lab report will be required. However, other suitable methods would include, but are not limited to an oral presentation or a lab memo.
The experiment described herein will be piloted during the 2016-2017 school year. However, all complexes have been prepared by undergraduate students/researchers at all levels during the completion of the original project.
This experiment, though not implemented in a teaching lab yet, has been successfully completed by undergraduate students in the research lab. It is my hope that this learning object will provide a useful organometallic/coordination chemistry experiment. And, those who implement will take advantage of Sheila Smith's recent BITeS blog on "Crowdsourcing Assessment Data" in order to further help turn this into an excellent and adaptable inorganic lab experiment.
John, I'm going to be trying this with my very small class this term. I may be hitting you up for advice and help
This looks really cool. A couple of questions/comments - the link on this page to the web resource is broken. Would these be amenable to analysis by CV? I'm looking for labs that incorporate more electrochemistry. Thanks!
Should be CV-amenable... the Ru(II/III) couple should move... I'd be interested in trying this next time I teach.
Thank you for all the feedback, and I apologize for not responding earlier. Sheila, glad you were able to use the experiment and I hope it worked. Vanessa and Kyle, yes you should be able to see the Ru(III/II) couple and indeed it should move. At the time we did not have electrochemical equipment available (coming soon though!) but please feel free to see what you find. All the complexes are soluble in acetonitrile.
It looks like the link is doubled on doi.org. Here it is:
https://doi.org/10.1080/00958972.2015.1114613
Hi John, you still interested in crowdsourcing data?
Kyle
The DOI link to the original article has been updated in the LO.
Hi John! In the interest of keeping costs down a little, are there any phosphines and phosphites in particular that give better results and you would recommend prioritizing for purchase? Thank you! -Karen
John, I've tried a few of these and I always seem to get oils instead of solids. I'm currently trying the p-tolyl ligand and it is just an intractable oil. Anyone else try these and have better luck than me?
I sometimes have issues getting complexes to precipitate from THF (or in this case 2-methylTHF). Maybe try adding a little DCM, just enough to dissolve the oil, and then add the hexanes.
yeah, i've tried that. its hit or miss. I just made the (4-FPh)3P derivative and got a nice powder, but the 4-CF3 one is just oiling out.