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This literature discussion explores the physical structure, electronic structure, and luminescent properties of a lanthanide coordination complex (dysprosium) through discussion of “Synthesis, Structure, Photoluminescence, and Electroluminescence Properties of a New Dysprosium Complex,” Li et al. J. Phys. Chem. C 2007, 111, 2295-2300, http://dx.doi.org/doi:10.1021/jp064749t. The activity gives students experience discussing and analyzing the electronic and luminescent properties of f-block compounds, including determining spin-orbit coupling (and its effects) and constructing Jablonski diagrams.
| Attachment | Size |
|---|---|
| Luminescence Properties of a Dysprosium(III) Complex_0.docx | 23.04 KB |
| Luminescence Properties of a Dysprosium(III) Complex_0.pdf | 112.24 KB |
Students will be able to:
- Describe a possible synthetic route to dysprosium complexes
- Apply knowledge of electron configuration and spin-orbit coupling to determine the electronic structure of a lanthanide complex
- Construct and interpret a Jablonski diagram based on experimental electronic spectra and calculated spin-orbit coupling
- Analyze the photoluminescent and electroluminescent properties of lanthanide complexes and the origin of these properties
- Discuss potential applications of luminescent properties
This literature discussion was used in an advanced (upper-level) inorganic chemistry course. This discussion is done during a unit on lanthanides that includes synthesis, structure, and typical chemistry of f-block compounds, and electronic configurations and properties of lanthanide compounds. Immediately before the lanthanides unit, we complete a unit on electronic spectra and transitions, including luminescence and spin-orbit coupling. We also complete a lab experiment around the same time where students synthesize a terbium complex and collect UV-Vis and fluorescence data on the complex. It was helpful to reference their experimental data and spectra from this lab for this discussion, but it’s not necessary to complete this discussion. This activity could probably be completed in one class period, provided that students are given the article ahead of time and encouraged to look it over, although it may be preferable to start the discussion in class and let students complete it on their own time. Students completed this activity in small groups.
Evaluation
Students completed this activity in small groups, then turned in individual worksheets. Student learning and performance were assessed through 1) in-class group discussion after they had worked on the activity in small groups, and 2) grading the individual worksheets. Participation was most important in the small-group portion.
In general, students enjoyed this exercise and many stated that they found it helpful for connecting experimental electronic spectra with the concepts discussed in class (fluorescence, singlet and triplet states of the ligand, spin-orbit coupling), and for putting some of these more theoretical-feeling concepts into context. Students were generally also very interested in discussion of the applications of these type of compounds in terms of the photo- and electroluminescent properties. We do short independent research projects later in this course, and this discussion generally encourages some students to pursue lanthanide complexes for their research project.
The biggest challenge for students seemed to be in deciding where to place the split states from spin-orbit coupling (6H5/2, 6H7/2, 6H9/2, 6H11/2). For this question, it was helpful to have them look at their experimental data. In a class where a similar lab in not done in conjunction, finding and comparing to Jablonski diagrams for similar complexes would also be helpful. Some students also struggled with calculating spin-orbit coupling and/or determining which state (15/2 or 5/2) should be lowest in energy. But all students were able to figure this out after a brief discussion of this material.