ORGANIC CHEMISTRY LABORATORY I
Separation and Purity Techniques: Thin–Layer Chromatography and Melting Point
OBJECTIVES:
1) Investigate solubility of organo–metallic compounds
2) Advise a solvent system for proper separation of organo–metallic compounds on TLC plate
3) Determine the melting point of organo–metallic compounds
Note: All background regarding TLC and melting point determination has been covered in previous activities. You are encouraged to refer to these documents for an overall review prior to completing this activity. Obtain some samples of ferrocene and its derivatives from the instructor and advise a solvent system for proper separation of these compounds on a TLC plate. Also, record melting points for these samples.
Research Proposal Preliminary Data Questionnaire – Review MEMO Grading Rubric
You are tasked to analyze ferrocene analogs and become familiar with working with a variety of these molecules. As organometallic complexes have distinct and diverse instrumental analyses resulting from the metal to organic ligand bonding, it is critical to note the difference and predict the instrumental signals for these complexes that might deviate from the original expected behavior of organic ligand in the absence of the metal. You are provided a set of analogs to analyze using organic techniques and instrumentation. An active anti–cancer ferrocene molecule will be assigned to your group and you are to predict the expected results using your information you find from studying the standard analogs.
1) From your measurements of the melting points of ferrocene, what did you note about purity? These samples have reported melting point ranges.
2) Was there a trend in the melting point with the change from the parent to the derivative compound? How does the structure of the analogs impact the melting point? Think about IMF/Supramolecular forces.
3) What solvent system worked for dissolving the solid samples prior to running a TLC plate? Why would you recommend that solvent system?
4) Did you establish a separation of the ferrocene compounds on TLC plate? What structural modifications does your assigned compound of interest have?
5) Based on the structure of our compound and the collected preliminary data, what do you expect the melting point and the polarity of your assigned compound of interest?
