Chemists use spectroscopy (Ir, UV-Vis, NMR) to determine molecular structure. spectroscopy: technique that measures the amount of radiation a substance absorbs at various wavelengths(based on the quantization of molecular energy levels Molecules exist in quantized energy states (rotational, vibrational, and electronic quantum states) Molecules absorb discrete amounts of energy(ae)and are excited to higher

described in these matorials arc potentinlly hazandous and require a high levd ofsafety training spccial facilitics and equip mant, and supervision by approp iate individuals. You bea the sole responsibility, lisbility, and risk for the implamnentation of such safcty procedures and mcasures. MIT shall have no respongibility, liability, or risk for the content or implementationc any of the material presanted. Legal Notices

described in these materials are potentially hazardous and require a high lcvel ofsafity training special facilitics and equipment, and supavision by approprinte duals. You bear the sol responsiblity, liability, and risk for the impkemcntation of such safety procedures and measures. MiT shall have no responsibility, liability, ar risk for the content ar implem of ay of the matcrial presented. Legal Notices

This is two-day- experiment. Do not start this experiment unless you have two free lab days to complete it.*** Techniques Checklist: Picking the correct eluent Adsorbtion of a crude mixture onto silica gel Separating complex mixtures using gradient elution Pre-lab Discussion: Suggest limited list of eluent solvent systems Discuss sample adsorption and gradient elution strategies

X-Ray diffraction is an important and powerful tool for determining the solid state structure of compounds. Modern advances have made data collection and structure solution almost routine for many small molecules To use this technique, however, good quality single crystals are still needed. In this exercise you will experiment with the art of growing single crystals

For a two-solvent recrystallization, you should have one solvent (solvent #1) in which your desired compound is soluble at the boiling point. The second solvent(solvent #)should induce crystallization when added to a saturated solution of your compound in the primary solvent. Reference:

Working on a vacuum manifold: See LLP chapter 9.2 for an excellent discussion on working with air-sensitive reagents, including how to use a two-way manifold. De-gassing solvents: The best way to remove water and oxygen from a solvent is to distill it over an appropriate drying agent (such as sodium). This can sometimes be a lengthy (and dangerous)task. Since we

Overview: A good 'H NMR sample contains about 10 mg of compound. The solution should contain no solids or paramagnetic impurities. Your deuterated NMR solvent should be free of water,and your NMR spectrum should contain no solvent peaks. Reference: Zubrick page 295 is relatively useful, but you should follow the specifics in this handout Also, keep in mind that we won't be running continuous wave spectrometers, so you should disregard any discussion of them. NMR Solvents:

Flash column chromatography is a quick and (usually) easy way to separate complex mixtures of compounds. We will be performing relatively large scale separations in 5.301,around 1.0 g of compound. Columns are often smaller in scale than this and some of you will experience these once you move into the research lab. Column chromatography uses the same principles

WARNING NOTICE: The erperimants described in these matcrials are potantially hazardous and require a high level ofsafcty training special facilities and equipment, and supervision by appro responsibility, liability, and risk for the implemontation of such safey procedures and meastncs. MIT shall have no responsibility, liability, or risk for the content or implementation any of the matainl presented. Legal Notices