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GENERAL INFORMATION
ON THE INORGANIC PREPARATIONS COURSE
CONTENTS
I. Nature of the Course
II. Text
III. Lectures
IV. Attendance
V. Plan of the Course
VI. Nature of the Syntheses
VII. Characterization
VIII. Difficulties to be Expected
IX. Grading
X. Useful References (Science Library)

I. Nature of the Course

Inorganic Preparations is a laboratory course dealing with the synthesis and characterization of inorganic and organometallic compounds. The syntheses assigned to you have been picked for at least one of three purposes:
  1. To introduce a new technique. In real synthesis work, many compounds have properties such as thermal instability, extreme ease of hydrolysis (moisture in the air or in wet solvents), extreme ease of oxidation (atmospheric oxygen), or inconveniently high or low volatility which make them difficult to handle on the open lab bench. The synthesis, manipulation, and characterization of such compounds thus requires exclusions of air and moisture, and equipment like inert atmosphere glove bags, Schlenk reaction vessels and vacuum lines have been developed for this purpose. Other compounds require special conditions for their formation, such as reactions in a high temperature tube furnace, or for their purification, like high vacuum sublimation.


  2. To introduce a new, different, or unusual type of inorganic or organometallic compound. The hundred-odd elements in addition to carbon form compounds exhibiting a fantastic variety of structures, reactions, reactivities, forms of bonding and stereochemistry.


  3. To prepare a starting material for a research laboratory. From time to time students doing research need compounds that are not commercially available. Thus, the purpose of some syntheses is to provide substances for ongoing and future research projects.

This course is required for the ACS approved B.S. degree in Chemistry. This relatively new requirement increases significantly the number of undergraduates taking the course each semester, which consequently makes it necessary to schedule the use of limited facilities (Schlenk lines, glove box, etc.). Therefore, the order in which you do certain experiments may be different than that listed on the course syllabus. Check with your TA to determine your actual schedule, including when your individual reports will be due.

 
II. Text
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The assigned text is "Microscale Inorganic Chemistry: A Comprehensive Laboratory Experience," by Zvi Szafran, Ronald M. Pike, and Mono M. Singh. A list of other important and useful books is attached at the end of this handout. The reserve room of the Science Library has Angelici’s, Jolly's, and Perrin and Perrin's books.

Many of the syntheses are found either in reference texts or in the research journals. The reserve room of the library has also been given several files containing some of the reports from the previous years' course. You may use these reports to obtain the references and to note any of the important comments and observations that were encountered by others.

 
III. Lectures
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There are regularly scheduled lectures each Wednesday noon (see Syllabus for scheduled topics). Topics to be covered include NMR, EPR and MS as applied to this course, how to keep a notebook and how to prepare your reports. There may be quizzes on the material covered in these lectures. From time to time the instructor or teaching assistant will also discuss selected techniques and methods. The instructor or the TA will always be in the lab with you to answer any questions you may have pertaining to your work.

 
IV. Attendance
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Technically, University regulations require three hours of class work per credit hour. Thus, each student should average about eight hours in the laboratory each week, plus one hour in lecture. The attendance of each student will be logged. Each student is expected to attend both 4-hour laboratory periods scheduled each week. It is expected that attendance will be scaled to properly finishing the assigned work by the established deadlines. The final grade contains a component based on attendance (see section IX).

 
V. Plan of the Course
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  1. General Syntheses. You will be expected to manage your time effectively to accomplish the synthesis of several compounds during the semester. A list of "general" preparations that are to be performed is available from the instructors. One of your preparations is a "Special Project" or "Advanced Preparation," which is one of your several compounds, but, as is described below, you are to find the preparation in the library.

    2. The order of the preparations must be carefully scheduled to allow the best use of all the equipment available. An approximate schedule is presented in the course syllabus, but the instructors in charge of the course will schedule the experiments. See your instructor one or two weeks before you finish your current preparation so that you will be able to plan for the next preparation. (See ‘Comments Concerning the Laboratory Notebook’).It is expected that the student will have researched the important aspects of a synthesis (such as the necessity for preliminary steps like solvent drying, distillation or purification of starting materials, etc.) and the nature of the compounds used before work begins and that the student has formulated a reasonable plan for using the laboratory time. The balanced chemical equation(s) for the synthesis to be done should appear at the beginning of your laboratory notebook page devoted to that synthesis.

  2. Special Project or Advanced Preparation. One of the special features of this course is that new experiments are tried each semester. The experiments that work well are added to the standard list of experiments for following semesters, and less valuable experiments are phased out.

    3. Each student is assigned the task of finding an experiment that can be adapted to this course. Common sources are Inorganic Syntheses, J. Chem. Ed., the Handbook of Preparative Inorganic Chemistry, G. Brauer (QD151 B7333) and other sources in the Science Library. The experiment should be the preparation of an interesting inorganic compound or material, or involve a useful technique. The object is not to attempt an extremely difficult experiment. It is more important to show that you can plan and accomplish an experiment within the time and equipment constraints of this course. You should begin plans immediately to allow time for collection of necessary chemicals and labware. All plans should be checked with the instructor before anything is done.

 
VI. Nature of the Syntheses
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Often the assigned synthesis will have to be modified in various ways. Probably the most common change will be scaling up or down the size of the reaction. This is done for several reasons, such as the fact that our text deals with microscale equipment, which is not available to us (scale up quantities by a factor of 3 or so), the lack of any current research need for the product and, recently, the cost of chemicals and equipment (scale down--- discuss with instructor). Before starting a synthesis, inform the instructor of the amounts of starting materials you intend to use and the amount of product you expect to obtain.

Occasionally a literature synthesis will call for a special piece of apparatus that may not be available in the lab or stockroom. This will necessitate improvising equipment or partially redesigning the experiment. When this occurs, consult the instructor. It should be noted that this is a common problem in real research labs. Occasionally it may be necessary to repeat a synthesis, since some reactions or techniques may be tricky and unfamiliar. This happens in real laboratories and there is no penalty for "blowing" (but not blowing up!) a synthesis and having to repeat it.

Grades (see below) are assigned on the basis of the final product turned in and on the write-up of the experiment.

 
VII. Characterization
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How does one know whether a reaction has produced the desired product or not? How does one know, if there are several isomers possible, whether only one is present or a mixture? Obviously, there must be ways to characterize inorganic compounds, just as there are for organic compounds. In fact, in many cases the methods of characterization are exactly the same as for organic compounds (1H, 13C NMR spectroscopy, infrared spectroscopy, and mass spectrometry). However, inorganic compounds, many of which are highly colored and/or have unpaired electrons, may be characterized by additional techniques as well, including UV-visible spectroscopy (because of what d-d transitions can tell us, based upon crystal field theory, about the oxidation state and spin state of a metal complex), EPR (electron paramagnetic resonance) spectroscopy, and magnetic susceptibility (magnetic moment) determination. If the product is volatile, another very informative technique is PES (photoelectron spectroscopy), which measures the ionization energies from the various molecular orbitals of the metal complex. Obviously, some spectroscopic or magnetic methods are more appropriate than others, depending on what reaction is being carried out.

The journal Inorganic Chemistry requires that papers that involve the synthesis of new inorganic compounds include three methods of characterization of each one. (One that we do not frequently use in this course, but may be used in a journal article, is chemical analysis (%C, H, N, metal, halogens or other elements). Thus, the characterization of the products of your reactions is a very important part of the overall experiment, and the report that you write. Any of the methods mentioned above can be used; if this were an analytical chemistry course, chemical analysis, at least of metal content, would be required. However, it should be noted that a mass spectrum can provide much the same information, and in addition, can help identify any impurities present. Although you may want to discuss chemical analysis with your TA or instructor at some point during the semester, the quickest and often most informative methods, which you are expected to use, are those spectroscopic and magnetic techniques mentioned above. In the case of NMR, IR and mass spectra, it will be important to obtain the spectrum not only of the product, but also of the reactants, in order to be able to reach a conclusion as to whether the reaction proceeded to completion or not. Characterization should be done during free time and should not take away from the time required to set up and carry out another synthesis. However, there are many times when a reaction is taking place (for example, if refluxing is involved), when there is some free time available when spectra may be obtained.

Both UV-visible and infrared spectrophotometers are available in the 412 laboratory. Additional (possibly newer) UV-vis and IR instruments, as well as a Gouy balance for measuring the magnetic moment of a paramagnetic sample, are available in the Chem. 400 labs (CBS, first floor) during the times when those laboratories are in session (MW 1-4, 6-9 PM, TTh 8-11 AM, 2-5, 6-9 PM). However, if the instruments are in use by the Chem. 400A,B students, you will have to come at a different time, including times when your instructor is able to let you into these labs. Unless you are incredibly lucky to walk into the NMR lab and find it empty, it is usually necessary to sign up for NMR time in advance of when one wishes to record an NMR spectrum, so plan ahead. Mass spec. samples may be submitted to the MS Facility (Old Chem 112a,b), to be run by the Facility personnel. You may be able to arrange to be present when the spectra are run. EPR samples may be submitted to the EPR Facility (Old Chem 218). Again, you can arrange to be present when the spectra are run. Volatile products (discuss with your instructor whether a product is expected to be volatile or not---metal carbonyl-containing compounds are usually volatile, for example) may be submitted to the PES Facility (CSML 318), and arrangements made with Dr. Gruhn to be present when the spectra are obtained.

 
VIII. Difficulties to be Expected
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The main difficulty you will experience will be collecting and assembling apparatus and chemicals. Sometimes the lab will be out of a chemical or a piece of equipment will not be available. Equipment scrounging will cost time. This can be minimized by a well thought-out approach to your work. These difficulties are common to just about any lab, teaching or research. Please do not attempt to do things without first consulting the TA. If a chemical is needed, the TA will then send you to the stockroom. If a piece of equipment is misplaced then the TA may know where it is or how to "improvise" a replacement. Please consult the Professor or the TA when a difficulty arises.

 
IX. Grading
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There will be several quizzes during the lecture period, but no hour examinations or final exam. Grades will be assigned on the basis of the following:

  1. a write-up on each synthesis, in the form suitable for publication.


  2. the quality and quantity of the product of your synthesis.


  3. the notebook detailing the preparation, actual observations and comments taken during the experiment and comments on the nature and characterization of the product and on the synthetic method.


  4. a judgment of the level of laboratory performance.


  5. the quality of the poster and your presentation of it.

Detailed discussion:

  1. Write-up. Each of your preparations will be written up in the form of a Note to the journal Inorganic Chemistry; therefore it will include a title, brief introduction, detailed experimental section, and a results and discussion section. See recent issues of Inorganic Chemistry for examples of Notes. Note that for figures showing NMR spectra, the peak assignments should be included on the spectrum. The structures of the reactant(s) and product(s), including expected bond angles, should be included.


  2. The product. Quality as well as quantity are important. Quality will be judged by purity (melting point, spectral characterization, etc.) and appearance (color, size of crystals, etc.). Quantity will be judged by the percent yield. This will be compared to the value claimed in the literature. It should be noted that these numbers usually seem too high.

    All products must be turned in, in a container suitable for long term storage in an ordinary laboratory. This means that products which hydrolyze or oxidize in air must be torch-sealed in a nitrogen-filled all-glass ampoule or storage tube (made from a test tube). The samples will be looked at when first turned in and then again every week until the end of the semester. All products must be well labeled with your name, the compound’s IUPAC name, experiment date, yield in grams, % yield.

  3. The notebook. In real life the purpose of a laboratory notebook is to provide an accurate permanent record of exactly what was done and of what happened as a result. Often years pass between the performance of an experiment and the realization of the complete significance of the result. Obviously one's memory cannot be trusted to retain all the details of the work and the existence of a well kept record under such circumstances is imperative. The notebook is also essential if a patent is to be applied for.Your lab notebook should be a clear record of how you performed your synthesis and of what happened. All difficulties you experienced, all modifications you made, and all suggestions for improvement you might make should be detailed. The notebook should be kept as work progresses, and not written up two weeks later. A number of notebooks of previous inorganic prep students are available and you are encouraged to consult them for a preview of difficulties and for suggestions and improvements when your synthesis has been done before (see the instructor for this information). Your notebook will be used for this purpose in the future.

    4. Specific expectations for the notebook are:

    * The notebook should be of the type that has duplicate pages with carbon paper between. This type of notebook is slightly more expensive but allows for the removal of the duplicate copy to serve as the report for the experiment, while you still have the notebook in your possession.

    * The notebook should be clearly labeled on the outside.

    * The first few pages should be reserved for an index.

    * Each entry should include the date at which it is entered into the notebook. Also include the time so that significant observations can be related to how long a reaction has been proceeding.

    * The description of each preparation should include, before any part of that experiment is performed, the following items:

    • A brief description of the purpose of the preparation including theory and the structure of the molecule being synthesized.
    • Any references to the literature which have been utilized.
    • MSDS sheets for each of the chemicals used.
    • A brief description of the best synthetic route for preparing the compound, including special techniques, precautions, expected yield, physical characteristics and method of characterization.
    • A list of the chemicals and items of equipment required, with quantities scaled to a suitable level.
    • Drawing of apparatus to be used, if a special setup.
    • The balanced chemical equation for the reaction to be carried out, with special conditions such as T, P, inert atmosphere, etc.
    • Structure of starting material and product, showing proper bond angles and stereochemistry, if appropriate.

    * A detailed description of the actual laboratory work is to follow. This should include diagrams of the apparatus utilized, balanced chemical equations representing the transformations to be carried out, and all observations, including spectra, and what you conclude from the spectra obtained. A well-written description will allow a reader to actually visualize what took place

    * The final comments and conclusions should include:

    • An identification of the purity of the product, as determined by physical or spectral properties. NMR spectral peaks should be labeled.
    • The percent yield of the product obtained.
    • A summary of the weaknesses of the preparation.
    • Any suggestions for improvement in the procedure.

    * Additional information on the laboratory notebook can be found in your text or the texts by Angelici (page 10) and Jolly (page 439), both of which are in the Reserve Room of the Science Library.

  4. Laboratory Performance.


    1. Be prepared when entering the lab. The TA should be informed before the lab of what you will be doing and if there are any special needs. You should know the material in the pre-lab notebook write- up.


    2. Schedule your time appropriately. Be prepared to finish on time. Take advantage of waiting times in a preparation to clean glassware, improve your notebook comments, prepare for the next step, study the next preparation, etc.


    3. Keep your working area clean and uncluttered both during the preparation and at the end of the day. Return all equipment to the proper storage locations. This will constitute a major portion of the laboratory performance grade!!


    4. Always be conscious of the safety of yourself and those around you.


    5. Above all, think about what you are doing. Have in mind some explanation of what you are doing in each step and how it fits into the entire preparation. The instructors will be asking you to explain what you are doing.
X. Useful References (Science Library)
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  1. Common sources of syntheses.


    1. * Inorganic Syntheses (OD151 A 1 15)

      2. A multivolume collection of checked syntheses.

    2. * Handbook of Preparative Inorganic Chemistry. G. Brauer, ed. (QD151 B733)

      3. A two volume collection of strictly inorganic (no C- not even a CH, group) syntheses.

    3. The Synthesis and Characterization of Inorganic Compounds. W. L. Jolly (QD156 J65)A useful collection of lab techniques and 0 syntheses. Instructor also has a copy.


    4. Synthesis and Technique in Inorganic Chemistry. R. J. Angelici (QD155 A53)

  2. Sources of information on inorganic compounds, reactions, and chemistry.


    1. Inorganic Chemistry. Shriver and Atkins

      2. (Chem. 404 text)

    2. Basic Inorganic Chemistry. F. A. Cotton and G. Wilkinson (QD151.2 C69)An excellent introductory text.


    3. Advanced Inorganic Chemistry. F. A. Cotton and G. Wilkinson (QD151.2 C681972, 1980, etc.)

      4. The best advanced one volume text (the big brother of b-2 above). The 1980, 1972, 1966 and 1962 editions are also good.

    4. Modern Inorganic Chemistry. J. J. Lagowski (QD151.2 L34)

      5. A good introductory text.

    5. Inorganic Chemistry. R. B. Heslop and P. C. Robinson (QD151 H47 1967)

      6. Similar to b-4, but older.

    6. Inorganic Chemistry. J. E. Huheey (QD151.2 H84)

      7. An excellent introductory text - especially good on transition metal compounds and bioinorganic chemistry.

    7. Coordination Chemistry. F. Basolo and R. Johnson (541.396 B316)

      8. An elementary text on transition metal complexes

    8. Elementary Coordination Chemistry. M. M. Jones (541-396 J78)

      9. An introductory text

    9. * Comprehensive Inorganic Chemistry. J.C. Bailar, et al., ed. (QD151.2 C64)

      10. A five volume treatise. When all else fails, try this.

    10. Advances in Inorganic Chemistry and Radiochemistry. (QD151 A45)

      11. A multivolume collection of reviews on specific topics.

    11. Progress in Inorganic Chemistry. (546 P964)

      12. Like b-10.


  3. Sources of information on lab methods and techniques.


    1. a-3 and a-4, above.

      2. Very useful.

    2. The Manipulation of Air Sensitive Compounds. D. F. Shriver (QD61 557)

      3. The best source of information on inert atmosphere and high vacuum methods and Schlenk techniques.

    3. Laboratory Technique in Organic Chemistry. K. B. Wiberg (547.072 W632)

      4. In spite of the title, a useful book on lab operations, especially solvent purification.

    4. Our text: "Microscale Inorganic Chemistry: A Comprehensive Laboratory Experience," by Zvi Szafran, Ronald M. Pike, and Mono M. Singh

  4. Sources of information on the characterization of compounds by spectroscopic methods.


    1. Spectrometric Identification of Organic Compounds. R. M. Silverstein, G. C. Bassler and T. C. Morrill (QD272 S6 555 1974)

      2. An excellent, practical introduction to nmr, ir, ms, etc. The earlier editions (547.364 S587) are also very good.

    2. * Instrumental Methods of Analysis. Willard, Merritt & Dean (QD79 15 W54 1974)

      3. Standard introductory text.

    3. Infrared Spectra of Inorganic and Coordination Compounds. K. Nakamoto (1st ed. (535.842 N163; 2nd ed. QC457 N3 1970)

      4. Excellent, but more advanced.

    4. * An Index of Vibrational Spectra of Inorganic and Organometallic Compounds Greenwood, Ross & Stranglian (QC453 G742)A bibliography of references to papers on the ir spectra of a huge number of inorganic compounds.

  5. Some advice on finding information.


    1. If a book is checked out, you can probably borrow the instructor's copy.


    2. If you really can't get to first base after an hour's honest effort, see the instructor.

(* indicates books located in reference room)
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