|Notebooks & Research|
|Maintaining an accurate, thorough and up-to-date notebook is
absolutely required in your research. The daily entry of your
laboratory work into a notebook is the key. Repeating experiments,
telling others how to do experiments, writing research reports
and writing your thesis will all be easier with a quality notebook.
The following are some guidelines.
Save pages at the beginning of your notebook for an index. The index should contain equations or experiment descriptions and page numbers for each experiment.
Always date each experiment.
Only put one experiment per page.
State what the objective or background is for each experiment.
Begin each experiment with an equation or other specific description. Then report amounts (weights or volume and concentration), molar quantities, molecular weights and critical physical properties (density, boiling point, etc.) for each reactant, reagent and solvent. If important, specify the source of reagents.
Record special glassware used, order of addition of reactants, times and temperatures for each step. Specify crude and purified yields and method of purification.
Workups should specify amounts and concentrations of solutions used. If a standard workup is used, specify on what page the "standard procedure" is detailed.
For distillations, record temperature range and pressure for each fraction. If important, record bath temperature.
Crystallization solvents and temperatures should be recorded. If a mixed solvent system was used, write approximate solvent ratios.
Tape TLC's into the notebook after circling key spots. Label to the side what the key spots are and record the solvent used. If important label what stain was used.
Tape GC traces into the notebook also. Label what the peaks are, what column was used and what conditions were used. (ie: SE-30, 100oC 1 min, 10oC / min, 200oC 5 min)
Tape HPLC traces into the notebook also. Label what the peaks are and what column, solvents and conditions were used.
If you are following a literature procedure, write the reference down in your notebook for easy access later.
All compounds and their spectra should be correlated by references to the notebook such as CAM-IX-147-A.
Label ALL spectra with a notebook reference, structure, solvent and instrument used.
End each experiment with a statement of the results. For aborted experiments, state when and why the experiment was terminated.
Cross index related experiments.
|Research reports are a crucial aspect of your research. The
regular preparation of a research report allows one to make sure
that all compounds are properly characterized before they are
used up (or decomposed); to see where additional experiments are
needed to fill in gaps in the research story; and to reflect on
the "big picture" so that the proper directions in research
are pursued. Most importantly, carefully preparing all research
reports will make the task of writing the final thesis infinitely
The general format of the research report should follow the following guidelines. Overall, the format of organic papers in recent issues of J. Am. Chem. Soc. should be used as models.
Results and Discussion:
Do not pad the report with excessive listings of failed results, particularly if they were due to experimental errors or contaminated and/or bad reagents. Do include informative failed results such as the case of screening reactions. Unsuccessful experiments do not need to be included in the Experimental Section, but their description in a reaction drawing, table, or text should be detailed enough to indicate how the reaction was carried out.
All NEW compounds that were synthesized must have full experimental details and spectral characterization. KNOWN compounds need not have experimentals, but literature citations should be given in the General section. KNOWN compounds that were prepared in a manner significantly different from the literature should have an experimental. This last point can sometimes be tricky, so it is always best to err on the cautious side and include more experimentals.
Each experimental should begin with the proper full name of the compound prepared or an informative title for the experiment and a specific notebook reference. The text of the experimental should be completely unambiguous. The following are the standard abbreviations (no periods): s, min, h, d, mL, mL, L, mg, mg, g, mmol, mmol, mol, mp, bp.
The infrared data is reported in decreasing wavenumbers. The state of the sample should be clearly indicated by KBr, Nujol, or solvent name.
The 1H NMR data is reported in increasing d. The solvent and spectrometer frequency must be listed. Use the following abbreviations for multiplicities: s, m, d, t, q, pent, sext, hept. The listings d 2.35 (1H, dt, J = 8.6, 3.1 Hz) and d 2.35 (1H, td, J = 8.6, 3.1 Hz) are VERY different. In the first, 8.6 Hz is the doublet coupling and 3.1 Hz is the triplet coupling while this is reversed in the second. Always list the largest coupling first.
The 13C NMR data should also be reported in increasing d with the solvent and spectrometer frequency listed. Note that the operating frequency for 13C NMR is roughly one quarter of that for 1H NMR. Ideally, the carbon NMR data should include multiplicities (s, d, t, q) obtained from off-resonance decoupled or DEPT spectra.
The mass spectral data includes the significant peaks of the fragmentation pattern listed in decreasing mass with their intensities and the high resolution peak match. The use of special techniques such as CI, FAB, etc should be indicated. The high resolution peak match should be within 10 parts per million.
Carbon and hydrogen microanalyses are required for at least twenty five percent of all new compounds. The analyses should be within 0.4% of the calculated values. Where needed, analyses for other elements can be obtained.
Optical rotations are reported as Specific Rotations with the
temperature, wavelength, concentration and solvent reported. The
Specific Rotation is given by the formula:
[a] = Specific Rotation T = temperature l = wavelength
Copies of important spectra can be included in the report at the end of the Experimental section.
Final note: The ACS Style Guide by Janet S. Dodd is an excellent source for all aspects of writing on and presenting chemical information. Definitely read it before starting a thesis.