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4.1: Prelaboratory Assignment

  • Page ID
    371214
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    Pre-Lab assignment for Absorption Spectra of Conjugated Dyes

    Complete the General Pre-Lab Assignment, and the following: 

    1. Find structures and literature values for \( { \lambda }_{max} \) for the four dyes to be studied in this experiment:
      • Dye #1: 1,1’-diethyl-2,2’-cyanine iodide
      • Dye #2: 1,1’-diethyl-2,2’-carbocyanine chloride
      • Dye #3: 1,1’-diethyl-2,2’-dicarbocyanine iodide
      • Dye #4: 1,1’-diethyl-4-4’-carbocyanine iodide

        Some helpful resources include
        • The Aldrich chemical web site (http://www.sigmaaldrich.com), Fisher, N.I.,
        • Hamer, F.M., A Comparison of the Absorption Spectra of Some Typical Symmetrical Cyanine Dyes, Proceedings of the Royal Society of London, Series A, 154 (883), 1936, pps. 703-723, and/or find other sources for these values.
           
    2. Define the terms, highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). Describe what you understand about HOMO and LUMO.
    3. Read McQuarrie, D.A., and Simon, J.D., Physical Chemistry: A Molecular Approach, University Science Books, CA, 1997 (Section 3.4). Read also, Cotton, F.A., "Chemical Applications of Group Theory", Wiley, New York, 1971, Section 7.1 and pp. 366-367
    4. Access to resources:
      • The ELN template: This is your first "in-lab" session, and you will need a notebook for recording the work you do in lab. During each lab meeting, your group will use the ELN Template to record data. Here is the ELN template for this experiment (Duke students click here). Please download this template and peruse its contents. This template was created in an effort to make it clear what is expected during and after the laboratory session. 
      • MatLab files: be sure you have all of the matlab scripts for this course in the appropriate directory of MatLab. (Duke students click here).

     


    4.1: Prelaboratory Assignment is shared under a not declared license and was authored, remixed, and/or curated by LibreTexts.

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