Introduction

An overview of how to determine unknown molecular structures from infrared spectra. We’ll begin with how molecules absorb infrared radiation; and what peak positions, heights, and widths mean. Next, a systematic, 10-step strategy to successfully interpret spectra is presented.

The bulk of the course is a discussion of important infrared bands of a number of economically important molecules including alkanes, aromatics, alcohols, esters, and amines. Special discussions of polymers and inorganics are included.

The course concludes with a practical discussion of how library searching and spectral subtraction make interpreting spectra faster and easier. Interpretation workshops, where attendees interpret unknown spectra with the help of the instructor, are held throughout the course.


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Across the Spectrum: Infrared Spectral Interpretation - Module 01

Module 1 Covers:

  • The Properties of Light
  • Molecular Vibrations
  • The Meaning of Peak Positions, Heights, and Widths
  • How Molecules Absorb Infrared Radiation
  • Assigning All the Features in a Spectrum
  • A Strategic Approach to Spectral Interpretation
  • Dealing with Mixtures
  • Performing Spectral Comparisons (Identities) Properly
  • A 10-Step Method for Infrared Interpretation.


Across the Spectrum: Infrared Spectral Interpretation - Module 02

Module 2 Covers:

  • Straight Chain Alkanes: Methyl and Methylene Groups
  • Estimating Hydrocarbon Chain Length
  • Branched Alkanes (introduction)


Across the Spectrum: Infrared Spectral Interpretation - Module 03

Module 3 Covers:

  • Branched Alkanes (continued)
  • CH2 in Cyclic Structures: Cyclohexyl and Cyclopentyl Rings
  • Alkenes
  • Substitution Patterns
  • Distinguishing Cis/Trans Isomers
  • Natural and Synthetic Rubbers
  • Alkynes


Across the Spectrum: Infrared Spectral Interpretation - Module 04

Module 4 Covers:

  • Aromatic Hydrocarbons
  • Mono-Substituted Benzene Rings
  • Distinguishing Ortho, Meta, and Para Isomers
  • The Benzene Fingers
  • Highly Substituted Benzene Rings
  • Tri-substituted Rings
  • Tetra-substituted Rings


Across the Spectrum: Infrared Spectral Interpretation - Module 05

Module 5 Covers:

  • Heterocyclic and Polycyclic Aromatic Hydrocarbons
  • Pyridines
  • Naphthalenes
  • Functional Groups Containing the C-O Bond
  • Overview: The C-O Stretch
  • Alcohols & Phenols
  • Differentiating Saturated Alcohols
  • Phenols
  • Distinguishing Alcohols and Water


Across the Spectrum: Infrared Spectral Interpretation - Module 06

Module 6 Covers: 

  • More Functional Groups with C-O Single Bonds
  • Ethers
  • Saturated Ethers
  • Aromatic Ethers
  • The Methoxy Group
  • Sugars and Carbohydrates
  • Sugars
  • Oligosaccharides
  • Cellulose
  • Introduction to the Carbonyl (C=O) Group
  • The C=O Stretch
  • Ketones


Across the Spectrum: Infrared Spectral Interpretation - Module 07

Module 7 Covers:

  • How Molecules Absorb Infrared Radiation
  • When Particles Collide
  • A Close Encounter of the Electrostatic Kind
  • Assigning All the Features in a Spectrum
  • Complex Carbonyl Molecules
    • Aldehydes
    • Carboxylic Acids
    • Carboxylates (Soaps)


Across the Spectrum: Infrared Spectral Interpretation - Module 08

Module 8 Covers:

  • Even More Carbonyl Molecules
  • Acid Anhydrides
  • Esters: The Rule of 3
  • Organic Carbonates
  • Summary of Carbonyl Containing Functional Groups


Across the Spectrum: Infrared Spectral Interpretation - Module 09

Module 9 Covers:

  • Organic Nitrogen Compounds
  • Amides
  • Structure, Nomenclature, and Bonding
  • Primary Amides
  • Secondary Amides
  • Proteins
  • Imides
  • Urethanes
  • Amines
  • Primary Amines


Across the Spectrum: Infrared Spectral Interpretation - Module 10

Module 10 Covers:

  • Spectral Subtraction: Simplifying Mixture Spectra
  • Theory
  • Optimizing Subtraction Results
  • Spotting Artifacts
  • Library Searching
  • Background and Theory
  • The Search Process
  • Property Interpreting Search Results
  • Subtract and Search Again: Deconstructing Mixtures