INFRARED (IR) SPECTROSCOPY

IR Spectroscopy – The Spectrum

IR Spectroscopy – The Spectrum

IR Spectroscopy

h

IR Spectroscopy - Theory

Energy is proportional to the frequency n of the vibration

Frequency is related to the force constant (K) and the Reduced mass (

En = (n + ½)h, n = 0, 1, 2, 3,….

IR – Bond Properties and Absorption Trends

The molecule may possess only quantized amounts of energy.

IR – Bond Properties and Absorption Trends

IR – Modes of Stretching and Bending

IR – Correlation Chart

IR – Pentane; neat vs gas phase vs CCl4 solution

neat

CCl4 solution

Gas phase

IR – Alkyl Halides

IR – Alkenes

IR – Alkenes: Out Of Plane bending (the oop region)

IR – Alkynes

1-heptyne

IR – Aromatics

IR – Aromatics; Substitution Pattern

IR – Alkenes: Out Of Plane bending (the oop region)

IR – Alcohols and Phenols

IR – Alcohols; 1o vs 2o vs 3o

IR – Unknown (C6H14 O)

IR – Ethers

IR – Carbonyl compounds

IR – KetonesConjugation effects

IR – KetonesConjugation effects

IR – Aldehydes

UNKNOWN C8H8O

IR – Carboxylic Acids

IR – Esters

UNKNOWN C8H8O2

IR – Amides

Nitrogen Containing Compounds

Amides

Amines

Nitro-

Nitrile

IR – AmidesC5H11NO Isomers

IR – Amines (Anilines)

IR – Nitriles and Nitros

IR Problem 5c (page 92, Intro to Spectroscopy, 3rd Ed.)

IR Problem 5g (page 94, Intro to Spectroscopy, 3rd Ed.)