6b. Structure Elucidation IR and 13C-NMR Spectroscopies

6b. Structure Elucidation IR and 13C-NMR Spectroscopies -...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
© 2010 Department of Chemistry, The University of Western Ontario 7.1 6b. Structure Elucidation: IR and 13 C-NMR Spectroscopies (text 11.1 – 11.4, 12.1 – 12.4, 12.9) A. Electromagnetic Radiation Energy is transmitted through space in the form of electromagnetic radiation , which are oscillating waves of electric and magnetic fields, and this is term used to describe all the component waves found in a continuous spectrum known as the electromagnetic spectrum. The spectrum stretches from the very short wavelength (high energy) gamma rays to the very long wavelength (low energy) radio waves. Humans can see the 400 – 700 nm visible region (colour).
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
7a.2 Regardless of wavelength, all electromagnetic radiation propagates through space at the speed of light ( c ). Radiation is characterized its wavelength ( in metres) and frequency (vibrations per second, in s 1 ). The shorter the , the higher the (more waves go by per second if the wavelength is shorter). B. Review of Infrared Spectroscopy IR spectra are normally scanned from 4000 to 600 cm 1 (wavenumbers, reciprocal of in cm). Spectra can be divided into the functional group and fingerprint regions. The absorption of IR light causes vibrational excitation. Different functional groups absorb at different wavelengths, which in turn allows the identification of functional groups. Absorption appears as peaks of lowered transmittance. Correlation tables list the characteristic absorptions, as well as their intensities, for various functional groups. Aspirin
Background image of page 2
7a.3 Alkanes, alkenes, and alkynes Sample spectra are shown below. Note that the alkene and alkyne signals near 3100 and 3300 cm 1 , respectively, are only present if an alkenyl or alkynyl hydrogen is present.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
7a.4
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 14

6b. Structure Elucidation IR and 13C-NMR Spectroscopies -...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online