1. Anvendt Spektroskopi Applied Spectroscopy KJM3000 Vår 2015 Curriculum : ”Introduction to Spectroscopy” by Pavia, Lampman, Kriz

2. Practical information Teacher: Tore Bonge-Hansen, rom Ø303, torehans@kjemi.uio.notorehans@kjemi.uio.no Lectures and problems: Avogadro, Wed/Fri 12.15 og 10.15 Communication: e-mail og homepage. 80% of the problemsets must be approved/passed in order to take the exam. No grade on the problemsets.

3. Goal : The student should be able to use spectroscopic methods to determine the constitution of organic molecules. Plan:ca. 25 hours of lectures and ca. 40 hours problem solving. Less focus on theory, more on solving problems. Last problem: Fri 15/5. Exam: beginning of june, 4h written exam, letter grade. Four spectrocopic methods : UV/VIS, IR, NMR og MS. These methods give complementary info, and together they are a a very powerful tool for identification and structure elucidation of small amounts (mg) of unknown compounds.

4. Progress plan KJM3000 - Spring 2015 weekWedFri 4GenNMR1/NMR2 5NMR3/NMR4NMR5/NMR6 6NMR7/NMR8NMR9/NMR10 7NMR11/NMR12K1 8K2K3 9K4MS1/MS2 10MS3/MS4K5 11K6K7 12K8UV1/UV2 13K9IR1/IR2 14EasterEaster 15IR3/IR4K10 16K11K12 17K13K14 18K15K16 19K17K18 20K19K20 Last colloquium: K20, Friday 15th of May. Exam: Beginning of June, 4 hours written.

5. General Spectroscopy : The study of interaction between electro- magnetic radiation and matter (molecules)

6. Electromagnetic radiation Electromagnetic radiation can be described as: a wave motion = wavelength, = frequency, c = speed og light a particle motion E = energy, = frequency, h = Planck’s constant = c E = h

7. Frequency and wavelength will be inversely proportional to each other since c = constant If the frequency of the electromagnetic radiation is the same as a frequency within a molecule (vibration), the molecule can absorb energy. The ‘light’ and the molecule’s motion are in resonans. reorganization: = c/

8. A molecular motion can be the vibration of a chemical bond. HCl = 9 · 10 13 s -1 This frequency and wavelength corresponds to electromagnetic radiation in the IR-area.

9. Interaction between light and matter in a more general way A molecule has many stationary energy levels (E). For every energi level there is a wave funvtion (Ψ). E 2 _____________ Ψ 2 E 1 _____________ Ψ 1 ΔE = E 1 – E 2 = hν If we shine light on a molecule with a frequency corresponding to ΔE, the molecule can absorb energy and move to a higher energy level.

10. Emission spectroscopy : The molecule moves from a higher energy level (E 2 ) to a lower energy level (E 1 ) by emitting a quantum of light. Absorption spectroscopy : The amount of light absorbed as a function of wavelength. A quantum of light is absorbed and the molecule moves from a lower energy level (E 1 ) to a higher energy level (E 2 ). E 2 _____________ Ψ 2 E 1 _____________ Ψ 1 ΔE = E 1 – E 2 = hν

11. A general spectroscopic experiment Light source: Often poly chromatic UV/Vis: Light bulbs (Hg, Na) IR: Heater (Nernst filament) > 1000 deg C NMR: radio transmitter

12. Detectors UV/VIS: diode array (photon counter) IR: heat sensitive electronic componen (semi conductor) NMR: radio receiver The detected energy is converted to voltage and transferred to a computer A spectrum is recorded by measuring absorbance while changing the wavelength of light (scanning).

13. Four methods UV:200 – 380 nm. Used primarily to detect conjugated systems. Excitation of electrons in conjugated systems give absorbance in this area. IR:4000 – 400 cm -1. Used to detect and identify vibrations related to different functional groups. NMR:Atomic nuclei absorbing radiowaves when placed in a strong magnetic field. MS:Measures mass/charge ratios of organic ions

14. 200 MHz NMR-instrument

15. 1 H-NMR spectrum

16. UV og IR instruments

17. UV og IR spectrum

18. MS-instrument in series with GC

19. MS-spectrum