OUTLINE

INTRODUCTION

      Back ground of organic spectroscopy

Spectrometry

Application of spectroscopic technique

Spectroscopic methods based on EM spectrum (VU-VIS, IR, NMR)

Approaches in solving chemical structures

IR ( INFRARED SPECTROSCOPY)

Introduction to IR

Vibrational modes in IR spectroscopy (Stretching and Bending)

Schematic representation of IR spectrometer

The IR spectrum (scale, band intensity, FGs region, Fingerprint region)

Chemical bonds vs IR absorption

Interpretation of IR spectrum

 

ULTRAVIOLET-VISIBLE SPECTROSCOPY (UV-VIS)

Basics of UV-vis

Terminologies

Application of UV-vis and UV maximum determination

 

NUCLEAR MAGNETIC RESONANCE (NMR)

Introduction to NMR (1H and 13C)

Schematic representation of NMR machine

Features leading to the NMR – phenomenon (nuclear spin state, nuclear magnetic moment, nuclear magnetic resonance)

Mechanism of absorption (Resonance): splitting of nuclear spin energy levels in applied magnetic field

1H-NMR CHEMICAL SHIFTS

Chemical shift (δ in ppm)

Factors influencing chemical shifts ( deshielding and anisotropy)

Integrations

Shielding in 1H-NMR

Factors that influence shielding (electronegativity, hybridization of adjacent atoms, acids and exchangeable protons, magnetic anisotropy, hydrogen bonding)

Chemical equivalence and number of signals

 

COUPLING IN 1H-NMR

Spin-spin coupling

1st Order coupling (n+1) Rule

Pascal triangle and multiplicity

Coupling constant, J

       Types of nuclear coupling : homonuclear, heteronuclear

 

Factors influencing magnitude of coupling constant

Karplus Relationship-Dihedral Angle

Long range coupling: 4J- nJ and W-conformation (4J)

Magnetic equivalent vs symmetry in molecule

Non-equivalent protons (free rotation, locked conformation)

2nd Order spectra

NMR spectra of aromatic compounds

Homotopic, enantiotopic and diastereotopic system

Interpretation of 1H-NMR spectra: calculation of HDI (or UN); analysis of the spectrum; integration of the spectrum; determination of types of protons; identification of splitting patterns (multiplicity).

13C- SPECTROSCOPY

Basics on 13C-NMR

Interpretation of 13C-NMR

Basics and interpretation of carbon DEPT

2D NMR

2D experiments and interpretations (COSY, NOE, HETCOR, HMQC/HSQC, HMBC)

 

MASS SPECTROMETRY

MS spectrometer.

MS background and theory (principle operation, fragmentation detection,…)

Application of MS (determination of molecular formula)

Resolution of mass spectrometers (low and high resolution)

Isotopic effect

Calculation of relative abundance of M+1 and M+2 peaks

Common fragments of Organic compounds: (alkanes; Cycloalkanes; alkenes. Alkynes; alcohols; aldehyde and ketones:McLafferty rearrangement)

REFERENCE

1. Jones, M. Jr. (2000). Organic chemistry 2nd ed., p641-691

2. Schoffstall, A.M., Gaddis, B.A, Druelinger, M.L., (2000). Microscle and miniscale organic chemistry laboratory experiments, p., 113-180

3. Jacabsen, N.E. (2007). NMR Spectroscopy explained, Simplified theory, Applications, and Examples for organic chemistry and structural biology, A. John Willey & Sons Inc. Publications

4. Lambert, J.B., and Mazola, E.P. Nuclear Magnetic Resonance Spectroscopy. An Introduction to principles, Application, and Experimental methods, Pearson Education Inc. (eBook)

5. Wade, L.G.,Jr (1995), Organic Chemistry, 3rd ed., Prentice Hall-Hall

6. Morison R.T., and Boyd, R.N., (1987). Organic Chemistry, 5th ed., Allyn and Bacon Inc. pp. 569-631

7. Pavia,D.L.,Lampman G.M., and Kriz, G.S. (1979), Introduction to spectroscopy. Saunders College Publishing.

8. Pavia,D.L.,Lampman G.M., and Kriz, G.S. (2001), Introduction to spectroscopy, 3rd ed., Thomson Learning, Inc.

9. http://www.chemlin.net/chemistry/ir_spectrosocpy.htm ( searched October 2009)

10. http://www.chem.ucalgary/courses/351 ( searched October 2009, google search “Chapter 13: Spectroscopy”)

11. http://www.chemistry.ccsu.edu/glagovich/teaching/316/nmr/couplingbasics.html (searched July,2008)

12. Yadav, L.D.S. Organic spectroscopy

13. www2.chemistry.msu.edu/faculty/.../Spectrpy/UV-Vis/spectrum.htm

14.Basic One- and Two-Dimensional NMR Spectroscopy by H. Friebolin ; Wiley & VCH, ; 2004

15.Introduction to NMR Spectroscopy by R.J. Abraham, J. Fisher and P.Loftus; J. Wiley & Sons, 1988.

16.High Resolution NMR techniques in Organic Chemistry by T.D.W. Claridge; Pergamon, 2009.

17.http://www.kayelaby.npl.co.uk/chemistry/3_8/3_8_7.html

18.http://chem.ch.huji.ac.il/nmr/whatisnmr/whatisnmr.html [©Roy Hoffman and Yair Ozery, The Hebrew University, Revised 2009-07-20T10:57+03]

Go to Introduction >> Lecture Notes