Structural Analysis
Code
7107
Academic unit
Faculdade de Ciências e Tecnologia
Department
Departamento de Química
Credits
6.0
Teacher in charge
António Gil de Oliveira Santos, Eurico José da Silva Cabrita
Weekly hours
4
Total hours
63
Teaching language
Português
Objectives
Prerequisites
General knowledge of quantum chemistry, physical chemistry and spectroscopy and organic chemistry.
Subject matter
Infrared spectroscopy. Revision of important theoretical concepts. Spectra interpretation. Characteristic group absorption of organic compounds.
Mass spectrometry. Instrumentation. Ionization and fragmentation. Fragmentation mechanisms. Structure elucidation.
Nuclear magnetic resonance. General theoretical concepts and experimental applications.
Structure elucidation based on UV/Vis, IV, MS and NMR spectra.
NMR of heteroatoms.
Advanced theoretical concepts in uni-dimensional NMR. Presentation of some common pulse sequences. Spectral simulation.
Introduction to bi-dimensional NMR techniques. COSY, NOESY, HMQC. HMBC.
Detailed program
1. Review of general concepts in spectroscopy Ultraviolet / Visible.
2. Review of general concepts in infrared spectroscopy.
3. Introduction to mass spectrometry.
Basics.
Instrumentation.
Mass spectra.
Spectra of high and low resolution.
Exact masses.
Molecular ionization and cleavage.
Functional groups.
Fragmentation mechanisms.
Degradations: simple and complex degradations.
4. Nuclear Magnetic Resonance.
4.1 Chemical and physical aspects.
Active nuclei in NMR.
NMR energy transitions.
Chemical shift in 1H NMR.
Chemical shift in 13C NMR.
References for chemical shift.
D scale of chemical shift.
Intensity of signals in NMR.
Spin coupling in 1H and 13C NMR.
Spin systems.
Analysis of first order spectra
Second order spectra.
Spin decoupling.
Saturation.
Relaxation.
Nuclear Overhauser effect (NOE).
Structural analysis on the basis of coupling constants.
4.2 Theoretical aspects of nuclear magnetic resonance.
Precession.
Larmor frequency.
Coherence of spin.
Magnetization.
Radio frequency pulses.
Obtaining the FID.
Fourier transform.
Phase.
Scan.
Acquisition time.
Digital resolution and actual resolution.
Quadrature detection.
Phase Cycle.
Spin decoupling.
Experiments using multiple pulses.
4.3 instrumental aspects of nuclear magnetic resonance.
Continuous waves spectrometers
Fourier transform spectrometers
Lock.
Shim.
Accumulation of transients.
Signal to noise ratio.
4.4 NMR spectroscopy in two dimensions.
Analysis heteronuclear correlation spectra. HMQC, HMBC.
Homonuclear correlation spectroscopy. COSY.
Contacts through space. NOESY.
Bibliography
1. T. D. W. Claridge, High-Resolution NMR Techniques in Organic Chemistry, Pergamon (Tetrahedron Organic Chemistry Series, Volume 19).
2. E. De Hoffmann, J. Charette, V. Stroobant , Mass Spectrometry, Principles and Applications, John Wiley & Sons.
3. R. M. Silverstein, F. X. Webster, D. J. Kiemle, Spectrometric Identification of Organic Compounds, John Wiley & Sons, Inc.
4. D. A. Skoog, F. James. Holler, T. A. Nieman, Principles of Instrumental Analysis, Saunders College Publishing.
5. J. K. M. Sanders, B. K. Hunter, Modern NMR Spectrosocpy: A Guide for Chemists, Oxford University
Teaching method
Classes use modern multimedia techniques, including 3D animation. Students have access to all necessary equipment, as spectrometers and desktop computers with software for spectral processing and 3D modelling and visualization.
Evaluation method
Overall assessment of the course:
Throughout the semester, students complete three (3) partial tests at weeks 13-17 October (25%), 17-21 November (35%) and 8-12 December (40%). The final (overall score) will be the weighted average of the partial test scores. Only students who obtain at least 9.50 in the overall score will be approved.
Frequency (Exclusion from final exam):
Students that do not have "Frequência" from past years will be excluded from final exam if they do not attend at least 2/3 of the TP classes of the semester.
"RECURSO" Examination:
Students who are not excluded from the final exam (obtainded "Frequência") and are not approved in the tests, have access to a single final exam - RECURSO. The exam focuses on the entire course content. Only students who obtain at least 9,50 score will be approved. The overall score obtained after the final examination, will be the grade obtained in this exam.