IR spectroscopy and mass spectrmetry. Nuclear magnetic resonance. Larmor frquency. Nuclei magnetic properties. NMR instrumentation. Chemical shift. Shielding effect, coupling constant J. Diamagnetic anisotropy. Spin-spin coupling. Chemical and magnetic equivalence. 13C NMR. Dehydration and thermal degradation of carbohydrates. Browning reactions. Caramelization. Maillard reaction. Strecker degradation. Lipolysis. Lipids autooxidation. Feed antioxidants. Lipids thermal decomposition. Terpenes
1. Hesse Meier
“Metodi spettroscopici nella chimica organica”
EdiSES
2. Robert M. Silverstein, Francis X. Webster, David J. Kiemle
“Identificazione spettrometrica di composti organici”
Casa Editrice Ambrosiana
3. D. Williams, I. Fleming
“Spectroscopic methods in organic chemistry”
McGraw –Hill
Learning Objectives
The course objectives are to illustrate the use of spectroscopic techniques for determination of structure of organic molecules. Infrared spectroscopy, mono- and bidimensional nuclear magnetic resonance (homonuclear and heteronuclear 2D-NMR), mass spectrometry and a short account of ultraviolet spectroscopy will be discussed, aiming to give students a basic knowledge that allows them to be trained in analysis of IR, NMR, MS and UV spectra for the identification of organic compounds. In the final part, reactions which involve organic products present in foods, as carbohydrates, lipids and terpenes, will be briefly discussed.
Prerequisites
Organic Chemistry examination.
Teaching Methods
Frontal lessons and exercises to resolve structure of organic compounds through spectroscopic methods
Copies of slides used during the course.
Further information
Class attendance: not mandatory but strongly recommended.
- Reception hours:
Every day after appointment
- Address:
Department of Chemistry "Ugo Schiff"
Via della Lastruccia 3-13, 50019 Sesto F.no, Florence
Tel. 055 4573550
e-mail: antonella.capperucci@unifi.it
Type of Assessment
The final examination consists in an oral exam, to evaluate the ability of students to use and identify an unknown simple organic structure by using IR, MS and NMR spectra.
Daytime of exams can be found on the web page of the Corso di Laurea. On-line registration is required for the exam.
Course program
Fundamentals of IR spectroscopy. Vibrational motions. Properties of bonds and absorption. Instrumentation. Functional groups. Analysis of the IR spectra of the main classes of organic compounds. Fundamentals of nuclear magnetic resonance (NMR) spectroscopy. Magnetic resonance. Nuclear spin states, nuclear magnetic moment, energy absorption and its effects. The phenomenon of precession. Larmor frequancy. Magnetic properties of nuclei. Brief overview on the physical basis of the NMR. The NMR spectrometer. Chemical shift: shielding and deshielding effect. Chemical shift definition, integrals, multiplicity and coupling constant (J). Interpretation of an NMR spectrum. Diamagnetic anisotropy. Spin-spin coupling. Rules of the 1st order. Chemical and magnetic equivalence. Classification of spectra. Weakly and strongly coupled systems. Delta Report (v) / J. Coupling constants 1J, 2J, 3J and long-range. Influence of molecular symmetry and chirality. Homotopic, enantiotopic and diastereotopic protons. Overview of 13C spectroscopy. Effect of symmetry on NMR spectra. The chemical shift in 13C. Mass spectrometry: fundamental principles. Generation, fragmentation and detection of ions. Instrumentation. Interpretation of the main fragmentations of organic compounds. Dehydration and thermal degradation of carbohydrates. Decomposition of glucose to 3-deoxy glucosone. Browning reactions. Caramelization. Maillard's reaction. Strecker degradation. Lipolysis. Self-oxidation of lipids. Food antioxidants. Phenolic antioxidants. 2- and 3-BHA, BHT. TBHC, PG, THBP. Characteristics of food antioxidants. Thermal decomposition of lipids. Terpens. Generalities and classification: Emiterpenoids. Monoterpenoidi. Importance of monoterpenoids in food. Mono- and bicyclic monoterpenoids. Sesquiterpenoids. Diterpenoids. Triterpenoids. Squalene and lanosterol. Carotenoids