Chemical Reaction Mechanisms
Code
10710
Academic unit
Faculdade de Ciências e Tecnologia
Department
Departamento de Química
Credits
6.0
Teacher in charge
Luísa Maria da Silva Pinto Ferreira
Weekly hours
4
Total hours
63
Teaching language
Português
Objectives
It is of interest to use a mechanistic approach which permits the use of a small number of principles derived from a large amount of data to explain and predict experimental results and the consequences of altering conditions for known reactions. Small molecules are typically used for this purpose but the use of biologically important molecules could alert us to some specific characteristics of living systems.
Prerequisites
Extensive knowledge in Organic chemistry, Introduction to physical chemistry and thermodynamics. Stereochemistry.
Subject matter
Revision of some basic principles Structure and Reactivity. Thermodynamic and kinetic effects associated with reaction mechanisms. Elementary reactions, concerted mechanisms, activated complex, transition state, molecularity, Reaction coordinates, kinetic and thermodynamic control, Hammond postulate. Stability of ionic intermediates, leaving groups, nucleophiles, electrophiles, acids and bases. Acid/base characteristics. Methods for investigating reaction mechanisms; kinetic and non-kinetic. Ionic intermediates. Study and Determination of Reaction Mechanisms Mechanism and molecular orbitals. Stereoelectronic effects. Reactions involving nucleophiles and bases. Reactions involving electrophiles and acids. Reactions involving neutral reactive species (carbenes, nitrenes, Arynes and free radicals. Rearrangments (pinacol, Curtius, Favorski, Baeyer-Villiger, Beckmann) and intermediates containing electron deficient nitrogen and oxygen atoms. Annomeric effect. Reactions without intermediates (concerted pericyclic reactions). Mechanisms in aromatic systems. Mechanisms in radical reactions. Cyclisation reactions (Baldwin rules). Ex. of mechanisms in biological systems.
Bibliography
Felix A. Carroll, Perspectives on Structure and Mechanism in Organic Chemistry, Wiley, 2010.
P. A. Sykes, A Primer to Mechanism in Organic Chemistry, Longman Scientific & Technical: Essex, 1995.
H. Maskill, Mechanisms of Organic Reactions, Oxford Chemistry Primers, 45, ed. S. G. Davies: Oxford Science Pub., Oxford Univ. Press, 1996.
P. A. Sykes, A Guidebook to Mechanism in Organic Chemistry, 6 ed., Longman, 1985.
Teaching method
Theoretical lectures are given in way to avoid monotony. During the lectures experimental results are used to demonstrate concepts which exemplify the importance of the understanding of chemistry.
Problem sessions are an essential part of the course and two and alf hours per week are dedicated to this. Although in the first sessions the lecturer leads the students into discussions it is expected that later the students will be encouraged take over this initiative.
When justified molecular models are used as a visual aid. 3D graphics and other audio-visual aids are used whenever possible.
Problem sessions are also very important for the lecturer to identify difficulties that the students may have in their understanding and to find solutions to these difficulties by discussion. This is done in such a way that the high level of the course is maintained
Evaluation method
There will be continuous evaluation with three tests during the semester. The first after about 6-8 hours of lectures, the second after 18-20 hours of lectures and the third after completion of the lecture program.