TKJ4180 - Physical Organic Chemistry
Examination arrangement: Written examination
|Evaluation form||Weighting||Duration||Examination aids||Grade deviation|
|Written examination||100/100||4 hours||D|
The course deals with fundamental principles and methods used in physical and mechanistically organic chemistry: (i) Description of molecules (includes reactive intermediates as radicals, carbenes, carbocations and carbanions) based on the valence bond theory and molecular orbital theory. (ii) Conformational analysis of organic molecules, NMR analysis of hindered rotation (determination of the rate constant at the coalescence temperature), energy-reaction coordinate diagram for simultaneously rotation of two C-C bonds and a short introduction to molecular mechanic calculations. (iii) Stereochemistry and symmetry topics. Keywords: prochirality, stereospecific and stereoselective reactions, Cram's rule and Felkin-Ahn's model, symmetry operations, symmetry elements, symmetry point groups and topical relationships related to symmetry. (iv) Substituent effects: steric, resonance, inductive and field effects. (v) General tools for mechanistically studies of organic reactions, e.g. crossover experiments (intramolecular or intermolecular reaction?) and isotope labelling experiments (which bonds are broken / formed?). (vi) Energy surfaces (2D and 3D) and kinetic analyses in the study of reaction mechanisms. Keywords: More O'Ferral-Jencks plot (variable transition-state diagram), reaction order and rate laws, the steady-state approximation in the study of complex reactions, kinetic versus thermodynamic control, the principle of microscopic reversibility, the Curtin-Hammett principle, the Hammonds postulate. Energy functions from rate constants and reaction temperatures: The Arrhenius (activation energy) and the Eyring (enthalpy and entropy of activation) equations. Kinetic isotope effects (primary and secondary). (vii) Linear free energy relationships (LFERs): (a) The Hammett equation for aromatic compounds, substituent and reaction constants, significance of the Hammett reaction constant values, deviations from linearity - mechanistic information in multi-step reactions. (b) The Swain-Scott equation (nuclophilicity versus basicity). (c) The Grunwald-Winstein and the Schleyer equations (quantifying solvent effects and nucleophilicity). (viii) Classification of solvents based on physical properties: dielectric constant, refractive index, dipole moment, donor number, acceptor number, hydrogen bond acceptor capacity alpha, hydrogen bond donor capacity beta and the Reichardt's Et scales. (ix) Acid-base chemistry: gas phase vs. aqueous acidities and acidities in water vs. organic solvents, aqueous pKa scale (leveling effect), chemistry in extremely acidic media, acidity function scale Ho, acid-base catalysis (specific and general), Lewis acid and base (hard / soft). (x) Detailed mechanistic description and discussion of basic organic reactions using the tools described above for: (a) nucleophilic addition to aldehyde / ketone (acid and base catalysis); (b) hydrolysis of acetal (acid catalysis); (c) hydrolysis of ester (acid and base catalysis); (d) nucleophilic aliphatic substitution (SN2 / SN1, neighboring group assistance, ion pairs, non-classical cations); (e) elimination (E1 / E2 / E1cb, stereo and regiochemistry). (xi) Pericyclic reactions: electrocyclic, sigmatropic, cycloaddition and cheletropic reactions. Keywords: Woodward and Hoffmann's "selection rules" for thermal and photochemical reactions, MO correlation diagrams.
After completion of the course the student should be able to:
- describe molecular structure by the use of the valens bonding theory and molecular orbital theory
- predict stereoselectivity in reaction involving the attack of nucleophiles on the carbonyl group (Cram's rule and the Felkin Ahn model)
- use kinetics as a tool for understanding reaction mechanisms
- use kinetical data for interpretation of reaction mechansims
- calculate a reactions activation energy, enthalpy of activation and entropy of activation by help of Arrhenius and Eyrings equations
- determine if a reaction is acid or base catalyzed (specific or general catalysis) from kinetic data
- use of the Hammett equation as a tool in studies of organic reactions
- interpret data for the inclusion of isotops and how this can be used in mechanistically studies of organic reactions
- explain steric and electronic effects in several important reactions
- choose a suitable solvent for a reaction based on the solvent physical properties and knowledge about the mechanism of the reaction
- connect names to important reactions and reaction mechanisms
- be familiar with different types of reaction mechanisms
- propose a reaction mechanism using the principles described above
- suggest additional experiments to "prove" or "disprove" a proposed reaction mechanism
- use Woodward and Hoffman's "selection rules" for pericyclic reactions
- deduce MO correlation diagrams for pericyclic reactions
Learning methods and activities
Lectures and exercises 4 and 2 hour per week, respectively. If there is a re-sit examination, the examination form may be changed from written to oral. Lectures are given in English on request.
Required previous knowledge
Knowledge corresponding to TKJ4102/TKJ4100/KJ1020, TKJ4150 and KJ2022 or similiar courses.
E. V. Anslyn; D. A. Dougherty: "Modern Physical Organic Chemistry", University Science Books, 2006.
Examination arrangement: Written examination
|Term||Statuskode||Evaluation form||Weighting||Examination aids||Date||Time||Room *|
- * The location (room) for a written examination is published 3 days before examination date.