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Reaction Mechanisms. Presented by Leticia Bonita Prince Newcastle University 4 th Year MChem Student. Aims of Today. Increase your understanding of reaction mechanisms and the bromination of alkenes. Increase your spatial skills and awareness using software designed by the CCDC.
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Reaction Mechanisms Presented by Leticia Bonita Prince Newcastle University 4th Year MChem Student
Aims of Today • Increase your understanding of reaction mechanisms and the bromination of alkenes • Increase your spatial skills and awareness using software designed by the CCDC
What are Spatial Skills? • The ability to mentally manipulate 2-dimensional and 3-dimensional figures. • Important in chemistry, biology, medicine, mathematics, physics and everyday life.
Curly Arrows • In a chemical reaction NEW BONDS ARE MADE and BONDS ARE BROKEN. A reaction mechanism illustrates how this happens. • Curly Arrows are used to highlight the MOVEMENT OF ELECTRONS. H+ + Cl- 2Cl. A HALF ARROW REPRESENTS 1 ELECTRON A FULL ARROW REPRESENTS 2 ELECTRONS Heterolytic Fission Homolytic Fission
Direction of Movement NUCLEOPHILE ELECTROPHILE
Nucleophiles • Electron Pair DONORS • Lewis Bases -CN, -OH, Cl-
Electrophiles • Electron Pair ACCEPTOR • Lewis Acids H+, CH3+, NO2+
Electrophilic Addition to Ethene (Bromination) • Ethene has a π bond which has high electron density – NUCLEOPHILE • Bromine molecule will have a δ+ from Van der Waals’ - ELECTROPHILE
The WebCSD • Type in http://webcsd.ccdc.cam.ac.uk/teaching_database_demo.php • Answer the questions by typing the refcodes into the “find entry” box
THANK YOU! ENJOY THE REST OF YOUR DAY!