SOME IMPORTANT CHARACTERS FOR ORGANIC REACTIONS MECHANISMS

1. SOME IMPORTANT CHARACTERS FOR ORGANIC REACTIONS MECHANISMS Dr Seemal Jlani Chem-240

2. MEET THE ATTACKERS Dr Seemal Jlani Chem-240 Press the space bar

3. MEET THE ATTACKERS I AM A NUCLEOPHILE I HAVE A LONE PAIR WHICH I CAN USE TO FORM A NEW BOND. I ATTACK ELECTRON DEFICIENT AREAS (those with a + ord+) Dr Seemal Jlani Chem-240

4. MEET THE ATTACKERS Dr Seemal Jlani Chem-240 Press the space bar

5. MEET THE ATTACKERS I AM AN ELECTROPHILE I HAVE A + CHARGE or ad+ CHARGE. I ATTACK ELECTRON RICH AREAS SUCH AS C=C DOUBLE BONDS. Dr Seemal Jlani Chem-240

6. MEET THE ATTACKERS Dr Seemal Jlani Chem-240 Press the space bar

7. MEET THE ATTACKERS AND I AM A FREE RADICAL I HAVE AN UNPAIRED ELECTRON WHICH I WANT TO PAIR UP. I AM VERY REACTIVE AND DON’T MIND WHERE I ATTACK… WATCH OUT! Dr Seemal Jlani Chem-240

8. WHO IS ATTACKED? THE BONDING IN A MOLECULE INFLUENCES WHAT WILL ATTACK IT Dr Seemal Jlani Chem-240

9. WHO IS ATTACKED? THE BONDING IN A MOLECULE INFLUENCES WHAT WILL ATTACK IT SINGLE A typical covalent bond with one shared pair – nothing to tempt an attacking species Dr Seemal Jlani Chem-240

10. WHO IS ATTACKED? THE BONDING IN A MOLECULE INFLUENCES WHAT WILL ATTACK IT SINGLE MULTIPLE A typical covalent bond with one shared pair – nothing to tempt an attacking species Bond has twice as many electrons – species which like electrons will be attracted Dr Seemal Jlani Chem-240

11. WHO IS ATTACKED? THE BONDING IN A MOLECULE INFLUENCES WHAT WILL ATTACK IT SINGLE MULTIPLE NON-POLAR A typical covalent bond with one shared pair – nothing to tempt an attacking species Bond has twice as many electrons – species which like electrons will be attracted Similar atoms have an equal attraction for the shared pair of the covalent bond Dr Seemal Jlani Chem-240

12. WHO IS ATTACKED? THE BONDING IN A MOLECULE INFLUENCES WHAT WILL ATTACK IT SINGLE MULTIPLE NON-POLAR POLAR A typical covalent bond with one shared pair – nothing to tempt an attacking species Bond has twice as many electrons – species which like electrons will be attracted Similar atoms have an equal attraction for the shared pair of the covalent bond d+ d- Atoms have different electronegativities and the shared pair will be attracted more to one end – species known as nucleophiles will be attracted to the slightly positive end Dr Seemal Jlani Chem-240

13. WHO IS ATTACKED? THE BONDING IN A MOLECULE INFLUENCES WHAT WILL ATTACK IT SINGLE MULTIPLE NON-POLAR POLAR A typical covalent bond with one shared pair – nothing to tempt an attacking species Bond has twice as many electrons – species which like electrons will be attracted Similar atoms have an equal attraction for the shared pair of the covalent bond d+ d- Atoms have different electronegativities and the shared pair will be attracted more to one end – species known as nucleophiles will be attracted to the slightly positive end Dr Seemal Jlani Chem-240

14. WHAT ATTACKS ALKANES? ALKANES ARE RELATIVELY UNREACTIVE ORGANIC COMPOUNDS ALKANES CONTAIN TWO BOND TYPES C-H and C-C Both bonds are single – no electron rich areas Bonds are non-polar - no electron deficient areas Free radicals are very reactive and do attack FREE RADICAL SUBSTITUTION Dr Seemal Jlani Chem-240

15. WHAT ATTACKS ALKENES? ALKENES ARE MUCH MORE REACTIVE THAN ALKANES ALKENES CONTAIN A C=C BOND There will be twice as many electrons between the carbon atoms as there are in a single bond C=C bond is double – an electron rich area Bonds are non-polar - no electron deficient areas ELECTROPHILIC ADDITION Dr Seemal Jlani Chem-240

16. WHAT ATTACKS HALOGENOALKENES? HALOGENOALKANES ARE MUCH MORE REACTIVE THAN ALKANES HALOGENOALKANES CONTAIN A POLAR BOND The halogen is more electronegative than the carbon attracts the shared electron pair. d+ d- Bond is single – not an electron rich area Bond is polar – the greater electronegativity of the halogen creates a dipole making the carbon atom electron deficient. NUCLEOPHILIC SUBSTITUTION Dr Seemal Jlani Chem-240