Sn1 and sn2 reaction
- 1. THE H.N.S.B LTD. SCIENCE COLLEGE, HIMATNAGAR CLASS SEMINAR M.Sc SEM-I Subject :- INORGANIC CHEMISTRY Paper :- CHN- 401 Topic :- Nucleophilic displacement reaction Presented By Guided By Kajal Patel Dr. N. I. Patel sir
- 2. Content…… - SN1 Reaction - SN2 Reaction
- 3. The SN1Reaction Substitution Nucleophilic Unimolecular
- 4. The SN1Reaction SN1 reactions are nucleophilic substitutions, involving a nucleophile replacing a leaving group (just like SN2). However: SN1 reactions are unimolecular: the rate of this reaction depends only on the concentration of one reactant. ● SN1 reactions happen in two steps: 1. The leaving group leaves, and the substrate forms a carbocation intermediate. 2. The nucleophile attacks the carbocation, forming the product.
- 6. The SN1Reaction 1. The Slow Step: First step of the SN1 reaction: The leaving group leaves, and the substrate carbon now only has thre ●Carbocations are most stable when there are more atoms to distribute ●Carbocation stability: 3º > 2º >> 1º ●Tip: study the difference between reaction intermediates and transition state
- 7. The SN1Reaction 2. The Fast Step: Second step of the SN1 reaction: The nucleophile attacks the carbocation intermediate, bringing its ele ●The substrate loses any stereospecificity during the carbocation inter
- 9. The SN2Reaction Substitution: this reaction involves a substitution of players – two reactants produce two products, in which some things have been switched around: AB + C AC + B ● Tip: think of this if you get elimination (E1 and E2) reactions mixed up with substitution (SN1 and SN2) reactions.
- 10. The SN2Reaction Transition State SN2 summary: (1) Nucleophile back-side attacks the δ+ carbon center. (2) Transition state forms in which nucleophile is forming bo (3) The leaving group leaves, forming the final product. (2) (1) (3)
- 11. The SN2Reaction Nucleophilic: these reactions involve a nucleophile (Nuc:-) replacing a leaving group. ● Nucleophiles attack the substrate, donating an electron pair to the new bond, and replacing the leaving group (a substitution). ● Tip: Remember the role of a nucleophile by its Greek roots: Nucleo-(nucleus)-phile-(lover) – it is attracted to the nucleus, which is positively charged! Nucleophiles are therefore negatively charged or strongly δ-.
- 13. The SN2Reaction Bimolecular: A bimolecular reaction is one whose rate depends on the concentrations of two of its reactants. ● SN2 reactions happen in one step – the nucleophile attacks the substrate as the leaving group leaves the substrate. ● Tip: Recall that the rate of a reaction depends on the slowest step. In bimolecular reactions, therefore, the slow step involves two reactants. For SN2 reactions, there are only two reactants; this means that the slow step is the only step.
- 14. The SN2Reaction Notes: ●In the SN2 reaction, the nucleophile attacks from the most δ+ region ●This back-side attack causes an inversion (study the previous slide) ●The nucleophile must be able to reach the δ+ carbon center that it is ●Tip: see chapter 6 of your textbook to learn what makes a good nucleophile o