Fundamental Concepts In Organic Reaction Mechanism
Chapter Name : Organic Chemistry - Some Basic Principles And Techniques |
Sub Topic Code : 102_11_12_07_07 |
Topic Name : Fundamental Concepts In Organic Reaction Mechanism |
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Sub Topic Name : Resonance Effect |
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Introduction
Organic chemistry is a chemistry sub discipline involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.
Pre-Requisites:
Organic chemistry
Activity:
Aromatic compounds
Real Life Question:
What is organic chemistry?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Resonance | Resonance or mesomerism is a way of describing delocalized electrons within certain molecules or polyatomic ions where the bonding cannot be expressed by one single Lewis formula. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| Alcohols | Alcohols (R-OH) take the suffix "-ol" with an infix numerical bonding position: CH3CH2CH2OH is propan-1-ol. The suffixes -diol, -triol, -tetraol, etc., are used for multiple -OH groups: Ethylene glycol CH2OHCH2OH is ethane-1, 2-diol. |
Real life uses :
Study the nature of chemicals.
Places to visit :
Chemistry laboratory.
Practical examples around us
| Examples | Explainations |
|---|---|
| ketones | In general ketones (R-CO-R) take the suffix "-one" with an infix position number: CH3CH2CH2COCH3 is pentan-2-one. If a higher precedence suffix is in use, the prefix "oxo-" is used: CH3CH2CH2COCH2CHO is 3-oxohexanal. |
What you learn in Theory:
The electron withdrawing or releasing effect attributed to a substituent through delocalization of p or ? electrons, which can be visualized by drawing various canonical forms, is known as mesomeric effect or resonance effect. It is symbolized by M or R.
What you learn in Practice:
The actual structure is an approximate intermediate between the canonical forms, but its overall energy is lower than each of the contributors. This intermediate form between different contributing structures is called a resonance hybrid.