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Structure of Carbon Centered Free Radicals

Learning Objective: To study the structural features of a carbon-centered free radical in organic chemistry. 

Skill Level - Intermediate

 

Prerequisites: 

 

Chapter: Reactive Intermediates

Sub-topic: Free Radicals

 

Author's Note: Shape is an important concept in organic chemistry that  takes into cognizance multiple parameters that can affect reactivity. A molecule's shape can reveal its bulk and interatomic interactions, tell how a reagent must approach the reactant for viable reactions, and even control a reaction speed. 

Here, the shape of a carbon-centered free radical is understood from two perspectives: electron count and position of the orbitals housing the radical electron. Both side and top views of the carbon-centered free radical are provided for easier understanding.

 

Structure of Carbon Centered Free Radicals

An average carbon atom would always want to share its four valence electrons with other similar or dissimilar atoms so that it gets a total of eight valence electrons required for octet stability and, as a result, forms four covalent bonds.

However, when it loses one electron, it loses its octet stability. It becomes a highly reactive radical with only seven valence electrons, waiting to acquire the coveted eighth.

The carbon lost one electron and a covalent bond and is now down to three. This also leads to a change in ........

 

 

 

The alkyl carbon radical .....

Subscribe to learn about the structural features of a carbon-centered free radical in organic chemistry. 

 

Reactive Intermediates
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What is Organic Chemistry?

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Atom

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  • Power of Protons
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Bonding In Atoms

  • Octet Rule - Introduction and Bonding
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Covalent Bond

  • Theories on Covalent Bond Formation
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  • Electron Wave Property, LCAO and MOT - Introduction
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Electronic Displacement in a Covalent Bond

  • Electronegativity- Introduction
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  • Inductive effect - Introduction, Types, Classification, and Representation
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  • Factors Affecting Inductive Effect- Bonding Order and Charge
  • Factors Affecting Inductive Effect- Bonding Position
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  • Application of Inductive Effect-Stability of the Transition States
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  • Is the Inductive Effect the same as Electronegativity?
  • Resonance - Introduction and Electron Delocalization
  • Partial Double Bond Character and Resonance Hybrid
  • Resonance Energy
  • Significance of Planarity and Conjugation in Resonance
  • p-orbital Electron Delocalization in Resonance
  • Sigma Electron Delocalization (Hyperconjugation)
  • Significance of Hyperconjugation
  • Resonance Effect and Types
  • Structure Drawing Rules of Resonance (Includes Summary)
  • Application of Resonance
  • Introduction to Covalent Bond Polarity and Dipole Moment
  • Molecular Dipole Moment
  • Lone Pair in Molecular Dipole Moment
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  • Formal Charges - Introduction and Basics
  • How to Calculate Formal Charges (With Solved Examples)
  • Difference between Formal charges and Oxidation State

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Common Types of Reactions

  • Classification of common reactions based on mechanisms
  • Addition Reactions
  • Elimination Reactions (E1, E2, E1cb)
  • Substitutions (SN1, SN2, SNAr, Electrophilic, Nucleophilic)
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Drawing Organic Structures

  • Introduction
  • Empirical Formula
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  • Numerical Problems related to finding molecular formula  (Solved)
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  • Hill Nomenclature - The Empirical and Molecular Formula Writing Rules
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  • Newman Projection- Introduction and Importance
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Functional Groups in Organic Chemistry

  • What are functional groups?
  • Chemical and Physical Properties affected by the Functional Groups
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  • Functional Group Categorization- Exclusively Carbon-containing Functional Groups
  • Functional Group Categorization- Functional Groups with Carbon-Heteroatom Single Bond
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Structural Isomerism

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  • Tautomerism
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  • Ring-Chain Isomerism

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Intermolecular Forces

  • Ion-Dipole Interactions-Introduction and Occurrence
  • Factors Affecting the Ion-Dipole Strength
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  • Ion-Induced Dipole - Introduction, Strength and Occurrence
  • Factors Affecting the Strength of Ion-Induced Dipole Interactions
  • Ion-Induced Dipole Interactions in Polar Molecules
  • Vander Waals Forces -Introduction
  • Examples of Vander Waals' forces
  • Vander Waals Debye (Polar-Nonpolar) Interactions
  • Factors affecting the Strength of Debye Forces
  • Vander Waals Keesom Force - Introduction, Occurrence and Strength
  • Vander Waals London Force - Introduction, Occurrence, And Importance
  • Factors Affecting the Strength of London Dispersion Forces- Atomic size and Shape
  • Introduction, Occurrence and Donor, Acceptors of Hydrogen Bond
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Physical Properties

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  • Physical State Change-Melting Point
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Fundamentals of Organic Reactions

  • Types of Arrows Used in Chemistry
  • Curved Arrows in Organic Chemistry- with Examples
  • Electrophiles - Introduction, Identification and Reaction
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  • Lone Pair - Introduction and Formation
  • Physical Properties Affected by the Lone Pair- Shape and Bond Angle
  • Physical Properties Affected by the Lone Pair- Hydrogen Bonding
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  • Chemical property affected by the Lone pair- Nucleophilicity
  • Leaving Group - Introduction and Nature
  • Good and Bad Leaving Group
  • Factors Determining Stability of the Leaving Groups- Electronegativity, Size, Resonance Stability
  • Using pKa as a Measure of Leaving Group Ability
  • Leaving Groups in Displacement Reactions
  • Leaving Groups in Elimination Reactions

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Reactive Intermediates

  • Carbocation - Introduction, Nature, and Types
  • Formation of Carbocation
  • Stability of Carbocations- Inductive, Resonance, and Hyperconjugation
  • Other Structural Features Increasing Carbocation Stability
  • Structural Feature Decreasing Carbocation Stability
  • Fate of the Carbocation
  • General Carbocation Formation Reactions
  • Carbanion - Introduction, Nature, and Types
  • Formation of Carbanions
  • Carbanion Stabilization
  • Ease of Formation of Carbanion -Acidic proton
  • Fate of the Carbanion
  • Free Radical - Introduction and Types of Carbon-Centred Radicals
  • Structure of Carbon-Centred Free Radical
  • Formation of Radicals
  • Stability of the Carbon-Centred Radicals
  • Other Structural Feature Increasing Free Radical Stability
  • Comparing Free Radical Stability using Dissociation energies (D-H)
  • Fate of Free Radicals
  • Common Reactions Involving Carbon-Free Radicals

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Stereoisomerism - Conformation and Configurational Isomerism

  • Conformations in Organic Chemistry - An Introduction
  • How are Conformational Isomers Depicted
  • Open Chain and Closed Chain Conformations
  • Nomenclature related to sp3-sp3 and sp3-sp2 bond rotations
  • Conformational Analysis
  • Factors affecting the stability of conformers - Stabilizing Interactions |Hyperconjugation
  • Factors affecting the stability of conformers - Stabilizing Interactions | Intramolecular Hydrogen Bonding
  • Factors affecting the stability of conformers - Stabilizing Interactions | Dipole Minimizations
  • Factors affecting the stability of conformers - Destabilizing Interactions | Steric strain
  • Factors affecting the stability of conformers - Destabilizing Interactions | Torsional strain
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  • Importance of Conformational Analysis
  • Conformation in Compounds with Lone Pairs
  • Role of Solvents in Conformations
  • An Example of Conformation Dependent Reaction and Product Selectivity
  • Geometrical Isomerism - Introduction
  • Impact of cis-trans isomerism on physical properties
  • Impact of cis-trans isomerism on chemical reactions
  • Scope of Geometrical Isomerism in Biological Systems and Industrial Applications
  • E/Z Nomenclature in Substituted Alkenes
     

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