The study of organic chemistry hinges on an understanding and capacity to predict molecular properties and reactions. Molecular Orbital Theory is a model grounded in quantum mechanics deployed by chemists to describe electron organization within a chemical structure. It unlocks some of the most prevalent reactions in organic chemistry.
Basic Concepts of Orbital Theory in Organic Chemistry provides a concise, accessible overview of this theory and its applications. Beginning with fundamental concepts such as the shape and relative energy of atomic orbitals, it proceeds to describe the way these orbitals combine to form molecular orbitals, with important ramifications for molecular properties. The result is a work which helps students and readers move beyond localized bonding models and achieve a greater understanding of organic chemical interactions.
In Basic Concepts of Orbital Theory in Organic Chemistry readers will also find: - Comprehensive explorations of stereoelectronic interactions and sigmatropic, cheletropic, and electrocyclic reactions, - Detailed discussions of hybrid orbitals, bond formation in atomic orbitals, the Hückel Molecular Orbital Method, and the conservation of molecular orbital symmetry - Sample exercises for organic chemistry students to help reinforce and retain essential concepts
Basic Concepts of Orbital Theory in Organic Chemistry is ideal for advanced undergraduate and graduate students in chemistry, particularly organic chemistry.
Table of Contents
Chapter 1: Introduction and History of Molecular Orbital Theory.
Introduction.
Nature of electromagnetic radiation.
The wave nature of light.
Electromagnetic spectrum.
The distinction between energy and matter.
The particle nature of light
Mass and momentum associated with a light quantum
Wave-particle duality
Application of quantum mechanics to the atomic structure
Schrödinger's equation
Hydrogenic orbitals
Why doesn't the electron fall into the nucleus?
Bohr's legacy and the quantum mechanical model.
Bibliography
Exercises
Chapter 2. Hybrid Orbitals
Introduction
Hybridisation theory
Wavefunctions associated to hybrid orbitals.
Procedure to build a hybrid orbital.
Orthogonality of wave functions (orbitals)
The bent bond or tau model
Effects of hybridisation
Bibliography
Exercises
Chapter 3. Bond Formation from Atomic Orbitals
Introduction
Mixing of s orbitals.
Mixing of p orbitals.
Factors affecting the magnitude of orbital interactions.
Bonding in homo-diatomic molecules.
Bonding in hetero-diatomic molecules.
Bonding in triatomic molecules.
Conjugated systems.
Bibliography
Exercises
Chapter 4. The Hückel Molecular Orbital Method (HMO)
Simplified procedure for the application of Hückel´s method.
Application of Hückel´s method: several examples.
Application to larger molecules
Scope and limitations of the HMO method.
HMO in cyclic p-systems
Energy diagrams for acyclic polyenes
p-Systems containing heteroatoms.
The shape of the molecular orbitals.
Contribution of the atomic orbitals in a molecular orbital.
Symmetry simplifications in alternant hydrocarbons (AH)
Estimation of MO energies and coefficients
Bond orders (Pij)
Charge distribution (qi).
Index of free valence (Fi).
Bibliography
Exercises
Chapter 5. Interactions between molecular orbitals: chemical reactions.
Introduction
Molecular orbital theory of selected organic reactions.
Summary
Bibliography
Exercises
Chapter 6: Some Applications of Orbital Theory in Organic Chemistry
Introduction
Ultraviolet spectroscopy
Ionisation potentials
Photoelectron spectroscopy (PES)
Interactions between p Orbitals
Interactions between n-orbitals
ESCA spectroscopy
Charge transfer complexes (EDA complexes)
Bibliography
Exercises
Chapter 7: Conservation of Molecular Orbital Symmetry. Introduction to Pericyclic Reactions: Cycloaddition Reactions
Introduction
Concerted reactions
Pericyclic reactions
Principles of the conservation of orbital symmetry
Correlation diagrams of molecular orbitals
Analysis of the symmetry of the HOMO/LUMO frontier orbitals
Analysis of the nodal properties at the transition state of a cyclisation reaction.
Cycloaddition reactions
Starting material ⇌ product correlation diagram
HOMO/LUMO interactions
Nodal properties of the transition state
Two ethylene molecules ⇌ cyclobutane
Correlation diagram starting materials ⇌ product
HOMO/LUMO interaction
Supra- or antarafacial topicity in cycloaddition reactions
Effect of Secondary Interactions between molecular orbitals
Bibliography
Exercises
Chapter 8:Cheletropic Reactions.
Introduction.
[2+2] Cheletropic reactions.
[4+2] Cheletropic reactions.
[6+2] Cheletropic reactions.
Bibliography
Exercises
Chapter 9: Electrocyclic Reactions.
Introduction.
1,3-Butadiene cyclobutene
1,3,5-Hexatriene 1,3-cyclohexadiene
Photochemical electrocyclic reactions.
Bibliography
Exercises
Chapter 10: Sigmatropic Reactions
Introduction
[3,3] Sigmatropic rearrangements
[1,3] Sigmatropic rearrangements of alkyl groups
[1,5] Sigmatropic rearrangements of alkyl groups
[1,2] Sigmatropic rearrangements of alkyl groups.
[1,3] Sigmatropic rearrangements of hydrogen
[1,5] Sigmatropic rearrangements of hydrogen
Bibliography
Exercises
Chapter 11:1,3-Dipolar cycloadditions.
Introduction.
Classification of 1,3-dipolar reactants
FMO analysis
Analysis of nodal properties in the transition state
Types of 1,3-DPCA reactions and regioselectivity
1,3-DPCA reactions with diazoalkanes
1,3-DPCA reactions with nitrones
1,3-DPCA reactions with azomethine ylides as the 1,3-dipolar reactant.
1,3-DPCA reactions with nitrile oxides as 1,3-dipolar reactants.
1,3-DPCA reactions with azides, osmium tetroxide and ozone
Bibliography
Exercises
Chapter 12: Stereoelectronic interactions.
Introduction
Bibliography
Exercises
