Unified Valence Bond Theory of Electronic Structure: Applications

✍ Scribed by Nicolaos Demetrios Epiotis (auth.)

• Publisher: Springer-Verlag Berlin Heidelberg
• Year: 1983
• Tongue: English
• Leaves: 597
• Series: Lecture Notes in Chemistry 34
• Edition: 1
• Category: Library

✦ Synopsis

The bond diagrammatic representation of molecules is the foundation of MOVB theory. To a certain extent, this kind of representation is analogous to the one on which "resonance theory" is based and this fact can be projected by a comparison of the various ways in which MOVB theory depicts a species made up of three core and two ligand MO's which define two subsystems containing a total of six electrons and the ways in which "resonance theory" (i. e. , qualitative VB theory) depicts a six-electron-six-AO species such as the pi system of CH =CH-CH=CH-CH=O. The 2 different pictorial representations are shown in Scheme 1 so that the analogies are made evident. First of all, the total MOVB diagrammatic representation of the 6/5 species is obtained by a linear combination of three complete bond diagrams, as in Al, which describe the optimal linear combination of!l! MOVB Configuration Wavefunctions (CW's). By the same token, a total VB diagrammatic representation of the 6/6 species can be obtained by writing a "dot structure", as in Bl, and taking this to mean the optimal linear combination of all VB CW's. Next, we can approxi­ mate the MOVB wavefunction of the 6/5 species by one complete (or detailed) bond dia­ gram" (A2). No simple VB representation analogy can be given in this case. Alterna­ tively, we can approximate the MOVB wavefunction by a linear combination of compact bond diagrams, as in A3, in the way described before.

✦ Table of Contents

Front Matter....Pages N2-VIII
Front Matter....Pages 1-11
The Induced Deexcitation Model....Pages 12-59
Why do Organolithium Monomers have Strange Structures?....Pages 60-103
The Molecular Orbital-Valence Bond Theory of Excited States....Pages 104-150
The “Forbidden” World of Chemistry....Pages 151-185
The Concept of Natural Ligand Nonbonded Repulsion. The Ethane Paradigm....Pages 186-206
Conformational Isomerism of N 2 H 4 and Derivatives. The Stereochemical Consequences of “Forbiddenness” Removal....Pages 207-230
Geometric Isomerism: The Simplest Illustrator of Orbital Symmetry Control of Molecular Stereochemistry....Pages 231-249
Structural Isomerism and the Electronic Basis for Ligand Segregation on C 2 Cores....Pages 250-264
The Saga of “Hypervalent” Molecules....Pages 265-298
The Molecular Orbital-Valence Bond Theory of Inorganic Chemistry....Pages 299-340
How to build Bridges by Molecular Orbital-Valence Bond Theory: The Structures of A 2 X 4 Molecules....Pages 341-357
Why Benzene prefers to substitute and an Olefin likes to add?....Pages 358-371
Why “Effective” Bonds exist when “Real” Bonds are Absent: The Electronic Structure of the (1.1.1.) Propellane....Pages 372-380
The Detailed Electronic Structure of Carbocyclic Molecules and the Concept of Superaromaticity....Pages 381-390
The Explicit Theory of “Real” Electrocyclizations of Closed and Open Shell Molecules....Pages 391-417
Front Matter....Pages 418-419
Frontier Configurations and a New Classification of Annulenes....Pages 420-431
Frontier Configuration Theory of Spin Selection....Pages 432-456
Why a Net Bond exists when it appears to be Nonexistent: The Electronic Structures of F 2 and Inert Gas Fluorides....Pages 457-469
Chemical Anticooperativity and Sigma-Pi Hybridization....Pages 470-511
The Stereochemical Consequences of Coulomb Polarization in Ground State Molecules....Pages 512-545
Erratum....Pages 584-585
Front Matter....Pages 418-419
The Qualitative Rationalization and Prediction of “Correlation Effects” in “Complex” Ground State Molecules....Pages 546-559
Epilogue....Pages 560-583
Back Matter....Pages 587-589

✦ Subjects

Theoretical and Computational Chemistry