Discovering Chemistry With Natural Bond Orbitals

by Weinhold, Frank

• ISBN13: 9781118229101
• ISBN10: 111822910X
• Edition: 1st
• Format: eBook
• Copyright: 2012-06-22
• Publisher: Wiley

Summary

This book explores chemical bonds, their intrinsic energies, and the corresponding dissociation energies which are relevant in reactivity problems. It offers the first book on conceptual quantum chemistry, a key area for understanding chemical principles and predicting chemical properties. It presents NBO mathematical algorithms embedded in a well-tested and widely used computer program (currently, NBO 5.9). While encouraging a "look under the hood" (Appendix A), this book mainly enables students to gain proficiency in using the NBO program to re-express complex wavefunctions in terms of intuitive chemical concepts and orbital imagery.

Author Biography

FRANK WEINHOLD, PhD, is Emeritus Professor of Physical and Theoretical Chemistry at the University of Wisconsin–Madison. Professor Weinhold has served on the editorial advisory boards of the International Journal of Quantum Chemistry and Russian Journal of Physical Chemistry. He is the author of more than 170 technical publications and software packages, including the natural bond orbital program.

CLARK R. LANDIS, PhD, is Professor of Inorganic Chemistry at the University of Wisconsin–Madison. He has received teaching and lectureship awards for his contributions to chemical education. Dr. Landis's research focuses on catalysis in transition metal complexes.

Table of Contents

Preface

1 Getting Started

1.1 Talking to your electronic structure system

1.2 Helpful tools

1.3 General $NBO keylist usage

1.4 Producing orbital imagery

Problems and Exercises

2 Electrons in Atoms

2.1 Finding the electrons in atomic wavefunctions

2.2 Atomic orbitals and their graphical representation

2.3 Atomic electron configurations

2.4 How to find electronic orbitals and configurations in NBO output

2.5 Natural Atomic Orbitals and the Natural Minimal Basis

Problems and Exercises

3 Atoms in Molecules

3.1 Atomic orbitals in molecules

3.2 Atomic configurations and atomic charges in molecules

3.3 Atoms in open-shell molecules

Problems and Exercises

4 Hybrids and Bonds in Molecules

4.1 Bonds and lone pairs in molecules

4.2 Atomic hybrids and bonding geometry

4.3 Bond polarity, electronegativity, and Bent's rule

4.4 Electron-deficient 3-center bonds

4.5 Open-shell Lewis structures

4.6 Lewis-like structures in transition metal bonding

Problems and Exercises

5 Resonance Delocalization Corrections

5.1 The Natural Lewis Structure perturbative model

5.2 2nd-order perturbative analysis of donor-acceptor interactions

5.3 $DEL energetic analysis

5.4 Delocalization tails of Natural Localized Molecular Orbitals

5.5 How to $CHOOSE alternative Lewis structures

5.6 Natural Resonance Theory

Problems and Exercises

6 Steric and Electrostatic Effects

6.1 Nature and evaluation of steric interactions

6.2 Electrostatic and dipolar analysis

Problems and Exercises

7 Nuclear and Electronic Spin Effects

7.1 NMR chemical shielding analysis

7.2 NMR J-coupling analysis

7.3 ESR spin-density distribution

Problems and Exercises

8 Coordination and Hyperbonding

8.1 Lewis acid-base complexes

8.2 Transition metal coordinate bonding

8.3 Three-center, four-electron hyperbonding

Problems and Exercises

9 Intermolecular Interactions

9.1 Hydrogen-bonded complexes

9.2 Other donor-acceptor complexes

9.3 Natural energy decomposition analysis

Problems and Exercises

10 Transition State Species and Chemical Reactions

10.1 Ambivalent Lewis structures: the transition-state limit

10.2 Example: bimolecular formation of formaldehyde

10.3 Example: unimolecular isomerization of formaldehyde

10.4 Example: SN2 halide exchange reaction

Problems and Exercises

11 Excited State Chemistry

11.1 Getting to the “root” of the problem

11.2 Illustrative applications to NO excitations

11.3 Finding common ground: state-to-state NBO transferability

11.4 NBO/NRT description of excited state structure and reactivity

11.5 Conical intersections and intersystem crossings

Problems and Exercises

Appendix A: What's Under the Hood?

Appendix B: Orbital Graphics: The NBOView Orbital Plotter

Appendix C: Digging at the Details

Appendix D: What if Something Goes Wrong?

Appendix E: Atomic Units and Conversion Factors