"Lec 15 - Chemical Reactivity: SOMO, HOMO, and LUMO" Freshman Organic Chemistry (CHEM 125) Professor McBride begins by using previous examples of "pathological" bonding and the BH_3 molecule to illustrate how a chemist's use of localized bonds, vacant atomic orbitals, and unshared pairs to understand molecules compares with views based on the molecule's own total electron density or on computational molecular orbitals. This lecture then focuses on understanding reactivity in terms of the overlap of singly-occupied molecular orbitals (SOMOs) and, more commonly, of an unusually high-energy highest occupied molecular orbital (HOMO) with an unusually low-energy lowest unoccupied molecular orbital (LUMO). This is shown to be a generalization of the traditional concepts of acid and base. Criteria for assessing reactivity are outlined and illustrated. 00:00 - Chapter 1. Introduction: "Pathological" Bonding in the BH3 10:45 - Chapter 2. Viewing BH3 via Electron Density and Molecular Orbitals 20:25 - Chapter 3. Assessing Reactivity through HOMO-LUMO Interactions 40:15 - Chapter 4. Criteria for Assessing Reactivity Complete course materials are available at the Open Yale Courses website: http://open.yale.edu/courses This course was recorded in Fall 2008.
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Channels: Chemistry (General)
Tags: Pairwise orbitals localized bonding MO diagrams HOMO LUMO
Uploaded by: yalefreshorganic ( Send Message ) on 05-09-2012.
Duration: 47m 12s
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Lec 2 - Force Laws, Lewis Structures and Resonance
Lec 3 - Double Minima, Earnshaw's Theorem and Plum-Puddings
Lec 4 - Coping with Smallness and Scanning Probe Microscopy
Lec 6 - Seeing Bonds by Electron Difference Density
Lec 7 - Quantum Mechanical Kinetic Energy
Lec 8 - One-Dimensional Wave Functions
Lec 9 - Chladni Figures and One-Electron Atoms
Lec 10 - Reality and the Orbital Approximation
Lec 11 - Orbital Correction and Plum-Pudding Molecules
Lec 12 - Overlap and Atom-Pair Bonds
Lec 13 - Overlap and Energy-Match
Lec 14 - Checking Hybridization Theory with XH_3
Lec 16 - Recognizing Functional Groups
Lec 17 - Reaction Analogies and Carbonyl Reactivity
Lec 18 - Amide, Carboxylic Acid and Alkyl Lithium
Lec 19 - Oxygen and the Chemical Revolution (Beginning to 1789)
Lec 20 - Rise of the Atomic Theory (1790-1805)
Lec 21 - Berzelius to Liebig and Wöhler (1805-1832)
Lec 22 - Radical and Type Theories (1832-1850)
Lec 23 - Valence Theory and Constitutional Structure (1858)
Lec 24 - Determining Chemical Structure by Isomer Counting (1869)
Lec 25 - Models in 3D Space (1869-1877); Optical Isomers
Lec 26 - Van't Hoff's Tetrahedral Carbon and Chirality
Lec 27 - Communicating Molecular Structure in Diagrams and Words
Lec 28 - Stereochemical Nomenclature; Racemization and Resolution
Lec 29 - Preparing Single Enantiomers and the Mechanism of Optical Rotation
Lec 30 - Esomeprazole as an Example of Drug Testing and Usage
Lec 31 - Preparing Single Enantiomers and Conformational Energy
Lec 32 - Stereotopicity and Baeyer Strain Theory
Lec 33 - Conformational Energy and Molecular Mechanics
Lec 34 - Sharpless Oxidation Catalysts and the Conformation of Cycloalkanes
Lec 35 - Understanding Molecular Structure and Energy through Standard Bonds
Lec 36 - Bond Energies, the Boltzmann Factor and Entropy
Lec Last - Potential Energy Surfaces, Transition State Theory and Reaction Mechanism