Lecture DescriptionFreshman Organic Chemistry (CHEM 125)Professor McBride uses this lecture to show that covalent bonding depends primarily on two factors: orbital overlap and energy-match. First he discusses how overlap depends on hybridization; then how bond strength depends on the number of shared electrons. In this way quantum mechanics shows that Coulomb's law answers Newton's query about what "makes the Particles of Bodies stick together by very strong Attractions." Energy mismatch between the constituent orbitals is shown to weaken the influence of their overlap. The predictions of this theory are confirmed experimentally by measuring the bond strengths of H-H and H-F during heterolysis and homolysis.00:00 - Chapter 1. Distance and Hybridization in the Overlap Integral 18:49 - Chapter 2. Influence of Overlap on Molecular Orbital Energy 29:45 - Chapter 3. "Inferior" Orbitals and Energy-Matching 46:59 - Chapter 4. Experimental Evidence and ConclusionComplete course materials are available at the Open Yale Courses website: http://open.yale.edu/coursesThis course was recorded in Fall 2008.
How Do You Know – Force Laws, Lewis Structures and Resonance – Double Minima, Earnshaws Theorem and Plum – Puddings – Coping with Smallness and Scanning Probe Microscopy – X-Ray Diffraction-Seeing Bonds by Electron Difference Density – Quantum Mechanical Kinetic Energy – One-Dimensional Wave Functions – Chladni Figures and One – Electron Atoms – Reality and the Orbital Approximation – Orbital Correction and Plum – Pudding Molecules – Overlap and Atom – Pair Bonds – Overlap and Energy – Match – Checking Hybridization Theory with XH_3-Chemical Reactivity: SOMO, HOMO, and LUMO – Recognizing Functional Groups – Reaction Analogies and Carbonyl Reactivity – Amide, Carboxylic Acid and Alkyl Lithium-Oxygen and the Chemical Revolution – Rise of the Atomic Theory – Berzelius to Liebig and W�hler – Radical and Type Theories (1832-1850)-Valence Theory and Constitutional Structure (1858) – Determining Chemical Structure by Isomer Counting (1869)
Models in 3D Space (1869-1877); Optical Isomers – Vant Hoffs Tetrahedral Carbon and ChiralityCommunicating Molecular Structure in Diagrams and Words – Stereochemical Nomenclature; Racemization and Resolution – Preparing Single Enantiomers and the Mechanism of Optical Rotation – Esomeprazole as an Example of Drug Testing and Usage – Preparing Single Enantiomers and Conformational Energy – Stereotopicity and Baeyer Strain Theory -Conformational Energy and Molecular Mechanics – Sharpless Oxidation Catalysts and the Conformation of Cycloalkanes – Understanding Molecular Structure and Energy through Standard Bonds – Bond Energies, the Boltzmann Factor and Entropy – Potential Energy Surfaces, Transition State Theory and Reaction Mechanism