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CHEM 125B - Freshman Organic Chemistry II

Lecture 32 - Measuring Bond Energies: Guest Lecture by Prof. G. Barney Ellison. Spectroscopic determination of bond dissociation energies is relatively straightforward for many diatomic molecules, but for polyatomic molecules it requires merging the results from a variety of challenging experiments. Professor Ellison describes how such techniques as flowing-afterglow mass spectroscopy and negative-ion photoelectron spectroscopy together with data on free-radical kinetics and heats of formation have allowed precise determination of the O-H, C-H, and C-O bonds in methanol and other compounds. Interpreting these reliable data provides new insight into the nature of chemical bonding and "resonance." (from oyc.yale.edu)

Lecture 32 - Measuring Bond Energies: Guest Lecture by Prof. G. Barney Ellison

Time Lecture Chapters
[00:00:00] 1. Diatomic Bond Dissociation Energy from Spectroscopy
[00:01:28] 2. O-H BDE from Acidity in the Flowing Afterglow
[00:12:35] 3. C-H BDE from Radical Equilibrium
[00:18:34] 4. C-O BDE from Radical Heats of Formation; Potential Errors
[00:23:20] 5. Interpreting BDEs
[00:35:43] 6. Questions: Hot Bands and Resonance Stabilization

References
Lecture 32 - Measuring Bond Energies: Guest Lecture by Prof. G. Barney Ellison
Instructor: Professor J. Michael McBride. Resources: Professor McBride's website resource for CHEM 125b (Spring 2011). Transcript [html]. Audio [mp3]. Download Video [mov].

Go to the Course Home or watch other lectures:

Lecture 01 - Mechanism: How Energies and Kinetic Order Influence Reaction Rates
Lecture 02 - Peculiar Rate Laws, Bond Dissociation Energies, and Relative Reactivities
Lecture 03 - Rate and Selectivity in Radical-Chain Reactions
Lecture 04 - Electronegativity, Bond Strength, Electrostatics, and Non-Bonded Interactions
Lecture 05 - Solvation, H-Bonding, and Ionophores
Lecture 06 - Bronsted Acidity and the Generality of Nucleophilic Substitution
Lecture 07 - Nucleophilic Substitution Tools - Stereochemistry, Rate Law, Substrate, Nucleophile, Leaving Group
Lecture 08 - Solvent, Leaving Group, Bridgehead Substitution, and Pentavalent Carbon
Lecture 09 - Pentavalent Carbon? E2, SN1, E1
Lecture 10 - Cation Intermediates - Alkenes: Formation, Addition, and Stability
Lecture 11 - Carbocations and the Mechanism of Electrophilic Addition to Alkenes and Alkynes
Lecture 12 - Nucleophilic Participation During Electrophilic Addition to Alkenes
Lecture 13 - Addition to Form Three-Membered Rings: Carbenoids and Epoxidation
Lecture 14 - Epoxide Opening, Dipolar Cycloaddition, and Ozonolysis
Lecture 15 - Metals and Catalysis in Alkene Oxidation, Hydrogenation, Metathesis, and Polymerization
Lecture 16 - Isoprenoids, Rubber, and Tuning Polymer Properties
Lecture 17 - Alkynes; Conjugation in Allylic Intermediates and Dienes
Lecture 18 - Linear and Cyclic Conjugation Theory; 4n+2 Aromaticity
Lecture 19 - Aromatic Transition States: Cycloaddition and Electrocyclic Reactions
Lecture 20 - Electronic and Vibrational Spectroscopy
Lecture 21 - Functional Groups and Fingerprints in IR Spectroscopy; Precession of Magnetic Nuclei
Lecture 22 - Medical MRI and Chemical NMR
Lecture 23 - Diamagnetic Anisotropy and Spin-Spin Splitting
Lecture 24 - Higher-Order Effects, Dynamics, and the NMR Time Scale
Lecture 25 - C-13 and 2D NMR - Electrophilic Aromatic Substitution
Lecture 26 - Aromatic Substitution in Synthesis: Friedel-Crafts and Moses Gomberg
Lecture 27 - Triphenylmethyl and an Introduction to Carbonyl Chemistry
Lecture 28 - Mechanism and Equilibrium of Carbonyl Reactions
Lecture 29 - Imines and Enamines; Oxidation and Reduction
Lecture 30 - Oxidation States and Mechanisms
Lecture 31 - Periodate Cleavage, Retrosynthesis, and Green Chemistry
Lecture 32 - Measuring Bond Energies: Guest Lecture by Prof. G. Barney Ellison
Lecture 33 - Green Chemistry; Acids and Acid Derivatives
Lecture 34 - Acids and Acid Derivatives
Lecture 35 - Acyl Insertions and alpha-Reactivity
Lecture 36 - alpha-Reactivity and Condensation Reactions
Lecture 37 - Proving the Configuration of Glucose and Synthesizing Two Unnatural Products
Lecture 38 - Review: Synthesis of Cortisone