Radicals,Ion Radicals, and Triplets
A course about the spin-bearing intermediates
of organic chemistry
NATHAN L. BAULD
OFFICE:WELCH 5.232; OFFICE HOURS W,Th
CLASS and TIME:CH 391; MWF 1 - 2
LECTURE ROOM: WELCH 4.224
REFERENCE TEXT (Optional):"RADICALS,ION
RADICALS, AND TRIPLETS", WILEY-VCH, 1997.
EXAMS: TWO 100 POINT EXAMS (In class:
April 14 and May 7)
PROBLEMS: SEVERAL ASSIGNED PROBLEM
SETS: 50 POINTS MAX
NOTES: See NLB's
CH 368 Web Page
Unit One: Anion
- Basic concepts: MO
picture; three electron bonding; charge and spin coupling and uncoupling in
anion radicals; distonic anion radicals; the shape of the SOMO of anion radicals
(TCNE anion radical).
- Stable and Persistent Anion Radicals:
Examples; synthetic uses of persistent anion radicals.
- Anion Radicals in Familiar Organic
Reaction Mechanisms: protonation of anion radicals
(the Birch reaction; reductions of alkynes in
liquid ammonia); coupling of anion radicals (pinacol reaction; acyloin condensation).
- ET vs Nucleophilic Reactions of
Anion Radicals: The SRN1 mechanism; fullerene
anion radicals and dianions.
- Cycloaddition Reactions of Anion
- Anion Radical Cyclizations to
Carbonyl Groups: natural product synthesis.
concepts: MO picture; comparisons
with anion radicals (the Pairing Theorem); charge/spin coupling/uncoupling;
distonic cation radicals; one electron bonding (dihydrogen cation; diphenylcyclopropane
cation radical); three electron bonding (dihelium and dioxgen cation radicals).
of Cation Radicals: Long, 1 electron bond structures;
pi cation radicals; distonic cation radicals; dissociative cation radicals.
and Persistent Cation Radicals: Examples; methods of generation/synthesis
(Chemical, Photochemical, Electrochemical, etc.)
Transfer Reactions of Cation Radicals:
- Cation Radical Cycloadditions.
Cyclobutanation and Diels-Alder Addition; cation radical chain mechanisms.
- Cation Radical Chain Cycloaddition Polymerization.
Ion Radical Pairs and Electron Transfer
- Photosensitized electron transfer (PET);
cation radicals, anion radicals and triplets via PET
- The Marcus Equation
- Thermal electron transfer (TET); stable
ion radical pairs
- Intramolecular hole and electron transfer.
Unit 4: Radicals:
- Discovery and generation of radicals.
- Radical stabilizing effects.
- Stable and persistent radicals.
- Radical substituent constants.
- Polar effects in radical reactions.
- Radical scavengers; radical traps; radical
inhibitors; radical probes and clocks.
Reactions of Radicals.
- Radical chain additions: mechanisms,
kinetics, and stereochemistry.
- Radical cyclizations.
- Radical substitution reactions (halogenation,
autoxidation, tin hydride reduction).
- Non-chain radical reactions (cage and
Structures of Radicals
- Electron spin resonance spectroscopy.
Chemically induced dynamic nuclear polarization
- Triplet wave functions.
- Stable triplets.
- Triplet ESR spectra.
- Generation of unstable triplets.
- Reactions of diene and carbene triplets.