Physical Organic Chemistry – II
Course Goals
Provide you with a set of tools / principles to understand and rationalize photochemical and photophysical principles, photoreactivity of organic compounds, application and use of photochemistry in modern research areas.
Courese overview
Fundamental principles in Photochemistry and Photophysics, Jablonski diagram. Electronically excited states: electronic, vibrational and spin configurations, Born-Oppenheimer approximation, quantized vibrational levels within potential energy surfaces, spin: vectorial representation, triplets, magnetic moments due to spin and orbital motion, origin of energy difference between singlet and triplet states.
Rules involving Electronic transitions: radiative transitions: absorption and emission, absorption co-efficient, radiative rates, quantum yields, radiationless transitions, internal conversion, energy gap law, deuterium effect, Kasha’s rule.
Spin-forbidden transitions: phosphorescence, intersystem crossing, mechanisms of singlet-triplet conversion (spin-orbit coupling), spin rephasing, spin flip, importance of electron jump between perpendicular orbitals, heavy atom effect, examples of ISC between states of different configurations.
Energy Transfer. FRET, theory, fundamental principles.
Electron Transfer: Theory and fundamental principles. Electron transfer across DNA.
Theory of photoreactions: Visualization of reactions on excited state surfaces, minima, funnels and conical intersections. Identification of minima on excited state surfaces: Surface touching, cleavage of s and p bonds, diradicals, Salem diagrams. Photochemical generation and excited state reactions of reactive intermediates: carbenes, nitrenes, radicals, diradicals, and carbocations.
Photochemistry of Organic chromophores: Carbonyl compunds, Alkenes, Enones, Aromatics, fullerenes, Singlet oxygen.
Photochemistry in Organized and Confined Media. Organic solid state photochemistry, Chemiluminescent reactions.
If time permits or possible seminar topics
Applications of photochemistry and photophyscial principles: Light as a synthetic tool (laboratory and industrial). Photochromic reactions and memory devices. Sensors, switches and molecular machines. Phototriggers: medical, lithographic, synthetic (photoprotecting group) applications. Cis-trans isomerization as a biological switch: rhodopsin, bacteriorhodopsin, phytochrome, PYP, etc. Photosynthesis (plants) and artificial solar energy storage, PUVA, LASIK, photodynamic therapy, therapy for jaundice and related medical applications, Photolithography, photoimaging and related triumphs, TiO2 photocatalysis.
Instrumental methods in photophysics: Intermediates in photoreactions, identification and characterization through modern techniques, flash photolysis, CIDNP, photoacoustic, stepscan IR.
Recommended Text books
Modern Molecular Photochemistry of Organic Molecules
N. J. Turro, V. Ramamurthy and J. C. Scaiano, University Science Books: 2010.
Supplementary reading materials
Supplementary books:
Principles of Fluorescence Spectroscopy, Lackowtiz, Springer
Molecular and Supramolecular Photochemistry (Series), Volumes 1-14
Handbook of Organic Photochemistry and Photobiology, W. M. Horspool and P. S. Song (Ed.) , CRC Press, 1995 and 2004.
Handbook of Photochemistry, S. Murov, I. Carmichael and G. L. Hug, Marcell Dekker, 1993.
Advances in Photochemistry (Series)
Organic Photochemistry (Series),
Essentials of Molecular Photochemistry, A. Gilbert and J. Baggot, CRC Press, 1991.
Excited States and Photochemistry of Organic Molecules, V. B. Klessinger and J. Michl, VCH Publishers, 1995.
Organic Photochemistry: A Visual Approach, VCH Publishers, 1992.
Journals devoted entirely to photochemistry:
Journal of Photochemistry and Photobiology (sections A, B and C), 1972-present
Photochemistry and Photobiology, 1962-present
Photochemical and Photobioloical Sciences, 2002-present
All other regular journals, JACS, JOC, Chem. Commun, Angew Chem., etc.