67060 - Photochemistry and Supramolecular Chemestry

Learning outcomes

At the end of the course the student knows the basic principles of photochemistry and supramolecular chemistry, with particular attention to the potential applications in the field of new materials.

Course contents

PHOTOCHEMISTRY

Introduction – Photochemistry of natural and artificial processes. Electromagnetic radiation. 

Orbitals and electronic configuration – Hydrogen atom, polyelectronic atoms, molecules. From the orbitals diagram to the state diagram. From atomic to molecular orbitals (LCAO method); basic concepts of group theory.

Photophysics – Jablonski diagram. Armonic oscillator and Morse potential. Electronic excited states formation: Born-Oppenheimer approximation; selection rules (Franck-Condon principle, vibronic coupling, spin-orbit coupling). Electronic excited states decay: radiative transitions, non-radiative transitions, isomerization reactions. Bimolecular processes: excimers and exciplexes; energy transfer; electron transfer.

Photochemical techniques – Spectrophotometry. Spectrofluorimetry: emission and excitation spectra; emission quantum yield. Emission lifetime. Chemical actinometry.

SUPRAMOLECULAR CHEMISTRY

Introduction – Defintions. Coordination and supramolecular chemistry. Molecular recognition. Stability constant. Cooperativity, preorganization and complementarity. Supramolecular interactions. Supramolecular chemistry in Nature.

Host-guest systems – Host for cations: crown ethers and cryptands; selectivity and preorganization; synthesis; ditopic and amphiphilic receptors; calixarenes. Host for anions: cationic and neutral hosts. Ion-pair receptors. Hosts for molecular guests: interactions; cavitands, cyclodextrins, cyclophanes, carcerands.

Self-assembly –Bottom-up approach. Self-assembly in Nature. Template effect. Thermodynamic parameters. Proability of self-assembly. Helicates. Catenanes and rotaxanes: topology, synthetic strategies. Building-blocks.

Molecular wires and switches – Wires: diads and triads. Switch: single-pole and dual-pole molecular switch; fast and ultrafast switch; molecular plug, socket and extension cable.

Molecular memories and logic gates – Photocromics. “Write-lock-read-unlock-erase” cycle. Information processing: AND and XOR logic gates. Switch and chemical communications. Applications.

Sensors – Chemosensors. Luminescent sensors: raziometric sensors; sensors for Calcium; sensors based on photoinduced electron transfer. Signal amplification: nanoparticles. Electronic noses.

Dendrimers – Synthetic strategies. Building blocks. Host-guest systems: unimolecular micelles; drug delivery. Catalysis. Antenna systems: dendrimers containing porphyrins or metal complexes; host-guest systems containg organic chromophores or lanthanides.

Molecular machines – Definitions. Pseudorotaxanes: metal-ligand interactions; hydrogen bonding interactions; cyclodextrins and cucurbiturils; donor-acceptor interactions; electrochemically driven motions; light driven motions; unidirectional motions. Rotaxanes: : metal-ligand interactions; hydrogen bonding and donor-acceptor interactions, light driven motions; photoinduced memory effects. Catenanes: metal-ligand interactions; hydrogen bonding and donor-acceptor interactions; unidirectional motions.

Readings/Bibliography

PHOTOCHEMSITRY

A. Gilbert and J. Baggot, “Essentials of Molecular Photochemistry”

N. J. Turro, “Modern Molecular Photochemistry”

P. Suppan, “Chemistry and Light”

“Manuale del Fotochimico” , a cura di L. Moggi, A. Juris, M. T. Gandolfi

SUPRAMOLECULAR CHEMISTRY

J. W. Steed and J. L. Atwood, “Supramolecular Chemistry”

V. Balzani, M. Venturi, A. Credi, “ Molecular Devices and Machines - A Journey Into the Nanoworld”

Teaching methods

Lectures.

Assessment methods

Oral examination with two questions concerning photochemsitry and supramolecular chemistry.

Teaching tools

Power Point slides.

Office hours

See the website of Serena Silvi