67060 - Photochemistry and Supramolecular Chemestry

Learning outcomes

Upon completion of the course, students will acquire knowledge of the theoretical principles underlying photochemistry and supramolecular chemistry, with particular attention to possible applications in the field of new materials.

Course contents

Prerequisites and recommended background

There are no formal prerequisites. However, students are advised to have a sound knowledge of the fundamentals of general and inorganic chemistry and a basic understanding of the physical chemistry principles underlying the electronic and vibrational properties of polyatomic species.

Introduction to photochemistry and supramolecular chemistry

Historical development of both disciplines. Examples of natural processes and applications in technology and materials science. Review of the main intermolecular forces. Definition and distinctive features of supramolecular systems.

Supramolecular chemistry

Molecular recognition of cations, anions and neutral molecules using crown ethers and other receptors. Effects of encapsulation on redox and photophysical properties. Chelate, macrocyclic and macropolycyclic effects, including enthalpic and entropic contributions. Template effects.

Rational design criteria for supramolecular systems. Assembly and self-assembly in biological and artificial systems. Roles of hydrogen bonding, coordination bonding and electron donor-acceptor interactions. Principles of supramolecular photochemistry and overview of current applications.

Fundamentals of photochemical and photophysical processes

Excitation and deactivation of electronically excited states. Competition between radiative and non-radiative processes. Rate constants, efficiencies and quantum yields. Definition of excited-state lifetime and its relationship with deactivation constants. Examples of emissive and non-emissive species and their applications.

Molecular electronic states

Overview of quantum mechanics. Orbitals, electronic configurations and electronic states of diatomic and polyatomic molecules, including oxygen and water. Molecular wavefunctions and the Born-Oppenheimer approximation. Transition probabilities and selection rules for radiative absorption processes.

Emission and non-radiative transitions. Franck-Condon principle. Jablonski diagrams: approximations, representation of photophysical processes and information that can be derived from them.

Spectrophotometry

Block diagrams of single- and double-beam spectrophotometers. Interpretation of absorption spectra. Main electronic transitions in organic molecules and metal complexes. Quantitative analytical methods based on absorbance.

Spectrofluorimetry and bimolecular processes

Block diagram of a spectrofluorimeter. Emission and excitation spectra. Bimolecular quenching of electronically excited states and the Stern-Volmer equation. Exciplexes and excimers.

Photoinduced electronic energy transfer through Coulombic and exchange mechanisms. Sensitisation and quenching techniques for emissive excited states. Photoinduced electron transfer and excited-state redox potentials. Static and dynamic quenching.

Determination of the association constant of a supramolecular adduct from luminescence-intensity variations and the corresponding lifetime data.

Lifetime measurements and anisotropy

Main techniques and instrumentation for excited-state lifetime measurements, with emphasis on time-correlated single-photon counting. Introduction to the principles and applications of anisotropy.

Nanoparticles and functional systems

Metal and silica nanoparticles: overview of synthesis and characterisation, photophysical and electrochemical properties, and applications as sensors and biological tracers.

Electronic noses, luminescent sensors and tracers: operating principles and applications. Photothermal and photodynamic therapy: principles, mechanisms and examples.

Biomolecules

Absorption and emission properties of common biomolecules and their use in analytical and biophysical applications.

Readings/Bibliography

Teaching material provided by the lecturer

Slides and other material used in class will be made available as PDF files on the Virtuale platform (https://virtuale.unibo.it/) to students whose study plan includes the course unit. This material is the main reference for examination preparation.

Recommended readings - Photochemistry and photophysics (only some parts of the books)

• P. Suppan, Chemistry and Light, The Royal Society of Chemistry, Cambridge, 1994.
• A. Gilbert, J. Baggott, Essentials of Molecular Photochemistry, Blackwell, London, 1991.
• L. Moggi, A. Juris, M. T. Gandolfi, Il manuale del fotochimico, Bononia University Press, Bologna, 2006.

Recommended readings - Supramolecular chemistry (only some parts of the books)

• J. W. Steed, J. L. Atwood, Supramolecular Chemistry, Wiley, New York, 2000.
• J.-M. Lehn, Supramolecular Chemistry: Concepts and Perspectives, VCH, Weinheim, 1995.

Scientific articles

No compulsory scientific articles are specified. Additional readings on recent applications may be recommended during the course and made available through Virtuale.

Teaching methods

This elective course unit within a first-cycle degree programme consists of lectures supported by computer-based presentations. The lectures progressively introduce the theoretical foundations of photochemistry, photophysics and supramolecular chemistry and connect them with examples from research, functional materials and biological applications.

Guided analysis of energy diagrams, spectra, kinetic data and case studies supports the development of students’ ability to interpret photophysical and supramolecular phenomena and to relate structure, properties and function. No practical classes or laboratory activities are included.

There are no formal prerequisites. Students are nevertheless advised to possess the background in general and inorganic chemistry and physical chemistry described in the Course contents section.

Assessment methods

Learning is assessed through a single oral examination. Official examination dates are published on AlmaEsami. Questions may cover any topic included in the syllabus and are designed to assess achievement of the stated learning outcomes.

The examination assesses knowledge of the theoretical principles, the ability to interpret diagrams, spectra and photophysical data, the ability to connect photochemistry and supramolecular chemistry, appropriate use of scientific terminology, and autonomy in analysing examples and applications.

Grading criteria

30 with honours-30: complete, in-depth and integrated knowledge; confident and autonomous interpretation of processes, diagrams and data; excellent critical and connecting skills; precise scientific language; full autonomy in reasoning.

Fail: fragmentary or seriously incomplete knowledge; difficulty interpreting fundamental processes; inconsistent or absent connections; inappropriate terminology; insufficient autonomy in analysis and argumentation.

Intermediate grades: marks from 18 to 29 will be awarded proportionally, based on the level of knowledge demonstrated, the correctness and completeness of the answers, the ability to interpret processes, diagrams and data, the quality of critical connections, the appropriateness of scientific language, and the degree of autonomy shown during the examination.

The use of artificial intelligence is prohibited during assessment. Any use constitutes a breach of academic integrity.

Students facing justified timing constraints related to thesis-submission deadlines should contact the lecturer promptly to explore solutions compatible with the examination calendar and Degree Programme procedures.

Teaching tools

Lectures are delivered in the classroom using a computer, projector and digital presentations. Teaching material is organised by topic and made available on the Virtuale platform (https://virtuale.unibo.it/). The platform is also used for announcements and notifications to the whole class; students are therefore advised to enrol in the course unit’s Virtuale space.

Students with specific learning disorders or temporary or permanent disabilities are advised to contact the relevant University office well in advance (https://site.unibo.it/studenti-con-disabilita-e-dsa/en). The office will propose any appropriate adjustments, which must be submitted to the lecturer for approval at least 15 days in advance; the lecturer will assess their suitability in relation to the course learning outcomes.

Office hours

Please consult Professor Nelsi Zaccheroni’s website.

Office hours

See the website of Nelsi Zaccheroni