METODI PER LO STUDIO DI PROCESSI DI RICONOSCIMENTO MOLECOLARE

The course aims to provide students with fundamental concepts and tools for the study of solution equilibria and the determination of complex species, stability constants and driving forces of molecular recognition processes in solution by using common analytical techniques as well as methods and software for data analysis.

Knowledge and understanding:

Knowledge of the essential concepts for the study of molecular recognition and host-guest complex equilibria as well as for the determination of the main binding parameters.

Applying knowledge and understanding:

Development of tools for understanding and applying the most common analytical techniques for the optimization of the experimental conditions, the determination and quantification of the species and the driving forces of molecular recognition events. Development of a critical thinking for the presentation of the analytical data obtained.

Making judgements:

Capability to solve problems on solution equilibria involving ionic and/or molecular species as well as to collect, analyze and critically interpret experimental data basing on the acquired knowledge.

Communication skills:

Acquiring proper language skills and ability to rigorously expose the topics covered in the course.

Learning skills:

Capability to develop tools and skills to successfully undertake further study paths with a high level of autonomy.

Class lectures

Should teaching be carried out in mixed mode or remotely, it may be necessary to introduce changes with respect to previous statements, in line with the programme planned and outlined in the syllabus

Molecular recognition: basic principles. Weak, non-covalent interactions. Hydrophobic effect. Complexation of charged and/or neutral species in solution. Receptors and supramolecular capsules for the recognition of cationic, anionic and neutral guests.

Host-guest complex equilibria. Multiple equilibria. Ligand competition. Role of ionic strength, solvent and pH on molecular recognition equilibria. Acid-base equilibria and species distribution. Conditional stability constant. pH control: choice of the most efficient buffering agents.

Determination of complex species and stability constants through analytical techniques (UV-vis, fluorescence, NMR, ITC). Titration design. Optimization of the experimental conditions. Selection of the proper technique and of the concentration range. Complexation ratio and probability of binding. Relationship between the observable and the species concentration. Binding isotherm. Graphical methods for the determination of both stoichiometry and binding constant. Main issues.

Data treatment. Non-linear least-square analysis. Major software. Use of spreadsheets. Simulation of a UV-vis titration and data analysis.

Determination of the driving forces of molecular recognition processes in solution. Determination of ΔH for a reaction: direct measurement of the heat vs. van’t Hoff method. Isothermal titration calorimetry (ITC). Instrument calibration. Determination of K and ΔH of a reaction through ITC titrations. Calorimetric data analysis, main models and software. Simultaneous analysis of different observables for the study of multiple equilibria in complex host-guest systems.

Basic concepts on molecular recognition at the solid-liquid interface. SPR and QCM-D techniques. Real-time monitoring of molecular interactions at the interface.

Capitoli selezionati dai seguenti libri di testo:

1. J. W Steed, J. L. Atwood, Supramolecular Chemistry, 2° ed., John Wiley & Sons, 2009

2. J. W. Steed, D. R. Turner, K. Wallace, Core Concepts in Supramolecular Chemistry and Nanochemistry, John Wiley & Sons, 2007

3. E. V. Anslyn, D. A. Dougherty, Modern Physical Organic Chemistry, University Science Books, 2005

4. J. L. Atwood, G. W. Gokel, L. Barbour editors, Comprehensive Supramolecular Chemistry II, 2 ed., Vol. 2: Experimental and computational methods in supramolecular chemistry, Elsevier, 2017

5. J. W Steed, P. A. Gale editors, Supramolecular Chemistry: From Molecules to Nanomaterials, Vol. 1-3, John Wiley & Sons, 2012

6. D. C. Harris, Chimica Analitica Quantitativa, terza ed., Zanichelli, Bologna, 2017

7. D. A. Skoog, D. M. West, F. J. Holler, S. R. Crouch, Fondamenti di Chimica Analitica, 3° ed., Edises, 2015