Unit WEAK INTERACTIONS IN ORGANIC CHEMISTRY
- Course
- Chemical sciences
- Study-unit Code
- GP004030
- Curriculum
- Chimica organica
- Teacher
- Raimondo Germani
- Teachers
-
- Raimondo Germani
- Hours
- 63 ore - Raimondo Germani
- CFU
- 9
- Course Regulation
- Coorte 2022
- Offered
- 2022/23
- Learning activities
- Caratterizzante
- Area
- Discipline chimiche organiche
- Academic discipline
- CHIM/06
- Type of study-unit
- Obbligatorio (Required)
- Type of learning activities
- Attività formativa monodisciplinare
- Language of instruction
- Italian
- Contents
- The main purpose of the course is to provide a detailed overview of the implications and importance of weak interactions in many aspects of organic chemistry. Indeed, weak interactions determine all solvent effects, as well as affect ionic and molecular recognition processes. Topics covered. The general principles of interaction forces. Solute-solvent interactions. Solvent effects on the chemical equilibria and reaction rates in homogenous phase. Self-organized nanostructured systems. Micellar effects on chemical reactions.
- Reference texts
- Students can use the following texts to consult the topics discussed:
C. Reichardt, Solvent and Solvent Effects in Organic Chemistry, VCH third Ed. 2003
J. Israelachvili, Intermolecular and Surface Forces, Academic Press Ed. 1992.
M. J. Rosen. Surfactants and interfacial phenomena, Wiley-Interscience, 3rd Ed. 2004Teaching material of the course is provided directly by Lecturer in electronic form as pdf, ppt files and/or in paper form. - Educational objectives
- The course is centered on the study of weak interactions in organic systems, and is divided in two large blocks. The first part deals with the weak interactions, which may affect the chemical reactivity, the chemical equilibria, the stereochemistry and mechanisms of organic reactions. The second block deals with the importance of weak interactions in self-organized amphiphilic systems, and in ionic and molecular recognition.
The main aim of the course is to provide students with the basic concepts to analyze and interpret the effects of the reaction medium on chemical processes and the effects of weak interactions in ionic and molecular recognition.
At the end of the course the student should be able to determine qualitatively the effect that the reaction medium has on a generic chemical process and have a critical understanding of the main self-assembled colloidal systems and their properties.
The main knowledge acquired will be:
-Know the weak interactions, classifying them in terms of energy and distance of interaction;
-Know the classification of fluids according to its chemical and physical macroscopic and microscopic properties;
-Know the empirical parameters scales of the solvent polarity;
-Know the solvation process and the various types of solvation that you may have;
-Know the importance of solvation process by comparison with the processes in the gas phase;
-Know the conditions for which can form ion pairs;
-Know host-guest systems and assembled systems of amphiphile nature;
-Know the main characteristics, properties and applications of self-assembled systems.
The main competences (i.e. the ability to apply acquired knowledge) will be:
-Categorize the reaction media in according to their properties EPD / EPA, HBD / HDA and their ability to ionizing and / or dissociating;
-Be able to predict the leveling or differentiating effect of a reaction medium in respect of the acid-base properties of a solute;
-Be able to predict the medium effect on acid-based Lewis and Brønsted equilibria;
-Be able to predict the medium effect on tautomeric and conformational equilibria;
-Be able to predict the medium effect on the chemical reactivity;
-Be able to predict the medium effect on the stereochemical and the reaction mechanism control;
-Be able to predict micellar effects on reactivity and selectivity of chemical reaction;
-Be able to exploit self-organized systems as potential nano-reactors. - Prerequisites
- The student, to follow and learn conveniently the course contents, should have the following knowledge:
Knowledge of reaction mechanisms of the main organic reactions;
Knowledge of the transition state theory;
Knowledge of kinetic theory;
Knowledge of substituent effect and the free energy linear correlations;
Knowledge of prototropic equilibria such as: acid-base and tautomeric equilibria;
Knowledge of stereoisomerism and stereoselectivity;
These skills are important prerequisites for the student who wishes to follow the course profitably. - Teaching methods
- The course of Weak Interactions in Organic Chemistry does not include a separate lab activity and is organized as follows:
-Lectures on all the topics of the course lasting two hours each.
-Classroom demonstration. About 10-11 experimental demonstrations, related to aspects and concepts of the course, are organized and executed by the teacher during lecture. Experiments performed in the classroom, with the help of students, have a maximum duration of 20 minutes. The goal of these demonstrations is to increase students' interest and allow easier learning of the concepts formulated during the lesson.
-Ongoing testing of the student learning level through collegial resolution of case studies. This activity is a form of training to the oral exam. - Other information
- The files (pdf), used by the teacher for lessons in the classroom, will be available to all students who take the course.
- Learning verification modality
- The exam is an oral test, which consists of a discussion, lasting about 1 hour, to ascertain the student's ability to predict the effects that the weak interactions cause on chemical processes. More details are formulated 5 questions, covering the main contents of the course.
Three questions are related to the effects of solvents on the reactions and chemical equilibria and two questions are focused on the characteristics, properties and applications of self-assembled systems. The test aims to assess the student's ability to connect and apply the knowledge learned during the course and self-study, to solve problems of real cases. The overall assessment exam test shall embrace not only the student's ability to apply their knowledge, but even the presentation skills and mastery of the terms used. - Extended program
- Programma Esteso (programma del Corso)
The forces between atoms and molecules: principles and general concepts.
Some thermodynamic aspects of intermolecular forces. Intermolecular interactions. Covalent, coulombic and van der Waals interactions. Repulsive forces and structure of the liquid state.
Solute-solvent interaction
Interaction involving polar molecules. Ion-dipole, dipole-dipole, dipole-induced dipole, instantaneous dipole -induced dipole forces. Special interactions: hydrogen bond and water properties, hydrophobic and hydrophilic interactions. Electron pair donor and electron pair acceptor interactions. Solvation and selective solvation. Ionization and dissociation.
Solvent effects on chemical equilibria in homogenous phase
General concepts. Solvent effects on acid-base equilibria. Solvent effects on tautomeric equilibria. Solvent effects on keto-enol equilibria. Solvent effects on conformational equilibria. Solvent effects on cis/trans and E/Z equilibria. Solvent effects on electron transfer equilibria.
Solvent effects on chemical reaction rate in homogenous phase.
General considerations. Reactivity in the gas phase. Qualitative theory of solvent effects on reaction rate. Hughes-Ingold's rules and their limits. Solvent effect on reactions with dipolar or nonpolar transition state and free radical transition state. Quantitative theory of the solvent effects on reaction rate: general considerations and application to reactions between neutral-nonpolar, neutral-dipolar molecules and between neutral-ions and ion-ion. Specific salvation effects on reaction rate. Anionic specific salvation effects on SN reactions.
Effects of protic and dipolar aprotic solvents on nucleophilic substitution reactions, and separation of the effects. Acceleration of base-catalyzed reactions in dipolar aprotic solvents. Influence of the specific cation salvation on SN type reaction rate. Influence of solvent on the reactivity of bidentate nucleophiles. Solvent effects on mechanism and stereochemistry of some organic reactions. Salt effects on reaction constant rate.
Weak interactions in self-organized systems
General principles of self-organization. Order and mobility in supramolecular systems. Aggregation of amphiphilic molecules in micelles, liquid crystals, monolayers, bilayers, vesicles and biological membranes. Properties and applications. Effects on reactivity and selectivity of chemical processes. Interactions with biomolecules: enzymes and DNA.