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Lecture

Intermolecular Interactions: Polar Molecules and Hydrogen Bonds

In course

CH-110: Advanced general chemistry I

Le cours comporte deux parties. Les bases de la thermodynamique des équilibres et de la cinétique des réactions sont introduites dans l'une d'elles. Les premières notions de chimie quantique sur les électrons et les liaisons chimiques, exemplifiées en chim ...

Description

This lecture covers the principles of intermolecular forces, focusing on dipole-dipole and ion-dipole forces, as well as the formation of condensed phases. It discusses the significance of polar molecules in intermolecular interactions, including hydrogen bonding in biological molecules. The lecture also explores the concept of instantaneous dipoles and London forces, and how they contribute to the overall strength of intermolecular interactions. The role of polarizability and size in predicting the strength of these interactions is highlighted, along with the impact on the boiling and melting points of substances.

Instructors (7)

Marinella Mazzanti

Philippe Schwaller

Anne-Clémence Corminboeuf

Beat Fierz

Jacques-Edouard Moser

Jacques-Edouard Moser is titular professor in physical chemistry and is currently directing the Group for Photochemical Dynamics (Moser Group) of EPFL. He is a graduate of the École polytechnique fédérale de Lausanne, where he received a diploma degree (MSc) in chemical engineering in 1982. After two stays in 1984 and 1985 at Concordia University in Montréal (Canada), he earned in 1986 his Ph.D. in physical chemistry at EPFL (Michael Grätzel, thesis advisor). In 1986, he joined the Eastman Kodak Corporate Research Laboratories at Rochester (NY, USA) as a postdoctoral fellow and was later associated with the NSF Center for Photoinduced Electron Transfer at the University of Rochester. Returning to Switzerland, he was appointed as a lecturer of physical chemistry at EPFL in 1992 and was awarded the habilitation and the venia legendi in 1998. He is titular professor since 2005.His research activity focuses on the study of the dynamics of photoinduced electron transfer and charge carrier separation at donor-acceptor heterojunctions and in nanostructured semiconductors. He is the author and co-author of ca 200 scientific papers (H-index 75). He currently teaches general physical chemistry to freshmen students in chemistry. He gives two classes on general- and redox photochemistry in the MSc program in chemistry and chemical engineering and the doctoral programs in energy and photonics. Jacques-E. Moser presided the Swiss Society of Photochemistry and Photophysics (1995-1998) and chaired the jury of the Grammaticakis-Neumann international prize in photochemistry (1999-2001). He was a member of the board of the Swiss Chemical Society (2007-2012). He served as a member of the standing committee of the European Photochemistry Association (1992-2000) and of the executive committee of the division for fundamental research of the Swiss Chemical Society (1999-2014). He was the director of the Section of Chemistry and Chemical Engineering of EPFL and a member of the direction of the School of Basic Sciences from 2007 to 2015.

Jérôme Waser

Jérôme Waser biography and CV's are available on the following website: http://lcso.epfl.ch/waser

Official source

Ontological neighbourhood

Chemistry

Chemical reactions: Chemical substances

Related concepts (29)

Intermolecular force

An intermolecular force (IMF) (or secondary force) is the force that mediates interaction between molecules, including the electromagnetic forces of attraction or repulsion which act between atoms and other types of neighbouring particles, e.g. atoms or ions. Intermolecular forces are weak relative to intramolecular forces – the forces which hold a molecule together. For example, the covalent bond, involving sharing electron pairs between atoms, is much stronger than the forces present between neighboring molecules.

Van der Waals force

In molecular physics, the van der Waals force is a distance-dependent interaction between atoms or molecules. Unlike ionic or covalent bonds, these attractions do not result from a chemical electronic bond; they are comparatively weak and therefore more susceptible to disturbance. The van der Waals force quickly vanishes at longer distances between interacting molecules. Named after Dutch physicist Johannes Diderik van der Waals, the van der Waals force plays a fundamental role in fields as diverse as supramolecular chemistry, structural biology, polymer science, nanotechnology, surface science, and condensed matter physics.

Chemical polarity

In chemistry, polarity is a separation of electric charge leading to a molecule or its chemical groups having an electric dipole moment, with a negatively charged end and a positively charged end. Polar molecules must contain one or more polar bonds due to a difference in electronegativity between the bonded atoms. Molecules containing polar bonds have no molecular polarity if the bond dipoles cancel each other out by symmetry. Polar molecules interact through dipole-dipole intermolecular forces and hydrogen bonds.

Dipole

In physics, a dipole () is an electromagnetic phenomenon which occurs in two ways: An electric dipole deals with the separation of the positive and negative electric charges found in any electromagnetic system. A simple example of this system is a pair of charges of equal magnitude but opposite sign separated by some typically small distance. (A permanent electric dipole is called an electret.) A magnetic dipole is the closed circulation of an electric current system. A simple example is a single loop of wire with constant current through it.

Boiling point

The boiling point of a substance is the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid and the liquid changes into a vapor. The boiling point of a liquid varies depending upon the surrounding environmental pressure. A liquid in a partial vacuum, i.e., under a lower pressure, has a lower boiling point than when that liquid is at atmospheric pressure. Because of this, water boils at under standard pressure at sea level, but at at altitude.

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