Lecture

Organic Chemistry: Multiple Bonds and Delocalization

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In course

MSE-211: Organic chemistry

This course provides a basic foundation in organic chemistry and polymer chemistry, including chemical nomenclature of organic compounds and polymers, an understanding of chemical structures, chemical reaction mechanisms, as well as methods of organic and ...

Description

This lecture covers the concept of multiple bonds in organic chemistry, focusing on bond lengths, energy barriers, and the Valence Bond Model for cumulated, isolated, and conjugated double bonds. It also explores the Electron in a 1D Box model, Frontier Orbitals, and the delocalization of electrons in cyclic conjugated multiple bonds. The discussion extends to resonance structures, bond orders estimation, and the impact of electron-donating and electron-withdrawing groups on electron density and reactivity in conjugated systems.

Instructors (3)

Anne-Sophie Chauvin

Web of Science Researcher ID F-4905-2011 Google Scholar page: https://scholar.google.ch/citations?user=O_HhJUEAAAAJ&hl=fr&oi=ao ORCID number is 0000-0001-9222-3866 Anne-Sophie Chauvin studied chemistry and biology at the university Paris V-René Descartes in France where she did a PhD in organic chemistry, working on mimetic complexes of the active site of Nitrile Hydratase, under the supervision of Prof. Jean-Claude Chottard. On 1999 she moved for 20 months to the University of Geneva, for a post-doctoral stay under the supervision of Prof. Alexandre Alexakis, where she focused on the determination of the absolute configuration of chiral alcohols using Organophosphorous Diamine Derivatizing Agents by 31P and 1H NMR Spectroscopy. On 2000 she joined the group of Prof Jean-Claude G. Bünzli and was appointed part-time lecturer in 2001, assuming teaching and research responsibilities. On 2006, she obtained the habilitation to direct research from the University René Descartes (HDR, Paris V, France) and since october 2007 she is Maître d'Enseignement et de Recherche at the EPFL. In 2010, she joigned the Laboratory for Photonics and Interfaces (LPI), headed by Pr. Michaël Graëtzel. Since the end of 2014, with the arrival of Dr Marinella Mazzanti at EPFL, she is back to lanthanide chemistry, dealing with coordination polymers. Her research interests concern supramolecular chemistry with the design of ligands which form water soluble complexes with luminescent lanthanides in view of biological applications. She is also interested in the synthesis of ligands and polymers for the extraction of lanthanide ions with high selectivity, and in the development of invisibke inks. She also developed organic dyes for dyes sensitized solar cells DSSC. She is now focusing on coordination polymers with luminescent properties and catalytic activity. Anne-Sophie Chauvin is involved in the teaching of General and Analytical Chemistry for students enrolled on first year in Pharmacy and Biology (UNIL): ex-cathedra courses (Chimie Générale et analytique I et II, approfondissement en chimie analytique pour pharmaciens) and exercices. She is in charge of practical sessions for students enroled in chemistry, forensic sciences, pharmacy and biology. She is elected at the FSB Faculty Council and was member of the EPFL Assembly (AE) for 6 years, until 2018. She was member of the Management committee of the Cost CM 1006 action entitled Eufen: European F-Element Network. She is Member of the Swiss Chemical Society (SCS) and Fellow of the Royal Society of Chemistry (FRSC).

Holger Frauenrath

Official source

Ontological neighbourhood

Chemistry

Inorganic chemistry: Coordination chemistry

Related concepts (32)

Conjugated system

In theoretical chemistry, a conjugated system is a system of connected p-orbitals with delocalized electrons in a molecule, which in general lowers the overall energy of the molecule and increases stability. It is conventionally represented as having alternating single and multiple bonds. Lone pairs, radicals or carbenium ions may be part of the system, which may be cyclic, acyclic, linear or mixed. The term "conjugated" was coined in 1899 by the German chemist Johannes Thiele.

Resonance (chemistry)

In chemistry, resonance, also called mesomerism, is a way of describing bonding in certain molecules or polyatomic ions by the combination of several contributing structures (or forms, also variously known as resonance structures or canonical structures) into a resonance hybrid (or hybrid structure) in valence bond theory. It has particular value for analyzing delocalized electrons where the bonding cannot be expressed by one single Lewis structure.

Covalent bond

A covalent bond is a chemical bond that involves the sharing of electrons to form electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs. The stable balance of attractive and repulsive forces between atoms, when they share electrons, is known as covalent bonding. For many molecules, the sharing of electrons allows each atom to attain the equivalent of a full valence shell, corresponding to a stable electronic configuration. In organic chemistry, covalent bonding is much more common than ionic bonding.

Bond order

In chemistry, bond order is a formal measure of the multiplicity of a covalent bond between two atoms. As introduced by Linus Pauling, bond order is defined as the difference between the numbers of electron pairs in bonding and antibonding molecular orbitals. Bond order gives a rough indication of the stability of a bond. Isoelectronic species have the same bond order. The bond order itself is the number of electron pairs (covalent bonds) between two atoms.

Chemical bond

A chemical bond is a lasting attraction between atoms or ions that enables the formation of molecules, crystals, and other structures. The bond may result from the electrostatic force between oppositely charged ions as in ionic bonds, or through the sharing of electrons as in covalent bonds. The strength of chemical bonds varies considerably; there are "strong bonds" or "primary bonds" such as covalent, ionic and metallic bonds, and "weak bonds" or "secondary bonds" such as dipole–dipole interactions, the London dispersion force, and hydrogen bonding.

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