Lecture

Supramolecular Chemistry: Crown Ethers and Complexation

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In course

CH-424: Supramolecular chemistry

The course provides an introduction to supramolecular chemistry. In addition, current trends are discussed using recent publications in this area. ...

Description

This lecture covers the principles of supramolecular chemistry, focusing on crown ethers and their complexation with alkali metal ions. Topics include solvation enthalpy, accidental synthesis, extraction methods, host-guest interactions, sandwich complexes, and applications in phase transfer catalysis and anion activation. The lecture also discusses the complexation of ammonium ions, heterocrowns, podands, the macrocyclic effect, lariat ethers, cryptands, and the importance of preorganization in cation binding. Additionally, it explores chromo-ionophores, cation recognition by fluorescence, redox-responsive ionophores, and anion recognition considerations. Examples of fluorescence sensors, redox-responsive ionophores, and protein binding to anions are presented, along with the design of receptors for carboxylic acids.

Instructor

Kay Severin

Kay Severin was born in Germany in 1967. He obtained his Ph.D. in 1995 with a thesis in the group of Prof. W. Beck, University of Munich. Subsequently, he joined the group of Prof. M. R. Ghadiri as a postdoctoral fellow. In 1997, he started independent research projects ("Habilitation") at the Department of Chemistry, University of Munich. In 2001, he became assistant professor at the Institute of Chemical Sciences and Engineering at the Swiss Federal Institute of Technology, Lausanne (EPFL). Since 2009, he is full professor at the same institute. Awards: Bayerischer Habilitations Förderpreis (1997), ADUC award of the year (2001), Heinz Maier-Leibnitz award of the DFG (2001), award of the Karl-Ziegler foundation (2001), Arnold Sommerfeld award of the Bavarian Academy of Science (2001), Werner Prize of The Swiss Chemical Society (2003), Otto Roelen Medal of the DECHEMA (2005), award for chemistry of the Academy of Sciences, Göttingen (2007), Dalton Transactions European Lectureship (2008).

Official source

Ontological neighbourhood

Chemical engineering

Nanotechnology: Topics in nanotechnology

Related concepts (32)

Crown ether

In organic chemistry, crown ethers are cyclic chemical compounds that consist of a ring containing several ether groups (). The most common crown ethers are cyclic oligomers of ethylene oxide, the repeating unit being ethyleneoxy, i.e., . Important members of this series are the tetramer (n = 4), the pentamer (n = 5), and the hexamer (n = 6). The term "crown" refers to the resemblance between the structure of a crown ether bound to a cation, and a crown sitting on a person's head.

Supramolecular chemistry

Supramolecular chemistry refers to the branch of chemistry concerning chemical systems composed of a discrete number of molecules. The strength of the forces responsible for spatial organization of the system range from weak intermolecular forces, electrostatic charge, or hydrogen bonding to strong covalent bonding, provided that the electronic coupling strength remains small relative to the energy parameters of the component.

Cation–π interaction

Cation–π interaction is a noncovalent molecular interaction between the face of an electron-rich π system (e.g. benzene, ethylene, acetylene) and an adjacent cation (e.g. Li+, Na+). This interaction is an example of noncovalent bonding between a monopole (cation) and a quadrupole (π system). Bonding energies are significant, with solution-phase values falling within the same order of magnitude as hydrogen bonds and salt bridges.

Host–guest chemistry

In supramolecular chemistry, host–guest chemistry describes complexes that are composed of two or more molecules or ions that are held together in unique structural relationships by forces other than those of full covalent bonds. Host–guest chemistry encompasses the idea of molecular recognition and interactions through non-covalent bonding. Non-covalent bonding is critical in maintaining the 3D structure of large molecules, such as proteins and is involved in many biological processes in which large molecules bind specifically but transiently to one another.

Ammonium

The ammonium cation is a positively charged polyatomic ion with the chemical formula or . It is formed by the protonation of ammonia (). Ammonium is also a general name for positively charged (protonated) substituted amines and quaternary ammonium cations (), where one or more hydrogen atoms are replaced by organic or other groups (indicated by R). The ammonium ion is generated when ammonia, a weak base, reacts with Brønsted acids (proton donors): The ammonium ion is mildly acidic, reacting with Brønsted bases to return to the uncharged ammonia molecule: Thus, the treatment of concentrated solutions of ammonium salts with a strong base gives ammonia.

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