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Updated: Jul 6, 2026

A Simple, Low-cost, and Robust System to Measure the Volume of Hydrogen Evolved by Chemical Reactions with Aqueous Solutions
06:32

A Simple, Low-cost, and Robust System to Measure the Volume of Hydrogen Evolved by Chemical Reactions with Aqueous Solutions

Published on: August 17, 2016

なぜBINOLベースのモノフォスフィートは,Rh触媒による非対称オレフィン水素化の効率的なリガンドなのか?

Manfred T Reetz1, Andreas Meiswinkel, Gerlinde Mehler

  • 1Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim/Ruhr, Germany. reetz@mpi-muelheim.mpg.de

Journal of the American Chemical Society
|July 21, 2005
PubMed
まとめ

この研究は,キラル・フォスフィート・リガンドが,ロジウム触媒によるオレフィン水素化における高いエナチオセレクティビティを生成する方法を明らかにしています. 古典的な方法とは異なるロック&キーメカニズムが,ステレオ化学的結果を決定する.

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関連する概念動画

Lewis Acids and Bases02:33

Lewis Acids and Bases

In 1923, G. N. Lewis proposed a generalized definition of acid-base behavior in which acids and bases are identified by their ability to accept or to donate a pair of electrons and form a coordinate covalent bond.
A coordinate covalent bond (or dative bond) occurs when one of the atoms in the bond provides both bonding electrons. For example, a coordinate covalent bond occurs when a water molecule combines with a hydrogen ion to form a hydronium ion. A coordinate covalent bond also results when...
Brønsted-Lowry Acids and Bases02:16

Brønsted-Lowry Acids and Bases

In 1923, the Brønsted–Lowry definition of acids and bases was proposed by Johannes Brønsted and Thomas Lowry. According to this theory, a Brønsted acid is defined as a species that donates a proton in a chemical reaction and gets converted to its conjugate base. A Brønsted base is defined as a species that accepts a proton in a chemical reaction and gets converted into its conjugate acid. These transfers of protons are caused by the displacement of electrons in these reactions, which is...
Lewis Acids and Bases02:16

Lewis Acids and Bases

This lesson delves into Lewis acids and bases in the context of the octet rule for electron-deficient compounds. Here, the concept is discussed, emphasizing the group 13 elements like boron or aluminium. Since group 13 elements possess three valence electrons, they form trivalent compounds with a sextet of electrons and a vacant orbital for the central atom. Consequently, these electron-deficient compounds accept electrons from other species to complete their octet in a chemical reaction. They...
Leveling Effect and Non-Aqueous Acid-Base Solutions02:11

Leveling Effect and Non-Aqueous Acid-Base Solutions

This lesson defines the leveling effect in acidic and basic solutions and its role in aqueous and non-aqueous solutions. It is essential to understand the competing nature of various species in a chemical system.
The Leveling Effect of a Solvent
A generic acid (HA) reacts with the generic base (B-) to yield the corresponding conjugate base (A-) and conjugate acid (HB):
Acidity of 1-Alkynes02:42

Acidity of 1-Alkynes


The acidic strength of hydrocarbons follows the order: Alkynes > Alkenes > Alkanes. The strength of an acid is commonly expressed in units of pKa — the lower the pKa, the stronger the acid. Among the hydrocarbons, terminal alkynes have lower pKa values and are, therefore, more acidic. For example, the pKa values for ethane, ethene, and acetylene are 51, 44, and 25, respectively, as shown here.
Leveling Effect01:29

Leveling Effect

In acid-base chemistry, the leveling effect refers to the limitation imposed by the solvent on the strength of acids and bases in solution. When a base stronger than the solvent's conjugate base is used, it deprotonates the solvent until the base is entirely consumed, making it ineffective against weaker acids. Conversely, an acid stronger than the solvent's conjugate acid protonates the solvent until the acid is depleted, rendering it ineffective against weaker bases. Essentially, the solvent...