関連する実験動画
Updated: Jul 6, 2026
11:00
Determination of the Gas-phase Acidities of Oligopeptides
Published on: June 24, 2013
カチオンの電極性および中性核性粒子の特徴付けのための基準スケール
1Department Chemie der Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13 (Haus F), D-81377 München, Germany. Herbert.Mayr@cup.uni-muenchen.de
Journal of the American Chemical Society
|September 27, 2001
まとめ
この研究では,ダイアリルカルベニウムイオンとパイ系を用いた電ophilesとnucleophilesの一般的な反応性スケールを確立しました. 派生したパラメータは,幅広い化学物質の反応速度を正確に予測します.
科学分野:
- 有機化学 オーガニック・ケミストリー
- 物理化学 物理化学
背景:
- 定量反応性スケールは,化学反応を理解し予測するために不可欠です.
- 既存のスケールは,さまざまな電愛性および核愛性種にわたって広範な適用性が欠けていることが多い.
研究 の 目的:
- エレクトロフィールとヌクレオフィールの包括的で一般的な反応性スケールを確立する.
- 様々な有機および無機種の反応性を特徴付けるための統一されたシステムを開発する.
主な方法:
- ベースセットとして23個のダイアリルカルベニウムイオンと38個のパイ系を用いた.
- 209の電ophilic-nucleophilic 組み合わせのための速度定数.
- 電子性 (E) と核性 (N,s) のパラメータを導出するために相関分析を適用した.
主要な成果:
- 高精度 (標準偏差1.19) で16度以上の大きさをカバーする反応性スケールを開発.
- アルキン,金属pi複合体,ドナー水素,および様々なカルベニウムイオンに対する派生パラメータの適用性を実証した.
- 10の置換物に対して新しいハメットシグマ (((+)) 定数を提供した.
結論:
- 確立された反応性スケールは,新しい電ophilesとnucleophilesを特徴付けるための堅牢な枠組みを提供します.
- パラメータは広く適用され,多様な化学システムにおける予測を容易にする.
- この研究は,有機化学における定量的な構造-活性関係研究を進めています.
さらに関連する動画
10:03Characterization of Electrode Materials for Lithium Ion and Sodium Ion Batteries Using Synchrotron Radiation Techniques
Published on: November 12, 2013
11:04Synthesis of Ionic Liquid Based Electrolytes, Assembly of Li-ion Batteries, and Measurements of Performance at High Temperature
Published on: December 20, 2016
関連する概念動画
02:30Water: A Bronsted-Lowry Acid and Base
The reaction between a Brønsted-Lowry acid and water is called acid ionization. For example, when hydrogen fluoride dissolves in water and ionizes, protons are transferred from hydrogen fluoride molecules to water molecules, yielding hydronium ions and fluoride ions:
02:30Nucleophiles
The word “nucleophile” has a Greek root and translates to nucleus-loving. Nucleophiles are either negatively charged or neutral species with a pair of electrons in a high-energy occupied molecular orbital (HOMO). As these species tend to donate electron pairs, nucleophiles are considered Lewis bases as well. Negatively charged species, like OH−, Cl−, or HS−, with one or several pairs of electrons, are typically nucleophiles. Similarly, neutral species such as ammonia, amines, water, and alcohol...
02:28Electrophiles
This lesson explains the definition, classification, and characteristic features of an electrophile that are key features of nucleophilic substitution reactions. An analysis of their charge and orbital picture helps understand their reactivity for seeking electrons. Electrophiles can be classified into positive and neutral species. Other classes include free radicals and polar functional groups.
While a positive electrophile, like a proton, reacts due to its vacant, low-energy 1s orbital, the...
While a positive electrophile, like a proton, reacts due to its vacant, low-energy 1s orbital, the...
01:16Titration in Nonaqueous Solvents
Most acid-base titrations are performed in an aqueous medium. In aqueous titrations, water competes with weaker acids or bases for proton donation or acceptance, leading to ambiguous endpoints in the titration curve. Water also affects the partial ionization of weak acids or bases. For example, water accepts a proton from acetic acid to form hydronium and acetate ions. The hydronium ion formed is a stronger acid than acetic acid, and the acetate ion is a stronger base than water. As a result,...
01:17Ion Exchange
Ion exchange chromatography separates charged molecules from a solution by reversibly exchanging them with mobile, or 'active', ions associated with the oppositely charged stationary phase. This method can be used to separate ions, soften and deionize water, and purify solutions. The polymers comprising the ion-exchange column are high-molecular-weight and chemically stable polymers, crosslinked to be porous and essentially insoluble. They are also functionalized with either acidic or basic...
01:09Ion-Exchange Chromatography
Ion-exchange chromatography, or IEC, is a technique for separating ions based on their affinity for the stationary phase. The stationary phase is a cross-linked polymer resin with covalently attached ionic functional groups. The functional groups can be either positively charged (cation exchangers) or negatively charged (anion exchangers). A cation exchanger consists of a polymeric anion and active cations, while an anion exchanger is a polymeric cation with active anions. The choice of...