リソルク[4]アレンのニトロゾニウム複合体:スペクトル,運動,理論的な研究
Bruno Botta1, Ilaria D'Acquarica, Giuliano Delle Monache
1Dipartimento di Studi di Chimica e Tecnologia delle Sostanze Biologicamente Attive, Università La Sapienza, P.le A. Moro 5, 00185 Roma, Italy. bruno.botta@uniroma1.it
Journal of the American Chemical Society
|August 21, 2007
まとめ
Resorc[4]areneエーテルは,メタノールや水を加えると逆転する安定した,色のついたニトロゾニウム (NO+) 複合体を形成する. 顕微鏡分析により,NO+は,レソルカレンの構造とサイドチェーンに基づいて異なった相互作用をします.
科学分野:
- 超分子化学 超分子化学
- 有機化学 オーガニック・ケミストリー
- スペクトロスコーピーは,スペクトロスコーピーを用います.
背景:
- Resorc[4]arenesは,バスケットのような空洞を持つマクロサイクル化合物である.
- ニトロゾニウム (NO+) は,合成とセンシングにおける応用がある反応性カチオンである.
- マクロサイクルのゲスト-ホストの相互作用を理解することは,新しい機能的材料を設計するための鍵です.
研究 の 目的:
- ニトロゾニウム (NO+) とレソルク[4]アレンオクタメチルエーテルとの複合性を調査する.
- NO+結合に影響を与える構造的および電子的要因を解明する.
- これらの複合体の可逆性とスペクトル特性を探求する.
主な方法:
- レソルク[4]アレンオクタメチルエーテル (1-3) の合成.
- クロロフォームに含まれるNOBF4塩を用いた複合性研究.
- 運動およびスペクトル分析のための紫外線可視光谱学.
- 1H NMRスペクトル検査と分子モデリング.
主要な成果:
- 安定した,色が濃い1:1のニトロソニウム-レソルク[4]アレン複合体が形成された.
- 複合体は逆行性であり,メタノールや水で解離する.
- Resorc[4]arenes 1と2は,空洞の内外の両方でNO+相互作用を示し,明確なスペクトルパターン (HEBとLEB) を示した.
- resorc[4]arene 2のエステルカルボニル基は,NO+結合を外部に誘導し,その一方で,resorc[4]arene 3のエステルカルボニル基は,電荷移転相互作用とともに,NO+結合を誘導する.
結論:
- Resorc[4]arenesは,ニトロゾニウムイオンと安定した複合体を形成することができる.
- resorc[4]arenesの形状とサイドチェーン機能は,NO+相互作用のモードを決定する.
- これらの複合体は,可逆的な行動とユニークなスペクトルシグネチャーを示し,感知または分離における潜在的な応用を示唆しています.
関連する概念動画
Resonance and Hybrid Structures
According to the theory of resonance, if two or more Lewis structures with the same arrangement of atoms can be written for a molecule, ion, or radical, the actual distribution of electrons is an average of that shown by the various Lewis structures.
Resonance Structures and Resonance Hybrids
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N–O and N=O bonds.
Resonance Structures and Resonance Hybrids
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N–O and N=O bonds.
2° Amines to N-Nitrosamines: Reaction with NaNO2
Secondary amines react with nitrous acid to form N-nitrosamines, as depicted in Figure 1. Nitrous acid, a weak and unstable acid, is formed in situ from an aqueous solution of sodium nitrite and strong acids, such as hydrochloric acid or sulfuric acid, in cold conditions. In the presence of an acid, the nitrous acid gets protonated. The subsequent loss of water results in the formation of the electrophile known as nitrosonium ion.
Resonance
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N-O and N=O bonds.
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Overview
Nitrous acid and nitric acids are two types of acids containing nitrogen, among which nitrous acid is weaker than nitric acid. Nitrous acid with a pKa value of 3.37 ionizes in water to give a nitrite ion and the hydronium ion.
The nitrous acid is unstable. Hence, it is formed in situ from a solution of sodium nitrite and cold aqueous acids such as hydrochloric or sulfuric acid. In an acidic solution, the –OH group of nitrous acid undergoes protonation to give oxonium ion, followed by water loss...
The nitrous acid is unstable. Hence, it is formed in situ from a solution of sodium nitrite and cold aqueous acids such as hydrochloric or sulfuric acid. In an acidic solution, the –OH group of nitrous acid undergoes protonation to give oxonium ion, followed by water loss...
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism
Nitrous acid is a relatively weak and unstable acid prepared in situ by the reaction of sodium nitrite and cold, dilute hydrochloric acid. In an acidic solution, the nitrous acid undergoes protonation when it loses water to form a nitrosonium ion—an electrophile. Nitrous acid reacts with primary amines to give diazonium salts. The reaction is called diazotization of primary amines.
Diazonium Group Substitution: –OH and –H
Nitrous acid, a weak acid, is prepared in situ via the reaction of sodium nitrite with a strong acid under cold conditions. This nitrous acid prepared in situ reacts with primary arylamines to form arenediazonium salts. Such reactions are known as diazotization reactions. As shown in Figure 1, the formation of arenediazonium salts begins with the decomposition of nitrous acid in an acidic solution to give nitrosonium ions.


