ピロリル基のトリアゾロファン: CHおよびNHドナー群を持つマクロサイクル受容体で,ピロホスファートアニオンに好みを示す
Jonathan L Sessler1, Jiajia Cai, Han-Yuan Gong
1Department of Chemistry and Biochemistry, 1 University Station-A5300, The University of Texas, Austin, Texas 78712-0165, USA.
Journal of the American Chemical Society
|September 22, 2010
まとめ
この研究では,溶液および固体状態のピロホスファートアニオンを選択的に結合できるピロリル基トリアゾロファンを導入しています. 受容体は,CHとNHドナー群の両方を有効なアニオン認識のために利用します.
科学分野:
- 超分子化学 超分子化学
- アニオン認識 アニオン認識
- ホスト・ゲスト・ケミストリー
背景:
- 選択性アニオン受容体の開発は,化学物質の検出と分離に不可欠です.
- ピロリル基のマクロサイクルは,ホスト-ゲストの相互作用のためにユニークな電子および構造的特性を提供します.
- アニオン結合における異なるドナー群 (CH対NH) の役割を理解することは不可欠です.
研究 の 目的:
- ピロリル基トリアゾロファン受容体の新型を合成し,特徴づけること.
- 溶液中の受容体のアニオン結合特性と選択性を調査する.
- 固体状態のピロホスファートと受容体の結合モードを探求する.
主な方法:
- ピロリル基トリアゾロファンの合成.
- クロロフォームで,アニオン結合を評価するために,光学定位試験 (例えば,NMR) を行う.
- 固体構造と結合相互作用を決定するための単結晶X線 difraktion.
主要な成果:
- トリアゾロファンは,他のテストアニオン (HSO) よりもピロフォスファート (PPi) アニオンを選択的に結合する (HSO) 〜4〜-),H〜2〜PO〜4〜-),Cl〜-),Br〜-)).
- 結合選択性は主にNH-アニオン相互作用,次にCH-アニオン相互作用によって引き起こされます.
- 固体状態では,ピロホスファートはNHとCHの水素結合を通してクリップ状に結合しています.
結論:
- 設計されたピロリル基トリアゾロファンは,ピロホスファートアニオンの有効で選択的な受容体です.
- この研究は,アニオン認識におけるNHとCHの結合された水素結合の重要性を強調しています.
- この受容体は,ピロホスファートの検知または分離における応用の可能性を秘めている.
関連する概念動画
Basicity of Heterocyclic Aromatic Amines
Heterocyclic amines, where the N atom is a part of an alicyclic system, are similar in basicity to alkylamines. Interestingly, the heterocyclic amine having a nitrogen atom as part of an aromatic ring has much less basicity than its corresponding alicyclic counterpart. For this reason, as presented in Figure 1, piperidine (pKb = 2.8) is significantly more basic than pyridine (pKb = 8.8).
Aromatic Hydrocarbon Cations: Structural Overview
Cycloheptatriene is a neutral monocyclic unsaturated hydrocarbon that consists of an odd number of carbon atoms and an intervening sp3 carbon in the ring. The three double bonds in the ring correspond to 6 π electrons, which is a Huckel number, and therefore satisfies the criteria of 4n + 2 π electrons. However, the intervening sp3 carbon disrupts the continuous overlap of p orbitals. As a result, cycloheptatriene is not aromatic.
Removing one hydrogen from the intervening CH2 group with both...
Removing one hydrogen from the intervening CH2 group with both...
Five-Membered Heterocyclic Aromatic Compounds: Overview
Heterocyclic aromatic compounds are cyclic compounds that are aromatic and have one or more heteroatoms—atoms other than carbon, in the ring. Depending upon the number of atoms present in the ring, they can be either five or six-membered. Examples of five-membered heterocyclic aromatic compounds include pyrrole, furan, thiophene, and imidazole. Pyrrole consists of one nitrogen atom having one lone pair of electrons. Furan and thiophene have one oxygen and one sulfur heteroatom, respectively.
ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH3
All ortho–para directors, excluding halogens, are activating groups. These groups donate electrons to the ring, making the ring carbons electron-rich. Consequently, the reactivity of the aromatic ring towards electrophilic substitution increases. For instance, the nitration of anisole is about 10,000 times faster than the nitration of benzene. The electron-donating effect of the methoxy group in anisole activates the ortho and para positions on the ring and stabilizes the corresponding...
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.
Aryldiazonium Salts to Azo Dyes: Diazo Coupling
The reaction of weakly electrophilic aryldiazonium (also called arenediazonium) salts with highly activated aromatic compounds leads to the formation of products with an —N=N— link, called an azo linkage. This reaction, presented in Figure 1, is known as diazo coupling and occurs without the loss of the nitrogen atoms of the aryldiazonium salt. Highly activated aromatic compounds such as phenols or arylamines favor the diazo coupling reaction. The coupling generally occurs at the para position.


