分子トンネル交差点におけるポラライズ可能なハリド置換剤によって誘発されるコヘレントとインコヘレントのトンネリングレジムの間の漸進的な変化
Xiaoping Chen1,2, Ira Volkova2, Yulong Wang2
1College of Chemistry, Chemical Engineering and Environment, Fujian Provincial Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou 363000, China.
Journal of the American Chemical Society
|August 8, 2024
まとめ
研究者らは,ハリド置換剤の極化性を増加させることで,分子結合における一貫性から不一致性への電荷輸送の漸進的なシフトを示した. この移行は分子ダイオードの性能を向上させ,分子電子機器を改善するための新しい方法を示唆した.
科学分野:
- 分子電子
- 凝縮物質物理学
- 材料科学
背景:
- 分子結合における電荷輸送メカニズムは 装置の性能にとって極めて重要です
- 前述の方法では 不協和型トンネリングを誘導するために レドックス群や 分子長さを増加させました
- 充電輸送における代替物質の性質の役割を理解することは鍵となる.
研究 の 目的:
- 分子結合における電荷輸送メカニズムに対するハリド置換剤の偏極性の効果を調査する.
- 一貫性のあるトンネリングから不一致のトンネリングへの電荷輸送を調整するための新しいアプローチを探求する.
- トンネルメカニズムの変化と分子ダイオードの性能を相関させる.
主な方法:
- 合成されたフェニル末付アリファティックモノレイヤーで,ハライド置換物 (F,Cl,Br,I) と数値 (n=0,1,2,3,5) が異なる.
- モノレイヤーを用いて分子結合を製造し特徴づけました
- トンネリングメカニズムを決定するために,アクティベーションエネルギーを含め,チャージ輸送特性を分析した.
主要な成果:
- ハライドの極化性が増加するにつれて,一貫したトンネルから不一致のトンネルへの漸進的な移行を示した.
- アクティベーションエネルギーは23 meVから257 meV (不一致) に大幅に増加した.
- 分子ダイオードの性能が改善され,不協和のトンネリング率が増加した.
結論:
- 分子置換剤の極化性は,電荷輸送メカニズムを制御する上で重要な要因である.
- トンネル掘削を一貫性のあるシステムから 矛盾したシステムに切り替えることが可能になるのです
- この戦略は分子デバイスの 電子機能を強化するための経路を提供します
さらに関連する動画
11:33All-electronic Nanosecond-resolved Scanning Tunneling Microscopy: Facilitating the Investigation of Single Dopant Charge Dynamics
Published on: January 19, 2018
9.6K
08:06Merging Ion Concentration Polarization between Juxtaposed Ion Exchange Membranes to Block the Propagation of the Polarization Zone
Published on: February 23, 2017
8.5K
関連する概念動画
02:26SN2 Reaction: Transition State
9.6K
An SN2 reaction of an alkyl halide is a single-step process in which bond formation between the nucleophile and the substrate and bond breaking between the substrate and the halide occurs simultaneously through a transition state without forming an intermediate.
When the nucleophile approaches the electrophilic carbon with its lone pairs, the halide acts as a leaving group and moves away with the electron-pair bonded to the carbon. Dotted partial bonds represent the bonds being formed or broken...
When the nucleophile approaches the electrophilic carbon with its lone pairs, the halide acts as a leaving group and moves away with the electron-pair bonded to the carbon. Dotted partial bonds represent the bonds being formed or broken...
9.6K
02:27Predicting Products: SN1 vs. SN2
13.3K
Nucleophilic substitution reactions of alkyl halides can proceed via an SN1 or an SN2 mechanism. While in SN2 reactions, the nucleophile attacks the substrate simultaneously as the leaving group departs, in SN1 reactions, the substrate first dissociates to give the carbocation intermediate. Various factors such as the structure of the substrate, the strength of the nucleophile, and the nature of the solvent promote one mechanism over the other.
With increased substitution on the alkyl halide,...
With increased substitution on the alkyl halide,...
13.3K
02:52Predicting Products: Substitution vs. Elimination
11.5K
When a nucleophile and an alkyl halide react, nucleophilic substitution and β-elimination reactions compete to generate products.
The following factors can influence the mechanisms competing against each other:
The following factors can influence the mechanisms competing against each other:
11.5K
02:05SN1 Reaction: Kinetics
7.7K
In an SN2 reaction, the reaction rate depends on both the type of nucleophile and the substrate. A hindered tertiary alkyl halide is practically inert to the SN2 mechanism despite using a strong nucleophile.
However, Sir Christopher Ingold and Edward D. Hughes, who studied the kinetics of various nucleophilic substitution reactions, noticed that a tertiary alkyl halide does undergo a nucleophilic substitution reaction in the presence of a weak nucleophile. While studying the substitution...
However, Sir Christopher Ingold and Edward D. Hughes, who studied the kinetics of various nucleophilic substitution reactions, noticed that a tertiary alkyl halide does undergo a nucleophilic substitution reaction in the presence of a weak nucleophile. While studying the substitution...
7.7K
02:46Halogenation of Alkenes
15.5K
Halogenation is the addition of chlorine or bromine across the double bond in an alkene to yield a vicinal dihalide. The reaction occurs in the presence of inert and non-nucleophilic solvents, such as methylene chloride, chloroform, or carbon tetrachloride.
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
15.5K
02:45Alkyl Halides
16.4K
Structural Properties
Alkyl halides are halogen-substituted alkanes wherein one or more hydrogen atoms of an alkane is replaced by a halogen atom such as fluorine, chlorine, bromine, or iodine. The carbon atom in an alkyl halide is bonded to the halogen atom, which is sp3-hybridized and exhibits a tetrahedral shape.
Unlike alkyl halides, compounds in which a halogen atom is bonded to an sp2 -hybridized carbon atom of a carbon-carbon double bond (C=C) are called vinyl halides. Whereas aryl...
Alkyl halides are halogen-substituted alkanes wherein one or more hydrogen atoms of an alkane is replaced by a halogen atom such as fluorine, chlorine, bromine, or iodine. The carbon atom in an alkyl halide is bonded to the halogen atom, which is sp3-hybridized and exhibits a tetrahedral shape.
Unlike alkyl halides, compounds in which a halogen atom is bonded to an sp2 -hybridized carbon atom of a carbon-carbon double bond (C=C) are called vinyl halides. Whereas aryl...
16.4K