通过融化结晶的记忆效应,在索-索衍生物的多态体中观察到
Ann Maria James1, Alessandro Greco2, Félix Devaux3
1Institute of Solid State Physics, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria.
Crystal growth & design
|November 8, 2023
概括
这项研究揭示了OEG-BTBT溶解物中晶体融记忆效应. 即使在化和冷却后,原始晶体相仍在重塑,显示出显著的分子记忆.
科学领域:
- 材料科学 材料科学 材料科学
- 晶体学 晶体学是指结晶学.
- 有机电子 有机电子
背景情况:
- 2,7-bis(2-(2-methoxyethoxy)ethoxy) benzo[b]benzo[4,5]thieno[2,3-d]thiophene (OEG-BTBT) 分子是一个关键的有机半导体.
- 了解有机材料的固态行为,包括它们对热应激的反应,对于设备应用至关重要.
研究的目的:
- 为了研究OEG-BTBT与二甲 (DCM) 的三种溶酸盐中的融化记忆效应.
- 在不同温度下描述这些溶酸盐的结构和形态特性.
主要方法:
- 结合光学显微镜和X射线衍射测量.
- 热分析包括点和同位素转变温度的确定.
- 结晶运动学的研究.
主要成果:
- 所有三种OEG-BTBT:DCM溶酸盐都表现出化记忆效应,在化后重塑它们的初始晶相,达到化和清除温度以上.
- 融化记忆效应归因于DCM分子和OEG侧链之间的强烈相互作用,即使在化状态下也会持续存在.
- 溶剂蒸汽与DCM的化诱导过渡到一个混乱状态,与融化记忆现象形成鲜明对比.
结论:
- OEG-BTBT:DCM系统显示了强大的融记忆效应,表明在化状态下结构保存的程度很高.
- DCM的存在及其与OEG侧链的相互作用对于观察这种记忆现象至关重要.
- 这一发现对有机电子材料的加工和稳定性有影响.
相关概念视频
01:21Polymer Classification: Crystallinity
2.9K
Unlike ionic or small covalent molecules, polymers do not form crystalline solids due to the diffusion limitations of their long-chain structures. However, polymers contain microscopic crystalline domains separated by amorphous domains.
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
2.9K
01:26Polymer Classification: Stereospecificity
2.4K
Polymerization generates chiral centers along the entire backbone of a polymer chain. Accordingly, the stereochemistry of the substituent group has a significant effect on polymer properties. Polymers formed from monosubstituted alkene monomers feature chiral carbons at every alternate position in the polymer backbone. Relative to the predominant orientation of substituents at the adjacent chiral carbons, the polymer can exist in three different configurations: isotactic, syndiotactic, and...
2.4K
01:18Directing and Steric Effects in Disubstituted Benzene Derivatives
3.1K
When disubstituted benzenes undergo electrophilic substitution, the product distribution depends on the directing effect of both substituents. When the directing effects of both substituents reinforce each other, a single product is obtained. For example, bromination of p-nitrotoluene occurs ortho to the methyl group and meta to the nitro group, which is the same position, resulting in a single product. However, if the directing effects of the two groups oppose each other, the...
3.1K
01:13Electrophilic Aromatic Substitution: Fluorination and Iodination of Benzene
6.1K
Bromination and chlorination of aromatic rings by electrophilic aromatic substitution reactions are easily achieved, but fluorination and iodination are difficult to achieve. Fluorine is so reactive that its reaction with benzene is difficult to control, resulting in poor yields of monofluoroaromatic products. To address this, Selectfluor reagent is used as a fluorine source in which a fluorine atom is bonded to a positively charged nitrogen.
6.1K
01:15Electrophilic Aromatic Substitution: Chlorination and Bromination of Benzene
8.2K
Chlorination and bromination are important classes of electrophilic aromatic substitutions, where benzene reacts with chlorine or bromine in the presence of a Lewis acid catalyst to give halogenated substitution products. A Lewis acid such as aluminium chloride or ferric chloride catalyzes the chlorination, and ferric bromide catalyzes the bromination reactions. During the bromination of alkenes, bromine polarizes and becomes electrophilic. However, in the bromination of benzene, the bromine...
8.2K
01:11Nucleophilic Aromatic Substitution: Elimination–Addition
4.0K
Simple aryl halides do not react with nucleophiles. However, nucleophilic aromatic substitutions can be forced under certain conditions, such as high temperatures or strong bases. The mechanism of substitution under such conditions involves the highly unstable and reactive benzyne intermediate. Benzyne contains equivalent carbon centers at both ends of the triple bond, each of which is equally susceptible to nucleophilic attack. This 50–50 distribution of products is...
4.0K