Close Non-Bonded Contacts: Effects on Structure and Conformational Reactions

紧密的非键接触：对结构和构象反应的影响

• 批准号: 1762452
• 负责人: Robert Pascal
• 金额: $ 50万
• 依托单位: Tulane University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-15 至 2022-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1762452&HistoricalAwards=false
• 关键词: Close; Non; Bonded; Contacts; Effects

In this NSF project, funded by the Chemical Structure, Dynamic & Mechanism B Program of the Chemistry Division, Professor Robert Pascal, Jr. of the Department of Chemistry at Tulane University prepares new compounds that contain interacting functional groups in very close, but non-bonded contact and/or interacting molecular surfaces whose extent of contact varies with conformation. Some of these molecules are likely to exhibit "world record" shortening of bond distances and non-bonded contact distances. Many of these compounds have highly unusual shapes that are essentially unknown in the natural world. The research is fundamental in nature and will improve our understanding of chemical bonding. These compounds may also possess unique chiroptical and photophysical properties that would make them candidates for chiral catalysts, chiral sensors, or organic electronic materials. They also provide stringent tests of the accuracy of computational methods that are widely used in the chemical and biological sciences. The research is ideal for the training of laboratory chemists at all levels, including students from underrepresented groups in science.In,in-cyclophanes, complex polyphenyl aromatic molecules, and polycyclic aromatic structures containing strongly interacting surfaces share a common feature: conventional and dispersion-corrected density functional theory (DFT) calculations describe them quite differently, but which of these methods better agrees with experiment? (1) The proposed in,in-cyclophanes contain functional groups pressed very close together along the central axes of the molecules, but the two types of DFT calculations give significantly different interatomic distances. (2) The proposed polyphenyl aromatics have chiral lowest-energy conformations, but the two types of DFT calculations give very different barriers for racemization. (3) The proposed molecules with interacting aromatic polycycles may adopt distinct conformations that either maximize or minimize intramolecular van der Waals interactions, but the two types of DFT calculations give very different equilibrium constants for their interconversion. X-ray crystallography, dynamic NMR spectroscopy, chromatographic resolution on chiral supports, and NMR determination of equilibrium constants are being employed to judge the accuracy of the various computational methods.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在这个由美国国家科学基金会资助的项目中，化学部的化学结构，动力学机制B计划，小罗伯特·帕斯卡教授。杜兰大学化学系的研究人员准备了新的化合物，这些化合物含有相互作用的官能团，这些官能团在非常接近但非键合的接触和/或相互作用的分子表面上，其接触程度随构象而变化。这些分子中的一些很可能表现出键距离和非键接触距离的缩短的“世界纪录”。其中许多化合物具有极不寻常的形状，在自然界中基本上是未知的。 这项研究在本质上是基础性的，将提高我们对化学键的理解。 这些化合物还可能具有独特的手性和电子物理性质，这将使它们成为手性催化剂，手性传感器或有机电子材料的候选者。 它们还对广泛用于化学和生物科学的计算方法的准确性进行了严格的测试。这项研究是理想的培训实验室化学家在所有级别，包括学生从代表性不足的群体在science.In，环番，复杂的多苯基芳香族分子，多环芳香族结构，含有强烈的相互作用的表面有一个共同的功能：传统的和色散校正的密度泛函理论（DFT）计算描述他们完全不同，但这些方法更好地符合实验？ (1)所提出的in，in-cyclophanes包含沿着分子的中心轴沿着压在一起的官能团，但是两种类型的DFT计算给出了显著不同的原子间距离。 (2)所提出的多苯基芳烃具有手性最低能量构象，但两种类型的DFT计算给出了非常不同的外消旋化障碍。 (3)所提出的分子与相互作用的芳香族多环可能会采取不同的构象，要么最大化或最小化分子内的货车德瓦尔斯相互作用，但两种类型的DFT计算给出了非常不同的平衡常数为他们的相互转换。 X射线晶体学、动态核磁共振光谱学、手性载体上的色谱分离和核磁共振测定平衡常数被用来判断各种计算方法的准确性。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Multiple Isomers of a Small, Strained Phosphaphane: Multiple Isomers of a Small, Strained Phosphaphane

小的、应变的磷酸烷的多种异构体： 小的、应变的磷酸烷的多种异构体

• DOI: 10.1002/ejoc.201801106
• 发表时间: 2018
• 期刊: European Journal of Organic Chemistry
• 影响因子: 2.8
• 作者: Xiao, Yonglong;Mague, Joel T.;Pascal, Jr., Robert A.
• 通讯作者: Pascal, Jr., Robert A.

The structure and racemization of 1,2-bis(pentaphenylphenyl)benzene

• DOI: 10.1016/j.tet.2019.03.055
• 发表时间: 2019-05
• 期刊: Tetrahedron
• 影响因子: 2.1
• 作者: H. Nguyen;J. Mague;Qi Zhao;C. Kraml;Neal Byrne;R. Pascal

An Exceptionally Close, Non‐Bonded Hydrogen–Hydrogen Contact with Strong Through‐Space Spin–Spin Coupling

异常紧密的非键合氢与强贯穿氢接触空间自旋自旋耦合

• DOI: 10.1002/anie.201712304
• 发表时间: 2018
• 期刊: Angewandte Chemie International Edition
• 作者: Xiao, Yonglong;Mague, Joel T.;Pascal, Jr., Robert A.
• 通讯作者: Pascal, Jr., Robert A.

in,in -Cyclophanes with Bridgehead Methyl Groups

具有桥头甲基的 in,in-环芳烃

• DOI: 10.1021/acs.orglett.8b00773
• 发表时间: 2018
• 期刊: Organic Letters
• 影响因子: 5.2
• 作者: Xiao, Yonglong;Mague, Joel T.;Pascal, Robert A.
• 通讯作者: Pascal, Robert A.

Extremely Crowded Biaryls

极其拥挤的联芳基化合物

• DOI: 10.1002/ejoc.202100399
• 发表时间: 2021
• 期刊: European Journal of Organic Chemistry
• 影响因子: 2.8
• 作者: Du, Yuchen;Mague, Joel T.;Pascal, Jr., Robert A.
• 通讯作者: Pascal, Jr., Robert A.