Conformational Analysis and Energetics of Cyclic and Open Chain Ketones, Ethers, and Hydrocarbons

环状和开链酮、醚和烃的构象分析和能量学

基本信息

批准号：
9727788
负责人：
Tomas Baer
金额：
$ 34万
依托单位：
University of North Carolina at Chapel Hill
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
1998
资助国家：
美国
起止时间：
1998-04-01 至 2002-03-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=9727788&HistoricalAwards=false
关键词：
Conformational Analysis Energetics Cyclic Open

项目摘要

In this project supported by the Experimental Physical Chemistry Program of the Chemistry Division, Tomas Baer will use resonance enhanced multi-photon ionization spectroscopy (REMPI) of jet-cooled molecules to investigate the ultraviolet spectra and conformational equilibria of ring and open-chain molecules such as ketones, ethers, and hydrocarbons. Temperature-dependent spectral data will yield conformational enthalpy differences which can be compared with values from calculations. Gas-phase measurements will be related to solution studies via solvent effects. Vibrational relaxation-isomerization rates in the supersonic expansion will be modeled using the master equation. The accurate measurement of interaction energies will provide valuable information about the nature and strength of non-bonded interactions of alkyl groups in organic molecules. Many molecules have flexible structures, where the overall positions of atoms can vary significantly without breaking or making any of the strong chemical bonds that connect the atoms. The many forces exerted among different regions of a molecule that are much weaker than chemical bonds can strongly influence the overall arrangement of atoms in the molecule. For large molecular systems (such as biological molecules), the collective effect of these small forces can play a dominant role in determining the structure, and thus the functional behavior, of the molecule. These studies will explore the nature of some of these weak interaction energies. Results from this project could help to refine the data bases used for computational predictions of properties of large organic molecules.

在这个由化学部实验物理化学项目支持的项目中，托马斯·贝尔将利用喷射冷却分子的共振增强多光子电离光谱（REMPI）来研究环状和开链分子的紫外光谱和构象平衡，例如如酮、醚和烃。与温度相关的光谱数据将产生构象焓差，可以将其与计算值进行比较。气相测量将通过溶剂效应与溶液研究相关。将使用主方程对超音速膨胀中的振动松弛异构化速率进行建模。相互作用能的精确测量将为有机分子中烷基非键相互作用的性质和强度提供有价值的信息。许多分子具有灵活的结构，其中原子的整体位置可以显着变化，而不会破坏或形成任何连接原子的强化学键。分子不同区域之间施加的许多比化学键弱得多的力可以强烈影响分子中原子的整体排列。对于大分子系统（例如生物分子），这些小力的集体效应可以在确定分子的结构以及功能行为方面发挥主导作用。这些研究将探索其中一些弱相互作用能量的性质。该项目的结果可以帮助完善用于计算预测大型有机分子特性的数据库。