Effect of Solvation and Hydrogen Bonding on Conformationally Fexible Molecules

鲍林格林州立大学的约翰·凯布尔得到了实验物理化学项目的支持，该项目旨在研究各种芳香族分子与水或氨之间形成的1：1团簇中的氢键。这些研究集中在构象柔性分子上；通过改变芳香族部分，空间位阻和结构扭曲对氢键相互作用的影响将被考察。在超音速喷嘴中展开的团簇的质量选择共振增强电离光谱和色散荧光将分别用于提供激发态和基电子态的信息。一项相关的理论工作包括模拟观察到的孤立和簇状溶质的能级，以表征氢键引起的详细结构扰动。这些研究结果将使我们更详细地了解影响氢键强度的因素，以及如何通过结构扭曲来调节共轭溶质分子的电子性质，从而优化氢键相互作用。氢键在化学中扮演着重要的角色，从强烈影响溶剂的物理性质到决定生物大分子的结构。尽管氢键比普通的共价键和离子键弱得多，但它对生物系统中重要的分子识别过程至关重要。这些研究将提高对与蛋白质和核酸相关的常见氢键类型的理解。

John Cable of Bowling Green State University is supported by the Experimental Physical Chemistry Program to investigate hydrogen bonding in 1:1 clusters formed between various aromatic molecules and either water or ammonia. These studies concentrate on conformationally flexible molecules; by varying the aromatic moiety, effects of steric hindrance and structural distortion on the hydrogen bonding interaction will be examined. Mass-selected resonance enhanced ionization spectroscopy and dispersed fluorescence of the cluster expanded in a supersonic nozzle will be used to yield information on the excited and ground electronic states, respectively. A related theoretical effort involves simulations of the observed energy levels of isolated and clustered solutes for chararacterization of the detailed structural perturbations resulting from hydrogen bonding. The results of these investigations will provide a more detailed understanding of the factors that affect the strength of a hydrogen bond and how the electronic properties of a conjugated solute molecule can be modulated by structural distortion in order to optimize the hydrogen bonding interaction. Hydrogen bonding plays an important role in chemistry, from strongly influencing the physical properties of solvents to determining the structures of biological macromolecules. Although much weaker than ordinary covalent and ionic bonds, hydrogen bonds are of crucial importance to the molecular recognition processes that are significant in biological systems. These studies will improve the understanding of the common types of hydrogen bonds that are relevant to proteins and nucleic acids.