chemical shift

简明释义

化学位移

英英释义

例句

1.A downfield chemical shift usually indicates a more deshielded proton.

向下偏移的化学位移通常表示一个去屏蔽的质子。

2.In this experiment, the chemical shift was measured to assess the purity of the sample.

在这个实验中，测量了化学位移以评估样品的纯度。

3.The chemical shift values help in identifying isomers in organic compounds.

在有机化合物中，化学位移值有助于识别异构体。

4.By analyzing the chemical shift, we can determine the molecular environment of the hydrogen atoms.

通过分析化学位移，我们可以确定氢原子的分子环境。

5.The chemical shift in the NMR spectrum indicates the presence of different functional groups.

NMR光谱中的化学位移指示了不同官能团的存在。

作文

In the field of chemistry, particularly in nuclear magnetic resonance (NMR) spectroscopy, the concept of chemical shift plays a crucial role in understanding the structure and environment of molecules. The chemical shift refers to the change in the resonant frequency of a nucleus when it is placed in a magnetic field, influenced by the electronic environment surrounding that nucleus. This phenomenon provides vital information about the molecular structure, as different atoms in various environments resonate at different frequencies. When we analyze a spectrum obtained from NMR spectroscopy, each peak corresponds to a different chemical shift, which is measured in parts per million (ppm). The position of these peaks allows chemists to deduce the presence of specific functional groups, the connectivity of atoms, and even the stereochemistry of the molecule. For instance, the chemical shift of hydrogen atoms in aliphatic chains differs significantly from those in aromatic rings due to the varying electron density around them. Moreover, the chemical shift can also be affected by factors such as electronegativity, hybridization, and the presence of neighboring atoms. For example, a hydrogen atom attached to a carbon that is bonded to an electronegative atom like chlorine will have a different chemical shift than one attached to a carbon in a hydrocarbon chain. This sensitivity to the electronic environment makes NMR a powerful tool for chemists in identifying and characterizing compounds. Understanding chemical shift is not only important for organic chemists but also for biochemists and pharmacologists who study complex biological molecules. For instance, proteins and nucleic acids exhibit unique chemical shifts that can provide insights into their structure and dynamics. By analyzing these shifts, researchers can infer how these biomolecules interact with each other and with potential drug candidates, paving the way for advances in drug design and development. In summary, the chemical shift is a fundamental concept in NMR spectroscopy that provides invaluable information about the molecular structure and electronic environment of atoms within a molecule. Its application spans across various fields of chemistry and biology, highlighting its significance in both academic research and practical applications. As technology advances, the ability to accurately measure and interpret chemical shifts continues to enhance our understanding of complex molecular systems, ultimately contributing to scientific progress and innovation in numerous disciplines.

在化学领域，特别是在核磁共振（NMR）光谱学中，化学位移的概念在理解分子的结构和环境方面起着至关重要的作用。化学位移是指当一个原子核置于磁场中时，由于周围电子环境的影响而导致其共振频率的变化。这一现象提供了关于分子结构的重要信息，因为不同环境中的原子在不同频率下共振。当我们分析从NMR光谱学获得的光谱时，每个峰值对应于不同的化学位移，其单位为百万分之一（ppm）。这些峰的位置使化学家能够推断出特定官能团的存在、原子的连接方式，甚至分子的立体化学。例如，烷基链中氢原子的化学位移与芳香环中的氢原子有显著不同，这是由于它们周围的电子密度差异。此外，化学位移还可以受到电负性、杂化以及邻近原子的影响。例如，连接到与电负性原子如氯相连的碳上的氢原子，其化学位移将与连接到烃链中碳的氢原子不同。这种对电子环境的敏感性使得NMR成为化学家识别和表征化合物的强大工具。理解化学位移不仅对有机化学家重要，对研究复杂生物分子的生物化学家和药理学家同样重要。例如，蛋白质和核酸表现出独特的化学位移，这可以提供关于其结构和动态的信息。通过分析这些位移，研究人员可以推断这些生物分子如何相互作用以及与潜在药物候选物的相互作用，从而为药物设计和开发的进步铺平道路。总之，化学位移是NMR光谱学中的一个基本概念，为分子内原子的结构和电子环境提供了无价的信息。它的应用跨越了化学和生物学的多个领域，突显了其在学术研究和实际应用中的重要性。随着技术的进步，准确测量和解释化学位移的能力不断增强，使我们对复杂分子系统的理解不断加深，最终推动了科学进步和各个学科的创新。