Enantiomerically pure chiral auxiliary agents are often used in NMR spectroscopy to facilitate the differentiation of enantiomers. Chiral derivatizing agents are covalently bound to the substrate and differences in chemical shifts of the resulting diastereomeric complexes are used in the analysis. Macrocycles such as cyclodextrins, crown ethers, and calix[4]resorcinarenes are chiral solvating agents that associate with the substrate through non-covalent interactions. Enantiomeric differentiation occurs in the NMR spectrum because of the diastereomeric nature of the associated complexes and/or because of the differences in association constants between the two enantiomers and the chiral reagent. Metal complexes are Lewis acids that bind to suitable Lewis base donor compounds. Exchange of substrate can be slow or fast depending on the particular metal ion, mimicking the behavior of a chiral derivatizing or solvating agent, respectively. Chiral liquid crystals undergo a partial alignment in an applied magnetic field and enantiomers dissolved in the liquid crystal undergo a partial alignment as well. If the alignment of the two enantiomers is different, enantiomeric differentiation can potentially be observed by differences in chemical shifts, differences in dipolar coupling constants, and different magnitudes of splitting of quadrupolar nuclei such as deuterium. The chiral reagents described herein can be used to determine enantiomeric composition and sometimes to assign absolute configuration. Significant discoveries as well as recent findings with each of these types of systems are described.

Chiral derivatizing agents, macrocycles, metal complexes, and liquid crystals for enantiomer differentiation in NMR spectroscopy.

Optically active binaphthyl-azobenezene cyclic dyads were synthesized to develop a photochromic switching molecule. Azobenezene moieties were cis-trans isomerized by photoirradiation. As a reflection of the structural change, the specific optical rotation and circular dichroism underwent significant shifts. Under certain conditions, the positive-negative and zero-positive (or zero-negative) signals were reversed. Optical rotation may potentially be applied in noise-cancelling nondestructive photoswiches. The conformations were studied by experimental and theoretical methods. The results revealed that the helical chirality, (P) or (M), of the cis-azobenzene moiety was induced by intramolecular axial chirality. The twist direction depended on the axial chirality as well as the azobenzene linkage position to the binaphthyls, but was independent of the identity of substituted groups. 2,2’-Linked-(R)-binaphthyl was found to induce cis-(P)-azobenzene, whereas symmetrically 7,7’-linked-(R)-binaphthyl was found to induce cis-(M)-azobenzene.

/pdf/synthesis-and-conformation-of-substituted-chiral-binaphthyl-k0upiicstx.pdf

Synthesis and conformation of substituted chiral binaphthyl-azobenzene cyclic dyads with chiroptical switching capabilities

Heteroditopic receptor based on crown ether and cyclen units for the recognition of zwitterionic amino acids

https://pubs.rsc.org/en/Content/ArticlePDF/2013/CC/C3CC43083A

Colorimetric enantioselective recognition of chiral secondary alcohols via hydrogen bonding to a chiral metallocene containing chemosensor

Chirality plays a central role in the world around us, with nature and scientists producing an ever-increasing number of chiral molecules that have a wide range of different applications. The word chirality is used as a term to describe a molecule whose enantiomers are non-superimposable on their mirror images. A chiral molecule that contains a single stereogenic center may exist in an enantiopure form or as a mixture of enantiomers in varying ratios. Enantiomers exhibit identical physical and chemical properties when present in an achiral environment; however, they often behave very differently when placed in a chiral environment. Many biologically active molecules such as proteins, nucleic acids, and sugars are chiral biopolymers that are constructed from homochiral building blocks.

8.29 Spectroscopic Analysis: Diastereomeric Derivatization for Spectroscopy

Effects of ring substituents on enantioselective recognition of amino alcohols and acids in uryl-based binol receptors

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Jayoung Ryu

Author Tools

Chat about Author

Papers

Effects of ring substituents on enantioselective recognition of amino alcohols and acids in uryl-based binol receptors