Chalcogen‐Containing Diols: A Novel Chiral Derivatizing Agent for 77 Se and 125 Te NMR Chiral Recognition of Primary Amines

Recognition in the Domain of Molecular Chirality: From Noncovalent Interactions to Separation of Enantiomers

It is not a coincidence that both chirality and noncovalent interactions are ubiquitous in nature and synthetic molecular systems. Noncovalent interactivity between chiral molecules underlies enantioselective recognition as a fundamental phenomenon regulating life and human activities. Thus, noncovalent interactions represent the narrative thread of a fascinating story which goes across several disciplines of medical, chemical, physical, biological, and other natural sciences. This review has been conceived with the awareness that a modern attitude toward molecular chirality and its consequences needs to be founded on multidisciplinary approaches to disclose the molecular basis of essential enantioselective phenomena in the domain of chemical, physical, and life sciences. With the primary aim of discussing this topic in an integrated way, a comprehensive pool of rational and systematic multidisciplinary information is provided, which concerns the fundamentals of chirality, a description of noncovalent interactions, and their implications in enantioselective processes occurring in different contexts. A specific focus is devoted to enantioselection in chromatography and electromigration techniques because of their unique feature as "multistep" processes. A second motivation for writing this review is to make a clear statement about the state of the art, the tools we have at our disposal, and what is still missing to fully understand the mechanisms underlying enantioselective recognition.

Application of aromatic amide-derived atropisomers as chiral solvating agents for discrimination of optically active mandelic acid derivatives in 1 H nuclear magnetic resonance spectroscopy

Non-biaryl atropisomers and their stereochemistry have attracted much attentions in the past years. However, application of the non-biaryl atropisomers as chiral solvating agents is yet to be explored. In this work, four aromatic amide-derived atropisomeric phosphine ligands (hosts) were used as chiral solvating agents to recognize various mandelic acid derivatives (guests) in ¹ H nuclear magnetic resonance (NMR) spectroscopy. It is found that chiral center configurations of the four hosts have different effects on the enantiorecognition to the used guests. In addition, the host and guest interaction was further investigated by determination of the host-guest complex stoichiometry using the Job's method and density functional theory calculation, respectively. Moreover, chiral analysis accuracy of these hosts was evaluated through relationship between enantiomeric excess values of 4-chloromandelic acid provided by NMR and gravimetry, respectively.

Chiral Recognition of In Situ-Oxidized Phosphine Oxides with Octahedral Indium Complexes by 31P NMR Spectroscopy

Herein, efficient chiral recognition of phosphine oxides with octahedral indium complexes was demonstrated. Direct chiral analysis of in situ-prepared phosphine oxides formed using phosphines and hydrogen peroxide was conducted effectively via ³¹P nuclear magnetic resonance spectroscopy. Sufficient peak resolution of chiral phosphines was obtained consistently, thereby enabling the reliable determination of absolute chirality. Rational 1:1 binding models based on experiments and density functional theory calculations have been proposed.