Chirality sensing using stereodynamic probes with distinct electronic circular dichroism output

Abstract

Circular dichroism (CD) spectroscopy is one of the most useful techniques for the stereochemical analysis of chiral biopolymers and fine chemicals. It has become invaluable for the assignment of the absolute configuration, the study of conformational isomers, and the determination of racemization kinetics of CD active chiral compounds. Molecular interactions between a nonracemic chiral substrate and a chromophoric, CD-silent probe that is achiral or exists as a racemic mixture of rapidly interconverting enantiomeric conformations or configurations can induce a strong, characteristic chiroptical readout. A covalent or noncovalent binding event that coincides with a well-defined asymmetric induction process can effectively imprint the chiral information of the substrate on the stereodynamic sensor and thus generate intense Cotton effects in the UV region of the latter. The probe can thus function as a stereochemical reporter unit and analysis of the CD spectrum often provides accurate information about the absolute configuration and enantiomeric composition of the substrate used. In this review, recent developments in circular dichroism analysis of chiral compounds with stereodynamic probes are described and particular emphasis is given to sensor design, chiral induction processes and applications scope.

Nonbiaryl and Heterobiaryl Atropisomers: Molecular Templates with Promise for Atropselective Chemical Transformations

“…Detailed experimental studies and concepts on these topics have already been discussed in various reports. 125,126,128,131,132 Table 1 provides the physical parameters of the racemization for some of the commonly occurring atropisomeric scaffolds. It should be noted that some of the Table 1 are not atropisomeric, as they do not have high energy barriers to separation.…”

Molecular imprinted photonic crystal for sensing of biomolecules

“…[76] Various analytical methods for chiral biomolecules recognition have been reported, such as circular dichroism(CD) [77], optical rotatory dispersion (ORD) [78] and Raman optical activity (ROA) [79]. Although big progress has been made in the field of instrumental analytical methods, low-cost and label-free sensors for chiral recognition have also attracted considerable attentions.…”

Ion and Molecular Recognition Using Aryl–Ethynyl Scaffolding

“…[12, 13] Chiroptical changes measured by circular dichroism (CD) enhancement is emerging as a new method for analyte detection. [14] Fluorescence remains the most commonly utilized spectroscopic change because of the enhanced sensitivity compared to colorimetric changes. [15] Fluorescence also lends itself well to sensing within biological microenvironments, such as those inside cells, as native fluorescence of cells can be filtered out by selecting a fluorophore possessing non-competitive emission or excitation.…”