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Manipulating plasmonic chirality has shown promising applications in nanophotonics, stereochemistry, chirality sensing, and biomedicine. However, to reconfigure plasmonic chirality, the strategy of constructing chiral plasmonic systems with a tunable morphology is cumbersome and complicated to apply for integrated devices. Here, we present a simple and effective method that can also manipulate chirality and control chiral light–matter interactions only via strong coupling between chiral plasmonic nanoparticles and excitons. This paper presents a chiral plexcitonic system consisting of L-shaped nanorod dimers and achiral molecule excitons. The circular dichroism (CD) spectra in our strong-coupling system can be calculated by finite element method simulations. We found that the formation of the chiral plexcitons can significantly modulate the CD spectra, including the appearance of new hybridized peaks, double Rabi splitting, and bisignate anti-crossing behaviors. This phenomenon can be explained by our extended coupled-mode theory. Moreover, we explored the applications of this method in enantiomer ratio sensing by using the properties of the CD spectra. We found a strong linear dependence of the CD spectra on the enantiomer ratio. Our work provides a facile and efficient method to modulate the chirality of nanosystems, deepens our understanding of chiral plexcitons in nanosystems, and facilitates the development of chiral devices and chiral sensing. [ABSTRACT FROM AUTHOR]

This paper explores and revisits in detail the formation and characterization of sugar-based aminonitriles, whose ultimate origin can be traced to the interaction of biomolecules with cyanide. Although the synthesis and spectroscopic data of 2-amino-aldononitriles were reported long ago, there are both contradictory and confusing results among the published data. We have now addressed this concern through an exhaustive structural elucidation of acylated 2-amino- and 2-alkyl(aryl)amino-2-deoxyaldonitriles using mass spectrometry and FT-IR, FT–Raman, and NMR spectroscopies. Several structures could be unambiguously determined through single-crystal X-ray diffraction, which allowed us to correct other misassignments. Moreover, this study unveils how steric and electronic effects influence the acylation outcome of the amino, (alkyl, aryl)amino, or acetamido group at C-2. The chirality at the latter, which was assigned tentatively through optical rotation correlation, and hence the preferential threo stereochemistry generated during the cyanohydrin synthesis of 2-amino-2-deoxy aldononitriles have now been established with confidence. [ABSTRACT FROM AUTHOR]

The year 1874 is considered to be the birth of stereochemistry when the third dimension in describing and discussing structures in chemistry was first introduced. Stereochemistry and structural chemistry are closely related though they are not each other's synonyms. Structural chemistry implies greater emphasis on metrical aspects and stereochemistry on shape, symmetry, and chirality. We review some of the nodal points in the early development of stereochemistry. [ABSTRACT FROM AUTHOR]

With this report, the space group of [ Z n (N a l) (D A C H) 2 ] C l is corrected ( N a l : nalidixic acid mono-anion; D A C H : diaminocyclohexane) from its wrong description in the literature. In the correct, non-centrosymmetric space group P 1 , the crystal structure is well ordered and the stereochemistry is correct. Crystallographic tools to recognize the correct symmetry are described. This work encourages experienced and inexperienced scientists to remain critical about the output of automatic, black-box crystallographic software. [ABSTRACT FROM AUTHOR]

The coexistence of two fragments, a chiral isosteviol moiety and an achiral pyridinoyl-hydrazone moiety, in the molecules of pyridinoyl-hydrazone derivatives of isosteviol results in the realization of two distinct supramolecular motifs in their crystals, namely, a true homochiral motif and a pseudosymmetric homochiral motif. [ABSTRACT FROM AUTHOR]