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1. Asymmetric Synthesis of P-Stereogenic Secondary Phosphine ­Oxides (SPOs)

   https://doi.org/10.1055/a-1582-0169  

   Glueck, David S. (January 2022, Synthesis)

   Abstract P-Stereogenic secondary phosphine oxides [SPOs, RR′P(O)H], valuable ligands for metal complexes in asymmetric catalysis, are also building blocks for other chiral phosphorus derivatives. This short review summarizes methods used for asymmetric synthesis of P-stereogenic SPOs. 1 Introduction 2 Configurational Stability of P-Stereogenic SPOs 3 Classical Resolution, HPLC Separation, and Dynamic Resolution 4 Synthesis via Chiral Auxiliaries 5 Kinetic Resolution 6 Conclusions and Outlook 

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2. Tuning metal–metal interactions for cooperative small molecule activation

   https://doi.org/10.1039/D0CC07721F  

   Wang, Qiuran; Brooks, Sam H.; Liu, Tianchang; Tomson, Neil C. (March 2021, Chemical Communications)

   null (Ed.)

   Cluster complexes have attracted interest for decades due to their promise of drawing analogies to metallic surfaces and metalloenzyme active sites, but only recently have chemists started to develop ligand scaffolds that are specifically designed to support multinuclear transition metal cores. Such ligands not only hold multiple metal centers in close proximity but also allow for fine-tuning of their electronic structures and surrounding steric environments. This Feature Article highlights ligand designs that allow for cooperative small molecule activation at cluster complexes, with a particular focus on complexes that contain metal–metal bonds. Two useful ligand-design elements have emerged from this work: a degree of geometric flexibility, which allows for novel small molecule activation modes, and the use of redox-active ligands to provide electronic flexibility to the cluster core. The authors have incorporated these factors into a unique class of dinucleating macrocycles ( n PDI 2 ). Redox-active fragments in n PDI 2 mimic the weak-overlap covalent bonding that is characteristic of M–M interactions, and aliphatic linkers in the ligand backbone provide geometric flexibility, allowing for interconversion between a range of geometries as the dinuclear core responds to the requirements of various small molecule substrates. The union of these design elements appears to be a powerful combination for analogizing critical aspects of heterogeneous and metalloenzyme catalysts. 

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3. Control of stereogenic oxygen in a helically chiral oxonium ion

   https://doi.org/10.1038/s41586-023-05719-z  

   Smith, Owen; Popescu, Mihai V.; Hindson, Madeleine J.; Paton, Robert S.; Burton, Jonathan W.; Smith, Martin D. (March 2023, Nature)

   Abstract The control of tetrahedral carbon stereocentres remains a focus of modern synthetic chemistry and is enabled by their configurational stability. By contrast, trisubstituted nitrogen 1 , phosphorus 2 and sulfur compounds 3 undergo pyramidal inversion, a fundamental and well-recognized stereochemical phenomenon that is widely exploited 4 . However, the stereochemistry of oxonium ions—compounds bearing three substituents on a positively charged oxygen atom—is poorly developed and there are few applications of oxonium ions in synthesis beyond their existence as reactive intermediates 5,6 . There are no examples of configurationally stable oxonium ions in which the oxygen atom is the sole stereogenic centre, probably owing to the low barrier to oxygen pyramidal inversion 7 and the perception that all oxonium ions are highly reactive. Here we describe the design, synthesis and characterization of a helically chiral triaryloxonium ion in which inversion of the oxygen lone pair is prevented through geometric restriction to enable it to function as a determinant of configuration. A combined synthesis and quantum calculation approach delineates design principles that enable configurationally stable and room-temperature isolable salts to be generated. We show that the barrier to inversion is greater than 110 kJ mol −1 and outline processes for resolution. This constitutes, to our knowledge, the only example of a chiral non-racemic and configurationally stable molecule in which the oxygen atom is the sole stereogenic centre. 

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4. The effect of molecular isomerism on the induced circular dichroism of cadmium sulfide quantum dots

   https://doi.org/10.1039/d1tc04496f  

   Joh, Yoonbin A.; Kwon, Yuri H.; Tannir, Shambhavi; Leonard, Brian M.; Kubelka, Jan; Varga, Krisztina; Balaz, Milan (December 2021, Journal of Materials Chemistry C)

   Post-synthetic phase transfer ligand exchange has been established as a simple, reliable, and versatile method for the synthesis of chiral, optically active colloidal nanocrystals displaying circular dichroism (CD) and circularly polarized luminescence (CPL). Herein we present a water-free and purification-free cyclohexane → methanol ligand exchange system that led to the synthesis of stable, non-aggregating chiral and fluorescent cadmium sulfide quantum dots (CdS QDs). Absorption and emission studies revealed that the carboxylate capping ligands can tune the band gap by up to 65 meV as well as control the band gap and deep trap emission pathways. The CD data revealed that the addition of a 2nd stereogenic center did not automatically lead to an increase of the CD anisotropy of QDs, but rather match/mismatch cooperativity effects must be considered in the transfer of the chirality from the capping ligands to the achiral nanocrystals. Variation in position of the functional groups as well as the chemical identity of the functional groups impacted both the shape and anisotropy of the induced CD spectra and revealed the importance of the functional groups’ coordination and polarity on the binding geometry and induced chiroptical properties. Finally, we describe the first example where CD spectra of QDs capped with the same ligand and dissolved in the same solvent displayed very different spectral profiles. This work provides deeper insight into induced CD of QDs and paves the path to rational design of chiral nanomaterials. 

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5. Distinct Chiral Nanostructures of Graphene Quantum Dots Govern Divergent Passive and Active Enantioselective Transport across Biological Membranes

   https://doi.org/10.64898/2026.02.16.706189  

   Shirinichi, Farbod; Liu, Yichen; Zhu, Runyao; Carpenter, James; Zhang, Wei; Colón, Yamil J; Wang, Yichun (February 2026, bioRxiv)

   ABSTRACT Chirality in two-dimensional nanomaterials provides a powerful lever to control biological interfaces, yet the structural origins of nanoscale chirality remain poorly understood. Here, we systematically investigate chiral ligand modulated graphene quantum dots (GQDs) and reveal how ligand stereochemistry and edge chemistry modulate the formation of diverse chiral or achiral nanostructures. Spectroscopy, microscopy, and density functional theory with ring-puckering analysis identified six structural motifs, twisted-, twisted-boat, saddle-shaped, hybrid, unbuckled, and random. Among these, twisted-, twisted-boat, and saddle-shaped GQDs exhibited genuine nanoscale structural chirality, while unbuckled, hybrid, and random conformations lacked organized distortion. Importantly, structural chirality governed passive permeation into biological membrane (e.g. lipid membrane of extracellular vesicles), whereas achiral variants relied mainly on hydrophobic interactions. In contrast, active transport across biological membrane (e.g. endocytosis) is insensitive to nanoscale structural chirality but strongly influenced by chiral ligand identity and transporter recognition. Collectively, these results establish chiral ligand conjugation as a modular route to program both chiral and achiral motifs in graphene nanostructures and highlight nanoscale structural chirality as a design principle for engineering bio-nano interactions. 

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