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1. Mirror-image antiparallel β-sheets organize water molecules into superstructures of opposite chirality

   https://doi.org/10.1073/pnas.2015567117  

   Perets, Ethan A.; Konstantinovsky, Daniel; Fu, Li; Chen, Jiantao; Wang, Hong-Fei; Hammes-Schiffer, Sharon; Yan, Elsa C. Y. (December 2020, Proceedings of the National Academy of Sciences)

   Biomolecular hydration is fundamental to biological functions. Using phase-resolved chiral sum-frequency generation spectroscopy (SFG), we probe molecular architectures and interactions of water molecules around a self-assembling antiparallel β-sheet protein. We find that the phase of the chiroptical response from the O-H stretching vibrational modes of water flips with the absolute chirality of the (l-) or (d-) antiparallel β-sheet. Therefore, we can conclude that the (d-) antiparallel β-sheet organizes water solvent into a chiral supermolecular structure with opposite handedness relative to that of the (l-) antiparallel β-sheet. We use molecular dynamics to characterize the chiral water superstructure at atomic resolution. The results show that the macroscopic chirality of antiparallel β-sheets breaks the symmetry of assemblies of surrounding water molecules. We also calculate the chiral SFG response of water surrounding (l-) and (d-) LK₇β to confirm the presence of chiral water structures. Our results offer a different perspective as well as introduce experimental and computational methodologies for elucidating hydration of biomacromolecules. The findings imply potentially important but largely unexplored roles of water solvent in chiral selectivity of biomolecular interactions and the molecular origins of homochirality in the biological world. 

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2. Enantiospecific equilibrium adsorption and chemistry of d ‐/ l ‐proline mixtures on chiral and achiral Cu surfaces

   https://doi.org/10.1002/chir.23153  

   Dutta, Soham; Gellman, Andrew J. (November 2019, Chirality)

   Abstract A fundamental understanding of the enantiospecific interactions between chiral adsorbates and understanding of their interactions with chiral surfaces is key to unlocking the origins of enantiospecific surface chemistry. Herein, the adsorption and decomposition of the amino acid proline (Pro) have been studied on the achiral Cu(110) and Cu(111) surfaces and on the chiral Cu(643)^R&Ssurfaces. Isotopically labelled 1‐¹³C‐l‐Pro has been used to probe the Pro decomposition mechanism and to allow mass spectrometric discrimination ofd‐Pro and 1‐¹³C‐l‐Pro when adsorbed as mixtures. On the Cu(111) surface, X‐ray photoelectron spectroscopy reveals that Pro adsorbs as an anionic species in the monolayer. On the chiral Cu(643)^R&Ssurface, adsorbed Pro enantiomers decompose with non‐enantiospecific kinetics. However, the decomposition kinetics were found to be different on the terraces versus the kinked steps. Exposure of the chiral Cu(643)^R&Ssurfaces to a racemic gas phase mixture ofd‐Pro and 1‐¹³C‐l‐Pro resulted in the adsorption of a racemic mixture; i.e., adsorption is not enantiospecific. However, exposure to non‐racemic mixtures ofd‐Pro and 1‐¹³C‐l‐Pro resulted in amplification of enantiomeric excess on the surface, indicative of homochiral aggregation of adsorbed Pro. During co‐adsorption, this amplification is observed even at very low coverages, quite distinct from the behavior of other amino acids, which begin to exhibit homochiral aggregation only after reaching monolayer coverages. The equilibrium adsorption ofd‐Pro and 1‐¹³C‐l‐Pro mixtures on achiral Cu(110) did not display any aggregation, consistent with prior scanning tunneling microscopy (STM) observations ofdl‐Pro/Cu(110). This demonstrates convergence between findings from equilibrium adsorption methods and STM experiments and corroborates formation of a 2D random solid solution. 

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3. Disparate reactivity of a chiral iron( ii ) tetracarbene complex with organic azides

   https://doi.org/10.1039/D4DT01422G  

   Russell, Jerred J; DeJesus, Joseph F; Smith, Brett A; Nalaoh, Phattananawee; Vogiatzis, Konstantinos D; Jenkins, David M (July 2024, Dalton Transactions)

   A chiral tetra-NHC iron(ii) complex and its disparate reactivity with multiple organic azides is reported. 

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4. Ring-opening polymerization of ε-caprolactone with a macrocyclic tetracarbene indium complex

   https://doi.org/10.1039/D4DT03198A  

   Brothers, Henry R; Chambenahalli, Raju; Nichol, Gary S; Garden, Jennifer A; Jenkins, David M (January 2025, Dalton Transactions)

   The first chiral tetracarbene indium(iii) complexes have been synthesized by employing a rigid dianionic macrocyclic tetra-NHC ligand. 

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5. Real-time chiral dynamics at finite temperature from quantum simulation

   https://doi.org/10.1007/JHEP10(2024)031  

   Ikeda, Kazuki; Kang, Zhong-Bo; Kharzeev, Dmitri E; Qian, Wenyang; Zhao, Fanyi (October 2024, Journal of High Energy Physics)

   A<sc>bstract</sc> In this study, we explore the real-time dynamics of the chiral magnetic effect (CME) at a finite temperature in the (1+1)-dimensional QED, the massive Schwinger model. By introducing a chiral chemical potentialμ₅through a quench process, we drive the system out of equilibrium and analyze the induced vector currents and their evolution over time. The Hamiltonian is modified to include the time-dependent chiral chemical potential, thus allowing the investigation of the CME within a quantum computing framework. We employ the quantum imaginary time evolution (QITE) algorithm to study the thermal states, and utilize the Suzuki-Trotter decomposition for the real-time evolution. This study provides insights into the quantum simulation capabilities for modeling the CME and offers a pathway for studying chiral dynamics in low-dimensional quantum field theories. 

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