Article
Chemistry, Physical
Tao Wu, Josef Kapitan, Petr Bour
Summary: Chiral metal complexes have rich photophysical properties and are important for various applications. This study combines experimental and computational approaches to investigate the energies and transition moments of excited electronic states in two chiral metal complexes. The experimental protocol involves multiple techniques, and a formula for subtracting interfering effects is provided. Density functional theory calculations are used to analyze the spectra and reveal the geometric and electronic structures of the molecules. This insight into molecular electronic states can be useful for understanding and manipulating the photochemical properties of metal-containing complexes, biomolecules, and supramolecules.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Materials Science, Multidisciplinary
D. M. Burn, R. Fan, O. Inyang, M. Tokac, L. Bouchenoire, A. T. Hindmarch, P. Steadman
Summary: Resonant soft-X-ray reflectivity and vibrating sample magnetometry were used to study field driven and spin orbit torque driven magnetization reversal in a CoFeTaB/Pt bilayer. Magnetization reversal can occur along the applied field direction or perpendicular to the current flow direction, with different effects of current and field on the reversal process. Experimental results indicate that only the layers near the Pt interface undergo magnetization reversal, possibly due to the proximity effects of magnetized Pt. Furthermore, magnetization reversal perpendicular to the beam results in hysteresis behavior in the reflected intensity that is independent of the helicity of the incident beam's circular polarization.
Article
Chemistry, Multidisciplinary
Aleksandra Kolodziejczyk, Laurence A. Nafie, Aleksandra Wajda, Agnieszka Kaczor
Summary: Amyloid fibrils exhibit multi-layered chiral supramolecular structures and are highly sensitive to vibrational circular dichroism (VCD) for fibril formation. In this study, we demonstrate an exceptionally large enhancement of Raman optical activity (ROA) signal in mature amyloid fibrils and their prefibrillar states. This enhanced ROA signal is observed in fibrils of different proteins, indicating a possible general phenomenon. The ROA signal appears earlier than VCD and provides access to a broader range of vibrations, suggesting its potential utility for analyzing amyloid fibrils.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Kevin Scholten, Christian Merten
Summary: The conformational preferences of peptides are determined by hydrogen bonding interactions, which can be studied using VCD spectroscopy. In chloroform, the peptide's conformational preferences can be described well by assuming implicit solvation effects. In DMSO-d(6), explicit solvation structures are required to match the experimental data. Structures with intramolecular hydrogen bonds contribute to the conformational distribution only when there is no strong interaction with the solvent.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Jennifer Dupont, Regis Guillotb, Valeria Lepere, Anne Zehnacker
Summary: The structures of diastereomer diketopiperazine dipeptides cyclo(LTyr-LPhe) and cyclo-(DTyr-LPhe) were studied in the gas phase using resonance-enhanced two-photon ionization, IR/UV double resonance spectroscopy, and quantum chemical calculation. Both diastereomers exhibit two conformations with slight differences in weak CH···ir and NH···ir interactions. The crystal structure and vibrational circular dichroism spectrum were determined, with quantum chemical calculation shedding light on structural modifications between the gas phase and the solid state.
JOURNAL OF MOLECULAR STRUCTURE
(2022)
Article
Optics
G. P. Katsoulis, Z. Dube, P. B. Corkum, A. Staudte, A. Emmanouilidou
Summary: We propose a measure that quantifies chirality in the ionization process of achiral atoms and validate it under realistic experimental conditions. This measure is based on the sign of the scalar triple product of the electron final momentum and the probability of ionization, integrated over all momentum components.
Article
Chemistry, Multidisciplinary
Xiang Jiang, Yeonsig Nam, Jeremy R. Rouxel, Haiwang Yong, Shaul Mukamel
Summary: Molecular chirality, a crucial property in biochemistry, is being studied in the time domain. The use of ultrafast techniques and X-ray element-sensitivity allows for the investigation of local chiral nuclear dynamics. However, the weakness of chiral-sensitive signals based on circularly polarized light poses a challenge to measuring transient chirality.
Article
Chemistry, Physical
Hisako Sato, Kazuyoshi Takimoto, Akihiko Yamagishi, Jun Yoshida, Mitsuo Hara
Summary: Solid state vibrational circular dichroism (SD-VCD) spectra were recorded on intercalation compounds of sodium montmorillonite with a chiral iridium(III) complex. The VCD signals were sensitive to molecular interactions in adsorption layers and signal enhancement was achieved through coherent delocalization of vibrational motions. Theoretical simulations were used to propose models of molecular packing.
APPLIED CLAY SCIENCE
(2022)
Article
Chemistry, Physical
Aidan P. Holman, Kimberly Quinn, Rakesh Kumar, Sebastian Kmiecik, Abid Ali, Dmitry Kurouski
Summary: Long-chain unsaturated and polyunsaturated fatty acids are important components of cell membranes and are involved in cell signaling and metabolism. They are widely used as food supplements but their role in the self-assembly of misfolded proteins is still unclear.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Michael Kemper, Elric Engelage, Christian Merten
Summary: This study demonstrates the efficient transfer of point chirality in side chains of chiral triarylborane-ammonia adducts to the propeller chirality of triarylboranes. By using X-ray crystallography and spectroscopy, the conformational preferences of molecular propellers were elucidated. Interestingly, computationally predicted conformational preferences were found to be opposite to the experimentally observed ones.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Analytical
Vinayaka Harshothama Damle, Hagit Aviv, Yaakov R. Tischler
Summary: This study successfully identifies enantiomers using low-frequency Raman spectroscopy. By comparing the spectral intensity on different polarization planes, chiral and nonchiral molecules can be distinguished. This technique is of great importance for the pharmaceutical industry.
ANALYTICAL CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Daniel P. Demarque, Michael Kemper, Christian Merten
Summary: In this study, the IR and VCD spectra of azithromycin were reported, with computational analysis revealing the importance of a single water molecule in stabilizing the hydrogen bonding network and determining the VCD spectral signatures. The presence of this water molecule was essential for understanding the conformational dynamics of azithromycin.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Analytical
Hisako Sato, Masaru Shimizu, Keisuke Watanabe, Jun Yoshida, Izuru Kawamura, Jun Koshoubu
Summary: A multidimensional vibrational circular dichroism system with a positional coordinate was developed, utilizing a Quantum cascade laser as a high-intensity light source for precise focusing. The instrument was operated to analyze samples containing amide groups, including measurements in high background absorbance due to water medium. The system allowed for movement in both x and y directions, maintaining a mirror-image relation between optical antipodes.
ANALYTICAL CHEMISTRY
(2021)
Article
Chemistry, Physical
Rosa E. del Rio, Julio C. Pardo-Novoa, Carlos M. Cerda-Garcia-Rojas, Pedro Joseph-Nathan
Summary: The study evaluated isomeric quinols, prepared experimental VCD spectra for comparison with calculated spectra, and found different compounds required analysis at different levels of DFT theory.
JOURNAL OF MOLECULAR STRUCTURE
(2021)
Article
Multidisciplinary Sciences
Dawrin Pech-Puch, Pedro Joseph-Nathan, Eleuterio Burgueno-Tapia, Carlos Gonzalez-Salas, Diana Martinez-Matamoros, David M. Pereira, Renato B. Pereira, Carlos Jimenez, Jaime Rodriguez
Summary: This study isolated six new briarane diterpenoids from the gorgonian coral collected from the Mexican Caribbean Sea and elucidated their structures using NMR and MS measurements. The structure of briarane B-3 was confirmed, and the use of VCD in briarane diterpenoids was reported for the first time. Biological evaluation showed moderate anti-inflammatory activity for some compounds but no other significant activities were observed.
SCIENTIFIC REPORTS
(2021)