Article
Biochemistry & Molecular Biology
Utana Umezaki, Miu Hatakenaka, Kana Onodera, Hiroto Mizutani, Suhyang Kim, Yusuke Nakasone, Masahide Terazima, Yoshifumi Kimura
Summary: This study investigated the photoexcitation dynamics of a photoactive yellow protein dissolved in hydrated choline dihydrogen phosphate through transient absorption and transient grating spectroscopy. The photocyclic reaction of the protein in this ionic liquid was similar to that in the buffer solution, but the structural change during the photocycle was different. The suppression of the known change in protein diffusion coefficient in high concentrations of [ch][dhp] may be attributed to stabilization of the secondary structure.
Article
Chemistry, Inorganic & Nuclear
Mikhail A. Volkov, Anton P. Novikov, Mikhail S. Grigoriev, Yuri M. Nevolin, Konstantin E. German
Summary: This paper presents synthetic methods for preparing Tc(III) and Tc(IV) coordination compounds with thiourea. The main product of synthesis was found to be [TcTu5X]X2 (Tu = (NH2)2CS, X = Cl, Br), rather than the previously believed [TcTu6]Cl3·4H2O. Tu2[TcX6]X2·3H2O was identified as the main byproduct of the reaction. All reaction products, including byproducts, were characterized by X-ray diffraction analysis. The solubility of the obtained Tc(III) complexes was also measured. This study explores the thermolysis process of the obtained Tc(III) complexes and demonstrates that the presence of sulfur atoms in the coordination sphere can inhibit metal formation in an argon-hydrogen medium. Analysis of nonvalent interactions in Tc(III) complexes reveals the significant contribution of van der Waals interactions and hydrogen bonds.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Yoshihiro Koyama, Seiya Shimono, Hiroaki Kishimura, Takahiro Takekiyo, Yukihiro Yoshimura, Hiroshi Abe, Kiyoto Matsuishi
Summary: The high-pressure crystal polymorph of a fluorinated ionic liquid was determined through X-ray diffraction and Raman spectroscopy, revealing irreversible changes in crystal structure upon compression and decompression. Conformational variance/invariance of the ions in the Raman spectra corresponded to the high-pressure crystal polymorph, indicating a switch in conformational variance at a specific pressure point leading to a change in crystal system. The high-pressure crystal polymorph was shown to be entirely different from the low-temperature crystal polymorph.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Article
Spectroscopy
Hiroshi Abe, Hiroaki Kishimura, Mikio Uruichi
Summary: The crystal polymorphs of fluorinated ionic liquids (fILs) were studied at low temperature, showing a correlation between conformational flexibility and alkyl chain length.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2023)
Article
Chemistry, Physical
Luuk J. G. W. van Wilderen, Larissa Blankenburg, Jens Bredenbeck
Summary: This study utilizes femtosecond-to-millisecond time-resolved mid-infrared spectroscopy to uncover structural details of photocycle intermediates in photoactive yellow protein (PYP), shedding light on the protonation of the chromophore and the formation of the partially unfolded signaling state. The findings suggest that a stable transient photocycle intermediate is formed after a sequence of smaller structural changes, and provide spectroscopic evidence for the delayed protonation of the chromophore compared to the nearby residue E46.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Zhen Wang, Xiaoxiao Cui, Antonino Famulari, Javier Marti-Rujas, Benson M. Kariuki, Fang Guo
Summary: This article reports the synthesis and structural analysis of two additional new polymorphs of a flexible organic molecule using single crystal X-ray diffraction and DFT calculations. The results show that the L beta-phase is the most stable and the L gamma-phase is the least stable. The potential use of conformational polymorphs to prepare second sphere adducts with marked polymorphism is also discussed.
Article
Chemistry, Analytical
Hiroshi Abe, Yoshihiro Koyama, Takahiro Takekiyo, Yukihiro Yoshimura
Summary: The ionic liquid [C6mim][PFBS] exhibited complicated phase transitions under high pressure, which were studied using high pressure Raman spectroscopy. The competition between cation and anion conformers determined the crystal polymorph of [C6mim][PFBS]. The flexible folding cation appeared at 3.7 GPa, while the rigid [PFBS]- anion formed the gauche' conformer at 7.6 GPa for higher packing efficiency.
VIBRATIONAL SPECTROSCOPY
(2023)
Article
Chemistry, Physical
Fowzia S. Alamro, Nada S. Al-Kadhi, Sobhi M. Gomha, Saheed A. Popoola, Muna S. Khushaim, Omaima A. Alhaddad, Hoda A. Ahmed
Summary: New three-ring ester/azomethine homologues series were synthesized and their properties were investigated experimentally and theoretically. The chemical structures of the synthesized compounds were confirmed using various analyses. It was found that all the homologues did not exhibit mesomorphic properties. Theoretical calculations validated the experimental data and discussed the thermal and molecular properties of the compounds.
Article
Biochemistry & Molecular Biology
K. Dileep, Kentaro Ihara, Chiemi Mishima-Tsumagari, Mutsuko Kukimoto-Niino, Mayumi Yonemochi, Kazuharu Hanada, Mikako Shirouzu, Kam Y. J. Zhang
Summary: Alzheimer's disease is a common neurodegenerative disorder in the elderly population, and impairment of the cholinergic system is a critical factor for its progression. Tacrine, as an AChE inhibitor, is promising for restoring cholinergic transmission. This study reveals the atomic level interactions between tacrine and human AChE, providing a mechanistic explanation for its high binding affinity.
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
(2022)
Article
Chemistry, Multidisciplinary
Jasmine Egli, Carmen Esposito, Mike Mueri, Sereina Riniker, Helma Wennemers
Summary: The presence of pendant fatty acids has been found to increase the stability and folding rate of collagen triple helices by interacting with the grooves and creating a molten globule-like intermediate. This interaction accelerates the folding and unfolding process, leading to hyperstability in collagen triple helices.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Jesus L. A. Ponce-Ruiz, Seiya Ishizuka, Yoshikazu Todaka, Yuki Yamada, Armando Reyes Serrato, J. M. Herrera-Ramirez
Summary: Pure CaMgSi was successfully synthesized, displaying small crystallite size, extensive interfaces, and nanoparticles. The material exhibited a small band gap and high thermoelectric performance.
Article
Chemistry, Inorganic & Nuclear
Santarupa Thakurta, Monami Maiti, Ray J. Butcher, Carlos J. Gomez-Garcia, Arshak A. Tsaturyan
Summary: A new trinuclear Ni(s) Schiff base complex was synthesized and characterized, showing a bent structure and weak antiferromagnetic coupling. The study revealed a linear correlation between the J value and certain angles, indicating a mechanism of exchange coupling through bridging groups.
DALTON TRANSACTIONS
(2021)
Article
Chemistry, Physical
Ariadne C. Catto, Marisa C. Oliveira, Renan A. P. Ribeiro, Waldir Avansi Jr, Luis F. da Silva, Elson Longo
Summary: This study investigates the ozone gas-sensing properties of hematite microrhombuses obtained via the hydrothermal method. Experimental results show the sensitivity and long-term stability of the microrhombuses towards O3 gas, while theoretical calculations highlight the importance of surfaces in the adsorption/desorption processes. The presence of (1 0 4) surfaces is found to enhance the sensitivity towards O3 molecules, confirming the experimental findings.
APPLIED SURFACE SCIENCE
(2021)
Article
Thermodynamics
Elena Crespi, Giulio Guandalini, Luca Mastropasqua, Stefano Campanari, Jacob Brouwer
Summary: Electrolysis systems based on low temperature PEM cells are suitable for providing services to the power grid due to their fast ramp rate and load-following capability. This work focuses on the dynamics of integrated components in order to enhance the flexible operation of an industrial-scale PEM electrolysis system. A numerical dynamic model is implemented to solve mass and energy balances during variable load operation, and the model is validated through experimental data. The control of water flowrate to the stack or the hydrogen dryer regeneration are suggested for further improvements of fast-changing load systems.
ENERGY CONVERSION AND MANAGEMENT
(2023)
Article
Chemistry, Multidisciplinary
Se Hwang Kang, Dinesh Thapa, Binod Regmi, Siyuan Ren, Young-Min Kim, Seong-Gon Kim, Sung Wng Kim
Summary: In this study, transition metal-rich monochalcogenides are identified as a new class of low-dimensional electrides with excellent chemical and thermal stability. New two-dimensional electrides are predicted and room-temperature stable electrides have been successfully synthesized. The role of anionic electrons in determining the physical properties of these electrides is also discussed.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)