Article
Chemistry, Physical
S. S. Setayandeh, E. G. Obbard, J. Stansby, D. Frost, Jack O. Astbury, C. L. Wilson, P. A. Burr
Summary: There is no consensus on the structure and composition of the epsilon phase in the W-B system. Ab initio calculations and experimental comparisons suggest that the epsilon phase is most likely a hypo-stoichiometric W2B5-x compound.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Physical
Ander Camiruaga, Rizalina Tama Saragi, Fernando Torres-Hernandez, Marcos Juanes, Imanol Usabiaga, Alberto Lesarri, Jose A. Fernandez
Summary: Gas-phase spectroscopic studies of alcohol clusters are important for understanding the influence of non-covalent interactions on molecular recognition and modeling supramolecular and biological chemical processes. In this study, a multi-methodological gas-phase approach combining microwave spectroscopy and mass-resolved electronic and vibrational laser spectroscopy was used to examine the role of the aliphatic side chain in the self-aggregation of aromatic alcohols. The results show that the conformational landscape of the clusters is shallow and multiple competing isomers are present, indicating a tendency for cyclic hydrogen bond structures during cluster growth.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Gabriel L. Murphy, Zhaoming Zhang, Helen E. Maynard-Casely, Joshua Stackhouse, Piotr M. Kowalski, Thomas Vogt, Evgeny Alekseev, Brendan J. Kennedy
Summary: A combined experimental and theoretical investigation was conducted to study the compressibility of two SrUO4-x polymorphs (alpha and fi) under hydrostatic conditions. The study explains the contrasting chemical and mechanical behaviors of these polymorphs by differences in oxygen defect formation chemistry. The experimental data and ab initio calculations revealed that the expansion of the uranyl bonds in alpha-SrUO4 and fi-SrUO4 under hydrostatic pressures is due to the reduction of uranium formal oxidation state and the formation of oxygen vacancies. The difference in preferred lattice sites for oxygen defect formation leads to the significant difference in apparent bulk moduli between the two polymorphs.
Article
Chemistry, Multidisciplinary
Aamir Iqbal Waidha, Humera Khatoon Siddiqui, Yuji Ikeda, Maren Lepple, Sami Vasala, Manuel Donzelli, A. D. Fortes, Peter Slater, Blazej Grabowski, Ulrike Kramm, Oliver Clemens
Summary: A new anion-deficient perovskite material with unique oxygen vacancy ordering has been synthesized through a two-step heating process, showing G-type antiferromagnetic ordering confirmed by neutron powder diffraction, magnetic measurements, and DFT studies. The compound exhibits a high electronic conductivity and remarkable bifunctional catalytic activity, comparable to that of Ba0.5Sr0.5Co0.8Fe0.2O3-y, making it a promising candidate for efficient catalysts in oxygen-related reactions.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Milan R. Milovanovic, Ivana M. Stankovic, Jelena M. Zivkovic, Dragan B. Ninkovic, Michael B. Hall, Snezana D. Zaric
Summary: By analyzing water-water contacts in crystal structures, various attractive interactions including classical hydrogen bonds and antiparallel dipolar interactions have been discovered. The study suggests that the geometric criteria for defining attractive water-water interactions should be broader.
Article
Materials Science, Multidisciplinary
Quoc Duy Ho, Eva Rauls
Summary: In this study, the adsorption behaviors of NO, NH3, CO, and NO2 on Pillar[5]arenes (P[5]A) were investigated using DFTB and DFT calculations. The results showed that P[5]A structures can adsorb these gases at both the cavity site and OH group, facilitated by it-it interactions and hydrogen bonding. The findings provide valuable insights for the targeted design and optimization of P[5]A for effectively capturing toxic gases.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Qian-Rui Huang, Ryunosuke Shishido, Chih-Kai Lin, Chen-Wei Tsai, Jake A. Tan, Asuka Fujii, Jer-Lai Kuo
Summary: The study analyzed the infrared spectra of a series of asymmetric proton-bound dimers with protonated trimethylamine as the proton donor, revealing a red shift in the N-H+ stretching mode frequency as the proton affinity of acceptors increases. Despite the expected pattern, the observed band showed a peculiar splitting of around 300 cm(-1) with intensity resembling a two-level system. Theoretical investigation attributed this band splitting to strong coupling between the proton stretching mode and overtone states of proton bending modes, known as Fermi resonance, providing a general theoretical model linking the strong coupling to a quasi-two-level system intrinsic to proton motions.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Yuehui Li, Yantao Shi, Xuedan Song, Zhengyan Zhao, Naitian Zhang, Ce Hao
Summary: In this study, the state and dynamic equilibrium of glycolaldehyde in methanol solution were systematically investigated. It was found that glycolaldehyde hemiacetal (GAHA) is the dominant component in methanol solution, with more than 90% abundance. The study provides important insights into the analysis of sugars and related compounds in biochemical reactions.
NEW JOURNAL OF CHEMISTRY
(2021)
Article
Materials Science, Multidisciplinary
Hou -Bo Zhou, Zi-Bing Yu, Feng-xia Hu, Jian-Tao Wang, Fei-Ran Shen, Jia-Zheng Hao, Lun-Hua He, Qing-Zhen Huang, Yi-Hong Gao, Bing-Jie Wang, Zhuo Yin, Zheng-Ying Tian, Jing Wang, Yun-Zhong Chen, Ji-Rong Sun, Tong-Yun Zhao, Bao-Gen Shen
Summary: This study reports the emergence of the Invar effect with excellent mechanical properties by modulating the electronic structure in LaFe11.6-xCoxSi1.4. The site occupancy of Co atoms was determined using neutron and X-ray diffraction, and ab initio calculations were performed to study the electronic band structure. The results show that the incorporation of Co atoms inhibits spontaneous magnetostriction and enhances the Invar effect in the ferromagnetic region of LaFe10.6Co1.0Si1.4.
Article
Chemistry, Physical
Hayden T. Robinson, Christian T. Haakansson, Timothy R. Corkish, Peter D. Watson, Allan J. McKinley, Duncan A. Wild
Summary: Hydrogen bonding and halogen bonding, two important non-covalent interactions, are widely found in proteins and crystal structures. This study examines their strengths and interactions in small gas-phase chemical species, providing fundamental insights. Anion photoelectron spectra are used to determine the stabilisation energy and electron binding energy of bromide complexes with chloromethanes. High-level CCSD(T) calculations are then used to rationalise the spectra and compare hydrogen bonding and halogen bonding.
Article
Chemistry, Multidisciplinary
Sarvesh Kumar Pandey, Elangannan Arunan
Summary: The study explores the impact of OH/SH substituents on the stability and aromaticity of benzene rings, acting as modulators when forming intramolecular hydrogen bonds. Different OH/SH substituents forming intramolecular hydrogen bonds play a vital role in modulating the aromaticity, with varying effects on the cyclic 4n+2 pi-electron delocalization. The aromaticity indices show small variations, indicating the modulatory effect of the pi-electron structure based on the substituent effect through intramolecular hydrogen bond formation.
Article
Chemistry, Multidisciplinary
Daniel A. Decato, Asia Marie S. Riel, James H. May, Vyacheslav S. Bryantsev, Orion B. Berryman
Summary: This paper experimentally quantifies a Hydrogen Bond-Enhanced Halogen Bond (HBeXB) for the first time, showing that electron-rich halogen bond donors are strengthened most by an adjacent hydrogen bond, and stronger hydrogen bond donors enhance the halogen bond the most. X-ray crystal structures and F-19 NMR titrations support the findings, laying the foundation for future studies on hydrogen bonds and halogen bonds in close proximity.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Crystallography
Nicolas Zapp, Denis Sheptyakov, Holger Kohlmann
Summary: Heteroanionic hydrides show great potential in functional materials design. By employing solid-state reactions, the cubic rare earth hydride oxides DyHO, ErHO, and LuHO were synthesized, each exhibiting unique crystal structures. Computational chemistry studies suggest that the formation of REHO compounds for smaller rare earth elements is less favorable compared to sesquioxides, requiring mild synthesis conditions for their synthesis.
Article
Materials Science, Multidisciplinary
J. Kong, S. K. Nayak, K. Co, S. Nayak, J. Wu, A. Feteira, K. A. Beyer, S. P. Alpay, A. Pramanick
Summary: The study utilized x-ray pair distribution function and density functional theory calculations to characterize the structure of cation-oxygen divacancy pairs in a Dion-Jacobson (D-J) layered perovskite, uncovering the relationship between local structural distortions and dielectric properties. The findings suggest that controlling atomic defects could potentially lead to significant control of dielectric properties in D-J layered perovskites.
Article
Chemistry, Physical
Leszek M. Malec, Mateusz Z. Brela, Katarzyna M. Stadnicka
Summary: This work investigates the dynamic character of hydrogen-bond networks in two three-component crystals comprising polycationic chains. X-ray diffraction measurements and molecular dynamics computations were used to study the hydrogen-bond systems in both crystals, revealing proton transfer phenomena occurring at 300 K.
Article
Chemistry, Physical
Mariela M. Nolasco, Paulo J. A. Ribeiro-Claro, Pedro D. Vaz
Summary: The structure and dynamics of crystalline 4-(dimethylamino) benzaldehyde (4DMAB) were studied using INS spectroscopy combined with periodic DFT calculations. The experimental and calculated spectra showed excellent agreement, allowing for reliable assignment of INS bands. The simulated spectrum accurately described the external phonon modes and low-frequency molecular vibrations. Crystal field splitting was observed for modes assigned to the dimethylamino group. The torsional motion of methyl groups was analyzed, and specific methyl groups were identified based on four individual bands. The torsional frequencies of these methyl groups fell within a range similar to that observed for methyl groups bonded to unsaturated carbon atoms. The hybridization state of the X atom in X-CH3 seemed to be crucial in determining the methyl torsional frequency.
Article
Physics, Multidisciplinary
Mariela M. Nolasco, Sonia N. Pedro, Carla Vilela, Pedro D. Vaz, Paulo Ribeiro-Claro, Svemir Rudic, Stewart F. Parker, Carmen S. R. Freire, Mara G. Freire, Armando J. D. Silvestre
Summary: This work investigates the effect of water on the physicochemical properties of deep eutectic solvents using inelastic neutron scattering spectroscopy. The results show that quenching samples in liquid nitrogen can retain the liquid phase morphology of DES at low temperatures. The preference of water molecules to bind to chloride anion is observed in the three studied systems, but they also present distinct features related to their unique properties and structure at the molecular level.
FRONTIERS IN PHYSICS
(2022)
Article
Biochemistry & Molecular Biology
Mariela M. Nolasco, Mariana Matos Coimbra, Stewart F. Parker, Pedro D. Vaz, Paulo J. A. Ribeiro-Claro
Summary: By comparing experimental and simulated spectra, the structural dynamics of chloromethanes were accurately evaluated, allowing for confident assignment of vibrational features including fundamental modes, lattice and combination modes. The overall excellent agreement between experimental and calculated spectra, particularly in describing the overtone sequence for CHCl3, was achieved.
Article
Chemistry, Multidisciplinary
Mariana M. Coimbra, Ines Martins, Sofia M. Bruno, Pedro D. Vaz, Paulo J. A. Ribeiro-Claro, Svemir Rudic, Mariela M. Nolasco
Summary: The unique properties of Egyptian blue, a cuprorivaite pigment, were studied using computational and experimental methods. A reliable model of the crystal was obtained, allowing for the evaluation of its lattice dynamics and properties. Inelastic neutron scattering and infrared spectroscopies provided information on the chemical surfaces of the pigment, confirming the simulation results.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Medicine, Legal
Ines Oliveira-Santos, Ricardo A. M. P. Gomes, Catarina Coelho, Francisco Gil, Eugenia Cunha, Isabel Poiares Baptista, Maria Teresa Ferreira
Summary: Access to better health care leads to the discovery of more medical devices near skeletal remains. Dental prostheses made of copper-aluminium alloys have been popular since the 1980s in the USA, Japan, and Eastern Europe. This study aimed to determine the elemental composition of a dental prosthesis alloy, and analysis showed higher levels of copper and aluminium, with no gold or palladium detected.
INTERNATIONAL JOURNAL OF LEGAL MEDICINE
(2023)
Article
Chemistry, Physical
Catarina F. Araujo, Paulo Ribeiro-Claro, Pedro D. Vaz, Svemir Rudic, Rafael A. F. Serrano, Liliana P. Silva, J. A. P. Coutinho, Mariela M. Nolasco
Summary: This study investigates the behavior of deep eutectic solvents (DES) using inelastic neutron scattering (INS) spectroscopy. By calculating the vibrational modes of pure compounds and analyzing the spectra of binary mixtures, deviations from ideality in the mixtures of tetraalkylammonium salts with urea are observed. Unlike other systems, the deviation from ideality in the deep eutectic system comprised of [N2,2,2,1]Cl and urea is attributed to entropic rather than enthalpic factors.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Biochemistry & Molecular Biology
Mariela M. Nolasco, Stewart F. Parker, Pedro D. Vaz, Paulo J. A. Ribeiro-Claro
Summary: In this study, a computational spectroscopy approach was used to analyze the inelastic neutron scattering spectra of three alkoxysilane derivatives. The results showed that incorporating non-covalent interactions in the theoretical model improved the description of the experimental band profiles. However, when considering optical vibrational techniques, the monomer model provided a reasonable description and no significant changes were observed with dimer and trimer models.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Chemistry, Multidisciplinary
Ines J. Marques, Pedro D. Vaz, Ana V. Girao, Mariela M. Nolasco, Carla D. Nunes
Summary: Silica-coated iron oxide and silica nanoparticles were prepared and derivatized with a europium complex to yield magneto-fluorescent and fluorescent nanomaterials. The fluorescence was enhanced by the anchored europium complex and maintained in cellular medium. These nanomaterials have potential applications as biosensors and in imaging.
NEW JOURNAL OF CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Mario R. Felicio, Pedro D. Vaz, Carla D. Nunes, Mariela M. Nolasco
Summary: In this study, novel Eu and Tb lanthanide complexes and their binuclear counterparts with Cu as the secondary metal were prepared and investigated for their potential applications as probes and cancer inhibitors. The results showed that the bimetallic complexes were more effective in promoting cancer cell death and sequestering Cu from the tumoral environment. Structural characterization and spectroscopic analysis were performed to reveal the properties of these complexes. Experimental data confirmed that the mononuclear complexes exhibited fluorescence and could sequester Cu ions. Cell viability tests demonstrated that these complexes induced cell death in breast and lung adenocarcinoma cancer cell lines. Overall, these complexes have significant potential as bioprobes and anticancer agents.
NEW JOURNAL OF CHEMISTRY
(2022)
