Article
Chemistry, Physical
Laura Abella, Adam Philips, Jochen Autschbach
Summary: The behavior of the sodium anion has been found to interact strongly with its chemical environment, isolating the core from the surroundings and appearing as a free ion in NMR experiments.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Federico Sebastiani, Chun Yu Ma, Sarah Funke, Alexander Baumer, Dominique Decka, Claudius Hoberg, Alexander Esser, Harald Forbert, Gerhard Schwaab, Dominik Marx, Martina Havenith
Summary: This study demonstrates the sensitivity of the N-C-C-O open/close mode at 315 cm(-1) as a label-free probe for the local protonation of the amide group using precise terahertz measurements and molecular dynamics simulations. The approach is shown to be more general, as it can also be applied to other amino acids and allows for direct correlation of titration spectra with pK(a) values, showcasing the potential of terahertz spectroscopy for label-free probing of the charge state of natural amino acids in water.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Engineering, Chemical
Peiyu Li, Guannan Li, Wu Xiao, Xuehua Ruan, Xiaoming Yan, Gaohong He, Xiaobin Jiang
Summary: It was found that increasing magnesium ions can alter the hydration structure of cations, affecting the diffusion capability of hydrated ions in the solution, ultimately leading to changes in permeation flux and crystal morphology.
SEPARATION AND PURIFICATION TECHNOLOGY
(2021)
Article
Chemistry, Multidisciplinary
Peng Gao, Xihao Chen, Jiwen Li, Yue Wang, Ya Liao, Shichang Liao, Guangyu Zhu, Yuebin Tan, Fuqiang Zhai
Summary: Density functional theory calculations were used to investigate the electronic structure and hydrogen storage performance of aluminum-doped g-CN material. The results showed that the doped aluminum atoms form chemical bonds and transfer partial charge with pyridinic nitrogen atoms, enabling polarization of H2 molecules and their adsorption. Each supercell can accommodate up to 24 H2 molecules, with a hydrogen storage capacity of 6.15 wt%. The study demonstrates the potential of aluminum-doped g-CN material for efficient hydrogen storage.
Article
Chemistry, Multidisciplinary
Rodolphe Pollet, Wutharath Chin
Summary: The photochemistry of oxocarboxylic acids plays a significant role in atmospheric chemistry. Pyruvic acid, when in the presence of sodium cation or its conjugate base, shows altered hydration equilibrium and photosensitivity to UV-visible light. Through ab initio metadynamics simulation, we reveal the reversible hydration reaction mechanism between the keto and diol forms of pyruvic acid, influenced by sodium, and provide insights into the photoactivity of these forms in the actinic region through calculations of electronic transition energies.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Physical
Dmitry A. Fedorov, Matthew J. Otten, Stephen K. Gray, Yuri Alexeev
Summary: The paper introduces a method for running AIMD simulations on NISQ-era quantum computers, utilizing numerical calculation of energy gradients and correlated sampling technique with additional classical computations. The method has been successfully demonstrated for the H2 molecule on IBM quantum devices, and shown to be valid for larger molecules using full configuration interaction wave functions as quantum hardware and noise mitigation techniques improve.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Multidisciplinary Sciences
Feihong Chu, Xianlin Qu, Yongcai He, Wenling Li, Xiaoqing Chen, Zilong Zheng, Miao Yang, Xiaoning Ru, Fuguo Peng, Minghao Qu, Kun Zheng, Xixiang Xu, Hui Yan, Yongzhe Zhang
Summary: The authors design a hybrid interface by tuning the pyramid apex-angle to improve the interfacial morphology of c-Si/a-Si:H in silicon solar cells. This hybrid interface prevents both c-Si epitaxial growth and nanotwin formation, leading to improved interfacial morphology. This method can be widely applied to all silicon-based solar cells without any additional industrial preparation processes.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Anatoly B. B. Belonoshko, Grigory S. S. Smirnov
Summary: Iron is the main component of Earth's core and exoplanetary cores. The crystal structure of iron under extreme conditions of high pressure and temperature is still unknown. Experimental data and simulations have contradictory results regarding the stability of different phases of iron. By using large-scale ab initio molecular dynamics simulations, this study compared the properties of iron phases at experimental conditions to provide a potential explanation for the experimental observations.
Article
Materials Science, Multidisciplinary
Luke J. Wirth, Christopher Woodward, Amir A. Farajian
Summary: Advances in first principles methods are used to study the atom-vacancy exchanges near a screw dislocation in fcc Ni, revealing direction-dependent free energy profiles and temperature-dependent correlation effects. The dynamic approach shows intra-cell energy profile asymmetry related to dynamic geometry rearrangements. Despite absolute values of rate constants being similar, the HTST method generally underestimates rates by a factor of 2-5, partially explaining discrepancies between theoretical works and experiments in pipe diffusion diffusivities.
Article
Chemistry, Physical
Debbie Zhuang, Marc Riera, Ruihan Zhou, Alexander Deary, Francesco Paesani
Summary: The study systematically investigated the hydration structure of Na+ and K+ ions in solution by progressively including many-body effects derived from the many-body expansion of the energy. It found that MB-nrg potential energy functions achieved nearly quantitative agreement with the experimental EXAFS spectra, providing accurate models for predicting properties of ionic aqueous systems from gas to liquid phase.
JOURNAL OF PHYSICAL CHEMISTRY B
(2022)
Article
Chemistry, Multidisciplinary
J. Patrick Zobel, Anna M. Wernbacher, Leticia Gonzalez
Summary: The mechanism of reverse intersystem crossing (rISC) in metal-based TADF emitters is still not clear, as the small singlet/triplet energy gaps necessary for thermal rISC in donor-acceptor systems with charge-transfer excited states have spin-orbit couplings that are too small for effective rISC. In this study, the first nonadiabatic dynamics simulation of rISC process in a carbene-copper(I)-carbazolyl TADF emitter is reported. Efficient rISC on a picosecond time scale is demonstrated, involving an intermediate higher-lying triplet state of metal-to-ligand charge transfer character ((MLCT)-M-3) that enables large spin-orbit couplings with the lowest singlet charge transfer state. The mechanism is completed in the S-1 state where the complex can return to a co-planar coordination geometry with high fluorescence efficiency.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Neha Yadav, T. J. Dhilip Kumar
Summary: Heteroatom doping into 2-dimensional lattices of materials, such as graphene, brings remarkable properties and finds wide applications in fields such as batteries.
NEW JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Physical
Seongchul Park, Juhyang Shin, Hojeong Yoon, Manho Lim
Summary: The rotational isomerization of 1,2-disubstituted ethyl radical derivatives in solution has been investigated, and the rotational time constants have been measured. This finding contributes to a better understanding of the reaction mechanism involving these radicals and provides insights into the formation of stereoisomers of compounds produced via the intermediates.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Swaroop Chandra, Nandalal Mahapatra, Nagarajan Ramanathan, Kalyanasundaram Sundararajan
Summary: This study reexamines the geometries of nitromethane homodimers and presents concrete evidence for the prevalence of O=N center dot center dot center dot O pnicogen bonding, contrary to previous claims. The formation of a nitromethane dimer with pnicogen bonding stabilization is confirmed using matrix isolation infrared spectroscopy and computations. The study also characterizes the interactions within homodimers using various methods, highlighting the prevalence of hydrogen and pnicogen bonds.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Chemistry, Physical
Li-Zhen Sun, Jun-Lin Qian, Pinggen Cai, Xiaojun Xu
Summary: The ion-dependence of ssDNA conformational changes under mixed Na+/Mg2+ ion conditions is investigated using Langevin dynamics simulations. A novel simulation model combining MCC theory and MCTBI model is developed to describe the ion-concentration-dependent and ssDNA conformation/structure-dependent electrostatic effects. The simulation results are validated against experimental results and reveal a quantitative relationship between ssDNA conformation and Na+-Mg2+ competition.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Xing Huang, Shuai Fu, Cong Lin, Yang Lu, Mingchao Wang, Peng Zhang, Chuanhui Huang, Zichao Li, Zhongquan Liao, Ye Zou, Jian Li, Shengqiang Zhou, Manfred Helm, Petko St. Petkov, Thomas Heine, Mischa Bonn, Hai I. Wang, Xinliang Feng, Renhao Dong
Summary: In this study, a strategy for synthesizing high-mobility semiconducting conjugated coordination polymers (c-CPs) using novel conjugated ligands with D2h symmetry was demonstrated. The reduced symmetry of the 4 + 2 ligands compared to conventional phenyl ligands led to anisotropic coordination in the formation of c-CPs. A single-crystalline three-dimensional (3D) c-CP Cu4DHTTB with orthogonal ribbon-like pi-d conjugated chains was successfully achieved. This c-CP exhibited a small band gap, dispersive energy bands, and high charge carrier mobilities, laying the foundation for high-performance c-CP-based (opto-)electronics.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Review
Chemistry, Multidisciplinary
Irena Senkovska, Volodymyr Bon, Leila Abylgazina, Matthias Mendt, Jan Berger, Gregor Kieslich, Petko Petkov, Jhonatan Luiz Fiorio, Jan-Ole Joswig, Thomas Heine, Larissa Schaper, Christopher Bachetzky, Rochus Schmid, Roland A. A. Fischer, Andreas Poeppl, Eike Brunner, Stefan Kaskel
Summary: Flexible porous frameworks are a cutting-edge area of materials research due to their ability to adaptively open and close pores induced by chemical and physical stimuli, offering a wide range of functions. However, the factors influencing the switchability are still poorly understood, including the role of building blocks, crystal size, defects, cooperativity, and host-guest interactions. This review discusses an integrated approach using idealized model materials to systematically investigate and understand the critical factors affecting framework dynamics, leading to progress in their understanding and application.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Lukas Sporrer, Guojun Zhou, Mingchao Wang, Vasileios Balos, Sergio Revuelta, Kamil Jastrzembski, Markus Loeffler, Petko Petkov, Thomas Heine, Angieszka Kuc, Enrique Canovas, Zhehao Huang, Xinliang Feng, Renhao Dong
Summary: By designing a new organic ligand (OHPTP), the first rhombic 2D metal-organic framework single crystals (Cu-2(OHPTP)) were synthesized. This material is a p-type semiconductor with an indirect band gap of approximately 0.50 eV, and exhibits high electrical conductivity and charge carrier mobility. Theoretical calculations confirm the predominant role of out-of-plane charge transport in this semiquinone-based 2D metal-organic framework.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Shengxu Li, Yikun Geng, Bo Teng, Shunqi Xu, Petko Stoev Petkov, Zhongquan Liao, Birgit Jost, Yu Liu, Xinliang Feng, Bozhen Wu, Tao Zhang
Summary: A novel pyrylium cation contained two-dimensional covalent organic framework (v-2D-COF-O1) with narrow band gap and wide-range light absorption was synthesized. Under simulated sunlight, v-2D-COF-O1 can activate molecular oxygen and generate highly reactive oxygen species, leading to efficient organic waste decomposition and water disinfection. This suggests the potential of v-2D-COFs as high-performance photocatalysts for water purification.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Physical
Eddy Dib, Svetlana Mintova, Georgi N. Vayssilov, Hristiyan A. Aleksandrov, Marina Carravetta
Summary: By using a combination of symmetry-based recoupling in 29Si NMR, spin dynamics-based simulations, and DFT-based theoretical calculations, we demonstrate how to characterize the 29Si NMR peaks of (Si-O-Si), Bronsted acid sites (Si-OH-Al), and silanols (Si-OH) in nanosized ZSM-5 zeolites. Theoretical calculations and experimental observations reveal significant differences in the chemical shift anisotropy for silicon nuclei close to aluminum (Q(4)(1Al)) compared to those which are not, allowing for clear assignment of Si-29 NMR peaks. The isotropic chemical shift alone cannot differentiate these differences.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Nikola L. Drenchev, Elena Z. Ivanova, Mihail Y. Mihaylov, Hristiyan A. Aleksandrov, Georgi N. Vayssilov, Konstantin I. Hadjiivanov
Summary: To design efficient CO2 capture materials, it is important to ensure a high adsorption capacity. We have recently discovered that one Na+ site in NaY zeolite can attach two CO2 molecules, but the process occurs at a low temperature and is not suitable for practical use. We have now found that one Ca2+ site in CaNaY zeolite can attach three CO2 molecules, making it a promising material for CO2 capture.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Iskra Z. Koleva, Hristiyan A. Aleksandrov, Georgi N. Vayssilov
Summary: The mechanism of CO oxidation on platinum species supported on ceria or alumina was investigated using periodic density functional calculations. Various reaction paths involving different oxidation states of monoatomic species and platinum clusters were modeled to identify the catalytically active species. The calculations revealed that the reaction paths via Pt2+ and Pt4+ cations had the lowest activation barriers, while those involving Ce4+ cations had significantly higher barriers. The results provide insights into the role of oxidants in CO oxidation on platinum species supported on ceria or alumina.
Article
Chemistry, Multidisciplinary
Edwin B. Clatworthy, Simona Moldovan, Kalthoum Nakouri, Stoyan P. Gramatikov, Francesco Dalena, Marco Daturi, Petko St. Petkov, Georgi N. Vayssilov, Svetlana Mintova
Summary: This study directly visualizes the structural flexibility of a high-aluminum nano-sized RHO zeolite using in situ TEM for the first time. Variable temperature experiments observe the physical expansion of nanocrystals in response to changes in guest-molecule chemistry and temperature. Operando FTIR spectroscopy complements the observations and verifies the nature of adsorbed CO2 and structural changes at high temperatures. Quantum chemical modeling substantiates the effect of cation mobility and CO2 on the flexibility behavior of the structure. The results demonstrate the combined influences of temperature and CO2 on the structural flexibility consistent with experimental observations.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Applied
Peng Peng, Simona Moldovan, Aurelie Vicente, Valerie Ruaux, Maxime Debost, Han Hu, Hristiyan A. Aleksandrov, Georgi N. Vayssilov, Zi-Feng Yan, Svetlana Mintova
Summary: Nanosized MFI type zeolites were synthesized using Cu-containing complexes. The use of EDTA as a ligand promoted solubility and ensured exclusive configuration of copper-bearing chelate. EDTA-assisted MFI zeolite nanocrystals (Cu-MFIEDTA) had low silanol content due to flexible Si-O-Cu bonds. NH3 as a ligand resulted in extra framework [Cu delta+,,,O delta- ,,,Cu delta+]n clusters in the corresponding sample (Cu-MFI-NH3).
MICROPOROUS AND MESOPOROUS MATERIALS
(2023)
Article
Chemistry, Medicinal
Violina Angelova, Borislav Georgiev, Tania Pencheva, Ilza Pajeva, Miroslav Rangelov, Nadezhda Todorova, Dimitrina Zheleva-Dimitrova, Elena Kalcheva-Yovkova, Iva Valkova, Nikolay Vassilev, Rositsa Mihaylova, Denitsa Stefanova, Boris Petrov, Yulian Voynikov, Virginia Tzankova
Summary: This study developed novel hybrid molecules targeting the key pathogenetic mechanisms of Alzheimer's disease (AD). The lead compounds exhibited promising multifunctional activity against AD-related neurodegenerative mechanisms, including inhibition of acetylcholinesterase (AChE), strong antioxidant activity, and protection against oxidative stress. These compounds also demonstrated low neurotoxicity and the ability to penetrate the blood-brain barrier, making them potential prototypes for the treatment of AD-associated neurodegeneration with oxidative stress.
Article
Chemistry, Physical
Eric Assen B. Kantchev, Petko S. Petkov
Summary: A full-DFT Born-Openheimer MD study was conducted to investigate the hydrogen bonding between 2-cyclohexenone and Rh(i) in explicit 1,4-dioxane. The results showed that the ketone O atom persistently acted as a hydrogen bond acceptor, while the donor was mobile and exchangeable. Model static DFT studies revealed that the hydrogen bonding with (H2O)3 cluster and H3BO3 was favorable in enthalpy but unfavorable in free energy when the entropy term was considered.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Iskra Z. Koleva, Hristiyan A. Aleksandrov, Georgi N. Vayssilov
Summary: The mechanism of CO oxidation on platinum species supported on ceria or alumina was investigated using periodic density functional calculations. Various reaction paths involving different oxidation states of monoatomic species-Pt0, Pt2+, and Pt4+-as well as platinum clusters were modeled to understand the nature of the catalytically active species. The activation barriers of the reaction paths involving complexes of Pt2+ and Pt4+ cations were found to be the lowest, ranging from 22 to 35 kJ/mol. The calculations also revealed that the activation energies for platinum clusters with high CO coverage supported on ceria were low, while those on gamma-alumina or involving preadsorbed oxygen on the platinum cluster were significantly higher, ranging from 90 to 120 kJ/mol. The role of the oxidant in the reaction paths was discriminated, indicating that the activation barriers are low when the oxidants are platinum species and notably higher when the oxidants are Ce4+ cations.
Article
Chemistry, Physical
Nikola L. Drenchev, Elena Z. Ivanova, Mihail Y. Mihaylov, Hristiyan A. Aleksandrov, Georgi N. Vayssilov, Konstantin I. Hadjiivanov
Summary: In order to design efficient CO2 capture materials, a high adsorption capacity is necessary. It has been found that one Na+ site in NaY zeolite can attach two CO2 molecules, while one Ca2+ site in CaNaY zeolite can attach three CO2 molecules. The results show that CaY zeolites can be very effective CO2 capture materials, with the potential for practical use.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Xing Huang, Shuai Fu, Cong Lin, Yang Lu, Mingchao Wang, Peng Zhang, Chuanhui Huang, Zichao Li, Zhongquan Liao, Ye Zou, Jian Li, Shengqiang Zhou, Manfred Helm, Petko St Petkov, Thomas Heine, Mischa Bonn, Hai I. Wang, Xinliang Feng, Renhao Dong
Summary: This study demonstrates a strategy for synthesizing high-mobility semiconducting coordination polymers (c-CPs) using novel conjugated ligands with reduced symmetry. The synthesized c-CPs exhibit a small band gap, dispersive energy bands, and high charge carrier mobilities, outperforming previously reported conductive coordination polymers. This molecular design strategy lays the foundation for achieving high-performance c-CP-based (opto-)electronics.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Teodor Milenov, Dimitar Trifonov, Dobromir A. Kalchevski, Stefan Kolev, Ivalina Avramova, Stoyan Russev, Kaloyan Genkov, Georgi Avdeev, Dimitar Dimov, Desislava M. Karaivanova, Evgenia Valcheva
Summary: Different nano-sized phases, including diamond and multilayered graphene, were synthesized using chemical vapor deposition. The deposition process was found to be influenced by the chemical ratios, resulting in visually distinct layers with different properties.