Article
Chemistry, Physical
M. A. Ambroise, F. Sacchetta, D. Graf, C. Ochsenfeld, A. Dreuw
Summary: A novel local approach is proposed for the quantum-chemical computation of excited states by extending the atomic-orbital formulation to the second-order algebraic diagrammatic construction scheme using Laplace transform. The CDD-DF-SOS-ADC(2) method achieves substantial reduction in computational effort by exploiting the sparsity of two-electron repulsion integrals, atomic ground-state density matrix, and atomic transition density matrix. It is shown that asymptotically linear scaling can be achieved for linear carboxylic acids, and sub-cubic scaling can be achieved for electron-dense systems with sparse transition density. The memory footprint and accuracy of the method are also explored.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Mohyeddine Al-Qubati, Hazem A. Ghabbour, Saied M. Soliman, Eman Alzahrani, Mujeeb A. Sultan
Summary: Two ethanoanthracenes 3 and 5 have been synthesized, crystallized and computationally studied, revealing their crystal structures and molecular packing. The Hirshfeld analysis was used to identify the intermolecular interactions of the crystals, showing different important contacts in the molecular packing of ethanoanthracene 3 and 5. Additionally, the dipole moments, atomic charge distribution, molecular electrostatic potential map and reactivity descriptors of ethanoanthracenes 3 and 5 were reported.
MOLECULAR CRYSTALS AND LIQUID CRYSTALS
(2022)
Article
Chemistry, Physical
David Mester, Mihaly Kallay
Summary: The spin-scaling techniques in the RS-DH method have shown robustness and reduced computational expenses, improving the functional methods and having a broad application scope.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2021)
Article
Engineering, Environmental
Yongjie Fan, Jing Yang, Kaicong Cai, Zhilei Lu, Jiejie Chen, Xingteng Lai, Zeping Xu, Zhenle He, Yuyi Zheng, Changqing Liu, Qiyuan Sun, Rongkun Jian, Feifeng Wang
Summary: In this study, the UV254/Sulfite process was used to remove DOPO flame retardant and it was found that the sulfite concentration had a significant impact on DOPO degradation, with low concentrations having a negative effect and high concentrations enhancing degradation. Additionally, the presence of water matrix in deionized water and natural surface water weakened DOPO degradation.
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
(2022)
Article
Chemistry, Multidisciplinary
Meihui Zhou, Yanji Liu, Dongwei Yao, Yan Jiang, Xinyu Zhang, De-Yi Wang, Na Wang
Summary: The flame retardancy of natural rubber was enhanced by introducing DGENR and EG, although the mechanical properties were decreased.
ARABIAN JOURNAL OF CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Marco Bortoluzzi, Lodovico Agostinis, Stefan Ghincolov, Valentina Ferraro, Giacomo Marra, Jesus Castro
Summary: Under mild conditions, the commercial compound DOPO was converted to related phosphonamidates using a one-pot method. The synthesized compounds, including 6-morpholinodibenzo[c,e][1,2]oxaphosphinine 6-oxide and 6-(methyl(phenyl)amino)dibenzo[c,e][1,2]oxaphosphinine 6-oxide, showed good yields and high purities. The characterization was further supported by single-crystal X-ray structure determination.
Article
Polymer Science
Juanzi Li, Duo Chen, Yunguang Cui, Shichao Li, Yuhuan Yuan, Cong Peng, Jia Yan, Hao Huang, Zhanjun Wu
Summary: The phosphorus-containing epoxy resin ODOPB is compatible with liquid oxygen and has potential as a matrix material for composites used in liquid oxygen tanks. The introduction of ODOPB reduces the generation of free radicals and combustible volatiles, and enhances the char-forming ability of the epoxy resin, which contributes to its compatibility with liquid oxygen.
POLYMER DEGRADATION AND STABILITY
(2022)
Article
Polymer Science
Qibin Xu, Shengchang Zhang, Zexi Su, Dazhe Li, Shuheng Liang, Bo Li, Tingting Lian, Xiangpu Qin, Mengjin Jiang, Pengqing Liu
Summary: In this study, a novel reactive flame retardant DOPOMAH was synthesized to significantly improve the flame retardancy of epoxy resin. The results showed that EP modified by DOPOMAH had good mechanical properties and flame retardancy, which was superior to EP modified by DOPO.
JOURNAL OF APPLIED POLYMER SCIENCE
(2022)
Article
Polymer Science
Michael Weinert, Manfred Doering
Summary: Two novel N-phosphorylated iminophosphoranes with DOPO moieties exhibit distinctive flame-retardant effects in two different epoxy resin systems, with one being more effective in the condensed phase and the other more suitable for the gas phase, depending on the chemical environment.
JOURNAL OF APPLIED POLYMER SCIENCE
(2021)
Article
Polymer Science
Qiuyue Wu, Manuel Jose Lis, Juan P. Hinestroza
Summary: We investigated the performance of cotton fabrics coated with DOPO-HQ and Zr-based Metal-organic Frameworks when exposed to fire. The coated cotton fabrics exhibited shorter combustion times, better thermal degradation properties, promoted the creation of heat-insulating layers, and exhibited improved smoke suppression behavior.
Article
Chemistry, Inorganic & Nuclear
Valentina Ferraro, Jesus Castro, Lodovico Agostinis, Marco Bortoluzzi
Summary: H-phosphinate 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) acts as O-donor ligand towards manganese(II) and zinc(II) halides, forming tetrahedral complexes [MX2(DOPO)2] (M = Mn, X = Cl, Br, I; M = Zn, X = Br). The structure of [ZnBr2(DOPO)2] was determined by X-ray diffraction. The compounds exhibit strong photoluminescence in the solid state, attributed to radiative decay from triplet states of the coordinated DOPO ligands.
INORGANICA CHIMICA ACTA
(2023)
Article
Polymer Science
Yao Xu, Jinhao Sun, Lijun Qian, Juan Li
Summary: The research shows that combining DOPO and PDA can significantly enhance the flame retardancy of epoxy resin and reduce the peak heat release rate. The volatilization of DOPO can quench free radicals and stop combustion. While increasing the amount of PDA/DOPO can raise the glass transition temperature, the aggregation of PDA in EP leads to decreased tensile properties of the composite material.
JOURNAL OF APPLIED POLYMER SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Hyeon-Ho Kang, Dong-Hoon Lee
Summary: Polymer electrolyte membranes with phase-separated hydrophilic and hydrophobic domains, prepared using DOPO-BPA and 1,4-FBB, exhibited lower water uptake and excellent dimensional stability compared to the commercially available Nafion 212 membrane, despite having a relatively high ion-exchange capacity.
Article
Optics
A. H. Ammar, A. A. M. Farag, M. A. Gouda, N. Roushdy
Summary: A novel nanostructured film of CDAPA was prepared and characterized using SEM and XRD techniques. Optical and electrical characteristics were investigated, showing good performance and sensitivity under dark and illumination conditions at 100 mW/cm(2) for potential applications in the field of optoelectronics.
Article
Materials Science, Multidisciplinary
Jinlong Zhuo, Xian Wang, Jingkui Gao, Yupu Wei, Jingquan Sha
Summary: To improve the combustion resistance properties of EVA resin, flame-retardant EVA composites (EVA/HGM/DOPO) were prepared by blending 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) with hollow glass microspheres (HGM). The composites exhibited better flame retardant performance, thermal stability, and smoke suppression performance due to the capture of free radicals by DOPO, promotion of carbonation by HGM, and synergistic effects between HGM and DOPO. Additionally, the composites showed higher thermal stability and improved Young's modulus compared to pure EVA.
Review
Chemistry, Organic
Akhilesh Krishnan, Aitor Diaz-Andres, Keerthy P. Sudhakaran, Athira T. John, Mahesh Hariharan, David Casanova
Summary: Excited state aromaticity is an important area of research, and this review focuses on the aromatic stabilization in spin singlet excimer and through-space aromatic character in triplet excimers of a series of linear [n]acenes. The study investigates the aromatic stabilization profile of singlet benzene excimer formation and the through-space ring current in triplet cofacial excimers. The results provide insights into the (anti)aromatic properties of polycyclic aromatic hydrocarbon excimers and their connection to the electronic structure.
JOURNAL OF PHYSICAL ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Junting Wang, Fernando Gordillo Gamez, Jose Marin-Beloqui, Aitor Diaz-Andres, Xiaohe Miao, David Casanova, Juan Casado, Junzhi Liu
Summary: We report the first bottom-up synthesis of a dicyclohepta[a,g]heptalene-embedded polycyclic conjugated hydrocarbon (PCH) with four continuous heptagons. Compound 1 exhibits a distinct antiaromatic character, especially the inner heptalene core. Furthermore, PCH 1 has a narrower highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy gap compared to its benzenoid counterpart, as confirmed by experimental measurements and theoretical calculations. This work not only provides a new method to synthesize PCHs with non-alternant topologies but also offers the potential to tune their electronic and optical properties.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Mahroof Kalathingal, Young Min Rhee
Summary: Macugen is a therapeutic RNA aptamer that specifically binds to the heparin binding domain (HBD) of VEGF165 to inhibit angiogenesis. Molecular dynamics simulations reveal that Macugen recognizes HBD through an induced-fit mechanism, resulting in major conformational changes in Macugen, while HBD recognizes Macugen through a conformational selection mechanism.
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2023)
Article
Chemistry, Physical
Thomas J. Gately, Roberto A. Boto, Michael J. Tauber, David Casanova, Christopher J. Bardeen
Summary: The structure, spectroscopy, and photochemistry of two compounds, 4-azidobenzoic acid (4ABC) and 4-azido-2,3,5,6-tetrafluorobenzoic acid (4F4ABC), were characterized in frozen glasses and crystals. Photolysis of the parent compounds produced nitrenes and other spin species, with higher yield of triplet nitrene in 4F4ABC and higher yield of quintet nitrene in 4ABC. The stability of the nitrene in the 4F4ABC crystal, with a 1/e lifetime of 20 days at room temperature, provides potential for creating stable, solid-state nitrene samples for applications in spintronics and quantum information science.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Tao Wang, Paula Angulo-Portugal, Alejandro Berdonces-Layunta, Andrej Jancarik, Andre Gourdon, Jan Holec, Manish Kumar, Diego Soler, Pavel Jelinek, David Casanova, Martina Corso, Dimas G. de Oteyza, Jan Patrick Calupitan
Summary: The coupling of a sterically demanded pentacene derivative on Au(111) into fused dimers connected by non-benzenoid rings was studied using high-resolution scanning tunneling microscopy/spectroscopy and density functional theory. The diradical character of the products was tuned by modifying the coupling section, with the antiaromaticity of cyclobutadiene and its position within the structure playing a significant role. Understanding these structure-property relationships is crucial for designing new complex and functional molecular structures.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Multidisciplinary Sciences
Yeon Ju Go, Mahroof Kalathingal, Young Min Rhee
Summary: This study investigated the activation and inactivation process of vascular endothelial growth factor receptor 2 (VEGFR-2) through coarse-grained molecular dynamics simulations. The results showed that the interconversion of helix structures and the change in crossing angle between helices are crucial for the transition from active to inactive TMD form. These findings not only shed light on the activation process of VEGFR-2, but also provide insights into the activation processes of other receptor tyrosine kinases.
Article
Quantum Science & Technology
Luning Zhao, Joshua Goings, Kyujin Shin, Woomin Kyoung, Johanna I. Fuks, June-Koo Kevin Rhee, Young Min Rhee, Kenneth Wright, Jason Nguyen, Jungsang Kim, Sonika Johri
Summary: Variational quantum eigensolvers (VQE) are a promising approach for solving electronic structure problems on near-term quantum computers. In this work, an efficient quantum circuit implementation for orbital-optimized pair-correlated approximation to the unitary coupled cluster with singles and doubles (uCCSD) ansatz is reported. The method recovers additional electron correlation energy without sacrificing efficiency through measurements of low-order reduced density matrices (RDMs). The predicted relative energies across different molecular geometries on trapped-ion quantum computers are in excellent agreement with noise-free simulators.
NPJ QUANTUM INFORMATION
(2023)
Article
Chemistry, Physical
Inkoo Kim, Daun Jeong, Won-Joon Son, Hyung-Jin Kim, Young Min Rhee, Yongsik Jung, Hyeonho Choi, Jinkyu Yim, Inkook Jang, Dae Sin Kim
Summary: We present a high-performance multi-GPU implementation of Kohn-Sham time-dependent density functional theory (TDDFT) within the Tamm-Dancoff approximation. Our algorithm scales optimally with material size on massively parallel computing systems, significantly reducing computational wall time. By performing a benchmark TDDFT study on a large green fluorescent protein complex, we demonstrated the efficiency of our approach, which utilized up to 256 GPUs on a state-of-the-art GPU computing system with Nvidia A100 GPUs. We believe that our GPU-oriented algorithms can enable first-principles simulations for very large-scale applications, leading to a deeper understanding of material behaviors and breakthrough designs.
NPJ COMPUTATIONAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Lanxin Long, Samara Medina Rivero, Fanxi Sun, Dongsheng Wang, Dimitri Chekulaev, Claire Tonnele, David Casanova, Juan Casado, Yonghao Zheng
Summary: A combined experimental and theoretical study was conducted to elucidate the polymerization mechanism of a bisindenedione compound in the solid state. The study revealed the reaction pathway, starting from the formation of a triplet excimer state to an intermolecularly bonded triplet state that initiates the polymerization. Various spectroscopic techniques and quantum chemical calculations were employed to analyze the process. The presented mechanistic insight is valuable for understanding the complexity of this important reaction and for predicting and diversifying the resulting products.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Sven Kahler, Antonio Cebreiro-Gallardo, Pavel Pokhilko, David Casanova, Anna I. Krylov
Summary: Electron paramagnetic resonance (EPR) spectroscopy is an important technique for studying open-shell species. This study describes and benchmarks the state-interaction approach for calculating the coupling between molecular electronic spin and an external magnetic field (g-tensor), using response theory and restricted-active-space configuration interaction wave functions. The analysis confirms the accuracy and applicability of this approach while identifying important considerations.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Physical
Bipeng Wang, Yifan Wu, Dongyu Liu, Andrey S. Vasenko, David Casanova, Oleg V. Prezhdo
Summary: Nonadiabatic molecular dynamics provides important insights into excited-state processes, and practical results can be obtained using short, partially equilibrated ab initio trajectories. This enables rapid exploration of excited-state dynamics for new materials.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Byeong Ki Min, Donggeon Kim, Dongwook Kim, Young Min Rhee
Summary: Understanding nonradiative transition mechanisms is important for designing optoelectronic materials. The correlation function formalism is a useful method for predicting nonradiative rate. Using internal coordinates can improve the reliability of nonradiative rate predictions, especially for transitions involving substantial structural changes.
BULLETIN OF THE KOREAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Aitor Diaz-Andres, Jose Marin-Beloqui, Junting Wang, Junzhi Liu, Juan Casado, David Casanova
Summary: The violation of the Kasha photoemission rule in organic molecules has intrigued chemists. However, the relationship between the molecular structure and anti-Kasha property in organic materials has not been well-established. In this study, a novel strategy is introduced to design organic emitters from high excited states by combining intramolecular J-coupling of anti-Kasha chromophores with the hindering of vibrationally-induced non-radiative decay channels through molecular rigidity. The photophysical properties of a pre-designed chemical derivative are validated by steady fluorescence and transient absorption spectroscopy studies.
Article
Chemistry, Physical
M. E. Sandoval-Salinas, G. Ricci, A. J. Perez-Jimenez, D. Casanova, Y. Olivier, J. C. Sancho-Garcia
Summary: In this work, we investigate the driving force and energy inversion mechanism behind the S-1-T-1 excited-state energy inversion of two non-benzenoid non-alternant hydrocarbons. By utilizing state-of-the-art calculations and post-HF methods, we accurately predict and analyze the delicate interplay between structural and electronic factors that induce inversion. The results obtained highlight the importance of theoretical methods in guiding and rationalizing the search for molecules violating Hund's rule.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Do Hyung Kang, Kwang Hyun Cho, Jinwoo Kim, Han Jun Eun, Young Min Rhee, Sang Kyu Kim
Summary: The nature of electron-binding forces in dipole-bound states of anions was examined through experimental and theoretical investigations. It was found that the conventional charge-dipole electrostatic potential alone could not rationalize the observed autodetachment dynamics. Nonclassical electron correlation and interaction among electrons played a significant role in the binding of excess electrons to the neutral core.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
