Article
Chemistry, Organic
Chinatsu Otake, Takuya Namba, Hidetsugu Tabata, Kosho Makino, Kiriko Hirano, Tetsuta Oshitari, Hideaki Natsugari, Takenori Kusumi, Hideyo Takahashi
Summary: 2'-Fluoro-substituted acetophenone derivatives preferentially adopt s-trans conformations in solution, with coupling constants linearly correlated to the dielectric constant of the solvents. The confirmation of these s-trans conformations by X-ray crystallography and DFT calculations further support this preference.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Xiaokun Zhang, Xiuqing Song, Jiwen Shi, Hong Yan, Nana Tian
Summary: The photocycloaddition of 1,4-dihydropyridines (1,4-DHPs) is a main approach for synthesizing structurally complex compounds, which serve as important intermediates for the preparation of cage compounds. This study aimed to investigate the effect of the structural characteristics on the chemoselectivity in [2 + 2]/[3 + 2] photocycloaddition of 1,4-DHPs. The research found that steric hindrance and chirality at specific positions in 1,4-DHPs play crucial roles in determining the chemoselectivity of the reaction.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Daniel N. S. Rodrigues, Paulo R. Olivato, Patrick R. Batista, Lucas C. Ducati, Maurizio Dal Colle
Summary: The conformational equilibrium of 2-(2'-ethylsulfanyl)acetyl-5-substituted furans and thiophenes was determined using infrared analysis and molecular dynamics simulations. Six stable conformations were obtained, and their characterization was achieved using IR spectra in different solvents. The conformational preferences are governed by a balance between orbital and coulombic interactions.
JOURNAL OF MOLECULAR STRUCTURE
(2022)
Article
Multidisciplinary Sciences
Josie Chen, Tai-Sen He, Hsin-Ya Liao
Summary: This study experimentally examines the impact of speech rate on intertemporal decisions. The overall treatment effect of the acoustic manipulation was not found in our research.
Article
Chemistry, Physical
He Bian, Fang Xu, Aiting Kan, Shengchao Wei, Huiming Zhang, Shiguo Zhang, Lijun Zhu, Daohong Xia
Summary: This research reveals the mechanism of asphaltene disaggregation by alkylated treatment through experimental and theoretical methods. The study shows that alkylated treatment can effectively disaggregate asphaltenes and delay their reaggregation. Molecular dynamics simulations confirm these findings. The research also explores the impact of different side-chains on asphaltene disaggregation and the role of solvents in affecting this behavior.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Article
Chemistry, Applied
Hsin-Yueh Chang, Lien-Chen Fu, He-Shin Huang, Yao-Chun Yeh, Mei-Yu Yeh
Summary: Diabetes is a global public health issue with significant consequences for daily functioning and health. A glucose sensor based on hydrazide-hydrazone phenyl-boronic acid (PBA) molecules has been developed, which does not require alkaline agents. Compound 3a showed high sensitivity to glucose due to intramolecular Lewis acid-base interactions, while compound 3c demonstrated selective glucose detection through intermolecular Lewis acid-base interactions.
Article
Chemistry, Applied
Merve Guzel, Eylem Celik, Sevgi Ozdemir Kart, Pinar Tunay Tasli, Erhan Karatas, Metin Ak
Summary: This study compares the structural and electrochemical properties of newly synthesized N-substituted carbazole monomers with different aniline derivatives using a combination of experimental and computational methods. The substitution of fluorine atoms leads to an anodic shift in the oxidation potential, and the poly(E)-N-(4-(9H-carbazol-9-yl) benzylidene) aniline (PACA) polymer film exhibits better optical contrast, response time, and electrochemical stability.
REACTIVE & FUNCTIONAL POLYMERS
(2022)
Article
Chemistry, Medicinal
Ariadni Zianna, George Geromichalos, Augusta-Maria Fiotaki, Antonios G. Hatzidimitriou, Stavros Kalogiannis, George Psomas
Summary: Five palladium complexes with substituted salicylaldehydes were synthesized and characterized. These complexes exhibited antioxidant and antibacterial activities, and showed strong interactions with DNA.
Article
Chemistry, Organic
Adam J. Youman, Samantha N. Rokey, Jacob P. Grabowski, Wentao Guo, Qing Sun, Susanna N. Angles, John R. Goodell, Dean J. Tantillo, T. Andrew Mitchell
Summary: The reactivity of silyloxypyrone-based (5 + 2) cycloadditions was found to be highly dependent on the dipolarophile. Neutral alkenes were least reactive, while both electron-deficient and electron-rich dipolarophiles showed higher reactivity, indicating the presence of ambident oxidopyrylium intermediates. Qualitative rate studies, Hammett linear free energy relationships, and theoretical calculations revealed a spectrum of reactivity that encompasses both concerted and stepwise pathways.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Engineering, Mechanical
Zhongliang Xie, Jian Jiao, Tao He, Fangcheng Xu, Jianbo Zhang
Summary: This paper investigates the lubrication mechanisms of a novel water-lubricated bearing considering thermal effect. A revised thermodynamic lubrication model with FSI and thermal methodology is built, and the static characteristic parameters of water-film and the variation laws of the liner are studied. The effects of rotational speeds, eccentricity ratios, and liner thickness on thermal performances are analyzed, and the internal mechanisms of the large temperature difference are revealed. Results provide theoretical support for the design and application of such bearings and enrich the theoretical systems of lubrication regime.
TRIBOLOGY INTERNATIONAL
(2023)
Article
Chemistry, Physical
Fan Xie, Sethupathy Mahendiran, Nathan A. Seifert, Yunjie Xu
Summary: The rotational spectrum of a binary complex formed between THFA and water was measured, and theoretical calculations were used to reveal the conformational preferences and differences in stability between different conformers. Experimental results show that the formation of different types of monohydrates in a jet expansion is kinetically controlled, in contrast to the thermodynamically controlled process within each conformational structure.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Spectroscopy
Fernando M. Carvalho, Alessandra Sofia Kiametis, Alan Leone de Araujo Oliveira, Fernando Pirani, Ricardo Gargano
Summary: An integrated experimental-theoretical investigation was conducted to study gas phase complexes of methanol with noble gases, determining their rovibrational energies, spectroscopic constants, and lifetime as a function of temperature. The results show that the methanol-noble gas compounds are generally stable under thermal conditions, with lifetimes exceeding 1 ps in the temperature range of 200 to 500 K. The dispersion force is identified as the essential long-range attractive contribution to the interaction energy, indicating that these compounds are mainly bonded by van der Waals forces in the gas phase.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2021)
Article
Polymer Science
Malik Abdul Rub, Naved Azum, Dileep Kumar, Muhammad Nadeem Arshad, Anish Khan, Maha Moteb Alotaibi, Abdullah M. Asiri
Summary: This study thoroughly examined the interaction of an antidepressant drug and a non-ionic surfactant mixture in different solvents, revealing nonideal behavior and attractive/synergistic interactions between the components. The presence of NaCl in the system increased synergism, while the presence of urea decreased it. Thermodynamic parameters showed that micellization was entropically spontaneous in water systems, with salt increasing spontaneity and urea decreasing it. UV-Visible studies confirmed the interaction between the drug and surfactant in aqueous systems.
Article
Chemistry, Physical
Jingjing Song, Feiwu Chen
Summary: Theoretical studies on the weak interactions in HXeF dot dot dot M3N3H5Y complexes reveal the influence of electron-withdrawing groups on stability and identify the dominant role of N-H dot dot dot F interaction. Furthermore, the dependence of potential energy curves on computational methods poses a challenge for accurately modeling these complexes.
CHEMICAL PHYSICS LETTERS
(2023)
Article
Chemistry, Physical
Shuangping Wang, Liangliang Chen, Baoqiang Xu, Wenlong Jiang, Lingxin Kong, Bin Yang, Heng Xiong, Chao Qu, Teng Zhang, Shanhui Zhang, Jiayou Cui, Zhunqin Dong
Summary: This study proposes an innovative method for vacuum gasification separation of Ag-Cu-Au alloy. The saturated vapor pressure and activities of Au-Cu and Ag-Cu-Au alloys are theoretically calculated. The results demonstrate the accuracy and reliability of the calculated activities of Au-Cu alloy. Based on activity prediction, the separation coefficients of Au-Cu alloy are calculated. The vapor-liquid equilibrium composition and equilibrium phase diagram of Au-Cu and Ag-Cu-Au alloys are calculated, and vapor-liquid equilibrium experiments are conducted for Ag-Cu-Au alloy.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Analytical
Luana Ferreira da Costa, Claudio Francisco Tormena, Marco Aurelio Zezzi Arruda
Summary: This study evaluated three generations of transgenic and non-transgenic soybean plants using multiomics, showing that some elements may share transport mechanisms and correlate with fatty acids, allowing for differentiation of generations and species.
MICROCHEMICAL JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Clebson J. Macrino, Alex S. Borges, Alvaro Cunha Neto, Valdemar Lacerda Jr, Wanderson Romao
Summary: This work describes the synthesis and application of a europium(III) complex that shows red emission in solution and high sensitivity for detecting PbII ions. The complex can also be used as an ethanol sensor.
JOURNAL OF THE BRAZILIAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Joao Vitor Soares, Guilherme Dal Poggetto, Renan V. Viesser, Uenifer R. Couto, Claudio F. Tormena
Summary: Long-range proton-fluorine coupling constants ((n)J(HF)) are important for the structure elucidation of fluorinated molecules. In this study, the transmission of (4)J(HF) was investigated using trans-4-tert-butyl-2-fluorocyclohexanone as the model compound. It was found that stereoelectronic interactions involving the pi system of the carbonyl group play a crucial role in the transmission pathway of (4)J(HF). Interactions where the pi system acts as an electron acceptor increase the value of (4)J(HF), while interactions where the pi system acts as an electron donor decrease it.
MAGNETIC RESONANCE IN CHEMISTRY
(2022)
Article
Food Science & Technology
Marliane Cassia Soares da Silva, Jose Maria Rodrigues da Luz, Tomas Gomes Reis Veloso, Willian dos Santos Gomes, Emanuele Catarina da Silva Oliveira, Larissa Marcia Anastacio, Alvaro Cunha Neto, Aldemar Polonini Moreli, Rogerio Carvalho Guarconi, Maria Catarina Megumi Kasuya, Lucas Louzada Pereira
Summary: This study analyzed the effects of coffee cherry processing and fermentation conditions on microbial communities, chemical composition, and sensory quality of the beverage. The results showed that different processing methods led to changes in microbial diversity and richness, which had an impact on the sensory score of the beverage.
EUROPEAN FOOD RESEARCH AND TECHNOLOGY
(2022)
Article
Biochemical Research Methods
Jose Roberto Aparecido dos Santos-Pinto, Franciele Grego Esteves, Claudio Francisco Tormena, Amilcar Perez-Riverol, Alexis Musacchio Lasa, Odair Correa Bueno, Mario Sergio Palma
Summary: The study investigated the fibroin-based silk fibers from weaver ants and provided a structural characterization of these fibers. It identified a glycoprotein with a molecular weight of around 40 kDa in the ant silk fibers and revealed a 3D structure predominantly composed of coiled-coil secondary units. The findings contribute to the development of new approaches for the production of silk-based polymers for biomedical applications.
JOURNAL OF PROTEOMICS
(2022)
Article
Chemistry, Multidisciplinary
Meire Y. Kawamura, Juan Alegre-Requena, Thais M. Barbosa, Claudio F. Tormena, Robert S. Paton, Marco A. B. Ferreira
Summary: [3+2] cycloadditions of nitroolefins are a selective and catalyst-free alternative for synthesizing 1,2,3-triazoles. Mechanistic studies reveal that the rate-limiting step is the cycloaddition, which shows high kinetic selectivity for the formation of 1,5-triazoles.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Organic
Shiwen Liu, Claudio F. Tormena, Gerald B. Hammond, Bo Xu
Summary: Alkynyltrifluoroborate nucleophiles can react with a wide range of sp(3)-carbon electrophiles to produce Sonogashira-type products, where an ion pair-organic complex may play a crucial role in the reaction.
Article
Biochemistry & Molecular Biology
Regina Westphal, Eclair Venturini Filho, Laiza Bruzadelle Loureiro, Claudio Francisco Tormena, Claudia Pessoa, Celina de Jesus Guimaraes, Mariana Palmeira Manso, Rodolfo Goetze Fiorot, Vinicius Rangel Campos, Jackson Antonio Lamounier Camargos Resende, Fabrizio Medici, Sandro Jose Greco
Summary: In this study, a microwave-assisted Knoevenagel/Michael/cyclization multicomponent domino methodology was developed for the synthesis of spiro compounds. Twelve spiro compounds were synthesized and one of them exhibited anti-cancer activity.
Article
Chemistry, Multidisciplinary
Coral Mycroft, Guilherme Dal Poggetto, Thaiis M. Barbosa, Claiudio F. Tormena, Mathias Nilsson, Gareth A. Morris, Laura Castanar
Summary: The NMR analysis of fluorine-containing molecules is important in pharmaceuticals and biochemistry, but faces challenges due to severe peak overlap. This study introduces a new method, IPAP-FESTA, that simplifies measurements of proton-fluorine couplings. Its usefulness is demonstrated in the structural study of the drug fluticasone propionate and in assessing solvent effects on fluorohydrin conformational equilibrium in a mixture.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Materials Science, Multidisciplinary
Luiz Gustavo Bonato, Guilherme Dal Poggetto, Raphael Fernando Moral, Brener Rodrigo de Carvalho Vale, Jose Carlos Germino, Diogo Burigo Almeida, Patricia Santiago, Pablo Sebastian Fernandez, Claudio Francisco Tormena, Lazaro A. Padilha, Ana Flavia Nogueira
Summary: In this study, the influence of organic ligands on the photostability of CsPbBr3 perovskite nanocrystals was investigated. The results demonstrate that alkylphosphate ligands can improve the photostability of colloidal nanocrystals dispersions, which is important for applications requiring continuous excitation.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Review
Chemistry, Organic
Pedro Alves Bezerra Morais, Clara Lirian Javarini, Thays Cardoso Valim, Carla Santana Francisco, Lara Chaves de Freitas Ferreira, Ramon Ramires Trancoso Bottocim, Alvaro Cunha Neto, Valdemar Lacerda Junior
Summary: Triazole is an important molecular structure with recognized potential in various fields. It has gained attention for its physicochemical properties and its ability to enhance specific biological activities or add different properties when connected with other bioactive and functional molecules.
CURRENT ORGANIC CHEMISTRY
(2022)
Article
Polymer Science
Manami Kawakami, Karl H. G. Schulz, Anthony J. Varni, Claudio F. Tormena, Roberto R. Gil, Kevin J. T. Noonan
Summary: This study demonstrates the feasibility of homopolymerization and statistical copolymerization of 2-ethylhexyl thiophene-3-carboxylate and 2-ethylhexyl selenophene-3-carboxylate monomers via Suzuki-Miyaura cross-coupling. The use of a specific palladium catalyst allows for the preparation of regioregular conjugated polymers with high molecular weights and relatively narrow molecular weight distributions. Increasing the concentration of selenophene-3-carboxylate in the copolymer series can reduce the optical bandgap.
Article
Chemistry, Organic
Attilio Chiavegatti Neto, Kelly Cintra Soares, Maiara da Silva Santos, Tulio Jardini Aimola, Antonio Gilberto Ferreira, Guilherme A. M. Jardim, Claudio Francisco Tormena, Marcio Weber Paixao, Marco Antonio Barbosa Ferreira
Summary: Here, a fully detailed mechanistic study on the organocatalyzed metal-free click reactions for the synthesis of 1,2,3-triazoles is reported. The elementary steps, intermediates, and transition states of the reactions are investigated using DFT calculations and H-1 NMR monitoring experiments, providing detailed profiles for both reaction mechanisms. DIAS analysis is also employed to elucidate the regioselectivity in these reactions.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Clebson J. Macrino, Elias M. Silva, Victor R. Cunha, Victor R. Fonseca, Alvaro Cunha Neto, Joyce R. Araujo, Valdemar Lacerda, Wanderson Romao
Summary: This work synthesized three complexes from the trivalent europium ion and tested them as luminescent markers on Brazilian banknotes, showing promising results for potential anti-counterfeiting applications.
JOURNAL OF THE BRAZILIAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Physical
Renan V. Viesser, Claudio F. Tormena
Summary: The study reveals an inverse halogen dependence (IHD) in the anion series due to negative spin-orbit contribution rather than scalar paramagnetic effects. The presence of a carbon nonbonding orbital in anions allows for magnetic couplings that generate a deshielding effect on the nucleus, contradicting the classical association between delta C-13 and atomic charge.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
