Article
Chemistry, Physical
Vinicius C. Port, Lucas A. Zeoly, Fernando Coelho, Rodrigo A. Cormanich
Summary: The study evaluates the participation of a fluorine atom in non-covalent interactions in different conformers, calculating the spin-spin coupling constant to determine the impact. The results suggest that the trans conformer plays a more significant role in the stabilization of conformer geometries.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Lorenz M. Urner, Ga Young Lee, Joseph W. Treacy, Aneta Turlik, Saeed Khan, K. N. Houk, Michael E. Jung
Summary: The 4-anilino-6,7-ethylenedioxy-5-fluoroquinazoline scaffold is proposed as a novel model system for studying weak NH...F hydrogen bonding interactions, with experimental and theoretical methods used to characterize this interaction. The results demonstrate that fluorine can act as a weak hydrogen bond acceptor, and the strength of the hydrogen bond can be modulated through changes in electron distribution and resonance.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Surbhi Tiwari, Neeru Arya, Sandeep Kumar Mishra, N. Suryaprakash
Summary: A series of N-benzoylanthranilamide derivatives were synthesized and studied using competitive HB acceptors, NMR spectroscopy, and single crystal XRD. The competition for HB acceptance between (sic)C= and X (F or OMe) in the molecules led to an unusual increase in electron density at one of the NH protons, resulting in high field resonance in the H-1 NMR spectrum. The experimental findings from NMR and single crystal XRD were further supported by DFT studies.
Article
Chemistry, Multidisciplinary
Henry W. Orton, Haocheng Qianzhu, Elwy H. Abdelkader, Edan I. Habel, Yi Jiun Tan, Rebecca L. Frkic, Colin J. Jackson, Thomas Huber, Gottfried Otting
Summary: In this study, it was demonstrated that fluorine atoms in noncanonical amino acids positioned in the hydrophobic core or on the surface of a protein can be linked by scalar through-space F-19-F-19 couplings, even if the F-19 spins are separated by more than the van der Waals distance. The use of fluorinated amino acids and F-19-F-19 interactions offer a straightforward way to probe the spatial proximity of selected sites in proteins, without requiring H-1 NMR resonance assignments.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Biochemistry & Molecular Biology
Wojciech Pietrus, Rafal Kafel, Andrzej J. Bojarski, Rafal Kurczab
Summary: This study presents a statistical analysis of fluorine-containing hydrogen bonds in medicinal chemistry. The results indicate that the interaction energy of F-containing HBs is determined by the donor-acceptor distance, and fluorine is a weak HB acceptor for all types of HB donors. In addition, the calculated energetic optima do not match the most commonly observed geometric parameters of HBs.
Article
Chemistry, Multidisciplinary
Giuseppe Ermondi, Francesca Lavore, Maura Vallaro, Guido Tiana, Francesca Vasile, Giulia Caron
Summary: The study characterized the conformational ensembles of the bRo5 drug rifampicin in different environments and found that its conformational behavior in solution and in the solid state is not superposable. Dynamic intramolecular hydrogen bonds were identified through NMR spectroscopy but were not found in X-ray structures, and it was revealed that they do not provide rifampicin with chameleonic properties. Overall, the unique properties of rifampicin, such as cell permeability and lack of chameleonic behavior, can be assessed by analyzing experimental 3D structures.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Energy & Fuels
Hang Cheong Sio, Josua Stuckelberger, Rabin Basnet, Daniel Macdonald
Summary: It is found that magnesium fluoride (MgFx) coatings can have comparable effects to aluminum oxide (AlOx) and silicon nitride (SiNx) on n-type polysilicon, enhance the passivation effect of SiNx on p-type polysilicon when used as an additional capping layer, and facilitate the recovery of firing-induced degradation in n-type polysilicon. In addition, MgFx exhibits better conductivity and lower work function compared to other dielectric films. By utilizing these properties, we have successfully demonstrated the use of 10 nm thick MgFx films as an interlayer to improve contact formation between n-type polysilicon and evaporated aluminum, achieving a contact resistivity of 1.6 m omega center dot cm2 while preserving the passivation. Our results highlight the potential use of MgFx to simultaneously improve the passivation and metallization of doped polysilicon contacts in industrial production.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2023)
Article
Chemistry, Multidisciplinary
Vijayanath Elakkat, Eskedar Tessema, Chia-Her Lin, Xiaoping Wang, Huan-Cheng Chang, You-Ning Zheng, Yu-Cheng Huang, Zhong-Yun Gurumallappa, Zhong-Yun Zhang, Ka Long A. Chan, Hening A. S. Rahayu, Joseph S. Francisco, Norman Lu
Summary: To understand the effect of non-covalent weak interactions on molecules, we investigated different types of weak interactions in fluorinated chiral zinc complexes, including improper H-bonding, tetrel bonds, and halogen bonds. High resolution neutron diffraction studies revealed elongation and shortening of the methylene carbon-hydrogen bond due to tetrel bonds and improper H-bond interactions, respectively. We demonstrated how multiple weak interactions can cumulatively affect the C-H bond and offset its elongation through formation of an improper H-bond. Non-covalent interaction and electrostatic potential analysis investigations confirmed the nature of these interactions using density functional theory (DFT) and related calculations.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Ryu Yamasaki, Mariko Ono, Kento Morita, Ai Ito, Kazuo Fukuda, Iwao Okamoto
Summary: Methyl substitution at the double bond of N-alkenyl anilides affects both the preferred conformation and susceptibility to acidic hydrolysis. Substitution at the R-1 position favors the trans conformation, while substitution at the R-2 or R-3 position favors the cis conformation. Substitution at the R-1 and R-3 positions increases the ratio of the trans conformer. DFT study reveals that these conformational preferences can be explained by torsion twisting induced by the substituent on the N-alkenyl moiety relative to the amide plane. R-1 substitution enhances susceptibility to acidic hydrolysis, while R-2 or R-3 substitution increases stability. The effect of the double bond on conformational preferences is demonstrated by comparing the preferred conformation of R-1-substituted anilide (trans) and hydrogenated N-isopropyl amide (cis).
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Shigeyuki Yamada, Tsutomu Konno
Summary: Fluorinated tolanes exhibit minimal fluorescence in a solution state but show enhanced fluorescence in the crystalline state due to hydrogen bonding. The fluorescence colors can be controlled by varying molecular orbitals, dipole moments, and molecular aggregated structures using terminal substituents. Introduction of long alkoxy or semifluoroalkoxy chains along the major molecular axis induces liquid-crystalline phase formation, allowing for the design of new photoluminescent liquid crystal molecules (PLLCs).
Article
Chemistry, Multidisciplinary
Subham Ranjan, Ryota Morioka, Meguya Ryu, Junko Morikawa, Satoshi Takamizawa
Summary: This study investigates the mechanical deformation in two cocrystals and reveals the relationship between structure and properties, providing guidance for the design of organic crystals with superelastic or ferroelastic properties based on rational selection of intermolecular interactions.
Article
Biochemistry & Molecular Biology
Elena Yu Tupikina, Mark Sigalov, Peter M. Tolstoy
Summary: A computational method for estimating the geometry of two coupled hydrogen bonds with geometries close to linear using NMR parameters was proposed. The method was developed based on the quantum-chemical investigation of complexes formed by oxygen and nitrogen atoms with substituted methanols. The method selects pairs of NMR chemical shifts to determine the geometry of two hydrogen bonds and shows good agreement with direct quantum-chemical calculations.
Article
Chemistry, Organic
Lei Sun, Jichun Cui, Shaozhen Nie, Lei Xie, Yanlan Wang, Lingang Wu
Summary: In this work, we have described the N-iodosuccinimide-mediated benzyl sp(3) C-H oxidation of 2-alkyl-substituted benzamide derivatives. This reaction, which involves intramolecular sp(3) C-O bond formation, is different from the classic and modified Hofmann-Loffler-Freytag reactions that construct C-N bonds. The reaction proceeds smoothly through 1,5-hydrogen atom transfer of N-centered radicals generated in situ through N-I bond formation, yielding iminoisobenzofuran derivatives with moderate to excellent yields and exclusive chemoselectivity.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Austin S. Flemming, Brendan C. Dutmer, Thomas M. Gilbert
Summary: Systematic computational studies were conducted to investigate the pericyclic Diels-Alder reactions between (H3C)2C=C(CH3)2 and various substituted cyclopentadienes. The effects of substitution on Gibbs free energy barrier heights and reaction Gibbs free energies were analyzed. The results showed that the substitution effects were additive, and the impacts on barriers varied depending on the position and type of substitution. The generated Gibbs free energy correction values are useful for predicting the reaction rates and product stability.
Article
Biochemistry & Molecular Biology
Guoxiong Hua, Cameron L. Carpenter-Warren, David B. Cordes, Alexandra M. Z. Slawin, J. Derek Woollins
Summary: A series of N-aryl-N-(2-oxo-2-arylethyl) benzamides and cinnamides were prepared and reacted with Woollins' reagent to yield N-aryl-N-(arylenethyl) benzoselenoamides in good yields. Five representative single crystal X-ray structures were discussed in the study.
Article
Chemistry, Inorganic & Nuclear
JR Angulo-Cornejo, K Ayala-León, GG Herbosa, JV Cuevas, V Diez, R Richter, L Hennig, L Beyer
ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES
(2005)
Article
Chemistry, Organic
JR Angulo-Cornejo, A Carbayo, E Cueva-Talledo, JV Cuevas, G García-Herbosa, A Muñoz
Article
Chemistry, Inorganic & Nuclear
U Schröder, L Beyer, R Richter, J Angulo-Cornejo, M Castillo-Montoya, M Lino-Pacheco
INORGANICA CHIMICA ACTA
(2003)
Article
Chemistry, Inorganic & Nuclear
U Schröder, R Richter, L Beyer, J Angulo-Cornejo, M Lino-Pacheco, A Guillen
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE
(2003)
Article
Chemistry, Inorganic & Nuclear
Xianda Wu, Minghong Chen, Shuiyun Zheng, Fu-Sheng He, Jie Wu
Summary: Here, we report a new method for synthesizing sulfilimines through an iron-catalyzed reaction between sulfenamides and 2,2,2-trifluor-diazoethane. This protocol features operational simplicity, mild conditions, and can be conducted in open air, providing a facile approach to trifloromethylated sulfilimines in moderate to good yields.
JOURNAL OF FLUORINE CHEMISTRY
(2024)
Article
Chemistry, Inorganic & Nuclear
Ita Hajdin, Romana Pajkert, Haibo Mei, Jianlin Han, Gerd-Volker Roeschenthaler
Summary: A catalyst- and solvent-free 1,3-dipolar cycloaddition reaction using a bench-stable diazo reagent has been developed to obtain a series of novel 3H-pyrazoles bearing difluoromethyl phosphonate unit in moderate-to-excellent yields. This method provides an efficient and easy route to synthesize valuable compounds.
JOURNAL OF FLUORINE CHEMISTRY
(2024)
