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Introducing an Extended covalent bond between Oxygen Atoms with an OXO-Shape in Ions and Molecules: Compatibility with the Even-Odd and the Isoelectronicity Rules

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Open Journal of Physical Chemistry 2016年第3期6卷 67-77页

作者： Geoffroy Auvert Marine Auvert Grenoble Alpes University Grenoble France Strasbourg University Strasbourg France

Building on the recent success of the even-odd rule, the present paper explores its implications by studying the very specific case of OXO compounds. These compounds are usually represented with double bonds linking two oxygen atoms to a central atom—as in carbon dioxyde—yet can sometimes be drawn in a triangular structure, such as in calcium dioxyde. Measurement data moreover indicate that most OXO compounds have an angle around 120° between oxygen atoms, although that seems incompatible with triangular representations. The aim here is to unify these commonly admitted representations by linking oxygen atoms through a single bond that is longer than usual covalent bonds: an “elongated bond”. This elongated bond has the interesting effect of suppressing the need for double bonds between oxygen and the central atom. The elongated bond concept is applied to about a hundred of molecules and ions and methodically compared to classical representations. It is shown that this new representation, associated to the even-odd rule, is compatible with all studied compounds and can be used in place of their classical drawings. Its usage greatly simplifies complex concepts like resonance and separated charges in gases. Elongated bonds are also shown to be practicable with the isoelectronic rule as well as isomers, and throughout chemical reactions. This study of an especially long and wide angle bond confirms the versatility of the even-odd rule: it is not limited to compounds with short covalent bonds and can include OO covalent bond lengths of more than 200 pm and with OXO angles above 90°.

关键词： Elongated bond covalent bond Even-Odd Double bond Isoelectronicity Rules Chemistry Ions Molecule

Biodegradation,hemocompatibility and covalent bonding mechanism of electrografting polyethylacrylate coating on Mg alloy for cardiovascular stent

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Journal of Materials Science & Technology 2020年第11期42卷 114-126页

作者： Yong-Xin Yang Zhe Fang Yi-Hao Liu Ya-Chen Hou Li-Guo Wang Yi-Fan Zhou Shi-Jie Zhu Rong-Chang Zeng Yu-Feng Zheng Shao-Kang Guan School of Materials Science and Engineering Zhengzhou UniversityZhengzhou450001China Henan Key Laboratory of Advanced Magnesium Alloys Zhengzhou450002China Key Laboratory of Advanced Materials Processing&Mold Ministry of Education Zhengzhou450002China Corrosion Laboratory of Light Metals College of Material Science and EngineeringShandong University of Science and TechnologyQingdao266590China State Key Laboratory for Turbulence and Complex System and Department of Materials Science and Engineering College of EngineeringPeking UniversityBeijing100871China

Organic coatings are the most widely employed approach for the promotion of corrosion resistance of magnesium(Mg)***,traditional organic coatings are weakly bonded to Mg substrates due to physical ***,a polyethylacrylate(PEA)coating was fabricated on Mg-Zn-YNd alloy via *** surface structure and chemical composition were characterized by means of scanning electron microscope(SEM),energy dispersive X-ray spectroscopy(EDS),atomic force microscope(AFM)and Fourier transform infrared(FTIR)as well as time of flight-secondary ion mass spectrometer(To F-SIMS).The results showed that the surface roughness of PEA coating was dominated by scan rate;while the coverage and integrity of PEA coating were mainly affected by the monomer concentration and sweep *** F-SIMS results indicated that PEA coating was wholly covered on Mg alloy,and the presence of C2H3Mg-fragment confirmed the covalent bond between PEA coating and Mg *** addition,DFT calculation results of the adsorption of EA molecules with Mg substrate agree well with the experimental phenomena and observation,suggesting that the electrons in 3s orbit of Mg atoms and 2pz orbit of C1 atom participated in the formation of covalent bond between PEA coating and Mg *** polarization curves and immersion test demonstrated that the PEA coatings could effectively enhance the corrosion resistance of Mg *** platelet adhesion results designated that platelets were barely visible on PEA coating,which implied that PEA coating could effectively prevent the thrombosis and coagulation of *** coating might be a promising candidate coating of Mg alloy for cardiovascular stent.

关键词： Magnesium alloy Organic coating Electro-grafting covalent bond Density functional theory Biomaterial

The Even-Odd and the Isoelectronicity Rules Applied to Single covalent bonds in Ionic, Double-Face-Centered Cubic and Diamond-Like Crystals

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Open Journal of Physical Chemistry 2016年第2期6卷 21-33页

作者： Geoffroy Auvert Marine Auvert Grenoble Alp University Grenoble France University of Strasbourg Strasbourg France

Although atom configuration in crystals is precisely known thanks to imaging techniques, there is no experimental way to know the exact location of bonds or charges. Many different representations have been proposed, yet no theory to unify conceptions. The present paper describes methods to derive bonds and charge location in double-face-centered cubic crystals with 4 and 6 atoms per unit cell using two novel rules introduced in earlier works: the even-odd and the isoelectronicity rules. Both of these rules were previously applied to ions, molecules and some solids, and the even-odd rule was also tested on two covalent crystal structures: centered-cubic and single-face-centered cubic crystals. In the present study, the diamond-like structure was subjected to the isoelectronicity rule in order to derive Zinc-blende structures. Rock-salt-like crystals were derived from each other using both rules. These structures represent together more than 230 different crystals. Findings for these structures are threefold: both rules describe a very sure method to obtain valid single covalent-bonded structures;single covalent structures can be used in every case instead of the classical ionic model;covalent bonds and charges positions do not have any relation with the valence number given in the periodic table.

关键词： covalent bond Even-Odd Rule Single bond Chemical Structure Crystal Solid Ionic Crystal Face-Centered Crystal Diamond-Like

covalent intermolecular interaction of the nitric oxide dimer (NO)_2

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Chinese Physics B 2015年第9期24卷 177-181页

作者：张辉郑桂丽吕刚耿轶钊纪青 School of Science Hebei University of Technology Changchun Institute of Optics Fine Mechanics and Physics Mathematical and Physical Science School North China Electric Power University Institute of Biophysics Hebei University of Technology State Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of Sciences

covalent bonds arise from the overlap of the electronic clouds in the internucleus region, which is a pure quantum effect and cannot be obtained in any classical way. If the intermolecular interaction is of covalent character, the result from direct applications of classical simulation methods to the molecular system would be questionable. Here, we analyze the special intermolecular interaction between two NO molecules based on quantum chemical calculation. This weak intermolecular interaction, which is of covalent character, is responsible for the formation of the NO dimer,（NO）2, in its most stable conformation, a cis conformation. The natural bond orbital（NBO） analysis gives an intuitive illustration of the formation of the dimer bonding and antibonding orbitals concomitant with the breaking of the πbonds with bond order 0.5of the monomers. The dimer bonding is counteracted by partially filling the antibonding dimer orbital and the repulsion between those fully or nearly fully occupied nonbonding dimer orbitals that make the dimer binding rather weak. The direct molecular mechanics（MM） calculation with the UFF force fields predicts a trans conformation as the most stable state, which contradicts the result of quantum mechanics（QM）. The lesson from the investigation of this special system is that for the case where intermolecular interaction is of covalent character, a specific modification of the force fields of the molecular simulation method is necessary.

关键词： nitric oxide dimer intermolecular interaction natural orbital covalent bond

covalent hadronic molecules induced by shared light quarks

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Communications in Theoretical Physics 2022年第12期74卷 62-86页

作者： Hua-Xing Chen School of Physics Southeast UniversityNanjing 210094China

After examining Feynman diagrams corresponding to the ■, ■, ■, and ■ hadronic molecular states, we propose a possible binding mechanism induced by shared light quarks. This mechanism is similar to the covalent bond in chemical molecules induced by shared electrons. We use the method of QCD sum rules to calculate its corresponding light-quark-exchange diagrams, and the obtained results indicate a model-independent hypothesis: the light-quark-exchange interaction is attractive when the shared light quarks are totally antisymmetric so they obey the Pauli principle. We build a toy model with four parameters to formulize this picture and estimate binding energies of some possibly-existing covalent hadronic molecules. A unique feature of this picture is that the binding energies of the(I)JP=(0)1+■ hadronic molecules are much larger than those of the (I)JP=(0)1+■ ones, while the(I)JP=(1/2)1/2+■ hadronic molecules have similar binding energies.

关键词： hadronic molecule covalent bond QCD sum rules

A perspective on functionalizing colloidal quantum dots with DNA

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Nano Research 2013年第12期6卷 853-870页

作者： Anirban Samanta Zhengtao Dengt Yan Liu Hao Yan Center for Single Molecule Biophysics the Biodesign Institute & Department of Chemistry and Biochemistry Arizona State University. TempeArizona 85281 USA Present address: MIT Synthetic Biology Center Boston MA USA

This perspective provides an overview of the techniques that have been developed for the conjugation of DNA to colloidal quantum dots （QDs）, or semiconductor nanocrystals. Methods described include： ligand exchange at the QD surface, covalent conjugation of DNA to the QD surface ligands, and one-step DNA functionalization on core QDs or during core/shell QD synthesis in aqueous solution, with an emphasis on tile most recent progress in our lab. We will also discuss emerging trends in DNA-functionalized QDs for potential applications.

关键词： colloidal quantum dots semiconductor nanocrystals DNA conjugation ligand exchange covalent bond core/shell

An effective method to generate controllable levels of ROS for the enhancement of HUVEC proliferation using a chlorin e6-immobilized PET film as a photo-functional biomaterial

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Regenerative Biomaterials 2021年第2期8卷 94-103页

作者： Seung Hee Hong Min-Ah Koo Mi Hee Lee Gyeung Mi Seon Ye Jin Park HaKyeong Jeong Dohyun Kim Jong-Chul Park Cellbiocontrol Laboratory Department of Medical Engineering Department of Medical Engineering Graduate School of Medical ScienceBrain Korea 21 Project Department of Medical Device Engineering and Management Yonsei UniversityCollege of MedicineSeoul 03722Republic of Korea

Reactive oxygen species(ROS)are byproducts of cellular metabolism;they play a significant role as secondary messengers in cell *** cells,high concentrations of ROS induce apoptosis,senescence,and contact inhibition,while low concentrations of ROS result in angiogenesis,proliferation,and cytoskeleton ***,controlling ROS generation is an important factor in cell *** designed a chlorin e6(Ce6)-immobilized polyethylene terephthalate(PET)film(Ce6-PET)to produce extracellular ROS under red-light *** application of Ce6-PET films can regulate the generation of ROS by altering the intensity of light-emitting diode *** confirmed that the Ce6-PET film could effectively promote cell growth under irradiation at 500 μW/cm^(2) for 30 min in human umbilical vein endothelial *** also found that the Ce6-PET film is more efficient in generating ROS than a Ce6-incorporated polyurethane film under the same ***6-PET fabrication shows promise for improving the localized delivery of extracellular ROS and regulating ROS formation through the optimization of irradiation intensity.

关键词： reactive oxygen species chlorin e6 dopamine covalent bond HUVEC proliferation

Synthesis of covalently bonded reduced graphene oxide-Fe_(3)O_(4) nanocomposites for efficient electromagnetic wave absorption

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Journal of Materials Science & Technology 2021年第13期72卷 93-103页

作者： Xudong Liu Ying Huang Ling Ding Xiaoxiao Zhao Panbo Liu Tiehu Li MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’an 710072China NPU-NCP Joint International Research Center on Advanced Nanomaterials&Defects Engineering State Key Laboratory of Solidification ProcessingShaanxi Engineering Laboratory for Graphene New Carbon Materials and ApplicationsSchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China

High-performance electromagnetic(EM)wave absorbers,covalently bonded reduced graphene oxideFe_(3)O_(4) nanocomposites(rGO-Fe_(3)O_(4)),are synthesized via hydrothermal reaction,amidation reaction and reduction *** microstructure,surface element composition and morphology of rGO-Fe_(3)O_(4) nanocomposites are characterized and corresponding EM wave absorption properties are analyzed in great *** demonstrates that Fe_(3)O_(4) nanoparticles are successfully covalently grafted onto graphene by amide *** the mass ratio of rGO and Fe_(3)O_(4) is 2:1(sample S2),the absorber exhibits the excellent EM wave absorption performance that the maximum reflection loss(RL)reaches up to-48.6 dB at 14.4 GHz,while the effective absorption bandwidth(RLcovalent bonds considered to be carrier channels can facilitate electron migration,adjust EM parameters and then enhance EM wave absorption perfo *** work provides a possible method for preparing efficient EM wave absorbers.

关键词： covalent bond EM wave absorption RCS simulation calculation rGO-Fe_(3)O_(4)nanocomposites

covalently bonded ternary photocatalyst comprising MoSe_(2)/black phosphorus nanosheet/graphitic carbon nitride for efficient moxifloxacin degradation

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Chinese Chemical Letters 2024年第9期35卷 356-359页

作者： Yuhao Ma Yufei Zhou Mingchuan Yu Cheng Fang Shaoxia Yang Junfeng Niu College of Environmental Science and Engineering North China Electric Power UniversityBeijing 102206China College of Water Conservancy and Hydropower Engineering North China Electric Power UniversityBeijing 102206China Global Centre for Environmental Remediation(GCER) University of NewcastleCallaghanNSW 2308Australia

covalently bonded bridging between different semiconductors is a remarkable approach to improve the transfer of charge carriers at *** this study,we designed a ternary heterojunction(MBG)combining of molybdenum diselenide(Mo Se_(2)),black phosphorus nanosheets(Bpn)and graphitic carbon nitride(GCN).Among this MBG of Mo Se_(2)/Bpn/GCN,(i)the covalently bonded bridging effect between Bpn/GCN facilitates directional charge carrier transfer,meanwhile(ii)a Z-scheme heterojunction is formed between Mo Se_(2)/GCN to enhance the separation of photogenerated ***,(iii)this composite exhibits an increased absorption for visible *** this MBG,photocatalytic degradation of over 98%of moxifloxacin is achieved within 20 min,with O_(2)·-confirmed as the primary photocatalytic active *** findings provide novel insights into the construction of efficient heterojunction by covalently bonded bridging.

关键词： Ternary heterojunction Black phosphorus nanosheets covalent bond Photocatalytic degradation Graphitic carbon nitride