scholarly journals Novel Mononuclear Divalent Zinc, Cadmium and Mercury Complexes of Tridentate Hydrazone Ended by Thiophene Ring

2021 ◽  
Vol 10 (4) ◽  
pp. 2680-2696
Keyword(s):  
Metal Ion ◽  
Density Functional ◽  
Thiophene Ring ◽  
Atomic Charge ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Mercury Complexes ◽  
Zinc Cadmium ◽  
Infrared Spectral ◽  
Global And Local

New hydrazone derivative, namely (Z)-4-((3-cyano-4,6-dimethyl pyridine-2-yl)amino)-N'-(thiophen-2-ylmethylene)benzohydrazide (H2BTH) and its mononuclear Zn(II), Cd(II) and Hg(II) complexes were prepared and characterized by conventional measurements. Infrared spectral data confirmed that the hydrazone coordinates to metal ion as neutral NS or NO. The structure of Cd(II) complex was further studied by x-ray powder diffraction. The density functional theory (DFT) based quantum chemical calculations were accomplished at B3LYP/6-level of theory andMuilikan atomic charge in a companion with global and local reactivities and various energetic values have been calculated at the selected atoms, and the reactive sites have been assigned on the surface of the molecules through molecular electrostatic potential (MEP) map. TGA and DrTGA were used to establish some compounds' thermal stability, and the kinetic parameters of activation such as ΔG*, ΔH*, and ΔS* were determined. Moreover, all investigated compounds were screened for antimicrobial and DNA binding activities.

scholarly journals Mononuclear Cr(III), Mn (II), and Fe(III) complexes derived from new ONO symmetrical flexible hydrazone: synthesis, spectral characterization, optical band gap and DFT computational study

2019 ◽  
Vol 8 (4) ◽  
pp. 743-753
Keyword(s):  
Band Gap ◽  
Density Functional ◽  
Molecular Electrostatic Potential ◽  
Optical Band Gap ◽  
Computational Study ◽  
Atomic Charge ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
The Stability ◽  
Global And Local

New mononuclear Mn (II), Cr (III) and Fe (III) complexes of flexible symmetrical 2-(2-(2-hydroxy-3-methoxybenzylidene) hydrazinyl)-2-oxo-N-(pyridine-2-yl) acetamid (H4MPA) were isolated and characterized. IR spectra proved that the hydrazone coordinates as ONO dibasic or monobasic in keto and enol forms. The density functional theory (DFT) based quantum chemical calculations were accomplished at B3LYP/6-level of theory. Muilikan atomic charge in a companion with global and local reactivities and various energitic values have been calculated at the selected atoms, and the reactive sites have been assigned on the surface of the molecules through molecular electrostatic potential (MEP) map. The stability of all compounds was examined by TGA and DrTGA and the associated kinetic parameters were determined. Also, the optical band gap values were evaluated and found to be comparable with those obtained by DFT suggesting the possibility of using the title compounds in solar cells.

Pyridine based cross-linked chitosan: a biopolymer adsorbent for the green removal of toxic metals from water

2021 ◽  
Author(s):  
Ibraheem Olayiwola Bisiriyu ◽  
Reinout Meijboom
Keyword(s):  
Toxic Metals ◽  
Contact Time ◽  
Metal Ion ◽  
Density Functional ◽  
Selective Adsorption ◽  
Ion Concentration ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Pyridine Dicarboxylic Acid ◽  
Selectivity Studies

Abstract Herein we report the green recovery of toxic metals [namely: Cd2+, Cr3+, Mn2+, Pb2+, and Ni2+] from water utilizing a biopolymer: 2,6-pyridine dicarboxylic acid cross-linked chitosan (PDC-CCS) as the adsorbent. Adsorption studies were performed at a previously determined optimum adsorption conditions for Cu(II) [i.e temperature = 30 ℃, pH of about 7.5, contact time = 60 mins and initial metal ion concentration of 2.5 mM]. At the RI-PB/def2-SVP level of theory, the Density Functional Theory (DFT) approach has been used to evaluate adsorption energy for metal ions. Selectivity studies were performed at pH 4.20, 5.56, 6.65 and 7.61. While Mn(II), Cd(II) and Ni(II) were strongly adsorbed at higher pH (7.5), Cr(III) and Pb(II) were seen to be strongly adsorbed at lower pH (around 4.0). Selectivity studies revealed that PDC-CCS can be utilized for simultaneous removal of the metals at pH 4.2; selective adsorption of Mn(II) at pH 5.56 as well as simultaneous-selective removal of Ni(II) and Mn(II) near neutral pH. The maximum adsorption limit of PDC-CCS for Mn(II), Cd(II) and Ni(II), were found to be 1258.79, 1118.70 and 829.62 mmol/g respectively. When compared with some relevant previously used adsorbent, PDC-CCS shows an exceptional adsorption capacity. Consequently, a successful biopolymer adsorbent for the treatment of water contaminated by hazardous metals.

scholarly journals Electronic and Magnetic Properties of Stone–Wales Defected Graphene Decorated with the Half-Metallocene of M (M = Fe, Co, Ni): A First Principle Study

Nanomaterials ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 552 ◽  
Author(s):  
Kefeng Xie ◽  
Qiangqiang Jia ◽  
Xiangtai Zhang ◽  
Li Fu ◽  
Guohu Zhao
Keyword(s):  
Magnetic Properties ◽  
Band Structure ◽  
Metal Ion ◽  
Density Functional ◽  
Electronic Devices ◽  
First Principle ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Potential Applications ◽  
Defected Graphene

The geometrical, electronic structure, and magnetic properties of the half-metallocene of M (M = Fe, Co, Ni) adsorbed on Stone–Wales defected graphene (SWG) were studied using the density functional theory (DFT), aiming to tune the band structure of SWG. The introduction of cyclopentadienyl (Cp) and half-metallocene strongly affected the band structure of SWG. The magnetic properties of the complex systems originated from the 3D orbitals of M (M = Fe, Co, Ni), the molecular orbital of Cp, and SWG. This phenomenon was different from that found in a previous study, which was due to metal ion-induced sandwich complexes. The results have potential applications in the design of electronic devices based on SWG.

scholarly journals Strain Investigation on Spin-Dependent Transport Properties of γ-Graphyne Nanoribbon Between Gold Electrodes

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yun Li ◽  
Xiaobo Li ◽  
Shidong Zhang ◽  
Liemao Cao ◽  
Fangping Ouyang ◽  
...  
Keyword(s):  
Transport Properties ◽  
High Performance ◽  
Density Functional ◽  
Strain Engineering ◽  
Molecular Junctions ◽  
Spin Splitting ◽  
Functional Theory ◽  
Spin Dependent Transport ◽  
The Density Functional Theory ◽  
Dependent Transport

AbstractStrain engineering has become one of the effective methods to tune the electronic structures of materials, which can be introduced into the molecular junction to induce some unique physical effects. The various γ-graphyne nanoribbons (γ-GYNRs) embedded between gold (Au) electrodes with strain controlling have been designed, involving the calculation of the spin-dependent transport properties by employing the density functional theory. Our calculated results exhibit that the presence of strain has a great effect on transport properties of molecular junctions, which can obviously enhance the coupling between the γ-GYNR and Au electrodes. We find that the current flowing through the strained nanojunction is larger than that of the unstrained one. What is more, the length and strained shape of the γ-GYNR serves as the important factors which affect the transport properties of molecular junctions. Simultaneously, the phenomenon of spin-splitting occurs after introducing strain into nanojunction, implying that strain engineering may be a new means to regulate the electron spin. Our work can provide theoretical basis for designing of high performance graphyne-based devices in the future.

scholarly journals Electron-phonon interaction in In-induced √7 ×√3 structures on Si(111) from first-principles

2021 ◽  
Author(s):  
I. Yu. Sklyadneva ◽  
Rolf Heid ◽  
Pedro Miguel Echenique ◽  
Evgueni Chulkov
Keyword(s):  
Density Functional Theory ◽  
Double Layer ◽  
First Principles ◽  
Linear Response ◽  
Density Functional ◽  
Single Layer ◽  
Phonon Interaction ◽  
Functional Theory ◽  
Electron Phonon Interaction ◽  
The Density Functional Theory

Electron-phonon interaction in the Si(111)-supported rectangular √(7 ) ×√3 phases of In is investigated within the density-functional theory and linear-response. For both single-layer and double-layer √(7 ) ×√3 structures, it...

scholarly journals Strain Effects on the Electronic and Thermoelectric Properties of n(PbTe)-m(Bi2Te3) System Compounds

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4086
Author(s):  
Weiliang Ma ◽  
Marie-Christine Record ◽  
Jing Tian ◽  
Pascal Boulet
Keyword(s):  
Density Functional ◽  
Lattice Thermal Conductivity ◽  
Compressive Strain ◽  
Van Der Waals Interactions ◽  
Functional Theory ◽  
Band Engineering ◽  
Seebeck Coefficients ◽  
The Density Functional Theory ◽  
P Type ◽  
Narrow Band Gap Semiconductors

Owing to their low lattice thermal conductivity, many compounds of the n(PbTe)-m(Bi2Te3) homologous series have been reported in the literature with thermoelectric (TE) properties that still need improvement. For this purpose, in this work, we have implemented the band engineering approach by applying biaxial tensile and compressive strains using the density functional theory (DFT) on various compounds of this series, namely Bi2Te3, PbBi2Te4, PbBi4Te7 and Pb2Bi2Te5. All the fully relaxed Bi2Te3, PbBi2Te4, PbBi4Te7 and Pb2Bi2Te5 compounds are narrow band-gap semiconductors. When applying strains, a semiconductor-to-metal transition occurs for all the compounds. Within the range of open-gap, the electrical conductivity decreases as the compressive strain increases. We also found that compressive strains cause larger Seebeck coefficients than tensile ones, with the maximum Seebeck coefficient being located at −2%, −6%, −3% and 0% strain for p-type Bi2Te3, PbBi2Te4, PbBi4Te7 and Pb2Bi2Te5, respectively. The use of the quantum theory of atoms in molecules (QTAIM) as a complementary tool has shown that the van der Waals interactions located between the structure slabs evolve with strains as well as the topological properties of Bi2Te3 and PbBi2Te4. This study shows that the TE performance of the n(PbTe)-m(Bi2Te3) compounds is modified under strains.

scholarly journals H2O coordination in macropa complexes of f elements (Ac, La, Lu): feasibility of the 11th coordination site

2021 ◽  
Author(s):  
Attila Kovács ◽  
Zoltán Varga
Keyword(s):  
Aqueous Solution ◽  
Metal Ion ◽  
Density Functional ◽  
Molecular Level ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Coordination Site ◽  
Additional Ligand ◽  
Ligand Coordination ◽  
Bonding Properties

AbstractThe feasibility of an additional ligand coordination at the 11th coordination site of actinium, lanthanum, and lutetium ions in 10-fold coordinated macropa complexes has been studied by means of density functional theory calculations. The study covered the two main macropa conformers, Δ(δλδ)(δλδ) and Δ(λδλ)(λδλ), favoured by larger (Ac3+, La3+) and smaller (Lu3+) ions, respectively. At the molecular level, the coordination of H2O is the most favourable to the largest Ac3+ while only slightly less to La3+. Protonation of the picoline arms enhances the coordination by shifting the metal ion closer to the open site of the ligand. The choice of macropa conformer has only a slight influence on the strength and bonding properties of the H2O coordination. Aqueous solution environment decreases considerably the energy gain of H2O coordination at the 11th coordination site.

scholarly journals Study on the interaction between catechin and cholesterol by the density functional theory

2020 ◽  
Vol 18 (1) ◽  
pp. 357-368
Author(s):  
Kaiwen Zheng ◽  
Kai Guo ◽  
Jing Xu ◽  
Wei Liu ◽  
Junlang Chen ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Charge Transfer ◽  
Density Functional ◽  
Antioxidant Properties ◽  
Micelle Formation ◽  
Aromatic Rings ◽  
Hydrogen Bond Interaction ◽  
Functional Theory ◽  
The Density Functional Theory

AbstractCatechin – a natural polyphenol substance – has excellent antioxidant properties for the treatment of diseases, especially for cholesterol lowering. Catechin can reduce cholesterol content in micelles by forming insoluble precipitation with cholesterol, thereby reducing the absorption of cholesterol in the intestine. In this study, to better understand the molecular mechanism of catechin and cholesterol, we studied the interaction between typical catechins and cholesterol by the density functional theory. Results show that the adsorption energies between the four catechins and cholesterol are obviously stronger than that of cholesterol themselves, indicating that catechin has an advantage in reducing cholesterol micelle formation. Moreover, it is found that the molecular interactions of the complexes are mainly due to charge transfer of the aromatic rings of the catechins as well as the hydrogen bond interactions. Unlike the intuitive understanding of a complex formed by hydrogen bond interaction, which is positively correlated with the number of hydrogen bonds, the most stable complexes (epicatechin–cholesterol or epigallocatechin–cholesterol) have only one but stronger hydrogen bond, due to charge transfer of the aromatic rings of catechins.

A trinuclear chromium(III) chlorocarbyne

2021 ◽  
Author(s):  
Takashi Kurogi ◽  
Keiichi Irifune ◽  
Takahiro Enoki ◽  
Kazuhiko Takai
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Terminal Alkynes ◽  
Functional Theory ◽  
The Density Functional Theory

Reduction of CCl4 by CrCl2 in THF afforded a trinuclear chromium(III) carbyne [CrCl(thf)2)]3(μ3-CCl)(μ-Cl)3. The chlorocarbyne complex reacted with aldehydes to afford chloroallylic alcohols and terminal alkynes. The density functional theory...

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