scholarly journals Spectroscopic Insight into Tetrahedrally Distorted Square Planar Copper(II) Complex: XRD/HSA, Physicochemical, DFT, and Thermal Investigations

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1179
Author(s):  
Ahmed Boshaala ◽  
Abrahem F. Abrahem ◽  
Abdulla Ali Almughery ◽  
Nabil Al-Zaqri ◽  
Abdelkader Zarrouk ◽  
...  
Keyword(s):  
Density Functional ◽  
Gravimetric Analysis ◽  
Perfect Agreement ◽  
Functional Theory ◽  
Square Planar ◽  
The Density Functional Theory ◽  
Thermal Investigations ◽  
Ligand Coordination ◽  
Thermal Stability Of ◽  
Cis Isomer

The reaction of bidentate N-S-thione-Schiff base, (E)-benzyl 2-(1-(4-chlorophenyl)- ethylidene)hydrazinecarbodithioate, with Cu(NO3)2·3H2O produced a cis-Cu(II) complex. The molecular structure was confirmed and characterized by CHN-EA, FAB-MS, IR, and UV-Vis analyses. The XRD supported cis-isomer of the bis anionic bidentate N (azomethine) and S (thiol) ligand coordination mode in tetrahedrally distorted square planar, rarely reported in the literature. The results of the XRD-bond lengths were in perfect agreement with the density functional theory (DFT) calculation. DFT-calculated angles around the Cu(II) center displayed slightly less distortion around the metal center from those of XRD. Additionally, the thermal stability of the complex was evaluated via thermal gravimetric analysis (TGA). Two-dimensional fingerprint (2D-FP), Hirshfeld surface analysis (HSA), and molecular electrostatic potential (MEP) support the XRD-packing results with the existence of the H⸱⸱⸱Cl and CH⸱⸱⸱π bonds as the main interactions in the crystal lattice of the desired complex.

A combined study of the equation of state of monazite-type lanthanum orthovanadate usingin situhigh-pressure diffraction andab initiocalculations

2014 ◽  
Vol 70 (3) ◽  
pp. 533-538 ◽  
Author(s):  
Olga Ermakova ◽  
Javier López-Solano ◽  
Roman Minikayev ◽  
Stefan Carlson ◽  
Agata Kamińska ◽  
...  
Keyword(s):  
Equation Of State ◽  
Density Functional ◽  
Room Temperature ◽  
Theoretical Data ◽  
Perfect Agreement ◽  
Functional Theory ◽  
Compression Direction ◽  
The Density Functional Theory ◽  
Murnaghan Equation

Lanthanum orthovanadate (LaVO4) is the only stable monazite-type rare-earth orthovanadate. In the present paper the equation of state of LaVO4is studied usingin situhigh-pressure powder diffraction at room temperature, andab initiocalculations within the framework of the density functional theory. The parameters of a second-order Birch–Murnaghan equation of state,i.e.those fitted to the experimental and theoretical data, are found to be in perfect agreement – in particular, the bulk moduli are almost identical, with values of 106 (1) and 105.8 (5) GPa, respectively. In agreement with recent reported experimental data, the compression is shown to be anisotropic. Its nature is comparable to that of some other monazite-type compounds. The softest compression direction is determined.

DFT STUDIES ON THE STABILITY OF THE TRANS AND CIS ISOMERS IN THE SQUARE PLANAR PALLADIUM(II) COMPLEXES Pd(I)(PPh3)(η3-XCHC(Ph)CHR) (X = CMe3, CO2Me, P(O)(OMe)2, AND SO2H; R = H, Me)

2008 ◽  
Vol 07 (04) ◽  
pp. 505-515
Author(s):  
LIQIN XUE ◽  
GUOCHEN JIA ◽  
ZHENYANG LIN
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Relative Stability ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Dft Studies ◽  
Functional Theory ◽  
Square Planar ◽  
The Stability ◽  
Cis Isomer

The relative stability of the trans and cis isomers in the square planar palladium(II) complexes Pd ( I )( PPh 3)(η3- XCHC ( Ph ) CHR ) ( X = H , Me , CMe 3, CO 2 Me , P ( O )( OMe )2, and SO 2 H ; R = H , Me ) was investigated with the aid of the B3LYP density functional theory calculations. We examined how the substituents X, with different electronic properties, of the η3-allyl ligands affect the relative stability of the trans and cis isomers. Through the investigation, we were able to explain the trans/cis relative stability derived from the experimentally measured trans/cis isomer ratios in the palladium(II) complexes.

AB INITIO STUDY OF THE MOLECULAR STRUCTURE AND THERMAL CIS–TRANS ISOMERIZATION OF 3,3′-DIAMINO-4,4′-AZOFURAZAN AND 3,3′-DIAMINO-4,4′-AZOXYFURAZAN

2009 ◽  
Vol 08 (03) ◽  
pp. 507-517 ◽  
Author(s):  
LUOXIN WANG ◽  
XINLIN TUO ◽  
HANTAO ZOU ◽  
CHANGHAI YI ◽  
XIAOGONG WANG
Keyword(s):  
Density Functional ◽  
Energy Difference ◽  
Molecular Structures ◽  
Ab Initio Study ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Azo Group ◽  
Low Sensitivity ◽  
Inversion Mechanism ◽  
Cis Isomer

In this work, we carried out the density functional theory (DFT) calculations in order to understand the molecular structures and thermal trans–cis isomerization of 3,3′-diamino-4,4′-azofurazan (DAAzF) and 3,3′-diamino-4,4′-azoxyfurazan (DAAF). We found that the azo group oxidation of DAAzF leading to the formation of DAAF induced evidently the twist of azofurazan molecule and weakened one of CN bonds connecting the furazan rings and azo group. This means that DAAzF is more stable than DAAF. In addition, the oxidation of azo group has a significant influence on the energy difference between trans- and cis-isomer of azofurazan. The energy difference between the isomers of DAAF is only about half of that of DAAzF. Furthermore, the thermal trans–cis isomerization of DAAzF and DAAF was found to follow a different mechanism: an inversion mechanism for DAAzF and a rotation mechanism for DAAF. By analyzing the reversible trans–cis isomerization process, we firstly proposed that a self-desensitization effect could be responsible for the low sensitivity of azofurazan. This new desensitization mechanism may be useful in the design of novel high energetic density material.

scholarly journals Theoretical Studies on The Mechanism of Pd2+-Catalyzed Regioselective C-H Alkylation of Indole With MesICH2CF3OTf

2021 ◽  
Author(s):  
Yao Shi ◽  
Hongsheng Ma ◽  
Jiaxuan Shao ◽  
chao deng
Keyword(s):  
Reaction Mechanism ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Activation Process ◽  
Acetate Anion ◽  
Functional Theory ◽  
Planar Configuration ◽  
Square Planar ◽  
The Density Functional Theory ◽  
Calculation Results

Abstract The reaction mechanism of Pd2+-catalyzed regioselective C–H alkylation of indole with MesICH2CF3OTf has been investigated by the density functional theory calculations. The reaction mechanism mainly contains four steps：C-H activation, oxidative addition, reductive elimination and ligands substitution. From our calculations, we find that the C-H activation step was realized by the acetate anion (-OAc) assisted CMD process and the transition state of C-H activation process is a square planar configuration. Moreover, the calculation results suggest that the regioselectivity of C-H bond alkylation of indole with MesICH2CF3OTf can be ascribed to the different stability of the CMD transition states in C-H activation step and different acidities of C-H bonds.

scholarly journals The Thermal Properties of L12 Phases in Aluminum Enhanced by Alloying Elements

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1420
Author(s):  
Jihang Lan ◽  
Zhaoqun Chen ◽  
Linghong Liu ◽  
Qingzhou Zhang ◽  
Mengdong He ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Density Functional ◽  
High Strength ◽  
Careful Analysis ◽  
Al Alloys ◽  
Functional Theory ◽  
Covalently Bonded ◽  
The Density Functional Theory ◽  
Firm Basis ◽  
Thermal Stability Of

The L12 type trialuminide compounds Al3M possess outstanding mechanical properties, which enable them to be ideal for dispersed strengthening phases for the high-strength thermally stable Al based alloys. Ab-initio calculations based on the density functional theory (DFT) were performed to study the structural, electronic, thermal, and thermodynamic properties of L12-Al3M (M = Er, Hf, Lu, Sc, Ti, Tm, Yb, Li, Mg, Zr) structures in Al alloys. The total energy calculations showed that the L12 structures are quite stable. On the basis of the thermodynamic calculation, we found that the Yb, Lu, Er, and Tm atoms with a larger atomic radii than Al promoted the thermal stability of the Al alloys, and the thermal stability rank has been constructed as: Al3Yb > Al3Lu > Al3Er > Al3Tm > Al, which shows an apparent positive correlation between the atomic size and thermal stability. The chemical bond offers a firm basis upon which to forge links not only within chemistry but also with the macroscopic properties of materials. A careful analysis of the charge density indicated that Yb, Lu, Er, and Tm atoms covalently bonded to Al, providing a strong intrinsic basis for the thermal stability of the respective structures, suggesting that the addition of big atoms (Yb, Lu, Er, and Tm) are beneficial for the thermal stability of Al alloys.

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.

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