Capto-Dative Stabilization by Thermal Oxidation of 2-Oxo-1,2,3,4-tetrahydropyrimidines

2016 ◽  
Vol 69 (8) ◽  
pp. 872 ◽  
Author(s):  
Hamid R. Memarian ◽  
Esmael Sanchooli ◽  
Hadi Amiri Rudbari ◽  
Giuseppe Bruno
Keyword(s):  
Density Functional ◽  
Population Analysis ◽  
Thermal Conditions ◽  
Acetonitrile Solution ◽  
Radical Intermediate ◽  
Mulliken Population ◽  
Functional Theory ◽  
Potassium Peroxydisulfate ◽  
The Density Functional Theory ◽  
Methoxy Substituent

Various 4,6-diaryl substituted 2-oxo-1,2,3,4-tetrahydropyrimidines (THPMs) were oxidized to 2-oxo-1,2-dihydropyrimidines (DHPMs) by potassium peroxydisulfate (PPS) in aqueous acetonitrile solution under thermal conditions. Based on the proposed oxidation reaction mechanism by way of a radical, a capto-dative stabilized radical intermediate, among two possible formed double benzylic/allylic radical centres, governs the type of product formed. Whereas the electron-donating nature of the additional methoxy-substituent enhances the rate of oxidation, its attachment to the radical intermediate decreases the radical stability, simultaneously causing the shift of the radical centre to the capto-dative stabilized benzylic radical centre. The data of the density functional theory computational studies concerning the bond lengths to the radical centres and Mulliken population analysis support the results of the experimental work.

First Principles Study of Surface Properties for Silicon Carbide-Derived Structures

2012 ◽  
Vol 433-440 ◽  
pp. 306-312
Author(s):  
Hong Ge Liu ◽  
Rui Jun Zhang ◽  
Hong Yan Jin ◽  
Qiu Xiang Liu
Keyword(s):  
Silicon Carbide ◽  
Surface Properties ◽  
First Principles ◽  
Density Functional ◽  
Population Analysis ◽  
Mulliken Population ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Nanoporous Surface ◽  
Pseudo Potential

Using first-principles ultra-soft pseudo-potential approach of the plane wave based on the density functional theory (DFT), we investigated the surface properties for silicon carbide-derived structure (i.e. SiCDS). The calculated results show that, movement of C and Si atoms caused by Si removal results in surface structural changing, and a nanoporous surface feature can be observed on the SiCDS surfaces when more Si atoms are removed. The mulliken population analysis indicates that the Si removal leads to the stronger chemical bonds between C–Si and the formation of new stronger chemical bands between C–C. From the density of states, as the Si removal proportion increases, C2p becomes gradually dominant in the SiCDS surface state electrons. Moreover, the Si removal leads to evidently different band gaps, indicating that the conductivity for SiCDS surface structures can be adjusted through the Si removal.

Fe-DOPED Ga12N12 CLUSTERS: ELECTRONIC AND MAGNETIC PROPERTIES

2013 ◽  
Vol 27 (30) ◽  
pp. 1350222 ◽  
Author(s):  
PENGFEI LU ◽  
CHENGJIE WU ◽  
ZIXIANG CONG ◽  
YILUAN LI ◽  
XIANLONG ZHANG ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Moment ◽  
Density Functional ◽  
Population Analysis ◽  
Mulliken Population Analysis ◽  
Mulliken Population ◽  
Functional Theory ◽  
Electronic And Magnetic Properties ◽  
The Density Functional Theory ◽  
Endohedral Doping

In this paper, we have investigated the structural, electronic and magnetic properties of Ga 12 N 12 cluster doped with monodoped and bidoped Fe atoms within the density functional theory (DFT). Substitutional, exohedral and endohedral doping are considered. It is observed that both monodoped and bidoped clusters tend to be in exohedral doping. Mulliken population analysis is performed to obtain the charge transfer and magnetic moment. The magnetic moment is mainly derived from 3d orbitals of Fe atom for all isomers, while the magnetic properties would rely on the Fe – Fe distance.

First-Principles Study of Ag3Sn, AgZn3 and Ag5Zn8 Intermetallic Compounds

2021 ◽  
Vol 871 ◽  
pp. 254-263
Author(s):  
Zhan Cheng ◽  
Guan Xing Zhang ◽  
Wei Min Long ◽  
Svitlana Maksymova ◽  
Jian Xiu Liu
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Elastic Anisotropy ◽  
Constant Density ◽  
Mulliken Population ◽  
Covalent Bonds ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Anisotropy Index ◽  
Ionic Bonds

The first-principles calculations by CASTEP program based on the density functional theory is applied to calculate the cohesive energy, enthalpy of formation, elastic constant, density of states and Mulliken population of Ag3Sn、AgZn3 and Ag5Zn8. Furthermore, the elastic properties, bonding characteristics, and intrinsic connections of different phases are investigated. The results show that Ag3Sn、AgZn3 and Ag5Zn8 have stability structural, plasticity characteristics and different degrees of elastic anisotropy; Ag3Sn is the most stable structural, has the strongest alloying ability and the best plasticity. AgZn3 is the most unstable structure, has the worst plasticity; The strength of Ag5Zn8 is strongest, AgZn3 has the weakest strength, the largest shear resistance, and the highest hardness. Ag5Zn8 has the maximum Anisotropy index and Ag3Sn has the minimum Anisotropy index. Ag3Sn、AgZn3 and Ag5Zn8 are all have covalent bonds and ionic bonds, the ionic bonds decrease in the order Ag3Sn>Ag5Zn8>AgZn3 and covalent bonds decreases in the order Ag5Zn8>Ag3Sn>AgZn3.

scholarly journals Novel Insights into the Hydroxylation Behaviors of α-Quartz (101) Surface and its Effects on the Adsorption of Sodium Oleate

Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 450 ◽  
Author(s):  
Zhang ◽  
Xu ◽  
Hu ◽  
He ◽  
Tian ◽  
...  
Keyword(s):  
Sodium Oleate ◽  
Density Functional ◽  
Population Analysis ◽  
Water Molecules ◽  
Mulliken Population ◽  
Flotation Reagents ◽  
Functional Theory ◽  
Rigorous Study ◽  
Adsorption Energies ◽  
Hydroxylated Surface

A scientific and rigorous study on the adsorption behavior and molecular mechanism of collector sodium oleate (NaOL) on a Ca2+-activated hydroxylated α-quartz surface was performed through experiments and density functional theory (DFT) simulations. The rarely reported hydroxylation behaviors of water molecules on the α-quartz (101) surface were first innovatively and systematically studied by DFT calculations. Both experimental and computational results consistently demonstrated that the adsorbed calcium species onto the hydroxylated structure can significantly enhance the adsorption of oleate ions, resulting in a higher quartz recovery. The calculated adsorption energies confirmed that the adsorbed hydrated Ca2+ in the form of Ca(H2O)3(OH)+ can greatly promote the adsorption of OL− on hydroxylated quartz (101). In addition, Mulliken population analysis together with electron density difference analysis intuitively illustrated the process of electron transfer and the Ca-bridge phenomenon between the hydroxylated surface and OL− ions. This work may offer new insights into the interaction mechanisms existing among oxidized minerals, aqueous medium, and flotation reagents.

scholarly journals Comparative DFT study on selective hydrogenation of acrolein catalyzed by pure Mo2C(001) and Pt/Mo2C(001)

2021 ◽  
Author(s):  
Jinrong Wu ◽  
Yanping Huang ◽  
Weiyan Wang ◽  
Wensong Li ◽  
Zhengke Li ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Allyl Alcohol ◽  
Active Sites ◽  
Density Functional ◽  
Population Analysis ◽  
Mulliken Population Analysis ◽  
Mulliken Population ◽  
Functional Theory ◽  
Elementary Reactions ◽  
Bond Hydrogenation

Abstract In this paper, Density Functional Theory (DFT) calculations were conducted to study the adsorption and stepwise hydrogenation of acrolein (CH 2 =CHCH=O) on pure Mo 2 C(001) and Pt/Mo 2 C(001). The electronic properties were investigated by Mulliken population analysis. The results showed that Mo atoms obtained some electrons from surrounding Pt and C atoms, thereby enhancing the hydrogenation activity of Mo atoms around Pt atoms and forming local active sites dominated by Mo atoms around Pt atoms. As a result, the adsorption energy of the species on Pt/Mo 2 C(001) is generally higher than that on Mo 2 C(001), and the activation energies of the elementary reactions involved in stepwise hydrogenation of acrolein on Pt/Mo 2 C(001) are lower than those on Mo 2 C(001). Moreover, Pt/Mo 2 C(001) exhibits higher selectivity for C=O bond hydrogenation than Mo 2 C(001) and produces more allyl alcohol.

Theoretical study of the geometrical and electronic properties of Be2Mg+ n (n = 1–11) clusters

2019 ◽  
Vol 9 (7) ◽  
pp. 778-785 ◽  
Author(s):  
Ben-Chao Zhu ◽  
Zhang Yu ◽  
Wang Ping ◽  
Lu Zeng ◽  
Shuai Zhang
Keyword(s):  
Electronic Properties ◽  
Ground State ◽  
Density Functional ◽  
Population Analysis ◽  
Dft Method ◽  
Mulliken Population ◽  
Functional Theory ◽  
Fragmentation Energy ◽  
Average Binding Energy ◽  
Ground State Structures

By using Density Functional Theory (DFT) method at the B3LYP/6-311G level, the structures, stabilities, and electronic properties of cationic Be2Mg+ n (n = 1–11) clusters have been systematically studied. The optimized geometry show that the ground state structures of cationic Be2Mg+ n (n = 1–11) clusters favor 3D structures except n = 1, 2. Furthermore, the average binding energy E b, the second-order energy differences Δ2E, the fragmentation energy Ef and the HOMO-LUMO energy Egap of the ground state of cationic Be2Mg– n (n = 1–11) clusters are calculated, the final results indicate that Be2Mg+6 and Be2Mg+9 clusters have a higher stability than other clusters. Additionally, the NCP, NEC and Mulliken population analysis reveal that the charges in cationic Be2Mg+ n (n = 1–11) clusters transfer from Mg atom to Be atoms, and strong sp hybridizations are presented in Be atoms of Be2Mg+ n clusters. Finally, the polarizability analysis indicates that the nuclei and electronic clouds of clusters are affected by external field with the increase of cluster size.

scholarly journals Dimethyl sulfoxide as a strongly coordinating solvent: 3′,4′-dihydroxyflavone-Cu(II)-DMSO system case study

2020 ◽  
Vol 13 (2) ◽  
pp. 38-48
Author(s):  
Miriama Šimunková ◽  
Michal Malček
Keyword(s):  
Dimethyl Sulfoxide ◽  
Density Functional ◽  
Chemical Interaction ◽  
Mulliken Population ◽  
Spin Distribution ◽  
Functional Theory ◽  
Dmso System ◽  
The Density Functional Theory ◽  
Coordination Ability

Abstract Dimethyl sulfoxide (DMSO) is an aprotic organic solvent widely used in laboratory practice due to its ability to dissolve both polar and nonpolar compounds. However, DMSO is also commonly known as a strongly coordinating solvent, especially towards transition metal containing complexes. In this study, estimation of the coordination ability of DMSO towards the Cu(II) ion was attempted, employing a model system composed of 3′,4′-dihydroxyflavone-Cu(II) complex in the presence of explicit DMSO molecules, using the density functional theory (DFT). Nature of the Cu-DMSO chemical interaction (i.e. Cu-O bonding) was studied within the framework of quantum theory of atoms in molecules (QTAIM). Impact of DMSO coordination on the charge and spin distribution at Cu(II) ion was inspected using Mulliken population and QTAIM analysis.

CO Adsorption on the AunS(n=1~6) Clusters: The First-Principles Study

2011 ◽  
Vol 341-342 ◽  
pp. 42-47
Author(s):  
Shui Lian Chi ◽  
Ming Chen ◽  
Song Lin Peng
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Population Analysis ◽  
Co Adsorption ◽  
Bimetallic Clusters ◽  
Mulliken Population Analysis ◽  
Mulliken Population ◽  
Functional Theory ◽  
Au Clusters ◽  
Adsorption Energies

Density functional theory (DFT) calculations are performed to investigate CO bonded on the AunS (n=1~6) bimetallic clusters. It is found that the adsorption energies of CO on the AunS(n=1~6) clusters are greater than those on the pure Au clusters of corresponding sizes. This means that doped S atom can enhance CO adsorption on the Au clusters. Furthermore, through the Mulliken population analysis, we can see that charges transfer from the Au clusters to S atom, while charges donate to the Au clusters from the CO in CO/AunS sytem.

A DFT and HRTEM Study on MoS2/Co: Locating Promoters in Catalytic Nanostructures

2011 ◽  
Vol 1309 ◽  
Author(s):  
Manuel Ramos ◽  
Gilles Berhault ◽  
Jose Rurik Farias ◽  
Jose Trinidad Elizalde ◽  
Domingo Ferrer ◽  
...  
Keyword(s):  
Lower Energy ◽  
Density Functional ◽  
Population Analysis ◽  
Mulliken Population Analysis ◽  
Density Functional Theory Study ◽  
Mulliken Population ◽  
Strong Electron ◽  
Functional Theory ◽  
Electron Donation ◽  
Energy Package

ABSTRACTLocating cobalt promoters on catalytically MoS2 structures is a challenging task to achieve; this is due to the size on those MoS2 nanostructures. Previous reports in the literature indicate that specific locations for Co in MoS2 slabs are (1010)-plane creating either a sulfur-Co or Molybdenum-Co termination edge, due to lower energy required for the permutation Mo, S and Co to occur. We present results obtained from Density Functional Theory study done on the interface between MoS2 and Co9S8 crystal structures; the interface show an interesting thiocubane cluster and it is suspected to be the responsible for Mo-S-Co bonding to exist, along with HDS reaction. In order to understand electronic properties on thiocubane Density of States and Mulliken Population Analysis calculations were implemented using Cambridge Serial Total Energy Package (CASTEP). Results indicate a strong electron donation from Co to Mo through intermediate sulfur atom bonded to both metals while an enhanced metallic character is also found.

Density functional theory study on silver clusters using dimers, trimers, and tetramers as building units

2015 ◽  
Vol 93 (3) ◽  
pp. 318-325 ◽  
Author(s):  
T.N. Rekha ◽  
Beulah J.M. Rajkumar
Keyword(s):  
Density Functional Theory ◽  
Molecular Orbital ◽  
Density Functional ◽  
Nearest Neighbor ◽  
Population Analysis ◽  
Growth Patterns ◽  
Binding Energies ◽  
Silver Clusters ◽  
Mulliken Population ◽  
Functional Theory

We systematically investigate growth patterns of small silver clusters, Agn (n ≤ 10), using density functional theory (DFT) and time-dependent density functional theory (TDDFT), considering Ag2, Ag3, and Ag4 as basic building units. Nearest-neighbor distances increase gradually with increasing n. Compared with an earlier study, where the clusters were developed by adding one atom at a time, the clusters derived in this investigation had considerably higher computed binding energies, confirming increased stability and suggesting possible growth patterns using these basic units. We used TDDFT methods to simulate the ultraviolet–visible spectra of the silver clusters, which are in good agreement with the reported experimental absorption spectrum of Ag nanoparticles. Our study indicates that the clusters formed with units of Ag3 tend to form more reactive clusters, particularly if an odd number of atoms is involved. Further, the higher level of computations employed gives better insight into the process of particle growth. The disproportionation energies of clusters built using this scheme are compared with those built one atom at a time. Mulliken population analysis of the distributions indicates the presence of polarities among the atoms in some of the cluster isomers, suggesting sites of increased activity. In addition, patterns established for the highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), and HOMO–LUMO energy gaps may be used to model stable clusters with modified optoelectrical properties.

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