scholarly journals Synthesis, characterization and biological study of new dinuclear zinc(II) and nickel(II) octaaza macrocyclic complexes

2019 ◽  
Vol 38 (1) ◽  
pp. 1
Author(s):  
Milena Krstic ◽  
Branka Petković ◽  
Miloš Milčić ◽  
Dušan Mišić ◽  
Juan Francisco Santibanez
Keyword(s):  
Density Functional ◽  
Zinc Complex ◽  
Complex Structure ◽  
Density Functional Theory Calculations ◽  
Biological Study ◽  
The Novel ◽  
Bacterial Strains ◽  
Electrical Conductivities ◽  
Spectral Peaks ◽  
Nitrato Complexes

Two new nitrato complexes of zinc and nickel with 1,4,8,11-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane (tpmc), have been synthesized and characterized. The IR spectral peaks showed that the coordinated and ionic nitrate ions are in agreement with the formula proposed by elemental analysis. Conductometric titrations predicted methanol to be a convenient solvent for synthesis and revealed the stoichiometry of the complexes, while molar electrical conductivities indicated a 1 : 3 complex electrolyte type for the zinc complex, and a 1 : 2 complex electrolyte type for the nickel complex. The optimized complex structure was obtained by molecular modeling and density functional theory calculations. The biological activity of the novel complexes was examined by screening eight different bacterial strains and two cancer cell lines. The zinc complex showed better antimicrobial activity against the bacterial strains, while the complexes did not show significance antiproliferative activity toward cancer cells MCF-7 and MDA-MB-231.

Targeting complex plutonium oxides by combining crystal chemical reasoning with density-functional theory calculations: the quaternary plutonium oxide Cs2PuSi6O15

2020 ◽  
Vol 56 (66) ◽  
pp. 9501-9504
Author(s):  
Kristen A. Pace ◽  
Vladislav V. Klepov ◽  
Matthew S. Christian ◽  
Gregory Morrison ◽  
Travis K. Deason ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Crystal Growth ◽  
Dft Calculations ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Crystal Chemical ◽  
The Novel ◽  
Functional Theory ◽  
The Stability ◽  
Chemical Reasoning

The stability of the novel Pu(iv) silicate, Cs2PuSi6O15, was predicted from a combination of crystal chemical reasoning and DFT calculations and confirmed by its synthesis via flux crystal growth.

scholarly journals Electrical Conductivities and Interactions in Binary Mixtures of Imidazolium-Based Ionic Liquids with Acetonitrile and Dimethyl Sulfoxide

2020 ◽  
Vol 71 (2) ◽  
pp. 392-402
Author(s):  
Oana Ciocirlan ◽  
Amalia Stefaniu
Keyword(s):  
Electrical Conductivity ◽  
Ionic Liquids ◽  
Dimethyl Sulfoxide ◽  
Binary Mixtures ◽  
Density Functional ◽  
Binary Systems ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Electrical Conductivities ◽  
Anion Type

This paper reports experimental electrical conductivities data of eight binary systems of four ionic liquids: 1-butyl-3-methylimidazolium tetrafluoroborate, [Bmim][BF4], 1-hexyl-3-methylimidazolium tetrafluoroborate, [Hmim][BF4], 1-butyl-3-methylimidazolium hexafluorophosphate, [Bmim][PF6] and 1-butyl-2,3-dimethyl-imidazolium tetrafluoroborate, [Bmmim][BF4] with the organic solvents dimethyl sulfoxide (DMSO) and acetonitrile (ACN) at atmospheric pressure and temperatures from 298.15 to 328.15 K. It was found that conductivities in the investigated ionic liquids follow the order: [Bmim][BF4] ] [Bmim][PF6] ][Bmmim][BF4] ] [Hmim][BF4]. Experimental results demonstrate that the binary mixtures possess higher electrical conductivity compared with pure components. Electrical conductivity data were correlated using Casteel�Amis and Arrhenius equations. The molar conductivity was derived from experimental data and fitted to Walden rule. The influence of the cation structure and anion type on the conductivity was discussed, which help understanding the intermolecular interactions in the binary systems. A deeper understanding of the transport behavior of ILs is given by means of density functional theory calculations (DFT)

scholarly journals Experimental and computational investigations of platinum complexes of selenium diimide and some novel selenium–nitrogen ligands

2016 ◽  
Vol 94 (4) ◽  
pp. 342-351
Author(s):  
Aino J. Karhu ◽  
Maarit Risto ◽  
J. Mikko Rautiainen ◽  
Raija Oilunkaniemi ◽  
Tristram Chivers ◽  
...  
Keyword(s):  
Density Functional ◽  
Platinum Complexes ◽  
Density Functional Theory Calculations ◽  
Major Product ◽  
Direct Reaction ◽  
The Novel ◽  
Functional Theory ◽  
Nmr Spectrum ◽  
Nitrogen Ligands ◽  
A Minor

The reaction of selenium diimide Se[N(t-Bu)]2 and PtCl2 afforded an N,N′-chelated complex [PtCl2{N,N′-Se[N(t-Bu)]2}] (1) in good yield and [PtCl2{N,N′-SeO[NH(t-Bu)]2}] (2) as a minor product. Attempts to prepare 2 by direct reaction of SeOCl2 with Li[NH(t-Bu)] in toluene followed by addition of PtCl2 produced cyclic Se4[N(t-Bu)]4 in solution (77Se NMR spectrum) and a small amount of the complex [PtCl3{Se,Se′,Se″-Se4[N(t-Bu)]4}][Pt2Cl5{Se,Se′,Se″-Se3[N(t-Bu)]2}]·3MeCN (3·3MeCN), which contains tridentate Se4[N(t-Bu)]4 in the cation and the novel, acyclic bridging ligand [SeN(t-Bu)SeN(t-Bu)Se]2– in the anion. The reaction of Se[N(t-Bu)]2 with [PtCl2(NCPh)2] in THF produced the dinuclear complex [Pt2Cl6{SeN(t-Bu)C(Ph)NH}2]·2C4H8O (4·2THF) as the major product and only a few crystals of 1. The possible formation of SeO[NH(t-Bu)]2 or 2 by the reaction of Se[N(t-Bu)]2 or 1, respectively, with adventitious water and the pathway for the production of 4 were investigated through density functional theory calculations. The X-ray structures of 1, 2, 3·3MeCN, and 4·2THF have been determined.

Theoretical Study of the Adsorption of Carbon Monoxide on Pristine and Silicon-Doped Boron Nitride Nanotubes

2008 ◽  
Vol 61 (12) ◽  
pp. 941 ◽  
Author(s):  
Ruoxi Wang ◽  
Dongju Zhang
Keyword(s):  
Boron Nitride ◽  
Density Functional ◽  
Chemical Interaction ◽  
Density Functional Theory Calculations ◽  
Boron Nitride Nanotubes ◽  
The Novel ◽  
Geometrical Structures ◽  
Si Doped ◽  
Silicon Doped ◽  
Novel Applications

In order to explore the novel application of boron nitride nanotubes (BNNTs), we investigate reactivities of pristine and silicon-doped (Si-doped) (8,0) single-walled BNNTs towards the CO molecule by performing density functional theory calculations. Compared with weak physisorption on the pristine BNNT, the CO molecule presents strong chemical interaction with the Si-doped BNNT, as indicated by the calculated geometrical structures and electronic properties for these systems. It is suggested that doping BNNTs with silicon is expected to be a suitable strategy for adjusting the properties of BNNTs, and that Si-doped BNNTs are expected to find novel applications in nanotechnology.

CONFORMATIONAL ANALYSIS OF NEVIRAPINE IN SOLUTIONS BASED ON NMR SPECTROSCOPY AND QUANTUM CHEMICAL CALCULATIONS

2006 ◽  
Vol 05 (04) ◽  
pp. 913-924 ◽  
Author(s):  
V. VAILIKHIT ◽  
P. BUNSAWANSONG ◽  
S. TECHASAKUL ◽  
S. HANNONGBUA
Keyword(s):  
Conformational Analysis ◽  
Reverse Transcriptase ◽  
Density Functional ◽  
Chemical Shifts ◽  
Complex Structure ◽  
Density Functional Theory Calculations ◽  
Transcriptase Inhibitor ◽  
Nmr Chemical Shifts ◽  
Solvation Free Energies ◽  
Hiv 1

The conformational analysis of HIV-1 Reverse Transcriptase Inhibitor, nevirapine, 11-cyclopropyl-5,-11dihydro-4-methyl-6H-dipyrido[3,2-b2′,3′-e][1,4]diazepin-6-one, was investigated using ab initio and density functional theory calculations. The fully optimized structures and rotational potential energies of the nitrogen and carbon bonds in the cyclopropyl ring (C15-N11-C17-C19, α) were examined in detail. Geometries obtained from all applied calculations show similarities to the complex structure with HIV-1 reverse transcriptase. To obtain more information on the structure, conformational minima of nevirapine, optimized at the B3LYP/6-31G** level, were calculated for the 1H, 13C, and 15N-NMR chemical shifts at the B3LYP/6-311++G** level using the GIAO approach in DMSO and chloroform IEFPCM solvation models. The calculated 1H, 13C-NMR chemical shifts agree well with the experimental data, which indicates that the geometry of nevirapine in solution is similar to that of the molecule in the inhibition complex. Solvation free energies (ΔG sol ) of nevirapine in DMSO and chloroform were also obtained.

scholarly journals Accelerated discovery of superoxide-dismutase nanozymes via high-throughput computational screening

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Zhenzhen Wang ◽  
Jiangjiexing Wu ◽  
Jia-Jia Zheng ◽  
Xiaomei Shen ◽  
Liang Yan ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Frontier Molecular Orbital ◽  
Side Reactions ◽  
The Novel ◽  
Energy Principle ◽  
Computational Screening ◽  
Metal Organic

AbstractThe activity of nanomaterials (NMs) in catalytically scavenging superoxide anions mimics that of superoxide dismutase (SOD). Although dozens of NMs have been demonstrated to possess such activity, the underlying principles are unclear, hindering the discovery of NMs as the novel SOD mimics. In this work, we use density functional theory calculations to study the thermodynamics and kinetics of the catalytic processes, and we develop two principles, namely, an energy level principle and an adsorption energy principle, for the activity. The first principle quantitatively describes the role of the intermediate frontier molecular orbital in transferring electrons for catalysis. The second one quantitatively describes the competition between the desired catalytic reaction and undesired side reactions. The ability of the principles to predict the SOD-like activities of metal-organic frameworks were verified by experiments. Both principles can be easily implemented in computer programs to computationally screen NMs with the intrinsic SOD-like activity.

scholarly journals Fluorescent Bis(guanidine) Copper Complexes as Precursors for Hydroxylation Catalysis

Inorganics ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 114 ◽  
Author(s):  
Florian Strassl ◽  
Alexander Hoffmann ◽  
Benjamin Grimm-Lebsanft ◽  
Dieter Rukser ◽  
Florian Biebl ◽  
...  
Keyword(s):  
Density Functional ◽  
Copper Complexes ◽  
Density Functional Theory Calculations ◽  
Special Role ◽  
The Novel ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Copper Dioxygen

Bis(guanidine) copper complexes are known for their ability to activate dioxygen. Unfortunately, until now, no bis(guanidine) copper-dioxygen adduct has been able to transfer oxygen to substrates. Using an aromatic backbone, fluorescence properties can be added to the copper(I) complex which renders them useful for later reaction monitoring. The novel bis(guanidine) ligand DMEG2tol stabilizes copper(I) and copper(II) complexes (characterized by single crystal X-ray diffraction, IR spectroscopy, and mass spectrometry) and, after oxygen activation, bis(µ-oxido) dicopper(III) complexes which have been characterized by low-temperature UV/Vis and Raman spectroscopy. These bis(guanidine) stabilized bis(µ-oxido) complexes are able to mediate tyrosinase-like hydroxylation activity as first examples of bis(guanidine) stabilized complexes. The experimental study is accompanied by density functional theory calculations which highlight the special role of the different guanidine donors.

Synthesis, Structure, Photoluminescent and Semiconductor Properties of, and Theoretical Calculations for, a Novel Zinc Complex

2017 ◽  
Vol 41 (10) ◽  
pp. 586-590 ◽  
Author(s):  
Xiu-Guang Yi ◽  
Wen-Tong Chen ◽  
Jian-Gen Huang ◽  
Ding-Wa Zhang ◽  
Yin-Feng Wang
Keyword(s):  
Density Functional ◽  
Zinc Complex ◽  
Theoretical Calculations ◽  
Three Dimensional ◽  
Density Functional Theory Calculations ◽  
Solvothermal Reaction ◽  
X Ray Diffraction ◽  
Light Spectrum ◽  
Functional Theory ◽  
Ligand Charge Transfer

A novel zinc complex [Zn3(2,2′-bi-1H-imidazole)2(1H-biimidazole)2(SO4)2] n has been synthesised through a solvothermal reaction and structurally characterised by single-crystal X-ray diffraction. It has a one-dimensional chain-like structure with both tetrahedral and square pyramidal zinc atoms. A three-dimensional supramolecular framework is constructed through hydrogen-bonding interactions. Photoluminescence shows that the complex displays an emission in the blue region of the light spectrum that time-dependent density functional theory calculations reveal can be attributed to ligand-to-ligand charge transfer. Solid-state diffuse reflectance measurements show the existence of a narrow optical band gap of 2.08 eV.

Field Effect Modulation of Electrocatalytic Hydrogen Evolution at Back-Gated Two-Dimensional MoS2 Electrodes

2019 ◽  
Author(s):  
Yan Wang ◽  
Sagar Udyavara ◽  
Matthew Neurock ◽  
C. Daniel Frisbie
Keyword(s):  
Electric Field ◽  
Hydrogen Evolution ◽  
Active Sites ◽  
Density Functional ◽  
Electrode Materials ◽  
Density Functional Theory Calculations ◽  
Electronic Charge ◽  
Back Side ◽  
Gate Electrode ◽  
Conventional Manner

<div> <div> <div> <p> </p><div> <div> <div> <p>Electrocatalytic activity for hydrogen evolution at monolayer MoS2 electrodes can be enhanced by the application of an electric field normal to the electrode plane. The electric field is produced by a gate electrode lying underneath the MoS2 and separated from it by a dielectric. Application of a voltage to the back-side gate electrode while sweeping the MoS2 electrochemical potential in a conventional manner in 0.5 M H2SO4 results in up to a 140-mV reduction in overpotential for hydrogen evolution at current densities of 50 mA/cm2. Tafel analysis indicates that the exchange current density is correspondingly improved by a factor of 4 to 0.1 mA/cm2 as gate voltage is increased. Density functional theory calculations support a mechanism in which the higher hydrogen evolution activity is caused by gate-induced electronic charge on Mo metal centers adjacent the S vacancies (the active sites), leading to enhanced Mo-H bond strengths. Overall, our findings indicate that the back-gated working electrode architecture is a convenient and versatile platform for investigating the connection between tunable electronic charge at active sites and overpotential for electrocatalytic processes on ultrathin electrode materials.</p></div></div></div><br><p></p></div></div></div>

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