Electronic Parameters of Diode Based Organometallic Semiconductor Dyes Centered Ruthenium Complexes with Active COOH Terminals

In this study, the ruthenium complexes, which is an organometallic N-3 and C-106 semiconductor material, was coated on indium tin oxide (ITO) by using the self-assembled technique and thus a diode containing an organometallic interface was produced. The effects of this interface on the electronic parameters of the diode were investigated. It is aimed to improve the heterogeneity problem of the inorganic/organic interface by chemically bonding these materials from COOH active parts to the ITO surface. In order to understand how the electronic parameters of the diode change with this modification, the Schottky diode electrical characterization approach has been used. The charge mobility of the diode was calculated using the current density-voltage curve (J–V) characteristic with Space Charge Limited Current (SCLC) technique. When the electrical field is applied to the diode, it can be said that the ruthenium complexes molecules create an electrical dipole and the tunneling current is transferred to the anode contact ITO through the ruthenium molecule through the charge carrier, thus contributing to the hole injection. The morphology of these interface modifications was examined by Atomic Force Microscope (AFM) and surface potential energy by KelvinProbe Force Microscope (KPFM). To investigate local conductivity of bare ITO and modified ITO surface, Scanning Spreading Resistance Microscopy (SSRM) that is a conductive AFM analyzing technique were performed by applying voltage to the conductive tip and to the sample. According to the results of this work the diode containing N-3 material shows the best performance in terms of charge injection to the ITO due to possess the lowest barrier height Φb as 0.43 eV.

Investigation of the Two-Mode Regime of Two-Gap Photonic-Crystal Resonance Systems Produced on a Printed Circuit Board with Fractal Elements "Minkowski Island

Introduction. The development of new amplifiers and generators of the Ku- and K-bands (12…27 GHz) for use in onboard equipment is increasingly attracting research interest. Low-voltage multi-beam klystrons (LMBK) can be a promising element base for such devices. Serious problems are associated with the need to suppress parasitic modes of oscillations in NMLK operating in the centimeter and millimeter range. A possible solution is to use double-gap photonic-crystal resonators (DPCR) in LMBK. Another promising direction for improving the characteristics of such resonators is to use resonant segments of strip lines with fractal elements. In this case, the strip lines are placed on a dielectric substrate in the interaction space. Such resonators exhibit new properties that are useful for klystrons (an increase in characteristic impedance, suppression of the spectrum of unwanted frequencies, a reduction in mass and dimensions).Aim. Determination of an optimal set of electrodynamic and electronic parameters of double-gap photonic-crystal resonance systems with fractal elements "Minkowski Island" when operated as part of the LMBK resonator system, excited on π- and 2π-modes of oscillation.Materials and methods. To calculate the electrodynamic parameters of resonators, the method of finite differences in the time domain was used. The well-known Wessel-Berg method was used to calculate electronic parameters, such as the Ge / G0 electronic conductivity and the coupling coefficient M.Results. The main electrodynamic parameters of the resonator – Q-factor, resonant frequency and characteristic impedance – were investigated. The electronic parameters of the resonator, the coefficient of coupling with the electron beam, and the relative electronic conductivity for π- and 2π-modes of oscillations were calculated. In this case, three variants of the resonator with zero, first and second iterations of the fractal element were investigated. The amplitude-frequency characteristics of the resonator were investigated with a change in the pitch of the photonic crystal lattice. An estimation of the inhomogeneity of the high-frequency field in the interaction spaces of the resonator was carried out. Operational conditions were determined simultaneously for two types of oscillations without self-excitation.Conclusion. The results can find application in the development of resonator systems for klystron-type devices in the centimeter and millimeter ranges.

Tangeretin and its Derivatives: An Integrative Bioinformatic Study of Obesity and Related Immunodeficiency

Obesity is a complex and major public health concern known to exacerbate many diseases. There are increasing evidences stating the obese people due to adiposity are getting more susceptible to immune deficiency disorders. Tangeretin is a key member of flavonoids reported to have many favourable biological activities. In search of novel leads in ameliorating obesity and related immunodeficiency, the present study is aimed at the in silico evaluation of tangeretin derivatives to assess their biological role. Initially tangeretin derivatives are designed by molecular manipulation approach.Drug likeness and bioactivity score prediction was done using Molinspiration web tool. Swiss ADME prediction and toxicological predictions were performed. In silico Molecular Docking studies were performed by employing a flexible ligand docking approach using Schrodinger on the protein targets namely leptin, Fat mass and obesity associated protein (FTO), Pancreatic lipase, Peroxisome proliferated receptor (PPARɣ) and NADH oxidase. Further the electronic parameters were computed for the best fitted ligands by DFT analysis. The evaluation of results was made based on Glide (Schrodinger) dock score. Out of 18 screened compounds, some of them showed the best docking scores with the targets when compared with the standard (Lovastatin). Particularly the two ligands (L-13 and L-8) showed the best binding score with all five targets. Moreover, DFT analysis carried out for the tangeretin and best fitted ligands (L13 and L8) substantiated the other in silico studies. These findings probably provide excellent lead candidates for the development of therapeutic drugs in combating obesity and related immune deficiency.

Coordination Chemistry of Phosphinocarbonyls with Platinum

<p>This thesis reports the coordination chemistry of phosphinocarbonyl ligands with platinum and describes the influence of phosphine substituents on the mechanism of chelation and the coordination mode of the carbonyl moiety. The ligands synthesised were 2-diphenylphosphinobenzaldehyde (1), 2-diphenylphosphinoacetophenone (2), 2-bis(pentafluorophenyl)phosphinobenzaldehyde (3), and 2-di-tert-butylphosphinobenzaldehyde (4). Compounds 1, 3, and 4 were selected on the basis of their steric bulk and extent to which they donate electron density to the metal. Compound 2 contained the same phosphine substituents to 1, but is the methyl ketone analogue and therefore does not contain the CHO moiety. The cone angle and electronic parameter of compounds 1–4 were compared to the reported values of PPh3, PPh(C6F5)2, and PPhtBu2. Compounds 3 and 4 were similarly bulky, and had larger cone angles than 1. The electron donating capacity of compound 4 was greater than that of 1, and compound 3 was the least electron donating. A new synthetic method for the preparation of 4 is also reported. The coordination chemistry of ligands 1–4 was investigated with platinum(II) and platinum(0) starting materials to assess the influence of the steric and electronic parameters of the phosphine on the chelation of the ligand through the carbonyl to platinum. Coordination of the ligand went through the initial coordination of the phosphine and, depending on the identity of that phosphine, may be followed by chelation of the carbonyl moiety to form a P,C chelate. However, the site of the platinum–carbon bond in the P,C metallacycle depends on the ligand employed. Coordination of the phosphinoaldehyde ligands 1, 3, and 4 produced Pt-C bonds via the C-H activation of the aldehyde CHO group whereas for ketophosphine 2, C-H activation occurred at the α-methyl group. The rate at which C-H activation occurred increased with increasing electron donation from the phosphorus to platinum. Compound 4 chelates to platinum more rapidly than compound 1, while 3 did not undergo chelation at room temperature. Although chelation was only observed to occur via C-H activation, the final products of the coordination reactions of 1–4 with platinum starting materials differed depending on the identity of the ligand. The C-H activation of two molecules of 1 with platinum(II) or platinum(0) produced a platina-β-diketone, cis-[Pt(P,C-2-PPh2C6H4CO)2] (21), which is capable of coordinating to H+, Li+, BF2 +, and [Rh(1,5-cyclooctadiene)]+ between the mutually cis carbonyl groups. One carbonyl moiety of 21 can also undergo condensation with primary amines and ammonia to produce platina-β-ketoimine complexes. The ketone moiety of ligand 2 reacted with platinum(II) starting materials through C-H activation of the terminal methyl group to form the six-membered bis-chelate complex analogous to complex 21. The reaction of 2 with platinum(0) starting materials resulted in the formation of a platinum hydride intermediate which mediated chelation through the partial reduction of the ketone group of one ligand, to form the product, [Pt(P,C-2-PPh2C6H4COCH2)(P,C-2-PPh2C6H4C(OH)CH3)] (48) . The reaction of 3 with [PtMe2(1,5-hexadiene)] at elevated temperatures resulted in the formation of [Pt(P,C-2-PPh2C6H4)(P,C-2-PPh2C6H4CO)] (54) – a decarbonylated and ortho-metallated complex containing a four-membered metallacycle. The platinum-phosphorus bond in the four-membered ring of 54 has a bond distance of 2.385(2) Å – the longest Pt–P bond reported to date. Ligand 4 reacted rapidly with platinum(II) starting materials and produced numerous chelation products. Complexes of ligand 4 were only observed to contain mutually trans phosphines, likely due to the steric bulk of the tert-butyl substituents. Comparison of the coordination chemistry of ligands 1–4 suggests that the propensity toward C-H activation of the ligands is predominantly determined by the electronic character of the phosphine (although steric effects cannot be disregarded), and the more electron-rich the phosphine, the more rapidly chelation occurs.</p>

Coordination Chemistry of Phosphinocarbonyls with Platinum

<p>This thesis reports the coordination chemistry of phosphinocarbonyl ligands with platinum and describes the influence of phosphine substituents on the mechanism of chelation and the coordination mode of the carbonyl moiety. The ligands synthesised were 2-diphenylphosphinobenzaldehyde (1), 2-diphenylphosphinoacetophenone (2), 2-bis(pentafluorophenyl)phosphinobenzaldehyde (3), and 2-di-tert-butylphosphinobenzaldehyde (4). Compounds 1, 3, and 4 were selected on the basis of their steric bulk and extent to which they donate electron density to the metal. Compound 2 contained the same phosphine substituents to 1, but is the methyl ketone analogue and therefore does not contain the CHO moiety. The cone angle and electronic parameter of compounds 1–4 were compared to the reported values of PPh3, PPh(C6F5)2, and PPhtBu2. Compounds 3 and 4 were similarly bulky, and had larger cone angles than 1. The electron donating capacity of compound 4 was greater than that of 1, and compound 3 was the least electron donating. A new synthetic method for the preparation of 4 is also reported. The coordination chemistry of ligands 1–4 was investigated with platinum(II) and platinum(0) starting materials to assess the influence of the steric and electronic parameters of the phosphine on the chelation of the ligand through the carbonyl to platinum. Coordination of the ligand went through the initial coordination of the phosphine and, depending on the identity of that phosphine, may be followed by chelation of the carbonyl moiety to form a P,C chelate. However, the site of the platinum–carbon bond in the P,C metallacycle depends on the ligand employed. Coordination of the phosphinoaldehyde ligands 1, 3, and 4 produced Pt-C bonds via the C-H activation of the aldehyde CHO group whereas for ketophosphine 2, C-H activation occurred at the α-methyl group. The rate at which C-H activation occurred increased with increasing electron donation from the phosphorus to platinum. Compound 4 chelates to platinum more rapidly than compound 1, while 3 did not undergo chelation at room temperature. Although chelation was only observed to occur via C-H activation, the final products of the coordination reactions of 1–4 with platinum starting materials differed depending on the identity of the ligand. The C-H activation of two molecules of 1 with platinum(II) or platinum(0) produced a platina-β-diketone, cis-[Pt(P,C-2-PPh2C6H4CO)2] (21), which is capable of coordinating to H+, Li+, BF2 +, and [Rh(1,5-cyclooctadiene)]+ between the mutually cis carbonyl groups. One carbonyl moiety of 21 can also undergo condensation with primary amines and ammonia to produce platina-β-ketoimine complexes. The ketone moiety of ligand 2 reacted with platinum(II) starting materials through C-H activation of the terminal methyl group to form the six-membered bis-chelate complex analogous to complex 21. The reaction of 2 with platinum(0) starting materials resulted in the formation of a platinum hydride intermediate which mediated chelation through the partial reduction of the ketone group of one ligand, to form the product, [Pt(P,C-2-PPh2C6H4COCH2)(P,C-2-PPh2C6H4C(OH)CH3)] (48) . The reaction of 3 with [PtMe2(1,5-hexadiene)] at elevated temperatures resulted in the formation of [Pt(P,C-2-PPh2C6H4)(P,C-2-PPh2C6H4CO)] (54) – a decarbonylated and ortho-metallated complex containing a four-membered metallacycle. The platinum-phosphorus bond in the four-membered ring of 54 has a bond distance of 2.385(2) Å – the longest Pt–P bond reported to date. Ligand 4 reacted rapidly with platinum(II) starting materials and produced numerous chelation products. Complexes of ligand 4 were only observed to contain mutually trans phosphines, likely due to the steric bulk of the tert-butyl substituents. Comparison of the coordination chemistry of ligands 1–4 suggests that the propensity toward C-H activation of the ligands is predominantly determined by the electronic character of the phosphine (although steric effects cannot be disregarded), and the more electron-rich the phosphine, the more rapidly chelation occurs.</p>

Plant-Derived and Dietary Hydroxybenzoic Acids—A Comprehensive Study of Structural, Anti-/Pro-Oxidant, Lipophilic, Antimicrobial, and Cytotoxic Activity in MDA-MB-231 and MCF-7 Cell Lines

Seven derivatives of plant-derived hydroxybenzoic acid (HBA)—including 2,3-dihydroxybenzoic (2,3-DHB, pyrocatechuic), 2,4-dihydroxybenzoic (2,4-DHB, β-resorcylic), 2,5-dihydroxybenzoic (2,5-DHB, gentisic), 2,6-dihydroxybenzoic (2,6-DHB, γ-resorcylic acid), 3,4-dihydroxybenzoic (3,4-DHB, protocatechuic), 3,5-dihydroxybenzoic (3,5-DHB, α-resorcylic), and 3,4,5-trihydroxybenzoic (3,4,5-THB, gallic) acids—were studied for their structural and biological properties. Anti-/pro-oxidant properties were evaluated by using DPPH• (2,2-diphenyl-1-picrylhydrazyl), ABTS•+ (2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), FRAP (ferric-reducing antioxidant power), CUPRAC (cupric-reducing antioxidant power), and Trolox oxidation assays. Lipophilicity was estimated by means of experimental (HPLC) and theoretical methods. The antimicrobial activity against Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Staphylococcus aureus (S. aureus), Bacillus subtilis (B. subtilis), Salmonella enteritidis (S. enteritidis), and Candida albicans (C. albicans) was studied. The cytotoxicity of HBAs in MCF-7 and MDA-MB-231 cell lines was estimated. Moreover, the structure of HBAs was studied by means of experimental (FTIR, 1H, and 13C NMR) and quantum chemical DFT methods (the NBO and CHelpG charges, electrostatic potential maps, and electronic parameters based on the energy of HOMO and LUMO orbitals). The aromaticity of HBA was studied based on the calculated geometric and magnetic aromaticity indices (HOMA, Aj, BAC, I6, NICS). The biological activity of hydroxybenzoic acids was discussed in relation to their geometry, the electronic charge distribution in their molecules, their lipophilicity, and their acidity. Principal component analysis (PCA) was used in the statistical analysis of the obtained data and the discussion of the dependency between the structure and activity (SAR: structure–activity relationship) of HBAs. This work provides valuable information on the potential application of hydroxybenzoic acids as bioactive components in dietary supplements, functional foods, or even drugs.

Graphene/Fe3O4 Nanocomposite as a Promising Material for Chemical Current Sources: A Theoretical Study

The outstanding mechanical and conductive properties of graphene and high theoretical capacity of magnetite make a composite based on these two structures a prospective material for application in flexible energy storage devices. In this study using quantum chemical methods, the influence of magnetite concentration on energetic and electronic parameters of graphene/Fe3O4 composites is estimated. It is found that the addition of magnetite to pure graphene significantly changes its zone structure and capacitive properties. By varying the concentration of Fe3O4 particles, it is possible to tune the capacity of the composite for application in hybrid and symmetric supercapacitors.