Comparison of photoluminescence and capacitance spectroscopies as efficient tools for interface characterisation of heterojunction solar cells

The correlation between diffusion capacitance and photoluminescence as a method of interface-defect density characterisation in amorphous silicon/crystalline silicon heterojunction solar cells is explored by numerical modelling and experimentally. At open circuit, the influence of the defect density at the front amorphous silicon/crystalline silicon interface and the surface recombination velocity of the minority carriers in the bulk depend on the doping level of the crystalline silicon and the critical contribution of the majority carriers. Experimental illustration is given for five series of solar cells with different doping levels, interface properties and back contacts. We observe agreement between simulation and experimental results and a correlation between the two methods of measurement of interface defects.     

Mixed Ligand Complexes of Ni(II) with Arylidene- Anthranilic Acids and Some Lewis Bases

Some binary and ternary complexes of Ni(II) with arylideneanthranilic acids and Lewis bases have been prepared and characterized by elemental analyses, IR spectra and X-ray powder diffraction. On the basis of the IR spectra it was found that the Schiff bases used act as monobasic bidentate ligands except for the ortho-hydroxy derivative which acts as a dibasic tridentate ligand. From X-ray analysis it is concluded that the binary Ni(II) chelates are isostructural, and the ternary Ni(II) complexes are also isostructural.     

Synthesis of 3,3′-methylenebis(4-hydroxyquinolin-2(1H)-ones) of prospective anti-COVID-19 drugs

Molecular Diversity - During formylation of 2-quinolones by DMF/Et3N mixture, the unexpected 3,3′-methylenebis(4-hydroxyquinolin-2(1H)-ones) were formed. The discussed mechanism was proved as...     

Peculiar reaction behavior of 1,3-oxathiolan-5-one toward various reagents: Molecular modeling studies and in vitro antioxidant and cytotoxicity evaluation

Chemical reactivity of 2-methyl-2-phenyl-1,3-oxathiolan-5-one (1) toward various reagents such as hydroxyaldehyde, ketone, α,β unsaturated carbonyl compounds, heterocyclic amine, hydrazine, and hydrazide to give unpredicative opened and fused heterocyclic systems was investigated. Moreover, treatment of compound 1 with bromoester to afford the respective fused system, 2-methyl-2-phenylfuro[3,2-d][1,3]oxathiol-5(6H)-one (6) was implemented. Besides, ¹H–¹H nuclear overhauser effect spectroscopy was used for full confirmation of the compound 19. In addition, the density functional theory modeling study outcomes were discussed and all of the new synthesized compounds were evaluated as antioxidants and cytotoxicity assay against hepatocellular carcinoma cell line.     

Tetrathiafulvalene based electroactive ligands and complexes: Synthesis,crystal structures and antifungal activity

The synthesis of two tetrathiafulvalene-appended pyridinehydrazone pyrimidine ligands, namely (Z)-4-(2-((5-([2,2′-bi(1,3-dithiolylidene)]-4-yl)pyridin-2-yl)methylene) hydrazinyl)-6-chloropyrimidine L1 and (Z)-4-(2-((6-([2,2′-bi(1,3-dithiolylidene)]-4-yl)pyridin-2-yl)methylene) hydrazinyl)-6-chloropyrimidine L2 is described. Ligand L1 was reacted with cobalt(II) to yield a cationic metal complex [Co(L1)₂] while ligand L2 was reacted with zinc(II) to afford a neutral metal complex [ZnL2Cl₂]. The crystal structure analysis of [Co(L1)₂] indicate that Co(II) ion is coordinated by six nitrogen atoms from two perpendicular ligands while in [ZnL2Cl₂], Zn(II) is coordinated by two chlorine atoms and three nitrogen atoms. The electrochemical behavior indicate that ligands L1 and L2 and the zinc(II) complex are suitable fort the preparation of crystalline radical cation salts. Finally the determination of MIC₈₀ values against C. albicans, C. glabrata, C. parapsilosis, C. krusei and E. dermatitidis revealed that the cobalt(II) metal complex [Co(L1)₂] is active against all the studied fungi.     

A silica-supported palladium-bis(oxazoline) complex efficiently catalyzes the synthesis of cinnamic acid derivatives via Mizoroki–Heck coupling reactions

A palladium(II)-bis(oxazoline) complex supported on silica (Pd-BOX-Si) was prepared, characterized and applied as a catalyst in Mizoroki–Heck cross-coupling reactions. The bis(oxazoline) (BOX) ligand has a hydroxyl group that can be anchored to 4-benzyl chloride-functionalized silica gel, followed by the coordination of palladium(II) chloride. The catalytic activity and the recyclability of Pd-BOX-Si have been investigated in the production of cinnamic acid derivatives via Mizoroki–Heck coupling reactions of acrylates with aryl halides; The Pd-BOX-Si catalyst demonstrated excellent catalytic activity. Characterization of the recycled Pd-BOX-Si catalyst revealed its good stability under the reaction conditions employed.     

Stochastic non-linear flutter of a panel subjected to random in-plane forces

—An analysis of non-linear flutter of a simply-supported panel exposed to supersonic gas flow and random in-plane forces is presented for two- and three-mode interactions. A first order quasi-steady state aerodynamic piston theory is used to model the aerodynamic loading. The Fokker-Planck equation is used to derive a general moment equation for two- and three-mode interactions. For stability analysis the moment equation is consistent and the mean square stability boundaries of the equilibrium are obtained in terms of the system parameters. The stability boundaries reveal common features to those predicted by the deterministic theory of panel nutter. For the non-linear response the moment equation is found inconsistent and a cumulant-neglect closure is used by setting cumulants of fifth and sixth orders to zero. This first order non-Gaussian closure is carried out to solve for the response statistics in terms of the air-to-plate mass ratio, aerodynamic pressure, modal damping, and in-plane random force spectral density. It is found that the non-Gaussian solution yields higher levels for the response statistics than those obtained by the Gaussian solution. The inclusion of more modes results in a reduction of the response levels and expands the stability region.     

Spectrophotometric quantification of fluoxetine hydrochloride: Application to quality control and quality assurance processes

Simple and rapid spectrophotometric methods have been developed for the microdetermination of fluoxetine HCl. The proposed methods are based on the formation of ion-pair complexes between fluoxetine and bromophenol blue (BPB), bromothymol blue (BTB), bromocresol green (BCG), and bromocresol purple (BCP) which can be measured at optimum λ_max. Optimization of reaction conditions was investigated. Beerșs law was obeyed in the concentration ranges of 0.5–8.0 μg mL⁻¹, whereas optimum concentration as adopted from the Ringbom plots was 0.7–7.7 μg mL⁻¹. The molar absorptivity, Sandell sensitivity, and detection limit were also calculated. The most optimal and sensitive method was developed using BCG. The correlation coefficient was 0.9988 (n = 6) with a relative standard deviation of 1.25, for six determinations of 4.0 μg mL⁻¹. The proposed methods were successfully applied to the determination of fluoxetine hydrochloride in its dosage forms and in biological fluids (spiked plasma sample) using the standard addition technique.     

In vitro model on glass surfaces for complex interactions between different types of cells

This report establishes an in vitro model on glass surfaces for patterning multiple types of cells to simulate cell-cell interactions in vivo. The model employs a microfluidic system and poly(ethylene glycol)-terminated oxysilane (PEG-oxysilane) to modify glass surfaces in order to resist cell adhesion. The system allows the selective confinement of different types of cells to realize complete confinement, partial confinement, and no confinement of three types of cells on glass surfaces. The model was applied to study intercellular interactions among human umbilical vein endothelial cells (HUVEC), PLA 801 C and PLA801 D cells.     

Novel mono- and dinucleating ligands-containing artificial di- and tetrahistidine and their zinc(II) complexes as a structural phosphotriesterase models for the hydrolysis of p-nitrophenyl diphenylphosphate (p-NPDPP)

Two new artificial peptides with histidine side chains, namely N-methyl N,N′-bis(Im-bzl-l-histidylmethylestermethyl)amine L1 and N,N′,N″,N?-tetrakis(Im-bzl-l-histidylmethyl-estermethyl)ethylene diamine L2 have been synthesized and were shown to form stable zinc complexes [L1Zn(H₂O)₂](ClO₄)₂ 1 and [L2Zn₂(H₂O)₃](ClO₄)₄ 2, respectively. Solution studies (pH–¹NMR titrations) of the ligand L2 in the presence of zinc ions were also reported. The catalytic activity of zinc complex species 1 and 2 as structural phosphotriestrase models were tested on the hydrolysis/detoxification of p-nitrohenl diphenylphosphate (p-NPDPP). From the correlation between the pH-rate profiles and the species distribution curves, the catalytically active species could be identified. On the basis of R-dependence as well as the rate acceleration of each complex, the possibility of cooperative action of zincs in dinuclear zinc complex is debated.